Abstract: A piston for an internal combustion engine is located within a cylinder of the engine. The piston includes a dish-shaped depression in a surface of the piston exposed to a combustion chamber of the cylinder providing a recess from a nominal top of the piston. The depression includes a depression boundary located at the nominal top of the piston and proximate to an outer diameter of the piston, an apex, and inclined walls connecting the apex to the depression boundary.

Abstract: An engine is transitioned from a first combustion mode to a second combustion mode. Phase and lift of the intake and exhaust valves are sequentially adjusted corresponding to intake air cylinder volume and residual gas cylinder volume corresponding to the first and second combustion modes.

Abstract: A control system and method for operating an engine includes a spark ignited (SI) control module controlling the engine in a spark ignited mode, a pre-homogeneous charge compression (HCCI) module controlling the engine in an HCCI mode after the spark ignited mode, and an HCCI module controlling the engine in an HCCI mode after the pre-HCCI mode. The SI module controls the engine in the SI mode after the HCCI mode.

Abstract: An internal combustion engine operates in an unthrottled condition during HCCI operation while preferred combustion phasing is determined. An EGR mass flow rate is commanded to correspond with the preferred combustion phasing. The EGR valve is controlled to achieve commanded EGR mass flow rate. Position of the throttle valve is controlled to achieve commanded EGR mass flow rate when the commanded EGR mass flow rate exceeds control authority of the EGR valve.

Abstract: An internal combustion engine includes intake and exhaust camshafts including high-lift lobes and low-lift lobes separated by a lobe separation angle. The engine transitions between operating in a controlled auto-ignition combustion mode with positive valve overlap and a controlled auto-ignition combustion mode with negative valve overlap solely by selecting the corresponding one of the high-lift lobes and the low-lift lobes.

Abstract: An internal combustion engine system is equipped with a controllable engine valve actuation system. Controlling lift of an engine valve includes periodically monitoring engine valve lift and engine crank angle. A preferred engine valve lift profile is determined in a crank angle-domain. A preferred engine valve position is determined in the crank angle-domain. The preferred engine valve position is interpolated to determine a preferred engine valve position in the time-domain. The control circuit is actuated to control the engine valve in the time-domain.

Abstract: A spark-ignition direct-injection internal combustion engine is controlled at low loads through split fuel injections and spark discharges including one injection and spark during a negative valve overlap period and another injection and spark during a compression phase of the engine cycle.

Abstract: A method for controlling a multi-cylinder direct-injection internal combustion engine includes establishing an external exhaust gas recirculation valve from a present position to a target position to achieve a target exhaust gas recirculation, and synchronizing combustion initiation timing with actual exhaust gas recirculation as actual exhaust gas recirculation changes from a first exhaust gas recirculation value corresponding to the present position of the external exhaust gas recirculation valve to a second exhaust gas recirculation value corresponding to the target position of the external exhaust gas recirculation valve.

Abstract: A method for controlling combustion in a multi-cylinder spark-ignition direct-injection internal combustion engine includes determining a desired combustion phasing for maintaining acceptable combustion properties, monitoring combustion phasing of each cylinder, selecting a target combustion phasing corresponding to one of the cylinders having a most retarded combustion phasing, adjusting spark timing in each cylinder not having the most retarded combustion phasing to achieve the target combustion phasing to balance the combustion phasing in all the cylinders at the target combustion phasing, and adjusting an external EGR percentage to converge the balanced combustion phasing in all the cylinders toward the desired combustion phasing.

Abstract: A method for controlling combustion in a multi-cylinder internal combustion engine operating in a controlled auto-ignition mode includes providing combustion control parameters, determining peak cylinder pressures and crank angle location of the peak cylinder pressures. Cylinder volumes at the peak cylinder pressures and at intake valve closings are determined and cylinder pressures at intake valve closings are determined. A combustion parameter for each cylinder is calculated based upon the peak cylinder pressure, the cylinder pressure at the intake valve closing, the crank angle location of the peak cylinder pressure, the cylinder volume coincident with the peak cylinder pressure, and the cylinder volume at the intake valve closing. A target combustion parameter is determined and the calculated combustion parameter for each cylinder is compared to the target combustion parameter.

Abstract: A control system for an engine includes a feedback determination module, a feed-forward determination module, and a valve control module. The feedback determination module generates an exhaust gas recirculation (EGR) feedback value based on engine speed and a difference between desired and measured combustion phasing. The feed-forward determination module generates an EGR feed-forward value based on a difference between desired and measured mass air flow (MAF) rates. The valve control module controls an EGR valve based on the EGR feedback and feed-forward values, an intake manifold absolute pressure (MAP), an engine speed, and an exhaust back pressure (EBP).

Abstract: A control system for a homogeneous charge compression ignition (HCCI) engine includes a timing adjustment module and a combustion control module. The timing adjustment module, per combustion event, advances timings of N fuel injections and retards timings of M fuel injections and spark during a transition from HCCI combustion to mixed-mode combustion. The combustion control module subsequently retards the timings of the N fuel injections and advances the timings of the M fuel injections and the spark to desired timings, respectively, wherein the N fuel injections and the M fuel injections occur sequentially during each combustion event of the HCCI engine, and wherein N and M are integers greater than or equal to zero.

Abstract: A method for operating an internal combustion engine includes determining an actual combustion heat release during ongoing engine operation, calculating an expected combustion heat release corresponding to engine operation associated with the actual combustion heat release during ongoing engine operation, determining a difference between the actual combustion heat release and the expected combustion heat release, and operating the internal combustion engine in a homogeneous-charge compression-ignition combustion mode to achieve a preferred combustion phasing during each combustion cycle in response to the difference between the actual combustion heat release and the expected combustion heat release.

Abstract: A combustion mode transition control for controlling a transition between a homogeneous-charge compression-ignition (HCCI) combustion mode and a spark-ignition (SI) combustion mode includes slowly transitioning intake and exhaust camshafts from initial phase settings corresponding to one of the HCCI and SI combustion modes to target phase settings corresponding to the other of the HCCI and SI combustion modes. An ignition spark timing and an injected fuel mass are coordinated with the transitioning of the intake and exhaust camshaft phase settings to substantially maintain engine load continuity during the transitioning of the intake and exhaust camshaft phase settings.

Abstract: A direct-injection internal combustion engine is fluidly coupled to a passive SCR system including a three-way catalytic converter upstream to an ammonia-selective catalytic reduction catalyst. Transition from an HCCI combustion mode to an SI combustion mode includes determining a preferred air/fuel ratio to achieve a minimum fuel consumption and maintain combustion stability at an acceptable level for a predetermined engine operating point during the SI combustion mode. A fuel injection timing, an engine spark timing and an engine valve lift are substantially immediately controlled from respective HCCI combustion mode settings to respective SI combustion mode settings. A transition to the preferred air/fuel ratio is coordinated with a transition of an engine valve phase from a respective HCCI combustion mode setting to a respective SI combustion mode phase setting.

Abstract: A direct-injection internal combustion engine includes an intake camshaft with a low-lift intake cam and a high-lift intake cam, a variable lift control for selectively operating an intake valve in one of a low-lift intake valve profile with the low-lift intake cam and a high-lift intake valve profile with the high-lift intake cam, a variable cam phase control operative on the intake camshaft for simultaneously controlling the phase of the low-lift intake cam and the high-lift intake cam, an ignition spark control, a fuel injection control, an exhaust gas recirculation control, and an intake throttle control.

Abstract: An internal combustion engine is configured to operate in a homogeneous-charge compression-ignition combustion mode. Operating the internal combustion engine includes determining an integrated thermal state parameter from an aggregation of engine environment factors. A feed-forward engine control scheme is executed to determine states for engine control parameters. The states for the engine control parameters correspond to a preferred combustion phasing responsive to an operator torque request and the integrated thermal state parameter. Operation of the internal combustion engine is controlled to achieve the preferred combustion phasing using the states for the engine control parameters.

Abstract: An internal combustion engine system is equipped with a controllable engine valve actuation system. Controlling lift of an engine valve includes periodically monitoring engine valve lift and engine crank angle. A preferred engine valve lift profile is determined in a crank angle-domain. A preferred engine valve position is determined in the crank angle-domain. The preferred engine valve position is interpolated to determine a preferred engine valve position in the time-domain. The control circuit is actuated to control the engine valve in the time-domain.

Abstract: An engine is transitioned from a first combustion mode to a second combustion mode. Phase and lift of the intake and exhaust valves are sequentially adjusted corresponding to intake air cylinder volume and residual gas cylinder volume corresponding to the first and second combustion modes.

Abstract: A control system for an engine comprises an air per cylinder (APC) generating module that generates measured and desired APC values. A combustion transition module selectively transitions the engine from spark ignition (SI) combustion to homogeneous charge compression ignition (HCCI) combustion and from HCCI combustion to SI combustion. A spark control module selectively retards spark during the transitions based on a ratio of the measured APC value and the desired APC value. Alternately, spark retard can be based on measured and desired engine torque representing values (ETRVs).