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Carbon deposits in air compressors can build up and restrict the air delivery to vehicle brake systems. Field experience has shown that carbon deposits are excessive in some high stress applications. A study was conducted to understand the variables that affect carbon deposits, with the intent of identifying application changes that mitigate excessive build up. Oil passing in air compressors is a normal byproduct of the piston, ring and bore lubrication process. The oil in the discharge air is oxidized to form carbon deposits if there is sufficient heat. For the purposes of this study, the compressor is modeled as a chemical reactor. The formation of carbon can be minimized by diminishing both oil passing and discharge air temperature, which contribute to oxidation and deposits. Lab data demonstrates that inlet pressure and rotational speed have the largest impact on carbon, while inlet air humidity, oil composition, and coolant flow (above zero) have minimal impact.

Water-emulsified diesel fuel technology has been proven to reduce nitrogen oxides (NOx) and particulate matter (PM) simultaneously at relatively low cost compared to other pollution-reducing strategies. While the mechanisms which result in these reductions have been postulated, the development of new analytical tools to measure in-cylinder soot formation using optically accessible engines can lead to a deeper understanding of combustion and the chemical and physical mechanisms when water is present during combustion. In this study, an optically accessible single cylinder engine was used to study how water brought into the combustion chamber via an emulsified fuel changes the combustion process and thereby reduces emissions. In-cylinder measurements of relative soot concentrations were used to determine the effect of water-emulsified fuel on soot formation.

A prototype semi-active suspension system using fast, continuously variable, electrorheological (ER) shock absorbers was installed on a demonstration vehicle. The shock absorbers had no moving parts other than the piston/rod moving relative to the body of the device. Damping was obtained by controller/power supplies individually applying voltages to the four shock absorbers as determined by a modified sky-hook algorithm which included control of heave, pitch and roll body motions. The damping parameters could be adjusted for tuning ride and handling characteristics. The system was designed to respond in less than 10 ms with an average power requirement less than 40 W for normal road surfaces and handling. Data are presented that document the performance of the demonstration vehicle. Within the optimal temperature range of the system, the suspension performed as designed.

Electrorheological (ER) fluids, sometimes called “smart” fluids, are materials having flow properties that can be modified with electric field. This unique behavior is utilized in the design of a shock absorber with fast-acting electronic control. The damping force of the shock absorber is adjusted by selectively applying voltage to the ER fluid. In this paper, data are provided to illustrate that the damping forces needed for an automobile suspension are achieved using a device with realistic package size and power requirements. The data also demonstrate that the prototype shock absorber performs consistently in a durability test where the conditions are typical for life testing of commercial shock absorbers. The prototype is observed to operate successfully on a vehicle as a retrofit for an original equipment shock absorber with variable damping.

An adaptive engine mounting system is discussed that uses mounts filled with electrorheological (ER) fluid. The damping in the mounts is actively controlled based on feedback from sensors monitoring engine movement. Data are presented that demonstrate the performance of the adaptive system in controlling transient shocks superimposed on steady-state vibrations. These results were obtained using a custom-built test machine designed to simulate real-world operating conditions.