Abstract: A method is provided for control of a direct-injection engine operated with controlled auto-ignition (HCCI) during load transient operations between modes of lean combustion low load (HCCI/Lean) and stiochiometric combustion medium load (HCCI/Stoich.). The method includes 1) operating the engine at steady state, within a homogeneous charge compression-ignition (HCCI) load range, with fuel-air-exhaust gas mixtures at predetermined conditions, for each speed and load, and controlling the engine during changes of operating mode between one to another of the HCCI/Stoich. medium load mode and the HCCI/Lean lower load mode by synchronizing change rates of predetermined controlled inputs to the current engine fueling change rate.

Abstract: A direct injection controlled auto-ignition engine is operated at steady state, within a homogeneous charge compression-ignition (HCCI) load range and with fuel-air-diluent mixtures at predetermined conditions, for each speed and load, of engine control inputs, including at least injection timing (FI), spark timing (SI), throttle position, exhaust gas recirculation (EGR) valve setting and exhaust recompression obtained by negative valve overlap (NVO). During engine speed transients, the control inputs are synchronized to changes in the current engine speed, and also with any concurrent changes in the engine fueling rate. Inputs that are inactive during all or part of a speed change have a zero change rate while inactive. The method maintains robust auto-ignition combustion during speed transients with constant or variable fueling rates and with or without load changes.

Abstract: The invention provides a method for operating a multi-cylinder, spark-ignition, direct-injection, four-stroke internal-combustion engine adapted to operate in a controlled auto-ignition mode selectively operative at stoichiometry and lean of stoichiometry. The method comprises adapting an engine valve actuation system to control engine valve opening and closing, and monitoring engine operating conditions and ambient barometric pressure. The engine is operated unthrottled and the engine valve actuation system is controlled to effect a negative valve overlap period when the engine operating conditions are within predetermined ranges. A mass of fuel is injected during the negative valve overlap period. The magnitude of the negative valve overlap period is decreased with decreasing ambient pressure and increased with increasing ambient pressure.

Abstract: An internal combustion engine employs exhaust gas recompression and fuel injection during the recompression as part of an overall homogeneous charge compression ignition control. In-cylinder fuel reformation is estimated using exhaust gas burned gas fractions determined from sensed exhaust gases and models. Models include air actually consumed in in-cylinder fuel combustion and reforming processes and air required to complete in-cylinder combustion reactions of reformed fuel. Reformed fuel is calculated based on the modeled and measured exhaust gas burned gas fractions.

Abstract: Operation of a homogeneous charge compression ignition engine is adapted to fuel variations. A variable valve actuating system is employed to effect conditions conducive to homogeneous charge compression ignition operation. Nominal valve timing is selected and adjustments thereto are made based on deviations in combustion phasing from a desired combustion phasing. Fuel delivery timing and quantity are adjusted once valve timing authority limits are reached to achieve further combustion phasing improvement.

Abstract: The invention provides a method for operating a multi-cylinder, spark-ignition, direct-injection, four-stroke internal-combustion engine adapted to operate in a controlled auto-ignition mode selectively operative at stoichiometry and lean of stoichiometry. The method comprises adapting an engine valve actuation system to control engine valve opening and closing, and monitoring engine operating conditions and ambient barometric pressure. The engine is operated unthrottled and the engine valve actuation system is controlled to effect a negative valve overlap period when the engine operating conditions are within predetermined ranges. A mass of fuel is injected during the negative valve overlap period. The magnitude of the negative valve overlap period is decreased with decreasing ambient pressure and increased with increasing ambient pressure.

Abstract: A method to operate a multi-cylinder direct-injection engine in one of a controlled auto-ignition and a spark-ignition combustion mode is described. Engine operation and an operator torque request are monitored. Fuel delivery to a portion of the cylinders is selectively deactivated and torque output from non-deactivated cylinders is selectively increased to achieve the operator torque request when the monitored engine operation is above a predetermined threshold. An engine operating point at which an engine load demand exceeds an operating capability of the engine in a stoichiometric HCCI mode is identified. The engine is selectively operated in an unthrottled spark-ignition mode with at least one cylinder unfueled and torque output from the remaining cylinders is selectively increased.

Abstract: The present invention provides a valve actuation system for an internal combustion engine. The valve actuation system of the present invention may provide an increased range of auto-ignition operation by providing a valve re-opening mechanism to provide products of combustion into the cylinder to increase the thermal efficiency and stability of the auto-ignition combustion process. The present invention allows the poppet valve re-opening timing, lift and duration to be tailored to specific engine architecture and operating conditions. Additionally, the present invention provides a method of re-opening a poppet valve of an internal combustion engine.

Abstract: An HCCI engine is operated by controlling a plurality of engine operating parameters in accordance with a calibration data set representing equilibrium set-points of engine operation characterized by combustion phasing that is relatively least sensitive to cylinder charge temperature deviations.

Abstract: The present invention relates to methods for robust controlled auto-ignition and spark ignited combustion controls in gasoline direct-injection engines, including transients, using either exhaust re-breathing or a combination of exhaust re-compression and re-breathing valve strategy. These methods are capable of enabling engine operation with either lean of stoichiometric or stoichiometric air/fuel ratio for oxides of nitrogen (NOx) control, with varying exhaust gas recirculation (EGR) rates and throttle valve positions for knock control, and with a combination of homogeneous charge compression ignition (HCCI) and spark ignition (SI) combustion modes to optimize fuel economy over a wide range of engine operating conditions.

Abstract: A method and apparatus for controlling engine operation to compensate for effects of combustion chamber deposits (CCDs) on combustion in a controlled auto-ignition engine is presented. Control methodologies comprise operation of variable valve actuation, fuel injection, spark timing, and intake air and coolant temperature to dynamically compensate for the effect of CCDs. A sensitivity to core gas temperature and chamber wall thermal conditions is shown, which is correlatable to in-cylinder CCD formation. Intake charge or coolant temperature control can be used to compensate for CCD effects. An engine control scheme relies upon a parametric input that quantifies instantaneous CCD formation in the combustion chamber. The result is further applicable to control pre-ignition in a conventional spark-ignition engine.

Abstract: A four-stroke internal combustion engine is operated in controlled auto-ignition mode by any of a variety of valve control strategies conducive to controlled auto-ignition conditions in conjunction with in-cylinder fuel charges that are at either stoichiometric or lean of stoichiometric air-fuel ratios. A measure of engine NOx emission is provided and when it crosses a predetermined threshold, the in-cylinder fuel charge is transitioned from the operative one of the stoichiometric or lean of stoichiometric air-fuel ratios to the inoperative one of the stoichiometric or lean of stoichiometric air-fuel ratios.

Abstract: Operation of a homogeneous charge compression ignition engine is adapted to fuel variations. A variable valve actuating system is employed to effect conditions conducive to homogeneous charge compression ignition operation. Nominal valve timing is selected and adjustments thereto are made based on deviations in combustion phasing from a desired combustion phasing. Fuel delivery timing and quantity are adjusted once valve timing authority limits are reached to achieve further combustion phasing improvement.

Abstract: An internal combustion engine employs exhaust gas recompression and fuel injection during the recompression as part of an overall homogeneous charge compression ignition control. In-cylinder fuel reformation is estimated using exhaust gas burned gas fractions determined from sensed exhaust gases and models. Models include air actually consumed in in-cylinder fuel combustion and reforming processes and air required to complete in-cylinder combustion reactions of reformed fuel. Reformed fuel is calculated based on the modeled and measured exhaust gas burned gas fractions.

Abstract: A method and apparatus are provided to control combustion in a multi-cylinder internal combustion engine operating in a controlled auto-ignition mode with minimum combustion phasing error using a least amount of fuel reforming. This comprises monitoring combustion in each cylinder, and determining a target combustion phasing. Fuel delivery to each cylinder is selectively controlled effective to achieve the target combustion phasing, and, effective to achieve the target combustion phasing further comprises controlling the fuel delivery effective to equilibrate combustion phasing of the cylinders.

Abstract: A control system and method to dynamically determine a parametric value for combustion chamber deposits (CCD), e.g. in a controlled auto-ignition engine, including in-situ evaluation of thickness of CCD, based on a sensor which monitors combustion. It includes a temperature sensor operative to monitor the combustion chamber, and a CCD parameter that is based upon a peak combustion temperature measured at a crank angle. A CCD parameter can also be determined utilizing an in-cylinder pressure monitor, wherein a combustion chamber deposit parameter is based upon crank angle location of a peak in-cylinder pressure parameter.

Abstract: A method and apparatus for controlling engine operation to compensate for effects of combustion chamber deposits (CCDs) on combustion in a controlled auto-ignition engine is presented. Control methodologies comprise operation of variable valve actuation, fuel injection, spark timing, and intake air and coolant temperature to dynamically compensate for the effect of CCDs. A sensitivity to core gas temperature and chamber wall thermal conditions is shown, which is correlatable to in-cylinder CCD formation. Intake charge or coolant temperature control can be used to compensate for CCD effects. An engine control scheme relies upon a parametric input that quantifies instantaneous CCD formation in the combustion chamber. The result is further applicable to control pre-ignition in a conventional spark-ignition engine.

Abstract: A powertrain, and a control method therefor, are provided, wherein ignition of a combustible charge in a combustion chamber of a controlled auto-ignition internal combustion engine equipped with in-cylinder fuel-injection and a spark ignition device is controlled. The method comprises generating a spark-discharge plasma channel between the electrodes of the spark ignition device, and igniting the combustible charge. The spark-discharge plasma channel is moved toward and entrained by the combustible charge, effective to advance phasing of controlled auto-ignition combustion.

Abstract: A method to control combustion in an HCCI engine, to mitigate effects of combustion chamber deposits is detailed. The method comprises applying a specific surface coating to a combustion chamber surface. The surface coating has thermal properties substantially similar to the combustion chamber deposits. The thermal properties preferably include a) thermal conductivity, b) heat capacity, and c) thermal diffusivity. Applying a surface coating results in a reduction of combustion variability due to variation in combustion chamber deposits, and an improvement on combustion stability at low loads due to reduced heat loss. A preferred thermally insulating surface coating includes thermal parameters of a heat capacity in a range of 0.03×106 J/m3-K to 2.0×106 J/m3-K; a thermal conductivity in a range of 0.25 W/m-K to 2.5 W/m-K; and, a thermal diffusivity in a range of 1×10?7 m2/s to 8×10?6 m2/s.

Abstract: Part load operating point for a controlled auto-ignition four-stroke internal combustion engine is reduced without compromising combustion stability through a valve control operative to establish low pressure conditions within the combustion chamber into which fuel and exhaust gases are introduced. Combustion chamber pressures during the intake cycle are controlled lower as engine load decreases. Combusted gases are recirculated into the combustion chamber through a variety of internal and external recirculation mechanizations. A split-injection fuel control is implemented during low part load operation whereas a single-injection fuel control is implemented during intermediate and high part load operation. Split-injections are characterized by lean fuel/air ratios and single-injections are characterized by either lean or stoichiometric fuel/air ratios. Controlled autoignition is thereby enabled through an extended range of engine loads while maintaining acceptable combustion stability and emissions.