Abstract: An internal combustion engine includes a controllable throttle and controllable engine valves and is selectively operative in one of a plurality of combustion modes. An engine control method includes monitoring engine operation, determining a desired air flow, estimating a cylinder air charge, and estimating an intake air partial pressure. The throttle control device and engine valves are controlled based upon the intake air partial pressure and the cylinder air charge to achieve the desired air flow.

Abstract: An internal combustion engine is selectively operative in one of a plurality of combustion modes. Engine operation is monitored and program code is concurrently executed to operate the engine in a first combustion mode and in a second combustion mode. The engine is preferentially operated in the second combustion mode when the engine operation is within a predetermined area, and selectively operated in the first combustion mode based upon the monitored engine operation.

Abstract: The invention comprises a method for controlling operation of a homogeneous charge combustion ignition engine operating in an auto-ignition mode. The method comprises determining a desired combustion phasing; and, controlling a mass flowrate of externally recirculated exhaust gas based upon an actual combustion phasing. A closed-loop control scheme is executed to control the mass flowrate of externally recirculated exhaust gas based upon a difference between the actual and the desired combustion phasing.

Abstract: There is provided a method for controlling engine valves of an internal combustion engine adapted to selectively operate at one of a first open position and a second open position, including controlling engine operation during a transition from a first to a second combustion mode. The method comprises determining a desired engine airflow based upon an operator torque request. A cylinder intake volume is determined for the desired engine airflow when operating at the first open position. A control scheme is determined to control the engine valves to attain the cylinder intake volume for the desired engine airflow when operating at the second open position. The control scheme is executed and the engine valve is transitioned to the second open position when the cylinder intake volume to operate at the second open position is within a range of authority of the engine valves.

Abstract: A method to control operation of an engine during a transition from a first to a second combustion mode is provided. The engine includes a controllable throttle valve, a variable valve actuation system for controlling openings and closings of intake and exhaust valves, and, an intake and an exhaust. Mass airflow, intake manifold pressure, and cylinder volume to operate the engine in the second combustion mode and meet an operator torque request are determined. Current states for mass airflow, intake manifold pressure, and cylinder volume are determined. An opening position of the controllable throttle valve and the openings and the closings of the intake and exhaust valves are controlled during the transition to the second combustion mode based upon differences between the current states for mass airflow, intake manifold pressure, and cylinder volume, and, the mass airflow, the intake manifold pressure, and the cylinder volume.

Abstract: A method for selecting a preferred combustion mode for an internal combustion engine operative in a plurality of combustion modes is described. The method includes selecting a combustion mode in terms of first and second engine parameters, and separating the engine operating region into zones defined by the first parameter. Each of the zones is further separated into sub-zones defined by the second parameter. A combustion mode is associated with each of the sub-zones. Operating states are determined for the first and second parameters. One of the zones is identified based upon the state for the first parameter. One of the sub-zones of the identified zone is identified based upon the state for the second parameter, along with a combustion mode associated with the identified sub-zone. The engine is controlled to the preferred combustion mode, depending upon hysteresis.

Abstract: A direct injection spark ignition multi-cylinder internal combustion engine operative in a controlled auto-ignition combustion mode includes a direct fuel injection system, a spark ignition system and a controllable engine valve system. The air/fuel ratio in the exhaust gas feedstream and an intake mass air flow are measured and an actual air/fuel ratio is calculated based upon the intake mass air flow and engine fueling. Magnitude of a negative valve overlap period between an exhaust valve closing and an intake valve opening is adjusted based upon the measured mass air flow. Timing of pre-injection fueling is adjusted during the negative valve overlap period based upon the measured air/fuel ratio.

Abstract: A multi-cylinder internal combustion engine is operative in a controlled auto-ignition combustion mode. The operation includes monitoring engine operation, and globally adapting fueling for all the cylinders based upon an engine intake mass air flow and an air/fuel ratio. The fueling for each cylinder is individually adapted based upon states of a combustion parameter for all the cylinders.

Abstract: The invention comprises a method for controlling operation of a homogeneous charge combustion ignition engine operating in an auto-ignition mode. The method comprises determining a desired combustion phasing; and, controlling a mass flowrate of externally recirculated exhaust gas based upon an actual combustion phasing. A closed-loop control scheme is executed to control the mass flowrate of externally recirculated exhaust gas based upon a difference between the actual and the desired combustion phasing.

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: A model-based estimation of mass airflow is provided which provides an accurate estimation of mass airflow without introducing undesirable time delays characteristic of filtered mass airflow signals.

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 fueling mass flow rate, injection timing (FI), spark timing (SI) and exhaust recompression obtained by negative valve overlap (NVO). During load change rates below a predetermined threshold, SI, FI and NVO change rates are synchronized to current changes in the fueling mass flow rate. For fast load increases above the threshold, the cylinder charge is temporarily enriched by increasing the percentage of residual gas or reducing the percentage of fresh air mass in the charge sufficiently to maintain auto-ignition temperature during the load change. This may be done by delaying NVO action for a predetermined speed-dependent number of engine cycles.

Abstract: A method is provided for control of transition between combustion modes of a direct-injection engine operable in a homogeneous charge compression ignition (HCCI) mode at lower loads and a spark ignition flame propagation (SI) mode at higher loads. The engine includes a variable valve actuation system including two-step high and low lift valve actuation and separate cam phasing for both intake and exhaust valves. The method includes operating the engine at steady state, with fuel-air-exhaust gas mixtures at predetermined conditions, for each speed and load, and controlling the engine during mode changes between the HCCI mode and the SI mode by switching the exhaust and intake valves between low lift for HCCI operation and high lift for SI operation.

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: 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: 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: 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 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: 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.