4 TECHNOLOGICAL AND CULTURAL BARRIERS
One should recognize that the heavy-duty (Class 7-8) truck industry is unique, and differs
from the automotive and light truck (e.g., pickup truck and SUV) industries in several important
ways: (1) It is a relatively low-volume industry, in terms of numbers of vehicles produced
compared to passenger car production, but has national implications relative to fuel usage and
emissions production; heavy-duty vehicles (including off-highway, buses, and rail) consume
more than 25% of the fuel used in the transportation sector. (2) Trucks are typically custom-
designed, with customers having the option to select the engine and in many cases the cooling
system components. (3) Reliability and durability are of the greatest importance (customers
expect extended warranties, and a future goal is a "million-mile" truck). (4) On-highway trucks
have unique service duties, including steady-state operation, high average speeds, extended idle
times, and modern convenience amenities. For these reasons, cooling system demands can be
very different from those for light trucks, yet the system designs are the same.
For many of the problems identified in the workshop, technologically feasible solutions
already exist but are not being implemented by the industry. In most cases, the reluctance is due
to concern that the potential benefits from a new technology cannot justify the added costs.
Usually there is insufficient information on both benefits and cost to make a rational decision.
Therefore, one potentially important role for DOE would be to help develop such information.
The two general approaches for developing benefits and cost information are modeling
and measurement. Modeling of benefits (fuel savings, emission reductions, fewer repairs, etc.)
requires complex computer codes that incorporate the behavior of, and interactions between, all
major components of the truck, along with air flow around them. Such comprehensive models do
not exist (although a number of elements do), and even if they did, they would be too
complicated and time-consuming for all but the largest and most sophisticated companies.
Therefore, development of simulation codes, both simple and comprehensive, is needed. This is
an area in which government laboratories have acknowledged expertise which can be brought to
Output from computer models is usually not accepted unless the models have been
validated with measured data. Generating such data is very expensive, and frequently the data are
unique to each system or manufacturer. Nevertheless, it might be possible for DOE to accumulate
a data base that could be used for generic validations. An indisputable data base would be one
obtained from detailed measurements from an instrumented truck operated over a specified drive
Generation of cost information should start with paper studies, but care must be exercised
to ensure that all elements and side effects are considered. The output from those paper studies
also should be validated from fleet data or dedicated experiments.