Abstract: A heavy-duty flame propagation engine has control systems and exhaust aftertreatment systems adapted to provide ultra-low emissions relative to Diesel engines while achieving comparable fuel consumption at reduced emission levels. The control systems include exhaust gas circulation, variable valve actuation, cylinder deactivation, pilot fuel injection, high energy ignition systems and combinations thereof to provide substantially stoichiometric combustion conditions over an entire load range of the engine. In one embodiment, the engine has direct in-cylinder fuel injection, is adapted for lean air-fuel mixture operation, and includes an oxidation catalyst and a lean NOx adsorber.

Abstract: A control system controls a turbo-charged trottled engine. The control system includes a throttle between the compressor and the engine, a wastegate communicated with exhaust upstream and downstream from the turbine, and a control unit for controlling the throttle and the wastegate. The control unit generates a desired air mass value per engine stroke as a function of a desired fuel flow amount and a stored compressor surge characteristic, generates a desired manifold air pressure value as a function of the desired air mass value and sensed engine parameters, and controls the throttle so that actual manifold air pressure matches the desired manifold air pressure. The control unit also generates a desired pressure boost value as a function of the desired manifold pressure value and a stored compressor surge characteristic, and controls the wastegate so that an actual boost pressure matches the desired boost pressure.

Abstract: A control system controls a turbo-charged throttled engine having intake air compressor, an exhaust turbine which receives engine exhaust. The control system includes an air throttle between the compressor and the engine, a wastegate communicated with engine exhaust upstream and downstream from the turbine, and a control unit for controlling the air throttle and the wastegate. The control unit generates a desired air mass value per engine stroke value as a function of a desired fuel flow amount and a stored a compressor surge characteristic, generates a desired manifold air pressure value as a function of the desired air mass value and sensed engine parameters, and controls the air throttle so that an actual manifold air pressure matches the desired manifold air pressure.

Abstract: A system and method of controlling an engine includes sensing a concentration of NOx in exhaust gases produced by the engine and generating a sensed NOx value representative thereof, and controlling an engine control set point as a function of the sensed NOx value. The system also calculates a NOx difference value by subtracting a base NOx value from the sensed NOx value, and if an absolute value of the difference value exceeds a threshold, modifying the set point as a function of the NOx difference value. The method also includes sensing engine RPM, sensing engine manifold absolute pressure (MAP), determining the NOx value as a function of sensed engine RPM and MAP.

Abstract: A system and method of controlling an engine includes sensing a concentration of NOx in exhaust gases produced by the engine and generating a sensed NOx value representative thereof, and controlling an engine control set point as a function of the sensed NOx value. The system also calculates a NOx difference value by subtracting a base NOx value from the sensed NOx value, and if an absolute value of the difference value exceeds a threshold, modifying the set point as a function of the NOx difference value. The method also includes sensing engine RPM, sensing engine manifold absolute pressure (MAP), determining the NOx value as a function of sensed engine RPM and MAP.

Abstract: The system for controlling the fuel/air mixture supplied to a lean burn engine when operating on natural gas, gasoline, hydrogen, alcohol, propane, butane, diesel or any other fuel as desired. As specific humidity of air supplied to the lean burn engine increases, the oxygen concentration of exhaust gas discharged by the engine for a given equivalence ratio will decrease. Closed loop fuel control systems typically attempt to maintain a constant exhaust gas oxygen concentration. Therefore, the decrease in the exhaust gas oxygen concentration resulting from increased specific humidity will often be improperly attributed to an excessive supply of fuel and the control system will incorrectly reduce the amount of fuel supplied to the engine. Also, the minimum fuel/air equivalence ratio for a lean burn engine to avoid misfiring will increase as specific humidity increases. A relative humidity sensor to allow the control system to provide a more enriched fuel/air mixture at high specific humidity levels.