A method of controlling a concentration of hydrocarbons in exhaust gas from an internal combustion engine includes sensing an oxygen percentage of the flow of exhaust gas from the internal combustion engine and determining a concentration of hydrocarbons in the flow of exhaust gas. An engine control module may then adjust the sensed oxygen percentage of the exhaust gas based on the determined concentration of hydrocarbons in the flow of exhaust gas to define a corrected oxygen percentage. The control module may then control at least one of a hydrocarbon injection rate for in-cylinder combustion of the internal combustion engine, and a hydrocarbon injection rate for a post combustion exhaust gas treatment process, based on the corrected oxygen percentage, to control the concentration of hydrocarbons in the exhaust gas.

A method of operating a gas or dual fuel engine having a plurality of cylinders, includes monitoring a characteristic of each of the plurality of cylinders during operation of the gas or dual fuel engine. The method also includes detecting a pre-ignition condition associated with one or more cylinders of the plurality of cylinders based on the monitored characteristic. The method further includes reducing fuel supply to the one or more cylinders having the pre-ignition condition. The fuel supply to remaining cylinders of the plurality of cylinders is increased, to maintain a constant power output of the gas or dual fuel engine. The method further includes adjusting an amount of air supplied to each of the plurality of cylinders based on the increased amount of fuel supplied to the remaining cylinders, to maintain an air-to-fuel ratio within a desired range.

A control apparatus for an internal combustion engine according to the invention is applied to an internal combustion engine that is equipped with an exhaust gas treatment device that is provided in an exhaust passage, and a burner device that is provided in the exhaust passage upstream of the exhaust gas treatment device so as to raise a temperature of exhaust gas supplied to the exhaust gas treatment device. The control apparatus performs an increase control for increasing a concentration of oxygen in exhaust gas supplied to the burner device if the concentration of oxygen is not higher than a predetermined required concentration of oxygen when there is a request to operate the burner device. The combustion performance of the burner device is stably ensured by securing or compensating for an insufficient concentration of oxygen.

A method of controlling a concentration of hydrocarbons in exhaust gas from an internal combustion engine includes sensing an oxygen percentage of the flow of exhaust gas from the internal combustion engine and determining a concentration of hydrocarbons in the flow of exhaust gas. An engine control module may then adjust the sensed oxygen percentage of the exhaust gas based on the determined concentration of hydrocarbons in the flow of exhaust gas to define a corrected oxygen percentage. The control module may then control at least one of a hydrocarbon injection rate for in-cylinder combustion of the internal combustion engine, and a hydrocarbon injection rate for a post combustion exhaust gas treatment process, based on the corrected oxygen percentage, to control the concentration of hydrocarbons in the exhaust gas.

It is an object of the present invention to improve estimation accuracy of an air excess ratio within a fuel spray and quickly cause the air excess ratio to approximate to a target value when the engine load factor rises. An internal combustion engine control apparatus includes a parameter acquiring section to acquire an air intake parameter and a fuel parameter, a first estimation section to estimate an in-fuel-spray air excess ratio using the air intake parameter and fuel parameter, and a pressure calculation section to calculate, if the in-fuel-spray air excess ratio is less than a target in-fuel-spray air excess ratio, a necessary fuel injection pressure to match the in-fuel-spray air excess ratio with the target in-fuel-spray air excess ratio, in which if the necessary fuel injection pressure is equal to or less than a maximum injection pressure, fuel injection is to be performed at the necessary fuel injection pressure.