AUTOMOTIVE TECHNOLOGIES IN JAPAN
Solutions for Greater Safety, Improved Environmental Performance and Increased User Convenience
Japan Automobile Manufacturers Association, Inc.
INTRODUCTION
TABLE OF CONTENTS
Since its introduction more than a century ago, the automobile
has been in a state of continuous development in response to
society’s needs and expectations. It continues to evolve today in
line with contemporary requirements, not only as a vital element
in global economic activity as a means of commercial and
passenger transport, but also as a means of enhancing people’s
lives.
As a result of its constant evolution, the automobile is today a
comfortable and convenient means of transportation that offers
greater safety than ever before and significantly reduced
environmental impact, in addition to highly improved
operational performance.
Particularly in the areas of safety, environmental performance
and user convenience, major progress has been made thanks to
breakthroughs in vehicle-based electronic technologies, engine
technologies and in the information and communication
technologies that underpin ITS (Intelligent Transport Systems).
Advanced and expanded applications are expected in the future.
The purpose of this booklet is to introduce and explain these
state-of-the-art technologies, focusing on those which are
currently in application in Japan. Developments or applications
anticipated for the near future are discussed or referred to
briefly.
We hope this publication will increase the general
understanding of readers in regard to contemporary automotive
technologies and their advancement and application by the
Japanese automobile industry.
I.
OVERVIEW OF AUTOMOTIVE TECHNOLOGIES CURRENTLY IN APPLICATION IN JAPAN ……………………………1
Timeline for the Introduction in Japan of Automotive Technologies for Greater Safety,
Improved Environmental Performance and Increased User Convenience (1993-2008) ………………………………………………………1
Automotive Technologies Currently in Application (In-Vehicle View) …………………………………………………………………………3
II. TECHNOLOGIES FOR GREATER SAFETY ………………………………………………………………………………………………………5
A. Active Safety Technologies
1. Driver Assist Technologies …………………………………………………………………………………………………………………5
Electronic Stability Control (ESC) / Driver Inattention Warning / Tire Pressure Monitoring /
Adaptive Cruise Control / Lane Deviation Warning & Lane-Keeping Assist
2. Visibility-Improving Technologies …………………………………………………………………………………………………………7
Adaptive Front-Lighting System (AFS) / Automatic Levelling / Night Vision Monitoring /
Vehicle Perimeter Monitoring / Blind-Corner Monitoring
3. Brake Technologies …………………………………………………………………………………………………………………………8
Collision-Mitigation Braking System / Brake Assist / Anti-Lock Braking System (ABS)
B. Passive Safety Technologies
1. Occupant Protection Technologies …………………………………………………………………………………………………………9
Active Head Restraint / SRS Side Airbag / SRS Curtain Airbag / Seatbelt Technology (Seatbelt
Pretensioner, Seatbelt Force Limiter, Pre-Crash Seatbelt) / Vehicle Compatibility / ISOFIX Anchorage
2. Pedestrian Protection Technology ………………………………………………………………………………………………………11
Pedestrian Protection Vehicle Design / Automatic Pop-Up Hood
III. TECHNOLOGIES FOR IMPROVED ENVIRONMENTAL PERFORMANCE ……………………………………………………12
1. Technologies to Reduce Exhaust Emissions ……………………………………………………………………………………………12
Catalyst Technology (Gasoline Engines, Diesel Engines: Urea-SCR, NOX Catalytic Converters) /
EGR / DPFs / Fuel Injection Technology (Common-Rail Fuel Injection)
2. Technologies to Increase Fuel Efficiency …………………………………………………………………………………………………15
High-Efficiency Engine Technologies (In-Cylinder Direct Injection Engine, Variable Valve Timing) / Technologies to Reduce Power Loss
(Reduction of Engine Friction Loss, Electric Power Steering) / Reduction of Aerodynamic Drag / Reduction of Rolling Resistance /
Reduction of Vehicle Weight / Technologies to Improve Powertrain Performance (CVT, Automated Manual Transmission) / Idling
Prevention
3. Alternative-Energy /Next-Generation Vehicles …………………………………………………………………………………………18
Hybrid Vehicles / Plug-In Hybrid Vehicles / Fuel Cell Vehicles / Electric Vehicles / Hydrogen Vehicles /
Natural Gas Vehicles / Clean Diesel Vehicles / Diesel-Alternative LPG Vehicles
4. Other Alternative Fuels ……………………………………………………………………………………………………………………21
CTL/GTL Fuels / Biodiesel Fuel / DME / Bioethanol
IV. HEAVY-DUTY VEHICLE TECHNOLOGIES ……………………………………………………………………………………………22
Front & Rear Underrun Protection / Speed Limiters / Digital Tachographs / Rollover Mitigation
Japan Automobile Manufacturers Association, Inc. (JAMA)
March 2008*
V. MOTORCYCLE TECHNOLOGIES ………………………………………………………………………………………………………23
Anti-Lock Braking System (ABS) / Dual Combined Braking System / Motorcycle Airbags
VI. TECHNOLOGIES FOR INCREASED USER CONVENIENCE ………………………………………………………………………24
*Publication date of original text (in Japanese; English version published November 2009)
Park Assist / Automatic Closing / Smart Keys / Electronic Toll Collection (ETC) / Smart Highway Toll Stations /
HELPNETTM (Emergency Call System) / Vehicle Information and Communication System (VICS)
VII. DRIVING THE AUTOMOTIVE FUTURE ………………………………………………………………………………………………27
ASV Technologies / ITS Technologies / Advanced Car Navigation Systems / Telematics
I. OVERVIEW OF AUTOMOTIVE TECHNOLOGIES CURRENTLY
IN APPLICATION IN JAPAN
■ Timeline for the Introduction in Japan of Automotive Technologies for Greater Safety, Improved Environmental Performance
and Increased User Convenience (1993-2008)
Technologies for Increased
User Convenience
Technologies for Improved
Environmental Performance
Technologies for Greater Safety
1993
1
1994
-SRS (Supplemental Restraint
System) rear-seat airbags
-Active limited slip differential
(LSD)
-Inter-vehicle distance warning
1995
-Impact-absorbing vehicle body/
High-strength cabin
-Adaptive cruise control
-Low-tire-pressure warning
-Impact-sensing auto door unlock
-Preview control of hydraulic active
suspension
-Mirror cycle engine
1996
1997
1999
-Vehicle perimeter monitoring
-Electronic stability control (ESC)
-Motorcycle anti-lock braking
system (ABS)
-Right-and-left power
distribution
-Discharge headlamps
-SRS side airbags
-Common-rail fuel injection
-Exhaust gas recirculation (EGR)
-Trucks with CNG engines
-Hybrid electric vehicles
-High-pressure, variable-rate
injection
-NOX-reducing three-way catalyst
-Pressure-accumulating diesel
hybrid buses
-Idling prevention for large vehicles
1998
-SRS curtain airbags
-Active head restraints
-Lane deviation warning
-Navigator-based gearshift control
(ATs only)
-Pedestrian protection vehicle design
-Four-bag air suspension
(large vehicles)
-Hybrid passenger cars
-Fuel cell vehicles [development]
-Nickel-metal hydride batteryoperated electric vehicles
-Lithium-ion battery-operated
electric vehicles
-In-cylinder direct-injection engine
-Bird’s-eye-view car navigation
-Vehicle Information and
Communication System
(VICS)-compatible car navigation
-Natural gas mini-vehicles
-Continuously variable
transmission (CVT) for
large-capacity engines
-Digital tachographs (large
vehicles)
-Expanded ICT* applications in car
navigation
*ICT=Information & communication
technologies
-Electronic toll collection (ETC)
[trial launch]
-HELPNET TM (emergency call
system)
2000
2001
2002
-Electronic brake-force distribution
(EBD)
-Run-flat tires
-Lane-keeping assist
-Idling prevention for passenger cars
-Natural gas (CNG) hybrid buses
-Electronically-controlled fuel injection
for motor-driven cycles
(50cc engines)
-Idling prevention for motorcycles
-Capacitor hybrid trucks
2003
2004
2005
2006
-Adaptive front-lighting system
(AFS)
-Pre-crash seatbelts (retracting on
automatic emergency braking)
-Collision-mitigation braking system
2007
2008
-Automatic pop-up hood
-Active drive assist (ADA) using
stereo image recognition
-Motorcycle airbags
-Night vision monitoring
-Rollover mitigation (large vehicles)
-Speed limiters (large vehicles)
-Fuel cell hybrid large buses
-Fuel cell mini-vehicles
-Variable-cylinder engine
-Ultra-wide low-profile single tires
(large vehicles)
-Series hybrid buses
-NOX-reducing urea-selective
catalytic reduction (SCR)
for diesel vehicles
-Fuel cell motorcycles
-Hybrid motor-driven cycles
-Fuel cell vehicles
[type approval]
-Eight-speed automatic
transmission (AT)
-Automated manual transmission
(AMT) for motorcycles
-In-vehicle terrestrial digital tuner
-HDD-operated car navigation
-Smart keys
-Park assist
-BHD (biodiesel) hybrid buses
-Synthetic diesel-fuelled
experimental vehicle
-Smart highway toll stations
(for ETC users exclusively)
[launch of wide-scale operation]
-GPS navigation for motorcycles
-ETC for motorcycles
2
■ Automotive Technologies Currently in Application (In-Vehicle View)
Applications of technologies for greater safety, improved environmental performance and increased user convenience in
currently in-use passenger cars are illustrated here. (Abbreviations are spelled out on pages 1-2.)
・Power window with jamming-prevention mechanism
・Idling prevention
・Water-repellent glass
・Lean-burn engine
・In-cylinder direct-injection engine
・HELPNET TM (emergency call system)
・UV-reducing glass
・Mirror cycle engine
・ICT applications in navigation system
・IR-reducing glass
・Twin camshaft
・Lane deviation warning/Lane-keeping assist
・Multi-valve engine
・Head-up display
・Driver inattention warning
・Electronically-controlled fuel injection
・UV-reducing glass
・Night vision monitoring
・Emergency locking retractor (ELR) seatbelt
・Rear wiper
・Variable valve timing
・IR-reducing glass
・VICS-compatible car navigation
・Deodorizing seat fabric
・Rear-window defogger
・Variable turbocharger
・Light-controlling glass
・SRS airbags for driver’s & front passenger’s seats
・Seatbelt pretensioner & force limiter ・Three-point seatbelt
・Intercooler
・Water-repellent glass
・HDD-operated car navigation
・Pre-crash seatbelt
・ISOFIX anchorage (for a child safety seat)
・UV-reducing glass
・Hollow camshaft/Aluminum cylinder block
・Low-reflecting glass
・In-vehicle terrestrial digital tuner
・SRS curtain airbag
・Split-folding seat
・IR-reducing glass
・Liquid-filled engine mount
・Noise-insulating glass
・SRS side airbag
・Rear power seat
・Common-rail fuel injection
・Snow-melting glass
・Active head restraint
・Heated seat
・High-mount brake lamp
・Privacy glass
・Light-controlling glass
・Rear spoiler
・Water-repellent glass
・Remote-control mirror
・Plastic resin fender
・Water-repellent side mirror
・Pedestrian protection front-end design
・Vehicle perimeter monitoring
・Aluminum hood
・Automatic pop-up hood
・AFS
・Hydraulic power steering
・Discharge headlamp
・Electric power steering
・Electric power steering
・Projector headlamp
・Rear fog lamp
・Automatic levelling
・Sensor for lateral distance between vehicles
・Fog lamp
・Rear sensor/Rear side sensor
・Cornering lamp
・Rear obstacle detection (back-up monitoring)
・Front air dam
・Inter-vehicle distance warning
・Adaptive cruise control
・Blind-corner monitoring
・Disc brake
・Disc brake
・ABS
・ABS
・ESC
・ESC
・Traction control
・Traction control
・Brake assist
・Brake assist
・EBD
・Studless tire
・Automatic air conditioning
・Anti-corrosive & anti-pitching paint ・Three-way catalytic converter ・Studless tire
・EBD
・Four-wheel steering
・Ultra-low-profile tire
・Hydraulic brake booster
・Anti-corrosive steel sheet
・NOX storage-reduction catalyst ・Ultra-low-profile tire
・Four-wheel steering
・Active suspension
・Economy tire
・Intermittent wiper
・High tensile steel sheet
・Urea-SCR
・Economy tire
・Active suspension
・Electronically-controlled suspension
・Tire pressure monitoring
・Rain-sensing wiper
・Impact-absorbing vehicle body
・Diesel NOX catalyst
・Tire pressure monitoring
・Electronically-controlled suspension
・Flat wiper blade
・Compatibility vehicle body
・Diesel particulate filter (DPF)
・Electronically-controlled air suspension
・Oxidation catalyst
・Collision-mitigation braking system
・Electronically-controlled air suspension
・CVT
・Collision-mitigation braking system
・AMT
・Eight-speed AT
・Navigator-based gearshift control (ATs only)
3
4
II. TECHNOLOGIES FOR GREATER SAFETY
Vehicle-based safety technologies comprise (a) technologies for active safety to help prevent accident
occurrence and (b) technologies for passive safety to mitigate injury when accidents do occur. Recent
years have seen important advances in pre-crash safety intelligent technologies aimed at boosting active
safety and reducing damage and injury from unavoidable collisions. Many of the following technologies
were developed as a result of research conducted on the Advanced Safety Vehicle (ASV) concept.
Maintaining tire pressure at appropriate levels helps prevent
the occurrence of accidents (attributable to the loss of
vehicle steerability and driving stability resulting from
underinflated tires) as well as a decline in vehicle fuelefficiency performance.
A. Active Safety Technologies
1
Driver Assist Technologies
■ Electronic Stability Control (ESC)
ESC is a system that automatically helps control vehicle
skidding—resulting, for example, from too sharp a turn at
relatively high speed or from a suddenly slippery road
surface—by activating braking for the individual wheels as
needed and controlling engine output to put the vehicle
back on course.
To counter understeering when taking a turn, ESC
automatically applies the brakes to the inner rear wheel and
reduces engine output. To counter oversteering, the brakes
are automatically applied to the outer wheels and engine
output is reduced, thereby maintaining stability and
keeping the vehicle on course.
■ Tire Pressure Monitoring
This system monitors tire air pressure and air temperature by
means of a sensor located inside each tire of the vehicle and
informs the driver when tire air pressure is low
(underinflation).
Electronic Stability Control: How It Works
Vehicle not equipped
with ESC
■ Adaptive Cruise Control (Inter-Vehicle Distance Monitoring)
This technology automatically maintains a safe distance
from the vehicle ahead using radar and an onboard camera
and by controlling vehicle speed.
■ Lane Deviation Warning & Lane-Keeping Assist
With this technology, an onboard camera monitors the road
ahead and alerts the driver with visual and auditory
warnings when the vehicle is about to deviate from its lane.
If no corrective action is taken by the driver, the
lane-keeping assist function activates steering torque
control to keep the vehicle running in its proper lane.
The lane-keeping assist function is automatically released by
the driver’s operation of the directional signals whenever a
lane change is intended.
Lane-Keeping Assist
The radar and camera provide the data needed for
computerized calculation of the distance to the vehicle
ahead. When that distance becomes unsafe based on
real-time speed calculations, the driver is alerted accordingly
and automatic auxiliary braking is performed as needed.
Vehicle equipped
with ESC
Braking applied to inner rear wheel
and engine output reduced.
Adaptive Cruise Control: Radar Helps Monitor the Distance to
the Vehicle Ahead
Countering understeering
Vehicle equipped
with ESC
Braking applied to outer wheels
and engine output reduced.
■ Driver Inattention Warning
This system monitors slight lateral deviations from the
vehicle’s course or trajectory and alerts the driver through
visual and auditory warnings when such deviations occur.
The system makes use of an onboard camera and a vibration
gyrosensor (steering angle sensor) to detect lateral
deviations caused by driver inattention or, for example, a
cross wind, and warns the driver accordingly.
To avoid the risk of false alarms, system application can be
customized for individual drivers by pre-setting certain
parameters including vehicle speed.
Steering torque control is activated as necessary to
prevent lane deviation.
Vehicle not equipped with ESC
Area monitored
Countering oversteering
Area monitored
Conditions Triggering Driver Inattention Warning
Yaw rate
Lateral deviation
Vehicle trajectory (x-axis)
5
The driver is alerted to imminent lane deviation by means
of a camera monitoring the road ahead.
6
Visibility-Improving Technologies
■ Adaptive Front-Lighting System (AFS)
AFS assists driving at night by automatically adjusting the
orientation of the front headlamps of the vehicle, taking into
account steering angle and vehicle speed, in order to
provide better nighttime visibility.
Because AFS interlocks automatic headlamp orientation
adjustment with steering angle and vehicle speed, it is
therefore especially helpful for drivers during cornering,
when it provides a significantly wider range of visibility than
fixed headlamps.
■ Night Vision Monitoring
Advanced night vision systems detect, by means of infrared
cameras, infrared radiation-emitting objects in or
approaching the vehicle’s forward path and determine
whether the “objects” are pedestrians. The driver is then
alerted accordingly, with visual and auditory information, in
order to prevent nighttime accidents involving pedestrians.
Example of Infrared Detection-Based Night Vision
to Assist Vehicle Drivers
Widens and extends range
of visibility at an intersection.
■ Automatic Levelling
This technology automatically adjusts the up-and-down
orientation (or “pitch angle”) of the vehicle’s front headlamps
to prevent blinding the vision of the driver of an oncoming
vehicle, taking into account vehicle speed and height.
■ Vehicle Perimeter Monitoring
This technology uses cameras mounted on the vehicle’s
exterior to transmit views of the vehicle’s periphery to the
display screen inside the car. Because the cameras detect
surrounding objects/obstacles that could otherwise not be
seen by drivers, this safety feature is helpful on narrow
roads, in tight spaces, and when parking.
■ Blind-Corner Monitoring
The purpose of this technology is to help reduce accident
occurrence at intersections. When the vehicle approaches a
blind intersection or “T” junction—that is, where visibility to
the right and left is dangerously reduced—a camera with a
built-in prism mounted on the front of the vehicle transmits
views of about 20 meters (roughly 60 feet) in both directions
to the in-cabin display screen. This greatly assists the driver
in safely navigating the vehicle through the intersection.
■ Collision-Mitigation Braking System
Based on the distance from and speed relative to the vehicle
ahead obtained from radar information, as well as on the
anticipated vehicle trajectory as determined by sensors
(including cameras), the system’s electronic control unit
calculates the risk of collision. When there is such a risk,
visual and auditory warnings are emitted and the driver’s
seatbelt is retracted gently a few times to alert him/her to
the imminent danger.
Collision-Mitigation Braking Using Millimeter-Wave Radar
■ Brake Assist
Brake assist (BA) technology monitors the force with which
the driver depresses the brake pedal, and automatically
applies supplementary braking power as needed. When
panic braking is detected—that is, when brake pedal force
exceeding a certain level is detected—the system
automatically
maximizes
brake
boost,
thereby
strengthening the force of brake pedal depression.
When a vehicle is equipped with both brake assist and an
anti-lock braking system, the result is more rapid, and
therefore safer, emergency braking (see diagram below).
■ Anti-Lock Braking System (ABS)
This system automatically regulates the hydraulic pressure
applied to the brakes for all the vehicle’s wheels at the time
of sudden, heavy braking, to prevent the wheels from
locking. This allows the driver to maintain steering control
and helps ensure vehicle stability. Most automobiles today
are equipped with ABS as a standard safety feature.
Benefits of Brake Assist
ABS operational range
With
brake
assist
Without
brake
assist
Millimeter-wave radar continuously monitors the distance to the vehicle ahead.
Audio
If the vehicle is not equipped with
BA, this comparative lag in brake
pedal force and in ABS activation
occurs. BA thus enables faster, safer
emergency braking.
alarm
Reinforced braking
When the distance to the vehicle ahead narrows dangerously, visual and audio
warnings are emitted and auxiliary braking is automatically applied.
Brake pedal force
Moderate
braking
range
Emergency
braking
range
Full braking
Vehicle Perimeter Monitoring & Blind-Corner Monitoring
When a collision is imminent, full braking power is automatically applied and
seatbelts are quickly retracted.
Side-view camera
Based on those variables, front headlamp orientation is
tilted vertically, up or down, to an appropriate height for
effective, non-blinding forward illumination.
Brake Technologies
When the driver applies the brakes, the system activates the
brake-assist function (also referred to here as “automatic
auxiliary braking”) to reinforce the driver’s own braking
action. If the driver’s braking pressure is insufficient or if
he/she fails to apply the brakes, the system applies full
braking power, thereby reducing the speed at the time of
collision.
Furthermore, the vehicle’s occupants are
effectively restrained in their seats by quickly-retracting
seatbelts (or “pre-crash seatbelts”) which also optimize
airbag deployment efficiency. In this way, the system
mitigates the impact of the collision on vehicle occupants
and on the vehicle itself, and thereby helps reduce injury
and damage.
Benefits of Adaptive Front-Lighting System
Widens and extends range
of visibility in a curve.
3
Braking force
2
Forwardview
camera
Rearview
camera
Side-view camera
7
8
B. Passive Safety Technologies
1
Occupant Protection Technologies
■ Active Head Restraint
This technology reduces whiplash injury to a front-seat
occupant by moving the seat’s headrest upward and
forward at the time of a rear-end collision. When such a
collision occurs, a hinge incorporated into the seatback
yields in response to the forward motion of the occupant’s
torso, allowing the seatback to move rearward and a
pressure plate inside it to move the headrest upward and
forward based on the lever principle, cradling and
protecting the occupant’s head and neck.
Active Head Restraint: Activation on Rear-End Collision
■ SRS Side Airbag
The SRS (Supplemental Restraint System) side-impact airbag
serves primarily to protect front-seat occupants from injuries
to the torso—specifically, to the chest and pelvis—at the
time of a side (or “lateral”) collision.
■ Seatbelt Technology
Seatbelts secure vehicle occupants in their seats at the time
of a collision or an abrupt stop. Their purpose is to reduce
injury and prevent occupants from being ejected from the
vehicle.
Upon detection of a lateral collision by means of a sensor,
the side airbag installed in the seatback deploys instantly.
Side airbags designed for head protection and for rear seats
have also been introduced.
Seatbelt pretensioners and force limiters (also called “load
limiters”) are now standard equipment. Pre-crash seatbelts
have also been introduced which work in conjunction with
the brake-assist function (or “automatic auxiliary braking”) to
hold vehicle occupants more securely in place when a
collision is unavoidable.
■ SRS Curtain Airbag
At the time of a lateral collision, this system deploys an
airbag installed in the side of the vehicle ceiling. This airbag
instantly inflates to form a curtain between the front- and
rear-seat occupants and the side window, running the entire
length of the side of the cabin, to protect them against head
and neck injuries.
Curtain airbags also help protect vehicle occupants from
injuries caused by shattered side-window glass.
● Pre-Crash Seatbelt
Quickly-retracting pre-crash seatbelts work in conjunction
with the brake-assist function to restrain occupants in their
seats when a collision is determined (by an electronic control
unit) to be unavoidable. Pre-crash seatbelts also optimize
airbag deployment efficiency.
■ Vehicle Compatibility
Advancing vehicle compatibility involves improving the
safety performance of a vehicle in the event of a crash with
another vehicle, with a particular focus on reducing the
ability of larger vehicles to cause damage to smaller vehicles
in a collision.
Benefits of the Seatbelt Pretensioner & Force Limiter
In vehicle-to-vehicle crashes, it is often the case that one
vehicle sustains greater damage (usually resulting in greater
injury to its occupants) because of differences in mass, size
and geometry—including, among other factors, body shape,
ride height and bumper height.
Studies in vehicle
compatibility seek to minimize injury to the occupants of
both vehicles involved in a crash through improvements to
body structure.
Pretensioner
Restrains forward
torso movement
by retracting seatbelt
at moment of collision.
Force Limiter
Reduces seatbelt
tautness.
SRS Side Airbag & SRS Curtain Airbag
Force of
impact on
torso
Effect of force limiter
Effect of
pretensioner
Conventional
seatbelt
Seatbelt with
pretensioner &
force limiter
Forward torso movement
During vehicle development, crash tests involving a larger car
and a smaller car are rigorously carried out in order to achieve
structural compatibility that will enhance a vehicle’s collision
impact-absorbing capacity by, for example, enabling the
absorption of impact energy over surfaces rather than at
specific points.
Examples of Incompatibility in Car-to-Car Collisions
[Schematic representation of benefits]
Chronology of SRS Airbag Introduction
Driver’s-seat airbags were the first to be introduced, with
dual front airbags introduced soon thereafter to protect
both front-seat occupants from injuries sustained in frontal
collisions. Airbag installation has since been extended to
the rear seats as well. Airbags are also used for occupant
protection in side collisions, as described on this page.
All of these are Supplemental Restraint System airbags,
which are designed to mitigate collision impact on vehicle
occupants restrained by seatbelts (the primary restraint
system) and are optimally effective in combination with
correct seatbelt use.
9
● Seatbelt Pretensioner
The pretensioner automatically tightens the seatbelt to hold
the vehicle occupant firmly in place in a frontal collision.
A double pretensioner retracts the seatbelt both at shoulder
height and at the level of the pelvis, for even greater restraint
at the moment of collision.
● Seatbelt Force Limiter
The force limiter automatically reduces seatbelt tautness (i.e.,
lets out a little slack) when the vehicle occupant’s seatbelt has
reached a threshold level of tension as his/her torso moves
forward in a frontal collision.
A car with greater mass is
likely to push back
a lighter car.
Impact-absorbing capacity
does not match because of
incompatible body frames.
Crumpling is likely to
occur in cars with
weaker front ends.
A variable force limiter helps distribute the force of the
impact of a frontal collision across the occupant’s body to
reduce the risk of chest injury.
10
III. TECHNOLOGIES FOR IMPROVED ENVIRONMENTAL PERFORMANCE
■ ISOFIX Anchorage (for child safety seats)
Established by the International Organization for
Standardization (ISO), ISOFIX is an international standard for
the accommodation of child safety seats in automobiles. It
specifies the built-in anchor points to be provided in the rear
seat of a vehicle so as to enable the rapid and safe installation
of a child safety seat.
ISOFIX also sets installation standards and categories with
respect both to child seats and the provisions for their
accommodation, enabling a “universal system” for child
safety-seat installation.
Now under development, pedestrian protection-enhancing
airbags will further buffer the impact of the collision on the
pedestrian by covering hard spots and components in the
lower windshield area such as the cowl and wiper bases, as
well as the structural pillars on each side of the windshield.
Examples of Front-End Vehicle Design for Pedestrian Protection
Collision Impact-Absorbing Features
Impact-Absorbing Hood Hinge Impact-Absorbing Cowl
Collapsible Wipers
Deformable
on impact
Pivots collapse easily under pressure.
Impact-Absorbing Fenders
The complete set of ISOFIX anchor points in the rear seat of
new cars became mandatory in Japan beginning in October
2006.
Plastic resin
makes possible
a deformable
edge.
Lamps
Deformable
mounts
ISOFIX Anchorage
Top tether anchor
Lower anchor
Impact-Absorbing Hood
Impact-Absorbing Bumpers
Space is provided between
Filled with resin foam
the hood and the engine to
reduce head injuries; also,
the frame structure on the
underside of the hood is deformable.
■ Automatic Pop-Up Hood
A sensor and an electronic control unit built into the
bumper detect a collision with a pedestrian. If necessary,
actuators instantly raise the back end of the hood, leaving a
space between the hood and the hard components
underneath it, including the engine, to reduce the force of
the impact on the pedestrian’s head.
Pedestrian Protection Technology
Actuators
■ Pedestrian Protection Vehicle Design
This is front-end vehicle design intended specifically to
reduce injuries (particularly head and lower limb injuries) to
a pedestrian involved in a pedestrian-vehicle collision.
11
Technologies to Reduce Exhaust Emissions
■ Catalyst Technology
● For Gasoline Engines
Exhaust emissions are produced when fuel is burned in a
vehicle’s engine. Emissions from gasoline engines include
pollutants such as carbon monoxide (CO), hydrocarbons
(HC), and nitrogen oxides (NOX).
There are two different methods for reducing these
emissions: One method is to reduce/eliminate them at the
source (namely, the engine), and the other is to eliminate
their toxicity using after-treatment technologies.
● For Diesel Engines
Diesel engines pose a particular challenge because of the
conflicting requirements involved in controlling the NOX and
particulate matter (PM) they emit. Overcoming that
challenge has involved various measures including
combustion chamber improvements, exhaust gas
recirculation (EGR), and the introduction of advanced
fuel-injection technology.
Significant progress has been made a) in cutting NOX
emissions from diesel engines through the use of ammonia
in the chemical reduction process and b) in reducing PM
emissions with the use of filters (DPFs).
Exhaust Emissions Reduction in a Diesel Engine
Intake throttle valve
Emissions are reduced or eliminated at the source by means
of electronically-controlled fuel injection and improvements
to the engine’s combustion chamber, as well as through
greater efficiency in the combustion process itself.
Engine
Air flow meter
EGR cooler
NOX &
air/fuel ratio sensor
NOX &
lambda sensor
Catalyst for
EGR cooler
Fuel
injection nozzle
NOX storage-reduction catalyst
& Diesel particulate diffuser
Bumper
Sensor
To reduce the force of the collision’s impact on the
pedestrian and therefore the extent of potential injury,
various provisions are made in the design of the hood,
fenders, wiper pivots and front bumper to allow for
sufficient clearance, collapsibility, or even ejection off the
vehicle.
1
Catalytic converters serve to cleanse or “purify” the engine’s
emissions. Three-way catalytic converters, which can
simultaneously perform the twin emissions-reducing
requirements of chemical oxidation and reduction, are now
the standard for gasoline engines.
Automatic Pop-Up Hood
2
Environmental protection is a pressing global issue, and initiatives are being taken around the world to
reduce the burdens imposed on the environment by human activity.
In road transport, environmental protection is being promoted through the adoption of wide-ranging
measures aimed at, among other objectives, improving air quality and addressing climate change
through the reduction of CO2 and other emissions. Such measures include the introduction of advanced
vehicle technologies to reduce exhaust emissions and increase fuel efficiency; the stepped-up
development of hybrid and electric vehicles and vehicles that run on alternative sources of energy, such
as fuel cell vehicles; and the development of environmentally sound biofuels.
Another method uses an NOX storage-reduction (NSR)
catalyst to temporarily store NOX emissions and reduce them
later.
Exhaust gas
temperature sensor
Differential
pressure sensor
Collision detection
12
- Urea-Selective Catalytic Reduction (SCR)
This technology reduces the nitrogen oxides (NOX) in the
diesel engine’s exhaust emissions by performing controlled
injection of urea solution into the hot exhaust gas, which
generates ammonia. The chemical reaction between the NOX
and the ammonia reduces the NOX to harmless nitrogen (N2)
and water vapor.
NOX Catalytic Converters for Diesel Engines: Schema of Operation
During
lean-burn
During
rich-burn
NOX
CO
H2O
NH3
NOX
NOX
absorption
layer
Exhaust
gas from
engine
Urea-SCR
Oxidation
catalyst
Oxidation
catalyst
Urea-SCR
catalyst
Ultra high-pressure
fuel injection
ECU
Urea injection
(controlled)
Storage tank for
urea solution
- NOX Catalytic Converters
The uniqueness of this breakthrough technology is
characterized by the fact that the ammonia it uses in the NOX
reduction process is generated by the catalytic converter
itself.
NOX catalytic converters feature a two-layer structure: One
layer absorbs NOX from the engine’s exhaust gas and converts
a portion of it into ammonia; the ammonia (NH3) is then
absorbed by the other layer, which uses it to convert the NOX
remaining in the exhaust gas into nitrogen (N2). The ability of
these catalytic converters to generate and store ammonia
and efficiently reduce NOX in a lean-burn atmosphere
enables diesel engines to rival gasoline engines in
cleanliness.
NOX
NH3
absorption
layer
H2O
This method for NOX reduction in diesel engines successfully
eliminates the NOX even when the exhaust gas temperature
is low. Moreover, the technology is cost-effective because, in
addition to its durability, it does not require the use of
precious metals.
During
lean-burn
Oxidation
catalyst
NH3
N2
Pt
NOX
absorbent
NOX
H2
Pt
N2
NH3
CO
NOx
adsorbent
O2
NOX
NOX
absorbent
DPF
NOX catalyst
Exhaust
gas
■ Diesel Particulate Filters (DPFs)
A diesel particulate filter is a device that is used to remove
particulate matter (PM) from the exhaust gas of a diesel
engine.
In turn, the PM accumulated in the filter must also be
removed to prevent clogging—a process referred to as
“regeneration.” Regeneration is carried out by various (mostly
onboard) methods. A typical onboard method is the use of a
fuel burner to increase the exhaust temperature, thus
enabling PM combustion.
Example of a Continuous Regeneration-Type DPF
Oxidation catalyst
Particulate filter with catalyst
CO/HC
purification
NOX
purification
PM removal
■ Exhaust Gas Recirculation Technology (EGR)
EGR reduces NOX emissions by recirculating a portion of the
engine’s exhaust gas and mixing it with intake air to lower the
temperature in the engine’s cylinders (because higher
combustion temperatures increase NOX formation).
In current EGR systems, the EGR valve that interlocks with the
intake throttle valve is continuously controlled by a
microprocessor for precision control of the ratio of
recirculated exhaust gas and intake air.
A system has also been developed for heavy-duty trucks,
which enables NOX reduction by cooling the hot recirculated
exhaust gas with an EGR cooler and mixing it with intake air
to further lower the temperature in the cylinders.
Example of a Cooled-EGR System for Heavy-Duty Trucks
Exhaust
gas
■ Fuel Injection Technology
Advanced fuel injection technology provides highly
sophisticated electronic control not only of the amount of
fuel injected in the engine’s cylinders (or “fuel metering”), but
also of the pressure and timing with which the fuel is
injected. The benefits of this technology are more efficient
engine performance and therefore increased fuel efficiency,
as well as reduced emissions of pollutants (NOX and PM) in
the engine’s exhaust.
● Common-Rail Fuel Injection
Common-rail fuel injection is a technology for diesel engines
that allows a pipe-shaped central accumulator—the
common rail—to store high-pressure fuel (produced by an
engine-driven pump) and then deliver it to all the individual
injectors (of which there is one for each cylinder).
Controlled by the engine’s electronic control unit, this system
makes possible high injection pressures at all times (for finer
atomization of the injected fuel, to enhance combustion
efficiency), in addition to precision control of fuel metering
and of the timing of the fuel injections.
Cell-sealed-type
ceramic honeycomb
Common-Rail Fuel Injection
Pressure sensor
Common rail
Highpressure
pump
Fuel tank
Injectors
Electronic control unit
Turbocharger
Exhaust
Air intake
Intercooler
Exhaust valve
Intake valve
Sub-lift
for EGR
Exhaust
cam
13
14
2
Technologies to Increase Fuel Efficiency
Road transport CO2 emissions represent a significant share of
CO2 emissions generated by human activity. Technologies
that boost vehicle fuel efficiency not only contribute to
energy conservation but also help counter global warming
through reductions in auto-emitted CO2; their further
advancement must therefore be pursued. The various
technologies described below are already in application.
■ High-Efficiency Engine Technologies
● In-Cylinder Direct Injection
In conventional gasoline engine systems, fuel is injected into
the intake valve (also referred to as the “cylinder port”) and
then mixed with air before the air-fuel mixture is injected into
the cylinders. In the case of in-cylinder direct injection
engines, however, fuel is sprayed directly into each cylinder’s
combustion chamber.
● Variable Valve Timing (VVT)
The flow of air and fuel into and out of (in the form of exhaust)
vehicle engines is controlled by valves. The engine’s energy
efficiency is affected by how long the valves open, referred to
as “valve timing.”
Optimum valve timing varies depending on engine speed
and load. Conventional engines rely on fixed valve timing
settings, which are a compromise between the variable
optimum timing settings.
VVT technology increases the engine’s energy efficiency by
providing continuously variable timing—in other words, by
automatically switching to optimum valve timing settings.
The engine’s efficiency is also affected by how much the
valves move, referred to as “valve lift.” VVT technology can
also feature valve lift control (VVT&L), which automatically
switches to optimum valve lift settings.
Variable Valve Timing: How It Works
Extremely high-pressure (more than 20 times higher than in
conventional systems) fuel injection enables very fine
atomization of the fuel particles, which in turn enables
combustion at very high air-to-fuel ratios (air is taken in
directly into each combustion chamber): from 40- to 50- to as
high as 60-to-1. This ultra lean-burn technology thus reduces
fuel consumption.
Control module
■ Technologies to Reduce Power Loss
● Reduction of Engine Friction Loss
Friction loss, which is a mechanical loss, occurs when the
engine’s moving metal parts—such as the pistons, crankshaft
and valves (specifically, the valves and valve seats)—rub
against each other. Friction loss results in reduced energy
efficiency.
Various measures are taken in engine design to prevent
friction loss, including the use of lighter parts (pistons, for
example) and reduction of the valve spring load. Friction can
also be reduced, particularly during engine warm-up, with
the use of low-viscosity lubricating oil, which will help reduce
fuel consumption.
Moreover, engines are now under development that will cut
fuel consumption when engine load is low not only by
closing and shutting down the operation of some intake and
exhaust valves, but also by reducing engine pumping loss
which occurs at the time of intake and exhaust.
Engine speed and load
ECU
Example of Friction Loss Reduction Technology
■ Reduction of Rolling Resistance
While aerodynamic drag accounts for 80 percent of total
vehicle drag, the rolling resistance of the tires accounts for
the remaining 20 percent.
The challenge in reducing the rolling resistance of tires is, at
the same time, to ensure optimal running performance and
riding comfort. Tires with less rolling resistance are currently
under development. For large vehicles, ultra-wide low-profile
single tires are now in use. These tires represent a new level
of tire technology, replacing the dual tires on rear wheels for
a smoother ride and improving fuel economy by reducing
unsprung mass.
■ Reduction of Vehicle Weight
Lighter vehicle weight means that less energy is required to
propel the vehicle.
Additional weight reduction will therefore enable further
increases in fuel economy. This can be achieved without
compromising safety through the use of lighter, stronger
materials such as polymers and resins in vehicle components
and by designing lighter vehicle architectures overall.
Motor
Rocker arm
Reducing Weight through Increased Use of Aluminum
Control cam
Control shaft
Drive shaft
Furthermore, direct injection of the fuel into the cylinders
allows air to be taken in with less throttling resistance, which
results in less pumping loss and, consequently, reduced fuel
consumption in this respect as well. This technology
therefore enables increased fuel efficiency and reduced
levels of CO2 emissions.
In-Cylinder Direct Injection
Conventional fuel injector
Ball screw
Link B
Input cam
Link A
[Mechanism & operational schema]
Output cam
Vacuum
pressure
● Electric Power Steering
With this technology, steering is assisted by an electric motor
rather than by hydraulic pressure. This boosts fuel efficiency
since the steering assistance does not place any load on the
engine.
Atmospheric
pressure
Throttle control
Valve lift control
Conventional
engine
Variable valve timing
Engine fuel efficiency and torque have been improved by
significantly reducing the throttling resistance that used to occur
when the throttle valve narrowed because of low engine load.
Fuel injector for
direct injection
R&D to Improve Aerodynamics
■ Reduction of Aerodynamic Drag (Improved Aerodynamics)
In addition to reducing mechanical loss, reducing vehicle
drag is an important concern. Aerodynamic drag (that is, the
force required to push a vehicle through the air) accounts for
80 percent of total vehicle drag.
Various measures have been taken in state-of-the-art vehicle
design to improve the aerodynamics, such as ensuring that
the external surfaces between windows and panels are flush.
15
In vehicle development, extensive studies and testing are
carried out to reduce resistance to air flow.
16
■ Technologies to Improve Powertrain Performance
● Continuously Variable Transmission (CVT)
The most common type of CVT transmits the power from the
engine to the wheels not by the shifting of actual gears but
by a pulley-and-belt system that allows stepless (or
“shiftless”) changing to an infinite number of gear ratios—or
gears as they are conventionally understood.
This technology involves two pulleys—the driving pulley
(which inputs engine power) and the driven pulley (which
outputs to the powertrain)—and a belt that connects them,
riding in a groove in the pulleys. When the cones of either
pulley move outward, the diameter of the pulley decreases
and the belt rides lower in the groove; when the cones move
inward, the diameter increases and the belt rides higher. The
varying diameters of the two pulleys in relation to each other
(i.e., their ratios) determine the gear ratio. This “continuous
variability” in power transmission enables increased fuel
efficiency.
● Automated Manual Transmission (AMT)
AMTs offer the excellent fuel efficiency of manual
transmissions and the smooth shifting of conventional
automatic transmissions, the basic difference compared to
MTs being that a hydraulically-controlled automatic clutch
makes clutch operation by the driver unnecessary. Some
AMTs also offer fully automatic shifting.
Although AMT systems vary in terms of the specific
technologies they incorporate, they all offer enhanced fuel
efficiency and better shifting performance. The diagram
below illustrates one type of AMT system.
The Twin Clutch-SST AMT System
Wet multi-plate twin clutch
Engine ECU
Engine
Odd (for 1st, 3rd, and 5th gears)
■ Hybrid Vehicles
A hybrid vehicle uses two power sources—an internal
combustion engine and an electric motor—for propulsion.
Initially, the most common types of hybrid vehicles were the
series type and the parallel type. In a series hybrid, the
electric motor alone drives the wheels (the engine’s only job
is to generate electricity), whereas in a parallel hybrid, both
the engine and the electric motor generate the power that
propels the vehicle (the engine is the primary
power-generator, while the electric motor assists the engine
when extra power is needed). More recently, combined
hybrids incorporating the features of both the series and
parallel hybrid types have increasingly come into use.
Series
Hybrid System
Configuration
Mechanical power
Electrical power
Battery
Inverter
Combustion engine
Electric motor
Generator
Wheel
Parallel
Hybrid System
Configuration
Mechanical power
Electrical power
Battery
Inverter
Combustion engine
Transmission
Electric motor/
Generator
Even (for 2nd, 4th, and 6th gears)
Precise
cooperative
electronic
control
Continuously Variable Transmission
Twin ClutchSST ECU
Hydraulic
control system
As with MT shifting,
a simple and rigid structure.
■ Idling Prevention
This technology, also called “stop-start,” reduces fuel
consumption by shutting down the engine when the vehicle
comes to a stop, thereby preventing it from idling, and
starting it up again when the driver applies the clutch.
Idling-prevention technology has been widely adopted in
Japan in transit buses and delivery trucks because of their
stop-and-go driving patterns.
How Idling Prevention Works (in a MT vehicle)
Engine Shutdown
Shift to neutral.
R
Apply the hand brake.
2 4 6
Automatic
shutdown
1 3 5 7
Engine Restart
Apply the clutch.
Automatic
start-up
17
3 Alternative-Energy / Next - Generation Vehicles
When stopping, the engine automatically
shuts down after the driver shifts to
neutral and applies the hand brake.
The engine automatically restarts after
the driver applies the clutch.
A combined hybrid enables significantly increased fuel
efficiency and reduced emissions by using only the electric
motor at the time of start-up, as with the series type; by using
both the engine and the electric motor when more power is
needed, as with the parallel type; and, at steady cruising
speeds, by storing the extra energy produced by the engine
in the battery for later use. A special feature of combined
hybrids is that they continuously optimize both the
mechanical and electrical power flows by means of a
power-splitting device.
Hybrid vehicles also incorporate regenerative braking
technology, which recovers energy (that would otherwise be
lost) during braking and stores it in the battery, to be used
later to help move the vehicle down the road. Energy
recovery with this fuel-economizing technology can be
considerable, particularly in hybrid transit buses and other
urban work vehicles, such as delivery trucks, that perform
mostly stop-and-go driving.
■ Plug-In Hybrid Vehicles
Plug-in hybrid vehicles (referred to as “PHEVs,” for “plug-in
hybrid electric vehicles”) operate on batteries that can be
recharged by hooking up to the electrical power
grid—typically, through a conventional home outlet. They
are powered exclusively by an electric motor for short trips
(and are thus highly energy-efficient for city driving), but
perform as hybrid vehicles for long-distance driving by
reverting to the use of a combustion engine.
Expansion of the electric-only travel range for these vehicles
should encourage their more widespread use in urban areas.
PHEVs offer excellent environmental performance as well as
significant reductions in overall fuel costs, particularly if they
are recharged at night when the cost of electrical power is
generally lower.
Wheel
Combined
Hybrid System
Configuration
Mechanical power
Electrical power
Battery
Generator
Inverter
Combustion engine
Electric
motor
Power-splitting device
(planetary gear unit)
Wheel
Notes: 1. The squiggly lines in the diagrams represent electrical connections.
2. The above diagrams do not show regenerative-braking energy flows.
Plug-In Hybrid Vehicles: How They Run and Recharge
Electric-only (battery) operation on short trips
Virtually zero emissions
Reduced fuel consumption
Hybrid operation (use of gasoline engine)
in long-distance driving
Recharging units
Combustion engine
Home electrical
power outlet
Charging
Battery
18
■ Fuel Cell Vehicles
A fuel cell vehicle is propelled by a motor that runs on
electricity generated by onboard fuel cells assembled into a
fuel cell stack.
Fuel cells create electricity through an electrochemical
reaction. The polymer electrolyte membrane (PEM) fuel cell
used in automobiles generates electricity by means of a
chemical process that uses only hydrogen gas and oxygen
from the air and emits only water, producing no harmful
emissions whatsoever.
The PEM is wedged between an anode and a cathode.
Hydrogen gas is conveyed to the anode on one side, where a
platinum catalyst splits the hydrogen into positively charged
hydrogen ions, or protons, and electrons (always negatively
charged). Only the hydrogen-ion protons can pass into the
PEM and through to the cathode on the other side.
Meanwhile, the electrons follow an external circuit to the
cathode, generating electricity. At the cathode, the electrons
and the hydrogen-ion protons combine with oxygen
channelled in from the air to form water—or water vapor, to
be precise—which then flows out of the cell.
■ Electric Vehicles
Electric vehicles (EVs) operate on electric power exclusively
and feature a power-generation system consisting of three
elements: an electric motor, a controller, and batteries. The
controller takes power from the batteries and conveys it to
the motor, which in turn transmits it directly to the wheels.
EVs are zero-emission vehicles.
In addition, power
generation in an EV creates much less vibration than it does
in a vehicle equipped with an internal combustion engine.
The major problems previously posed by EVs were their
limited travel range and the long time they required for
battery-recharging. However, the development of batteries
with higher energy density, such as nickel-metal hydride and
lithium-ion batteries, now enables a travel range of up to 200
kilometers (120 miles). A further development is the use of a
so-called quick charger in a 200-volt power supply, which
enables a travel range of 60 kilometers after only 15 minutes
of recharging.
■ Hydrogen Vehicles
Hydrogen vehicles are powered by hydrogen that is
subjected to combustion. (Fuel cell vehicles are also powered
by hydrogen which, without combustion, is converted into
electricity by the fuel cells—see text and diagram on
opposite page.)
The hydrogen combustion process
generates only water and some nitrogen oxides (NOX); no
CO2, carbon monoxide, hydrocarbons or sulfur compounds
are released.
■ Clean Diesel Vehicles
A chief merit of diesel engines is that they are more
fuel-efficient, and therefore emit fewer CO2 emissions, than
gasoline engines. This is one reason why diesel passenger
cars have, over time, steadily increased in popularity in
Europe.
However, major issues exist with respect to the
commercialization of hydrogen-powered vehicles for
widespread use. One problem, which of course also applies
to fuel cell vehicles, is the production and supply
infrastructure for this energy source; another problem is
posed by the need for a compact solution to the in-vehicle
storage of hydrogen.
Greater emissions of soot and nitrogen oxides were long
perceived to be the disadvantages of diesel engines
compared to gasoline engines. However, the overall
emissions performance of diesel engines has improved
dramatically in recent years in response to ever more
stringent regulatory requirements. Clean diesel engines now
provide significantly reduced emissions compared to
conventional diesel engines and, in comparison with
gasoline engines, considerably (up to 30 percent) greater fuel
efficiency.
A Hydrogen-Internal Combustion Engine Hybrid Vehicle
A Clean Diesel Engine
Example of an Electric Vehicle and How It Recharges
Energy loss (in the form of heat) in fuel cell vehicles is
minimal, which is not the case with conventional generators,
where the energy conversion process is accompanied by
significant mechanical/thermal loss.
■ Natural Gas Vehicles
Natural gas vehicles, or NGVs, use either compressed natural
gas (CNG) or liquefied natural gas (LNG) for propulsion. Most
are CNG vehicles.
The development of fuel cell hybrid vehicles (FCHVs) running
on a combination of fuel cells and batteries is currently
ongoing.
Powertrain Configuration in a Fuel Cell Vehicle (Example)
Recharging Through a Standard Power Outlet
Time required:
100V→14 hours/200V→7 hours
Plug-in to vehicle
Natural gas is composed of methane and other hydrocarbon
gases. Because NGVs generate roughly 20 percent fewer CO2
emissions than gasoline vehicles, they are likely to become a
practical alternative to gasoline vehicles. NGVs also release
fewer NOX emissions and, unlike diesel vehicles, no soot,
resulting therefore in reduced particulate matter (PM)
emissions.
■ Diesel-Alternative LPG Vehicles
The primary component of liquid petroleum gas, or LPG, is
either propane or butane, which is stored onboard a vehicle
in liquefied form.
Onboard charger
PEM Fuel Cell Energy Conversion
“Quick Charging” Recharging Method
Time required:
200V→30 minutes (80% of full capacity)
e-
e-
Electricity
PEM
O2
Hydrogen gas
(H2) induction
H2
Anode
19
LPG vehicles are the norm for passenger-car taxi fleets in
Japan. Because of its comparatively low cost and reduced
NOX and PM emissions, LPG is also widely used today in Japan
in small trucks, as an alternative to diesel power.
A CNG-Powered Small Truck
Oxygen
(O2) induction
Source: Tokyo Electric Power Co., Inc.
H+
H+
Plug-in to vehicle
Quick charger
CNG-powered commercial vehicles—transit buses and
trucks, for example—are in relatively widespread use in
Japan, and CNG passenger vehicles and minicars have
recently been introduced to the market. CNG-powered
hybrid buses are currently under development.
H 2O
Water
(H2O) emission
Cathode
20
IV. HEAVY-DUTY VEHICLE TECHNOLOGIES
4 Other Alternative Fuels
In the interest of increased energy security and reduced
environmental impact, the following fuels have been
developed for use in automobiles as alternatives to gasoline
and conventional diesel fuel. Research on alternative fuels is
ongoing.
■ Coal-to-Liquid and Gas-to-Liquid (CTL/GTL) Fuels
Cutting-edge CTL/GTL technology converts carbon
monoxide (CO) and hydrogen (H2) derived from coal and
natural gas into liquid fuels which can then be refined to
produce diesel fuel for use in conventional diesel engines. In
addition to their easy storage and handling, CTL/GTL fuels
release essentially no sulfur emissions and no aromatics
during combustion. These synthetic fuels are therefore
considered a promising alternative to petroleum-based
diesel fuel (or “petrodiesel”) and are increasingly sought after
today.
■ Biodiesel Fuel (BDF)
Biodiesel fuel consists of a vegetable oil (soybean, sunflower
or rapeseed oil, for example) or animal fat feedstock which
has undergone transesterification—a chemical process to
reduce high viscosity—to produce a fuel whose properties
are similar to those of petrodiesel and that can be used in
conventional diesel engines.
In addition, research and verification tests have recently been
carried out in Japan on what is being called “bio hydrofined
diesel,” or BHD, a renewable synthetic diesel fuel. Produced
using a vegetable oil feedstock and through the application
of refinery-based hydrogenation technology, sulfur- and
aromatics-free BHD has been shown to generate fewer
tailpipe hydrocarbon (HC), carbon monoxide (CO) and
particulate matter (PM) emissions while at the same time,
after improvements in oxidative stability, performing on a par
with conventional diesel fuel.
■ Dimethyl Ether (DME)
DME is a synthetic fuel produced from natural gas, coal seam
gas (also called “coalbed gas”) or biomass. It is clean-burning,
generating virtually no soot and no sulfur oxides (SOX), with
reduced emissions of nitrogen oxides (NOX) and particulate
matter. Easy to handle, it can serve as an alternative to
conventional diesel fuel and liquid petroleum gas (LPG).
21
■ Bioethanol
Bioethanol fuel is a renewable gasoline substitute that can be
produced from a wide variety of plants through a process of
decomposition into starch and sugar, fermentation, and
distillation.
It is environmentally friendly and, more
specifically, carbon neutral, because the CO2 produced
during its use is balanced (or “offset”) by the CO2 consumed in
the photosynthetic growth of the plants. For this reason, CO2
emitted in bioethanol combustion has been omitted from
calculations of greenhouse gas emissions under the Kyoto
Protocol.
However, the production of bioethanol from food crop
feedstocks such as corn and sugar cane raises major issues
including those of food supply and appropriate land use. In
contrast, the potential for cellulosic ethanol made from waste
residues and non-food crop feedstocks is promising, and
efforts to promote its production and commercialization are
underway worldwide.
In Japan, various initiatives launched in 2007 are being
pursued across the country to promote the production and
use of bioethanol. Currently in the Tokyo metropolitan area,
bioethanol is available at 100 filling stations in
gasoline-biofuel blends. At present, however, bioethanol
content in such blends is not allowed to exceed 3 percent,
owing to the concern that if used at a higher concentration in
in-use vehicles, corrosion of vehicle parts could result.
Offsetting Vehicle CO2 Emissions with the Use of Biofuels
Absorption
of CO2
■ Front & Rear Underrun Protection
In a car-to-truck collision, an underrun protection device
(UPD)—whether for the rear (RUPD) or the front
(FUPD)—prevents the car from running underneath the truck
and mitigates car occupant injury and vehicle damage by,
typically, maximizing structural energy absorption to reduce
the impact.
RUPDs have been mandatory on heavy-duty vehicles (i.e.,
whose gross vehicle weight exceeds 3.5 tons) in Japan since
1992. FUPDs for such vehicles have also been mandated by
legislation to be enforced beginning in 2011.
■ Digital Tachographs
A digital tachograph automatically records vehicle
operational data (speed, time, engine RPMs, sudden
accelerations and brakings, etc.) on a memory card or other
storage device.
Digital tachographs thus facilitate data analysis, which in turn
enables the monitoring of individual vehicles’ energy use and
CO2 emissions.
Example of a Digital Tachograph
Front Underrun Protection
Rear Underrun Protection
■ Speed Limiters
By controlling fuel injection into the engine, a speed limiter
device prevents a vehicle from exceeding a pre-set maximum
velocity, even when the accelerator pedal is depressed.
■ Rollover Mitigation
Using ESC (electronic stability control) sensors to detect
when a vehicle is in danger of rolling over, this technology
emits an audio warning to the driver and acts to correct the
vehicle’s position by controlling engine output and initiating
braking for wheels on both the tractor and the trailer. This
not only helps prevent trailer rollover but also mitigates
skidding and the jackknifing phenomenon.
Rollover Mitigation: How It Works
CO2
Emission
of CO2
At Start of Potential Rollover
CO2
CO2
CO2
CO2
CO2
CO2
In order to reduce the occurrence of serious accidents
resulting from excessive heavy-duty vehicle speed on
highways, Japan mandated the installation of speed limiters,
which allow a maximum speed of 90 km/h (55 mph) or less,
onboard all large-sized trucks, including in-use vehicles,
effective from September 2003.
Tractor
Trailer
Lateral G occurs first. Lateral G occurs later.
Determination of lateral G
Control actuation
Stable deceleration
Reduction of lateral G
Photosynthesis
With system operation
Supply of biofuels
Trailer wheel braking
Without system operation
Reduced
lateral G
Uncontrolled
lateral G
Tractor wheel braking
22
V. MOTORCYCLE TECHNOLOGIES
■ Anti-Lock Braking System (ABS)
An anti-lock braking system on a motorcycle prevents the
wheels from locking at the time of braking, ensuring stability
as the vehicle moves forward. Using sensors positioned on
both the front and rear wheels, the system’s ECU monitors
braking pressure and wheel speed and, when determining
the start of a lock-up (resulting from overbraking), causes the
ABS modulator (or “pressure modulator”) to adjust the
braking pressure on each wheel to ensure vehicle stability.
Functional Diagram of Motorcycle ABS
VI. TECHNOLOGIES FOR INCREASED USER CONVENIENCE
■ Motorcycle Airbags
Motorcycle airbags were developed for the purpose of
mitigating injuries to riders in frontal collisions. When a
frontal collision occurs, crash sensors detect acceleration
changes caused by the impact and convey that data to the
airbag ECU, which instantaneously determines whether or
not to deploy the airbag. In the event of deployment, an
electronic signal from the ECU causes activation of the airbag
inflator. The deployed airbag absorbs the rider’s kinetic
energy, preventing him/her from being thrown forward from
the motorcycle.
Example of an Inflated Motorcycle Airbag
Hydraulic
fluid line
Brake cable
Damper cable
Right brake lever
Front - and rear-wheel
interlocking ABS modulator
Front Wheel
Rear Wheel
Along with technologies advancing safety and environmental protection in road transport, technologies
that promote comfortable and more convenient vehicle use continue to evolve.
Innovations in the area of vehicle user convenience have been made possible by advances in
computer-controlled and communications technologies.
■ Park Assist
Park assist technology interfaces with electric power-assisted
steering, front and rear side sensors and a back-up
monitoring camera to enable a car to steer itself into a
parking space with no steering-wheel operation by the
driver. The driver needs only to position the vehicle, shift to
reverse, press relevant buttons on the in-dashboard, camera
image-supplied touchscreen and release the brake. The
system will disengage if the driver touches the steering
wheel or depresses the brake pedal. A visual or auditory
signal informs the driver of the completion of the parking
operation, whether parallel or reverse.
Left brake lever
Damper cable
ECU
Front-wheel
speed sensor
Rear-wheel
speed sensor
■ Dual Combined Braking System
So-called combined or dual combined braking systems (CBS
or DCBS) actuate a motorcycle’s front as well as rear brakes
when the rider applies either the front or the rear brake.
Monitoring the braking pressure thereby created, the ECU
calculates how much braking force should optimally be
applied to the front and rear wheels and then causes the
required amount of such force to be distributed over both
wheels. This system ensures optimum braking while
maintaining vehicle stability.
Recent advances in park assist technology have further
simplified the procedures involved in readying a vehicle for a
parallel or reverse parking maneuver. These advanced
functions automatically identify and target a potential
parking space through computer processing of
sensor-obtained data, at the same time verifying sufficient
clearance with respect to the positioning of vehicles parked
adjacent to the targeted space.
Automatic closing ensures that the doors and trunk are
closed gently.
■ Smart Keys
“Smart key” is one among various terms for this technology,
which allows automatic unlocking and locking of vehicle
doors (by means of an electric pulse generated inside the car
key) without conventional key operations or the use of a
remote control button. It also enables electronic ignition
activation—i.e., without insertion of the key into the ignition.
How a Smart Key Works
Diagrammatic Representation of Ultrasonic Sensor-Based
Park Assist in Operation
When parallel parking:
Sensor-detected
points
Targeted
parking space
Ultrasonic sensors
When a driver carrying the car key comes within a certain distance
of the vehicle, the door is automatically unlocked by an electric
pulse generated by the key, and locked when the key-carrying
driver leaves the vehicle.
When CBS/DCBS is combined with ABS, the result is a braking
system that performs with outstanding efficiency even when
road conditions are slippery.
Functional Diagram of Motorcycle CBS
■ Automatic Closing
A motor-based mechanical system that automatically closes
vehicle doors, sliding door and trunk when these are ajar.
When reverse parking:
Handbrake lever
Sensor-detected
points
Right front
brake caliper
Targeted
parking space
Ultrasonic sensors
Front master cylinder
Right
Side
Footbrake lever
Disc
rotor
Rear
master
cylinder
Servomechanism
Rear brake
caliper
Left
Side
PCV
Left front
brake caliper
Disc
rotor
Front brake
23
Disk
rotor
Rear brake
Ultrasonic sensors (on a forward-moving vehicle to be parked) detect
positioning of other, parked vehicles. Based on the data thereby obtained,
computer processing then identifies and targets a parking space.
24
■ Electronic Toll Collection (ETC)
Electronic toll collection in Japan requires the installation of
an in-vehicle device and the insertion of a card into that
device. The device communicates wirelessly with the
antenna at an ETC-equipped tollgate on a toll road and
payment is processed automatically by means of the card.
By enabling drivers to pass through tollgates without
stopping, ETC offers multiple advantages including increased
comfort and convenience for vehicle users and reduced
congestion at toll plazas, as well as the environmental
benefits derived from the resulting smoother traffic flow.
One principal benefit is a reduction in CO2 emissions, which
were estimated to have dropped by about 34 percent, or
130,000 tons a year, when the ETC use rate of 50 percent of all
expressway users nationwide was achieved in October 2005.
■ Smart Highway Toll Stations
Smart highway toll stations are toll payment sites for ETC
users exclusively. In addition to reducing road congestion, a
further benefit of smart toll stations, which are unmanned, is
their reduced cost of construction and operation. This
facilitates the expanded introduction of these toll stations,
which in turn promotes greater convenience in road use.
Smart toll stations were first introduced in Japan in a pilot
program implemented by the Ministry of Land,
Infrastructure, Transport and Tourism in cooperation with
local governments. The transition to their full-scale
availability in the national expressway network has been
underway since April 2007.
Conventional versus Smart Highway Toll Stations
ETC was launched for large-scale use in Japan in March 2001.
The cumulative total number of deliveries of in-vehicle
devices exceeded 20 million units in November 2007 and
continues to rise, as does the ETC use rate which, for the week
of February 15 through 21, 2008, stood at 73.1 percent of all
expressways users nationwide. During that same period, the
ETC use rate reached 81 percent on the Tokyo Metropolitan
Expressway road network.
■ HELPNET TM (Emergency Call System)
HELPNET TM is a service operating in Japan that, in the event of
an emergency involving an automobile—whether an
accident, breakdown, sudden driver incapacity or passenger
illness—enables the communication (automatic or manual)
of the vehicle’s registration data and current location to the
service’s operations center. That information is then relayed
to the police and emergency service providers with
jurisdiction in the location concerned. HELPNET’s purpose is
to reduce the interval of time between the reporting of an
emergency and the arrival on site of rescue personnel. In the
event of a collision, automatic communication of the
HELPNET user’s vehicle registration data and location is
activated by airbag inflation; in other types of emergencies,
manual communication is carried out instantaneously by
means of a one-touch device installed inside the vehicle
cabin. Other possible communication channels are via a
vehicle’s navigation system or a mobile (cell) phone.
■ VICS (Vehicle Information and Communication System)
At the forefront of ITS (Intelligent Transport Systems) in Japan
when it was launched in 1996, VICS uses advanced
communications technologies as well as FM multiplex
broadcasting to collect and transmit, in real time, information
on road traffic conditions, road use regulations and
restrictions, alternate routes and parking facility availability
to in-vehicle equipment enabling the display of this
information on the navigator screen in text, diagrams and
maps.
Example of a VICS Information-Enhanced Navigator Screen Display
HELPNET: How It Works
Police/Emergency
Service Providers
Onboard Emergency
Notification
Information on traffic conditions and road use restrictions is displayed
in real time.
4 Immediate dispatch
Via airbaginterlocking
device
Via in-cabin
one-touch
device
of rescue personnel
2 Confirmation
of content of
emergency
notification
ETC for motorcycles has been available in Japan since
November 2006.
A conventional set-up for highway toll collection, where a toll plaza
typically services an interchange and comprises multiple tollbooths,
requires considerable land allocation and infrastructure.
ETC Use & CO2 Emissions Reduction
(x 10,000 tCO2/year)
40
3 Relay of content
of emergency notification
1 Emergency notification
of vehicle registration
data and current location
communicated automatically
(airbag-interlocking device)
or manually (one-touch device)
35
An estimated reduction of approx.
130,000 tCO2/year
30
HELPNET Operations Center
25
How VICS Works
20
CO2
emissions
15
CO2
emissions
10
5
National Police Agency
(prefectural divisions)
Greater CO2
reductions
with
expanded
rates
of ETC use
National road network
authorities
FM Multiplex Broadcasting
Transmits a broad range of information relevant to the
prefecture in which the user vehicle is located,
broadcasting in FM from the dedicated central and relay
stations situated in each of Japan’s 47 prefectures.
Japan Road Traffic
Information Center
Information provided on:
0
Prior to ETC
introduction
ETC use rate 50%
(October 2005)
Road traffic
information
ETC use rate 66%
(March 2008)
Infrared Beacons
Installed on major “ordinary” roads to transmit
information on traffic conditions on these roads within
about a 30-km radius of the user vehicle.
VICS
Center
Traffic congestion spots within a prefecture-wide radius,
estimated travel times to designated destinations, road
accidents and roadwork locations, road use restrictions
including lane closures, speed limits in application,
parking facility locations and vacancy status, etc.
Microwave Beacons
Installed on expressways to transmit information on
traffic conditions on these roads within about a 200-km
radius of the user vehicle.
Information provided on:
Information provided on:
Because smart toll stations can be built at points directly accessing toll
roads, they require significantly less land allocation. Construction costs
are, comparatively, also much reduced.
25
Traffic congestion spots, estimated travel times to
designated destinations, road accidents and vehicle
breakdowns, road use restrictions owing to roadwork,
nearest parking facility locations and vacancy status, etc.
Estimated travel times to designated destinations, traffic
congestion spots, alternate routes, road accidents, speed
limits in application, lane closures, tire-chain use
warnings, parking facility locations and vacancy status,
etc.
26
VII. DRIVING THE AUTOMOTIVE FUTURE
Key elements in achieving sustainable mobility in the 21st century are greater safety and reduced
environmental impact. In road transport, however, efforts to increase safety and decrease the
environmental “footprint” involve a whole range of factors involving not only the automotive industry
but also government, fuel suppliers, and vehicle users. Nevertheless, in the years ahead the expanding
practical application in Japan of the continuously advancing vehicle safety, ITS and communication
technologies described below is expected to play a crucial role in improving road safety and traffic flow
by reducing accident occurrence and chronic congestion.
■ ASV (Advanced Safety Vehicle) Technologies
In the area of safe-driving assistance, many of the vehicle
safety technologies described in this publication and in
application in Japan today—including collision-mitigation
braking systems, lane-keeping assist systems and adaptive
cruise control systems—have been developed based on the
results of research conducted on the Advanced Safety
Vehicle concept.
publication on road safety in 1990, which called for research
on and the development of “motor vehicles ‘unlikely to
cause accidents’ through their incorporation of advanced
technologies.” Currently in its fourth phase which ends in
fiscal year 2010, the project has progressed from
technological verification of onboard autonomous systems
(Phase 1) to preparations for market introduction and the
development of new technologies (Phases 2 and 3) to the
promotion of the widespread use of ASV and ITS
technologies for road-to-vehicle and vehicle-to-vehicle
communication (Phase 4).
The 1991 launch of the ASV project by what is now Japan’s
Ministry of Land, Infrastructure, Transport and Tourism was
triggered by a Japan Automobile Manufacturers Association
Features of the Advanced Safety Vehicle
Sensors
Receives and interprets sensor signals and reports to control unit.
Based on information received from computer, commands emission of audible warnings and display of information to driver for safe
vehicle operation.
Control unit
Active head restraint, Motorized
seatbelt pretensioner
Camera for monitoring
driver alertness
Vehicle speed
sensor,
Acceleration
sensor
Infrared
camera
8
14
Cameras for
monitoring
perimeters, lane
deviation, etc.
1
3 ∼ 6
10
Head-up
display
1 ∼ 10
Road-vehicle/Inter-vehicle
communications antenna
Infrared sensor
14
12 ∼ 14
Brake sensor
Steering
sensor
Computer
Monitor road and vehicle conditions.
Special warning
light
13
13
Vehicle position
sensor
1 ∼ 5
7 10
Infrared sensor
6
6
Vehicle body design for mitigating
pedestrian injury, Airbag system for
pedestrian protection
Sensor for monitoring distance
between vehicles, Obstacle
sensor
9
12
Occupant sensor, Seatbelt
buckle switch
11
8
Monitor/speaker for information
delivery
Brake
control
device
1 3 9
Adaptive frontlighting system
Rearward/side sensor, Sensor
for lateral distance between
vehicles, Obstacle sensor
7
1 ∼ 3
Computer
6
Steering control device
4 5
Throttle control
device
Navigation system
2 7
2 3 6
Principal ASV Safety Technologies Developed (Second Phase)
1 Collision-Mitigation Braking System
6 Blind-Corner Monitoring
11 Unfastened Seatbelt Warning System (for all passengers)
2 Curve Detection System
7 Adaptive Front-Lighting System
12 Side Obstacle Warning System
3 Full-Range Adaptive Cruise Control
8 Rear-End Collision Neck Injury Mitigation System
13 Sudden Braking Warning System (for driver of vehicle in rear)
4 Lane Deviation Warning System
9 Vehicle Body Design for Mitigating Pedestrian Injury & Airbag System for Pedestrian Protection
14 Intelligent Night Vision
5 Lane-Keeping Assist System
27
■ ITS (Intelligent Transport Systems) Technologies
Intelligent Transport Systems use cutting-edge information
and communication technologies to network data between
road users, roads (i.e., infrastructure) and vehicles for the
dual purpose of reducing road congestion—and, as a result,
CO2 emissions—and accident occurrence. In 1996 the
Japanese government formulated a comprehensive concept
for the promotion of ITS, on the basis of which it
spearheaded, as a national project, ITS development in a
number of areas. ITS developmental guidelines aim to
achieve progress with respect to (i) safety and security,
(ii) fuel efficiency and environmental protection, and (iii) comfort
and convenience. A wide range of ITS technologies and
services have therefore been energetically promoted in
parallel with the further development of ASV technologies
(see opposite page).
Screen displays have also become more complex. It is now
possible to customize 2D map displays, to select 3D displays
of major intersections and, with a touchscreen, to obtain an
image showing the precise perimeter of a targeted parking
space (see “Park Assist” on page 24).
Advanced car navigation systems also offer driver-assistance
features such as lane deviation monitoring, navigator-based
gearshift control, curve detection, voice recognition,
advanced lane guidance, and handsfree calling, among
other functions.
Car navigation systems will, in the years ahead, continue to
become increasingly sophisticated with further advances in
telematics.
An HDD-Operated Car Navigation Display Screen
Many of these ITS technologies/services, including
electronic toll collection, VICS and HELPNET (see pages 25
and 26), are already in extensive use in Japan. Scheduled for
2010, meanwhile, is the practical introduction of two
intelligent communication-based emergency warning
systems—one a safe-driving support system and the other
an advanced cruise-assist system for highways/expressways
(“DSSS” and “AHS,” respectively)—that use vehicle navigation
system-integrated telematics.
These and other ITS
technologies are expected to see expanded development in
the coming years.
■ Advanced Car Navigation Systems
Car navigation systems equipped with digital road maps and
integrating Global Positioning System (GPS) technology
were first introduced in Japan in 1990. Initially, these
systems used only a single CD-ROM, but subsequent
systems enabled, first, the use of multiple CD-ROMs and,
beginning in 1997, a DVD-ROM. Car navigation systems
using hard-disk drives (HDDs), which obviously have a much
larger capacity, have been commercially available since
2001.
The use of large-capacity media has made possible
considerable progress in system functions. For example, the
quality of voice guidance (for spoken directions, etc.) has
improved significantly, the 3D screen indications and search
function have become much faster, and the real-time
transmission of information on road traffic conditions has
also advanced with the use of a range of data sources,
including VICS, that enables highly accurate optimal route
guidance.
■ Telematics
“Onboard telematics” refers to the integrated application of
GPS and mobile communications technologies in
automotive navigation systems. Telematics enables an
Internet-accessing vehicle navigation system to deliver a
broad spectrum of wireless functions and services: not only
real-time traffic and weather information and route
guidance, but also automatic reporting in the event and at
the time of theft, automatic roadside assistance, remote
diagnostics in the event of vehicle breakdown (by
connecting with a diagnostics consultation service),
entertainment and shopping information, voice recognition,
e-mail and fuel-efficient driving guidance.
Further
applications in various areas are anticipated in the near
future.
10 Driver Inattention Warning System
28
Japan Automobile Manufacturers Association, Inc.
Jidosha Kaikan, 1-30, Shiba Daimon 1-chome, Minato-ku, Tokyo, 105-0012 Japan
Visit us at http://www.jama.or.jp/ or www.jama.org.
© JAMA. All rights reserved. Printed in Japan.
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