A method for reducing NOx emissions during operation of an internal combustion engine in commerce which, when burning hydrocarbon fuel as a primary fuel, in the absence of any secondary fuel, has a characteristic stoichiometric ration. The method includes the following: in the absence of electrolytic activity, providing and entraining a quenching species in a gaseous medium and then interacting the quenching species with constituents present during oxidation of the primary fuel in a combustion chamber of the engine.

A combustion control system for an engine mounted on an automobile is provided, which includes an ignition plug, intake and exhaust passages, an EGR passage, an EGR valve, and a control device having a processor which controls the ignition plug and the EGR valve according to an engine operating state and reduces deposit being accumulated inside a combustion chamber. The control device performs a control in which an accumulating amount of the deposit is estimated, and a control in which the deposit is removed when the estimated accumulating amount becomes more than a given setting value. In the deposit removal control, a control of the ignition plug in which a mixture gas is caused to combust by igniting the mixture gas, and a control of the EGR valve in which an amount of exhaust gas introduced into the combustion chamber is decreased, are performed.

A compression ignition gasoline engine includes a fuel injection valve for injecting fuel containing gasoline as a main component into a cylinder; an EGR device operative to perform high-temperature EGR of introducing burnt gas generated in the cylinder into the cylinder at a high temperature; an octane number determination unit for determining whether fuel injected from the fuel injection valve has a prescribed octane number; and a combustion control unit for controlling the fuel injection valve and the EGR device in such a way that HCCI combustion occurs within the cylinder. The combustion control unit controls the EGR device, in at least a partial load operating range in which HCCI combustion is performed, in such a way that the EGR rate increases, as compared with a case where fuel is determined to have a prescribed octane number, when fuel is determined not to have a prescribed octane number.

Aspects of the disclosure are directed to controller for an internal combustion engine. The controller can, in each combustion cycle that composes a change cycle, calculate an average of control amounts from a first combustion cycle to an nth (1<=n<=N) combustion cycle and calculate an error of the average with respect to an average of a reference normal population. Further, the controller can set both a positive threshold and a negative threshold based on a standard error of the reference normal population in the case where the number of data is n. Subsequently, the controller can change the operation amount to make the error approach the positive threshold or the negative threshold when the error exceeds neither the positive threshold nor the negative threshold at any combustion cycle.

The present disclosure relates to exhaust treatment systems and engine systems. In one implementation, an engine system comprises an engine comprising an intake manifold and an exhaust manifold, the engine configured to combust a fuel-air mixture received via the intake manifold and produce a flow of exhaust gases via the exhaust manifold. The engine system also comprises a turbocharger comprising a turbine, an exhaust passageway fluidly connecting the exhaust manifold of the engine to the turbine and an intake passageway fluidly connected to the intake manifold of the engine for supplying the fuel-air mixture, a catalyzed member positioned along the exhaust passageway between the engine and the turbine, and an exhaust gas recirculation (EGR) loop fluidly connected downstream of the catalyzed member and fluidly connected to the exhaust passageway and the intake passageway.

A system for reducing emissions from an internal combustion engine includes a combustion chamber having an inlet and an outlet, a fuel delivery device for delivering fuel to the combustion chamber, and a control system for controlling a fuel to oxidizer ratio in the combustion chamber. A method of reducing emissions from an internal combustion engine includes the steps of: establishing a flow of oxygen-containing gas through a combustion chamber having an inlet and an outlet; introducing flow of fuel into the combustion chamber; igniting the fuel in the combustion chamber; operating an internal combustion engine to develop a stream of exhaust gas; introducing a flow of the exhaust gas into the combustion chamber; and controlling the flow of exhaust gas and the flow of fuel to minimize oxygen levels in exhaust gases downstream of the outlet.

A method for monitoring leakage of an exhaust gas recirculation system for an engine of a vehicle includes: determining, by a controller, whether the engine is in an idle state in which the exhaust gas recirculation system is not operated; determining, by the controller, whether small flow leakage of the exhaust gas recirculation system occurs based on a predicted pressure of gas sucked into an intake manifold connected to the engine and a measured pressure of gas sucked into the intake manifold when the engine is in the idle state; and determining, by the controller, that leakage of the exhaust gas recirculation system occurs when the measured pressure is greater than the predicted pressure.

One embodiment is a system comprising an engine including a dedicated EGR cylinder configured to provide EGR to the engine via an EGR loop, a non-dedicated cylinder, a plurality of injectors structured to inject fuel into the dedicated EGR cylinder and the non-dedicated EGR cylinder, and an electronic control system operatively coupled with the fueling system and the ignition system. The electronic control system is configured to evaluate engine operating parameters including an engine load and an engine speed. The electronic control system is responsive to variation of the engine operating parameters to control operation of the fueling system to vary combustion in the at least one dedicated cylinder between rich of stoichiometric and stoichiometric.

Provided is a control device and a control method of a high-efficiency internal combustion engine capable of stabilizing combustion and suppressing NO.sub.x emissions without unnecessarily increasing a mounting load on an ECU. Therefore, the control device of the internal combustion engine for controlling the internal combustion engine includes an ignition plug that ignites an air-fuel mixture of fuel and air in the combustion chamber, a combustion pressure estimation sensor that detects a combustion pressure in the combustion chamber, and a crank angle sensor that detects a crank angle of a crankshaft. An MBT region is set based on an ignition delay period from an ignition timing of the ignition plug calculated from a detection value of the combustion pressure estimation sensor and a detection value of the crank angle sensor to a combustion start timing in the combustion chamber, and a combustion period from the combustion start timing to a set amount combustion end timing when a set amount of combustion ends. An ignition timing of the ignition plug is controlled so as to fall within the set MBT region.

A control device for a compression ignition engine is provided. At least in a high-load range where an engine load is higher than a given value, among an operating range where a partial compression ignition combustion is performed, an EGR valve is opened, and a first injection in which fuel is injected at least from an intake stroke to the first half of a compression stroke is carried out. While an engine body is operated in the high-load range, when a torque down request and a request for reducing external EGR gas amount introduced into the cylinder are issued, the opening of the EGR valve is reduced, and a second injection in which fuel is injected in the second half of the compression stroke is carried out, and a ratio of a fuel amount of the second injection to the total fuel amount injected in a combustion cycle is increased.