A system, apparatus and method for exhaust gas thermal management can employ a homogenous charge compression event in one or more cylinders to increase the output temperature from the cylinder to heat the exhaust gas in response to a thermal management condition associated with operation of the internal combustion engine.

Methods and systems are provided for re-combustion of exhaust in a cylinder of a multi-cylinder engine in order to increase the temperature of the exhaust for enhancing catalytic conversion within the multi-cylinder engine. In one example, a method may include expelling combusted gases from the cylinder into an intake manifold via an intake valve during an exhaust stroke, in order to rebreathe in the combusted gases from the intake manifold via the intake valve in a subsequent intake stroke.

A variety of methods and arrangements are described for determining a pilot injection mass during skip fire operation of an internal combustion engine.

A system, apparatus, and method for controlling an engine system can provide fuel reactivity compensation control for an engine of the engine system. Pilot fuel quantity supplied to the engine can be controlled using a nitrous oxide (NOx) error. Likewise, air-to-fuel ratio (AFR) for the engine can be controlled using the NOx error. Each of a pilot fuel offset and an AFR control trim can be generated using the NOx error. The pilot fuel offset and the AFR control trim can be used to control the pilot fuel quantity and the AFR, respectively.

An ECU causes an injector to implement multiple split injections during a combustion cycle and to implement a final split injection among the split injections in the latter half of the compression stroke. The ECU further sets a time interval between the injection timing for the final split injection and the ignition timing of an ignition plug at a constant time in a region in which the fuel pressure is the same. Then, the ECU sets a crank angle position based on the time interval and a rotational speed of an output shaft.

A method of operating a gaseous fuel internal combustion engine comprises performing at least one measurement relating to the combustion of a mixture of gaseous fuel and air in a combustion chamber of an associated cylinder in a combustion cycle. At least one combustion parameter, for example, a start of combustion, is determined based on the at least one measurement. When the combustion parameter differs from a desired combustion parameter, an ignition device associated with the cylinder is controlled based on the comparison in order to control the combustion in the current combustion cycle.

A variety of methods and arrangements are described for determining a pilot injection mass during skip fire operation of an internal combustion engine.

A method for controlling fuel injection aspects of a fuel system of an internal combustion engine includes determining a fuel injection strategy for each engine cycle including a pilot fuel injection, a main fuel injection, and a dwell time between the pilot and main fuel injections. The method also includes automatically adjusting the dwell time for each engine cycle based on a sensed ambient temperature and ambient pressure associated with the internal combustion engine.

Methods and systems are provided for controlling fuel injectors of an engine. In one example, a system for an engine includes a fuel injector couplable to at least one engine cylinder; and a controller operatively couplable to the fuel injector. The controller is configured to during a first engine cycle, control injection of both a primary pulse of fuel and a pilot pulse of fuel into the at least one engine cylinder via the fuel injector, determining, for the at least one engine cylinder, an amount of adjustment to the primary pulse of fuel, the pilot pulse of fuel, or both the primary and the pilot pulse, and during a second engine cycle, following the first engine cycle, adjusting an amount of the primary pulse of fuel, the pilot pulse of fuel, or both based at least in part on the first response to the pilot pulse of fuel.

A combustion mode module is configured to switch operation of a low-temperature combustion (LTC) engine between a spark ignition (SI) mode, a positive valve overlap (PVO) mode, and a negative valve overlap (NVO) mode. A spark control module is configured to control a spark plug to generate a spark in a cylinder of the LTC engine when the LTC engine is operating in the SI mode. A valve control module is configured to control intake and exhaust valves of the cylinder to yield a PVO and a NVO when the LTC engine is operating in the PVO mode and the NVO mode, respectively. An air/fuel (A/F) control module is configured to adjust a desired A/F ratio of the LTC engine to a rich A/F ratio when operation of the LTC engine is switched to the PVO mode from either one of the SI mode and the NVO mode.