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An anti-backlash camshaft gear has been developed for the Cummins B Series 4-cylinder diesel engines. This gear reduces the gear train impact to result in lower engine noise levels and improved engine sound quality. The greatest benefit is at the low idle condition, where an engine noise reduction of about 2 dB(A) has been observed. Noise reductions throughout the engine speed and load range are also significant. The first application of this noise reduction gear is for a light duty pickup truck.

The effects of surface materials and extent of insulation on the heat transfer to the head of an open-chamber diesel were studied. A large instrumentation plug designed to incorporate plates of various materials on the gas-side surface was utilized with a special research head. Instantaneous rates of heat transfer to the plate gas-side surface were measured. Measurement results obtained with a zirconia plate and an insulated metal plate are compared to data for an uninsulated metal plate. The insulation of the metal plate increased its gas-side surface temperature over the uninsulated case by about the same amount achieved with a 6.35-mm-thick zirconia plate. The magnitude of the surface temperature swing for zirconia is not as high as expected from conduction theory, but is substantially higher than that for the uninsulated metal. Significant reductions of steady state heat fluxes were achieved with both the zirconia and the insulated metal compared to the uninsulated metal.