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Heavy fuel engines have typically been limited to large, heavy compression ignition engines. However, with the push by the US military to use a common fuel (JP5/JP8/diesel) there is a need to develop small, lightweight, high performance engines that are also capable of operating on heavy fuel. Recent advancements in air assisted direct injection technologies have improved fuel atomization to the level necessary to overcome the poor physical properties of heavy fuel. This has permitted the operation of small two-stroke engines which retain the advantage of a lightweight design with high power output. This paper discusses the process of benchmarking a two-stroke heavy fuel spark ignited engine with an integrated air-assist direct injection system. The setup and commissioning phases of the testing are outlined, including specific techniques for quantifying scavenging, burn rate, and heat release characteristics with the objective of validating a 1-D performance simulation model.

In response to environmental and fossil fuel usage concerns, the automotive industry will gradually move from Hybrid Electric Vehicles (HEV) which includes a shift of internal combustion engines toward Zero Emissions Vehicles (ZEV). Refinement is an important aspect in the successful adoption of any new technology and ZEV brings its own NVH challenges owing to the unique dynamic characteristics of the powertrain and driveline system. This paper presents considerations for addressing dynamic driveline NVH issues that are common to 100% electric vehicles; issues that manifest themselves as groans, rattles and clunks. A dynamic torsional analytical model of the powertrain & driveline will be presented. The analytical model served as the baseline for an extensive parametric study using the Genetic Algorithm (GA) technique, whereby the effectiveness of practical countermeasures was investigated.

As engines and powertrains become quieter, sound quality becomes more important as an indicator of product quality. As a consequence, there is a heightened need to reduce gear noise. The objective of this work was to identify the source and cause of a modulated gear whine. The approach taken to identify the source of the modulation involved running a full powertrain on a spin stand and minimizing the number of meshing gear pairs until the offending pairs were identified. Further experimental testing and analysis models were employed to determine the cause of the modulation. From proximity probe measurements and backed up by the analytical model, it was determined that one of the gear mesh suffered from inadequate bearing support and off-center gear loads. This condition caused a tilt in one of the meshing gears which created a sideband that modulated with the primary meshing frequency of the transfer gear at cruise speed.