California Hybrid, Efficient and Advanced Truck Research Center
CalHEAT is funded
by the California
Energy Commission
and operated by
CALSTART
About CalHEAT Class 8 Trucks: Testing &
Demo Project
This project evaluated the performance of advanced
Class 8 urban beverage delivery trucks in a limited
demonstration program in Southern California. The
primary goal was to evaluate the benefits of heavyduty hybrid vehicle technology compared to
conventional vehicles. The project team consisted of
Daimler Trucks as the vehicle supplier, a beverage
delivery company as the fleet operator, Eaton
Corporation as the hybrid drivetrain supplier, and
Telogis, Inc as the data acquisition system supplier.
The results provide early benchmark data in
expected fuel economy and efficiency improvements
from advanced Class 8 beverage delivery trucks and
provide the potential savings for this important
heavy-duty truck segment.
Results of On Road Testing
Test Vehicles
Four beverage delivery trucks, three hybrids and one
conventional diesel, were monitored over a 15month vehicle demonstration and testing period in
Los Angeles. These trucks are Class 8 short haul
urban delivery tractors with a GVWR of 30,000 lbs.,
fitting under the CalHEAT Class 8 tractors short
haul/regional category.
48 S. Chester Avenue
Pasadena, CA 91106
Tel (626) 744-5600
www.calstart.org
Vehicle
ID
Vehicle Make
and Model
HYBRID 1
Trans.
Manu.
Electric
Motor
Power
Engine
HP and
Torque
Freightliner
M-2 Hybrid
Engine
Make
and
Model
Cummins
ISB 6.7
Eaton
40 kW
Freightliner
M-2 Hybrid
Cummins
ISB 6.7
Eaton
40 kW
HYBRID 2
Kenworth T370
Hybrid
Paccar
PX6-325
Eaton
40 kW
HYBRID 3
280 HP
660
LB/FT
325 HP
750
LB/FT
325 HP
750
LB/FT
Freightliner
M-2
(Conventional)
Freightliner
M-2 Hybrid
Cummins
ISC-300
Allison
NA
Cummins
ISB 6.7
Eaton
40 kW
CONV
HYBRID 4
Data parameters collected by the system used
were: total engine hours; total miles traveled;
total fuel use; total idle time; derived average
speed. With this data CalHEAT analyzed the data
to compare average fuel economy for the hybrid
and diesel trucks during in-use operations
measured in gallons per hour (GPH) and miles per
gallon (MPG) to provide a better understanding of
vehicle use in relation to vehicle fuel economy.
325 HP
750
LB/FT
325 HP
750
LB/FT
A telemetric data acquisition system was installed to
extract the data from the vehicles. The vehicles used
their normal routes with the telemetric systems
tracking the performance of the vehicles in real time.
From the data collected, it was seen that the
operation of the vehicles played a key role in the
difference in fuel economy and fuel consumption
rates of the vehicles. Despite the difference in duty
cycle of the vehicles, the hybrid s showed an
improvement in fuel economy (MPG) ranging from
15.6% to 22.4%. While a number of variables can
contribute to the range of fuel economy benefits,
the difference may primarily be due to the
difference in duty cycle of the test vehicles.
The hybrid also showed a reduction of 19.6% to
26.9% in fuel consumption rate which showed the
hybrids were more efficient compared to the
conventional diesel in typical operation at the fleet.
Using the idling percentage and derived average
speed, a direct comparison was made between one
of the hybrid trucks and the conventional truck
which operated in similar routes with similar idling
percentages and derived average speeds. When
compared, the hybrid showed a 22.6%
improvement in MPG and a 20.8% in GPH.
Due to the difference in duty cycle, CalHEAT
performed a chassis dynamometer test at the
University of California, Riverside to assess the
efficiency and emissions of the hybrid truck
compared to a conventional truck.
Results of Dynamometer Testing
CalHEAT performed a chassis dynamometer test at
the
University of California, Riverside College of Engineering
Center for Environmental Research & Technology (CE-CERT)
to assess the efficiency and emissions of the hybrid truck
compared to a conventional truck.
Two speed-time driving schedules were developed using data
collected from the vehicles – one representing a “heavy” and
a “light” vehicle load. The two duty cycles were developed for
vehicle emissions and fuel economy evaluation while the
vehicles were operated over the duty cycles developed using
a chassis dynamometer.
A 1 minute key-off soak was performed to make sure the
catalyst was up to the required temperature to ensure
accurate emissions testing. With the 1 minute key-off soak,
the CO emissions for the hybrid were found to be lower
than the conventional diesel engine. All other emissions
such as NOx, THC, methane, and NMHC for the hybrid were
similar or lower than the conventional. It should be noted
that the CO emissions for all vehicles tested appear to be well
below the certification levels.
The hybrid truck showed an improvement of 30% over the
conventional truck on the “heavy” cycle. In addition, a new
battery with higher capacity for the hybrid was also tested.
The chassis dynamometer test indicated that the larger
battery system improved fuel economy performance by an
additional 4%, resulting in a 34% improvement over the
conventional unit.
Driver Acceptance Survey
Operator acceptance interviews were used to assess
drivers’ impressions of the performance of the hybrid
beverage delivery trucks during in-use operations
compared to typical diesel beverage deliver trucks. A
simple, relative rating scheme of “better,” “same,” or
“worse” was used to compare hybrid truck performance
characteristics to those of a typical conventional diesel
truck. The survey questions were designed to cover key
vehicle performance areas and other characteristics of
the vehicle that would directly affect the driver.
For more information, visit:
CalHEAT
California Energy Commission
CALSTART
www.calheat.org
www.energy.ca.gov
www.calstart.org
The specific areas covered by the survey questions included:
maneuverability at slow speeds; pulling power with load;
acceleration; coasting/deceleration; braking; smoothness of
shifting; in-cab controls; interior noise level; exterior noise level;
overall vehicle rating; any problems with the hybrid drive
system; and additional comments.
Driver Acceptance Survey Results
The results from the survey were generally positive with the
drivers viewing the hybrid beverage delivery truck as equal to or
better than the conventional truck on most vehicle
characteristics including overall vehicle rating. The features that
were rated most consistently as “worse” were for pulling power
with load and acceleration. The survey showed that at the end of
the project 34% felt the performance was the same while 66 %
of the drivers felt these features were poor. The features of the
hybrid beverage delivery truck most consistently rated the same
or better than the diesel truck were coasting, braking,
smoothness of shifting under acceleration, in-cab controls,
interior noise level, and exterior noise level. Approximately twothirds of the drivers also rated the overall vehicles as “better”
than conventional diesel beverage delivery trucks.
Fuel Use in California
Truck registrations in California for 2010 indicate that
approximately 111,000 short haul/regional tractors reside in
that state and consume roughly 635 million gallons of fuel
per year. Considering an average 20% fuel economy
improvement for hybrids, this would indicate a fuel savings
of over 125 million gallons per year.