34
The approach would involve identification of candidate materials from the
literature, laboratory testing, modification of materials if necessary, and finally
full-scale tests.
literature, laboratory testing, modification of materials if necessary, and finally
full-scale tests.
2.
Develop a rotary seal system that requires less downtime for inspection and
repair, either by extending the life or using sensors to indicate when
maintenance is needed rather than relying on scheduled inspections.
repair, either by extending the life or using sensors to indicate when
maintenance is needed rather than relying on scheduled inspections.
Current seal materials are not expected to hold up well under proposed increases
in engine power density. Two alternative or parallel approaches are suggested.
in engine power density. Two alternative or parallel approaches are suggested.
a.
Develop new seal designs, including the elastomer and the shaft surface, that
would last 100,000 miles in automobiles or 1 million miles in trucks.
would last 100,000 miles in automobiles or 1 million miles in trucks.
b.
Develop sensors to detect incipient failure of a seal. Initially, it would be
necessary to conduct experiments to assemble a data base of incipient failure
signs, such as noise or vibrations. The sensor systems would have to be
designed to detect these changes. If successful, this approach would allow
fleet operators to use a condition-based repair procedure rather than the less
efficient time-based inspection procedure.
necessary to conduct experiments to assemble a data base of incipient failure
signs, such as noise or vibrations. The sensor systems would have to be
designed to detect these changes. If successful, this approach would allow
fleet operators to use a condition-based repair procedure rather than the less
efficient time-based inspection procedure.
3.
Develop a bench-top test for piston-ring and cylinder-liner materials that is
predictive of full-scale behavior.
predictive of full-scale behavior.
New emission-control technologies such as EGR and alternative fuels are
expected to put new demands on piston rings and cylinder liners in terms of wear
and corrosion. Full-scale engine tests are very expensive, but current bench-top
tests do not correlate well with full-scale behavior.
expected to put new demands on piston rings and cylinder liners in terms of wear
and corrosion. Full-scale engine tests are very expensive, but current bench-top
tests do not correlate well with full-scale behavior.
The approach would first require a considerable amount of failure analysis to
identify the major failure modes and then the design of experiments to reliably
simulate those failure modes. Development of an analytical model of the failure
mechanisms would also be necessary to convert the laboratory data to full-scale
behavior with appropriate periodic validation checks.
identify the major failure modes and then the design of experiments to reliably
simulate those failure modes. Development of an analytical model of the failure
mechanisms would also be necessary to convert the laboratory data to full-scale
behavior with appropriate periodic validation checks.
4.
Develop materials and coatings for a high-pressure (2 kilobar), high-volume
fuel-injection system with a minimum life of 10
fuel-injection system with a minimum life of 10
9
cycles.
One of the important new emission-control technologies involves higher fuel-
injection pressures, which will require higher stresses and closer tolerances in the
fuel injectors. This could lead to shorter fatigue lives, along with cavitation,
wear, and corrosion. The challenge will be to find affordable, durable, low-
friction, wear-resistant coatings and affordable higher-strength materials.
injection pressures, which will require higher stresses and closer tolerances in the
fuel injectors. This could lead to shorter fatigue lives, along with cavitation,
wear, and corrosion. The challenge will be to find affordable, durable, low-
friction, wear-resistant coatings and affordable higher-strength materials.
5.
Develop premium steels that can tolerate the higher stresses and
temperatures that will be experienced by gears and bearings in the drive
train due to increases in power density. The steel should have high strength to
minimize weight, good wear resistance, and high contact-fatigue resistance.
temperatures that will be experienced by gears and bearings in the drive
train due to increases in power density. The steel should have high strength to
minimize weight, good wear resistance, and high contact-fatigue resistance.