The present invention relates generally to techniques for improving fuel efficiency of a vehicle powered by an internal combustion engine capable of operating at various displacement levels. An autonomous driving unit or cruise controller selects when possible an engine torque output that corresponds to a fuel efficient displacement level. The resultant vehicle speed profile and NVH level is acceptable to vehicle occupants.

In a control apparatus for an internal combustion engine, The ignition timing in a rich-cylinder is corrected toward a retardation side from a theoretical-MBT such that the torque generated in the rich-cylinder exceeds a torque generated in the rich-cylinder at the theoretical-MBT, and the ignition timing in a lean-cylinder is corrected toward an advancement side from the theoretical-MBT such that the torque generated in the lean-cylinder exceeds a torque generated in the lean-cylinder at the theoretical-MBT, when a temperature raising process is being executed, and the ignition timing in the rich-cylinder is corrected further toward the retardation side such that the torque generated in the rich-cylinder becomes equal to or smaller than a maximum theoretical generated torque and equal to or larger than the torque generated in the lean-cylinder at the theoretical-MBT, when the temperature raising process is being executed and the engine is in a low-load operating state.

A method for extracting characterizing features from an ion current trace retrieved from spark plugs of cylinders of an internal combustion engine, comprises the steps of: i. dividing the ion current signal into crank angle subintervals; ii. calculating a measure of ion current in each crank angle subinterval; and iii. Performing a calculation on the measure of ion currents from different subintervals such that the result of the calculation is dimension free. Further it relates to a method of monitoring combustion processes where a plurality of ion current signals from a number of spark plugs (4A, 4B) are retrieved and used in combination.

A controller for an internal combustion engine includes processing circuitry. The processing circuitry performs a dither control process. The dither control process includes a first mode in which a cylinder serving as a rich combustion cylinder is sequentially changed and a second mode in which a specified cylinder is fixed as one of a rich combustion cylinder and a lean combustion cylinder. The processing circuitry selects the first mode or the second mode based on an operating point of the internal combustion engine.

A variety of methods and arrangements for improving the fuel efficiency of internal combustion engines based on skip fire operation of the engine are described. In one aspect the skip fire decisions are made on a working cycle by working cycle basis. During selected skipped working cycles, the corresponding cylinders are deactivated such that air is not pumped through the cylinder during the selected skipped working cycles. In some implementations, the cylinders are deactivated by holding associated intake and exhaust valves closed such that an air charge is not present in the working chamber during the selected skipped working cycles.

Methods, devices, estimators, controllers and algorithms are described for estimating working chamber air charge during engine operations. The described approaches and devices are well suited for use in dynamic firing level modulation controlled engines. Manifold pressure is estimated for a time corresponding to an induction event associated with a selected working cycle. The manifold pressure estimate accounts for impacts from one or more intervening potential induction events that will occur between the time that the manifold pressure is estimated and the time that the induction event associated with the selected working cycle occurs. The estimated manifold pressure is used in the estimation of the air charge for the selected working cycle. The described approach may be used to individually calculate the air charge for each induction event at any time that the engine is operating in a mode that can benefit from the individual cylinder air charge estimations.

The presently disclosed subject matter relates to an apparatus which enables a use to easily and safely disable a vehicular variable cylinder management technology system, while enabling restoration of the VCM/ECO mode under certain vehicle-related conditions or driving conditions. The presently disclosed apparatus comprises a potentiometer capable of modifying the voltage input received by the vehicle sensors.

Methods and systems are provided for adjusting noise, vibration, and harshness (NVH) limits for a vehicle based on a number of occupants in the vehicle. In one example, a method may include responsive to detecting zero occupants, reducing NVH constraints for operating the vehicle and adjusting one or more vehicle operating parameters based on the reduced NVH constraints.

Embodiments for operating an engine with skip fire are provided. In one example, a method comprises during a skip fire mode or during a skip fire mode transition, port injecting a first fuel quantity to a cylinder of an engine, the first fuel quantity based on a first, predicted air charge amount for the cylinder and lean of a desired air-fuel ratio, and direct injecting a second fuel quantity to the cylinder, the second fuel quantity based on the first fuel quantity and a second, calculated air charge amount for the cylinder.

A internal combustion engine system includes a gasoline internal combustion engine having a set of donor cylinders and a set of non-donor cylinders. The donor cylinders provide a proportion of the exhaust gas to an exhaust gas recirculation system and the remainder of the exhaust gas to an exhaust gas aftertreatment system including a particulate filter. The non-donor cylinders also provide exhaust gas to exhaust gas aftertreatment system. An engine controller can determine whether the particulate filter needs regeneration, and in response, retard a spark timing of the non-donor cylinders by an amount that is different from an amount or retardation of the donor cylinders.