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An electromagnetic valve actuation (EVA) system was developed and applied to a Kohler Command Series engine. Engine development and testing was conducted for the purpose of evaluating the performance of the EVA-equipped engine, running on natural gas, in an engine-test laboratory environment. As part of this effort, a personal computer-based engine control system, which managed the fueling, ignition, throttling, and intake/exhaust valve control functions, was developed. The evaluation included an investigation into increasing engine power output and full load efficiency, as well as increased part load efficiency. Techniques including optimized valve events as a function of operating condition, and throttleless operation using early and late intake valve closing are presented. Engine simulation results are compared with actual engine data and presented in this paper.

Development of a state of the art, electronically controlled natural gas-fueled engine is detailed in this paper. The engine is a lean burn, turbochargedaftercooled engine controlled by a full authority electronic control system. This system controls fuel metering, spark timing, boost pressure, throttle position, and governing. The control system features closed-loop/adaptive-learn fuel control with feedback provided by a universal exhaust gas oxygen sensor. The development of the engine included development of the control system and other engine components, as well as a substantial amount of steady-state and transient control system calibration work. This effort led to a final engine calibration which provides good efficiency and transient response while meeting CARB ULEV emissions levels.

An emissions reduction strategy was developed and demonstrated to significantly reduce cold-start hydrocarbon (HC) and CO emissions from a spark ignition (SI), gasoline-fueled engine. This strategy involved cold-starting the engine with an ultra-fuel rich calibration, while metering near-stoichiometric fractions of air directly into the exhaust ports. Using this approach, exhaust constituents spontaneously ignited at the exhaust ports and burned into the exhaust manifold and exhaust pipe leading to the catalytic converter. The resulting exotherm accelerated catalyst heating and significantly decreased light-off time following a cold-start on the FTP-75 with a Ford Escort equipped with a 1.9L engine. Mass emissions measurements acquired during the first 70 seconds of the FTP-75 revealed total-HC and CO reductions of 68 and 50 percent, respectively, when compared to baseline measurements.