Many challenges, in addition to fuel efficiency, that the automotive industry faces also will
require technological advances related to friction, wear, and lubrication. Increasing power
density will lead to higher temperatures, which will require high-temperature coatings and
lubricants. High-power-density gears and journal bearings will require lower-friction surfaces.
Increasing durability will require wear-resistant components, control of oil quality, improved
antiwear additives, and long-drain oils. Using lightweight and advanced materials will require
new lubricants designed specifically for those materials. Reducing emissions will require clean-
burning lubricants and better oil control in the ring/liner area. Pollution control measures will
require new fluids for air-conditioning systems, biodegradable lubricants, and improved sealing.
Reducing manufacturing costs will depend upon improved metal-working lubricants.
Alternative fuels also are receiving considerable attention. Each fuel will introduce its own
unique problems related to friction and wear. For example, dimethyl ether, which produces very
low emissions and has good fuel economy for diesel engines, has much lower lubricity than do
conventional diesel fuels. Therefore, its use will probably require low-friction coatings in
critical engine parts such as fuel injectors. For vehicles powered by fuel cells, friction in the air
compressor is a serious problem that must be solved.
When faced with reducing friction and wear in spark-ignited engines, the automobile
manufacturers have very similar development needs to those of the diesel engine manufacturers:
New, preferably lightweight, materials that are compatible with alternative fuels and
higher operating temperatures and stresses.
Low-friction, wear-resistant coatings that are compatible with new lubricants and can
withstand increasingly severe operating conditions in engines and drivetrains.
Lubricants that can extend drain intervals, are biodegradable, and are compatible with
new materials and coatings.
Sensors to monitor oil quality.
Modeling capability for splash- and starved-lubrication conditions and for predicting
scuffing, wear, and seizure, including the effect of surface finish.
Bench-scale tests to reliably predict full-scale behavior and validate design
With the trend for industrial research to focus on shorter time frames and low- to medium-risk
technologies, there is a growing need for the national laboratories and universities to pursue and
evaluate emerging high-risk technologies.
Pistons, Rings, Connecting Rods, and Crankshafts
As mentioned previously, the cylinder kit and associated bearings account for the largest fraction
of energy loss due to friction in the engine. In addition, manufacturers of those components are
under considerable pressure to improve their durability because of expanding warranty periods.
Industry goals are at least million miles for heavy-duty vehicles and 150,000 to 200,000 miles
for automobiles. Thus, both wear and friction are critical issues with these manufacturers.
Furthermore, as engines become smaller, bearings become smaller, and operating stresses
increase for a given load.