A method of predicting a cylinder pressure of a diesel engine by a pressure predicting device may include predicting a pilot injection combustion pressure by pilot injection; predicting main combustion duration of main injection; and predicting a main injection combustion pressure after the main injection by using the pilot injection combustion pressure and the main combustion duration.

Unlike similar internal combustion engines that vary the fuel-air mixture, the Augmented Compression Engine (ACE) first and foremost sets and maintains an optimal stoichiometric fuel to air ratio, relying upon various implementations of Boyle's law to attain ignition of the stoichiometric fuel-air mixture in the combustion chamber while varying quantities of the fuel-air mixture to adjust output power.

An ACE uses fuel-air mixed prior to attainment of auto-ignition temperatures in the combustion chamber, compresses it and achieves ignition by an ignition source or use of compression heating the fuel-air to its auto-ignition temperature. Since different quantities of the fuel-air mix are needed for different loads (power outputs), to maintain reliable ignition the ACE uses one or more of: varying intake pressure; valve timing; recycled exhaust or other implementations of Boyle's law for adjusting compression such as, injected matter, modifying fuel or changing of combustion chamber volume.

A dual-fuel internal combustion engine including at least one combustion chamber. The at least one combustion chamber is paired with an inlet valve for a gas-air mixture and an injector for liquid fuel. The internal combustion engine also includes a regulating device which is designed to carry out a switchover in a switchover mode such that a quantity of energy supplied to the at least one combustion chamber by a gas-air mixture is changed, and a quantity of energy supplied to the at least one combustion chamber by the liquid fuel and/or the time of the injection of the liquid fuel is changed. The regulating device is designed to carry out the switchover on the basis of a current load of the dual-fuel internal combustion engine, wherein the regulating device is designed to select an excess air coefficient of the gas-air mixture in the switchover mode, the coefficient being larger than a target excess air coefficient in a pilot operation.

A neat-fuel direct-injected compression ignition engine having a thermal barrier coated combustion chamber, an injection port injects fuel that satisfies a stoichiometric condition with respect to the intake air, a mechanical exhaust regenerator transfers energy from exhaust gas to intake compression stages, an exhaust O.sub.2 sensor inputs to a feedback control to deliver quantified fuel, a variable valve actuation (VVA) controls valve positions, an exhaust gas temperature sensor controls exhaust feedback by closing the exhaust valve early according to the VVA, or recirculated to the chamber with an exhaust-gas-recirculation (EGR), heat exchanger, and flow path connecting an air intake, a load command input, and a computer operates the EGR from sensors to input exhaust gas according exhaust temperature signals and changes VVA timing, the load control is by chamber exhaust gas, the computer operates a fuel injector to deliver fuel independent of exhaust gas by the O.sub.2 signals.

A control device for an internal combustion engine including a fuel injection valve and an actuator includes an electronic control unit. The fuel injection valve directly injects fuel into a combustion chamber. The actuator is configured to change the oxygen concentration in intake gas supplied to the combustion chamber of the internal combustion engine. The electronic control unit is configured to control fuel injection from the fuel injection valve and the actuator.

A neat-fuel direct-injected compression ignition engine having a thermal barrier coated combustion chamber, an injection port injects fuel that satisfies a stoichiometric condition with respect to the intake air, a mechanical exhaust regenerator transfers energy from exhaust gas to intake compression stages, an exhaust O.sub.2 sensor inputs to a feedback control to deliver quantified fuel, a variable valve actuation (VVA) controls valve positions, an exhaust gas temperature sensor controls exhaust feedback by closing the exhaust valve early according to the VVA, or recirculated to the chamber with an exhaust-gas-recirculation (EGR), heat exchanger, and flow path connecting an air intake, a load command input, and a computer operates the EGR from sensors to input exhaust gas according exhaust temperature signals and changes VVA timing, the load control is by chamber exhaust gas, the computer operates a fuel injector to deliver fuel independent of exhaust gas by the O.sub.2 signals.

A method of predicting a cylinder pressure of a diesel engine by a pressure predicting device may include predicting a pilot injection combustion pressure by pilot injection; predicting main combustion duration of main injection; and predicting a main injection combustion pressure after the main injection by using the pilot injection combustion pressure and the main combustion duration.

A neat-fuel direct-injected compression ignition engine having a thermal barrier coated combustion chamber, an injection port injects fuel that satisfies a stoichiometric condition with respect to the intake air, a mechanical exhaust regenerator transfers energy from exhaust gas to intake compression stages, an exhaust O.sub.2 sensor inputs to a feedback control to deliver quantified fuel, a variable valve actuation (VVA) controls valve positions, an exhaust gas temperature sensor controls exhaust feedback by closing the exhaust valve early according to the VVA, or recirculated to the chamber with an exhaust-gas-recirculation (EGR), heat exchanger, and flow path connecting an air intake, a load command input, and a computer operates the EGR from sensors to input exhaust gas according exhaust temperature signals and changes VVA timing, the load control is by chamber exhaust gas, the computer operates a fuel injector to deliver fuel independent of exhaust gas by the O.sub.2 signals.

A method for managing temperatures in an aftertreatment system positioned downstream of an engine. The method includes (1) combusting a rich air/diesel mixture in a cylinder of the engine, and then (2) combusting a lean air/diesel mixture in the cylinder, in the next combustion event in the cylinder, after combusting the rich air/diesel mixture therein. The method further includes repeating steps (1) and (2) in the cylinder and basing a frequency thereof on a desired aftertreatment system temperature.

Systems and methods for identifying and mitigating air-fuel imbalance faults specific to an engine cylinder are provided. In one embodiment, a method comprises indicating a cylinder imbalance by comparing time-aligned readings from exhaust gas oxygen sensors, the exhaust gas oxygen sensors positioned symmetrically opposite each other within an exhaust passage downstream of a catalyst. In this way, an air-fuel imbalance fault may be accurately detected in a non-uniform exhaust flow so that mitigating actions can be taken, resulting in reduced tailpipe emissions.