A variable displacement controller for deactivating one or more cylinder assemblies of a vehicle engine can include a processor for performing various operations and the operations can include: receiving data indicative of a requested torque and vehicle speed, determining a torque variable timer threshold value based on the received data indicative of requested torque and vehicle speed, initiating a timer, comparing the timer value to the variable timer threshold value, and selectively activating/deactivating at least one of the engine cylinder assemblies based on the comparison between the timer value and the variable timer threshold value. At least one of the engine cylinder assemblies is activated if the timer value is less than the variable timer threshold value, and at least one of the engine cylinder assemblies is deactivated if the timer value is greater than or equal to the variable timer threshold value.

A method is disclosed for detecting a malfunction of an oxygen sensor in the exhaust gas system of an internal combustion engine having several cylinders. The cylinders are operated at the same air-fuel ratio and the resultant first output signal of the oxygen sensor is monitored. The cylinders are operated at varying air-fuel ratios and the resultant second output signal of the oxygen sensor is monitored. The first and second output signals are compared to determine whether the oxygen sensor has malfunctioned.

Various methods and systems are provided for skipping fire in one or more cylinders in a dual fuel engine. In one example, a method may include injecting a combination of two fuels to a first set of cylinders of the engine while disabling fuel injection to all remaining cylinders of the engine.

A method of controlling fuel injection to the cylinders of an internal combustion engine, the engine having exhaust gas recirculation (EGR) from at least one dedicated EGR (D-EGR) cylinder, with the other cylinders being main cylinders. The D-EGR cylinder is run at a richer equivalence ratio than the main cylinders, with the goal of providing increased H2 and CO in the recirculated exhaust. The rich limit of the D-EGR cylinder is maximized by dividing the fuel injection into multiple fuel injection events, with each fuel injection event occurring during the intake valve lift period of the engine cycle.

Methods and systems are provided for controlling a vehicle engine to reduce engine knock and increase fuel efficiency by reducing hydrocarbon breakthrough. In one example, a method may include adjusting a compression ratio of a variable compression engine in response to hydrocarbon breakthrough above a threshold from a fuel vapor canister of an evaporative emissions system.

Provided is a signal processing device capable of effectively reducing a work load of a parameter setting operator in response to an increase in parameters constituting complicated filter control. Therefore, in the signal processing device filters an output signal from a sensor mounted on a vehicle, setting is made with respect to a plurality of filters having different filter types or filter coefficients for setting a filter characteristic of a cutoff frequency or a pass band, an individual code is set for each of the plurality of filters, and the signal processing device includes a CPU that selects the individual code based on an engine operating state so that a corresponding filter is selected, and processes an output signal from the sensor using the filter that has been selected.

When the air fuel ratio dither control is carried out, an air fuel ratio of a mixture in each of one or more lean cylinders and one or more rich cylinders is controlled in a feedback manner based on an average value of a detected value of an air fuel ratio sensor, so that an average value of an air fuel ratio of exhaust gas flowing into the three-way catalyst becomes a predetermined target exhaust gas air fuel ratio. At this time, the air fuel ratio dither control is carried out, by setting at least a cylinder with the highest gas impingement intensity in a cylinder group of an internal combustion engine as the one or more lean cylinders.

When the air fuel ratio dither control is carried out, an air fuel ratio of a mixture in each of one or more lean cylinders and one or more rich cylinders is controlled so that an average value of an air fuel ratio of exhaust gas flowing into the three-way catalyst becomes a predetermined target exhaust gas air fuel ratio. At this time, the air fuel ratio dither control is carried out by setting, as the one or more rich cylinders, at least a cylinder for which a degree of uniformity of the flow speed distribution of exhaust gas, which is a degree of uniformity of the flow speed distribution of exhaust gas discharged from that cylinder on a cross section of the three-way catalyst, is the lowest in the cylinder group of an internal combustion engine.

An object of the present invention is to provide a technology that enables an abnormal combustion detection apparatus for a spark ignition internal combustion engine having a plurality of cylinders to detect abnormal combustion such as pre-ignition and knocking with improved accuracy. To achieve the object, according to the present invention, in an abnormal combustion detection apparatus for a spark-ignition internal combustion engine that determines or detects the occurrence of abnormal combustion by comparing a vibration intensity obtained from a measurement signal of a knock sensor and a determination threshold, when the occurrence of abnormal combustion is detected, the apparatus corrects a determination threshold for the next cylinder using as parameters the peak value of the vibration intensity at the time of the occurrence of abnormal combustion and the engine speed.

For exhaust gas recirculation (EGR) fueling control, at least one donor cylinder of a plurality of cylinders in an engine provides exhaust gas to an air intake for the plurality of cylinders. A fuel variable restriction initially provides fuel concurrent with an intake stroke for the at least one donor cylinder in response to a transition from withholding the fuel to the plurality of cylinders.