A variety of methods, diagnostic modules and other arrangements for detecting air induction faults during operation of an internal combustion engine are described. In some embodiments, the intake manifold pressure is monitored with the intake pressure being read for each induction opportunity. Induction faults may be detected based at least in part on a comparison of the manifold pressure readings for sequential induction opportunities. In some embodiments, an induction fault is identified when the difference between the manifold pressure associated with an induction opportunity and the immediately preceding induction opportunity exceeds an induction fault threshold.

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.

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.

An ECU outputs an ignition signal and a discharge waveform control signal. An ignition device performs a closing operation of an ignition switching device while the ignition signal is input into the ignition device. The ignition device adjusts a current flowing through a primary coil to a discharge current command value determined based on the discharge waveform control signal, by performing an opening-closing operation of a control switching device in a period in which the discharge waveform control signal is input into the ignition device after an input of the ignition signal into the ignition device is stopped. The ECU sets the discharge current command value that is a command value for a discharge current of a spark plug to a higher value as a rotation speed is higher, and prolongs a duration, in which discharge controller controls the discharge current, as the rotation speed is lower.

Systems and methods for determining when one or more cylinders of an engine may be deactivated are presented. In one example, different cylinder deactivation strategies are used to determine which engine cylinders are deactivated during an engine cycle in response to an actual total number of valve actuator state changes being greater than a first threshold.

An ignition unit for a turbojet engine, including: an electrical power supply, a single control channel to receive a control signal from a computer, a main sparkplug ignition channel to energize at least one main sparkplug of a main combustion chamber, and an afterburner sparkplug ignition channel to energize at least one afterburner sparkplug of an afterburner chamber. The ignition unit is configured, in response to pulsed controls on the single control channel, to selectively activate the main sparkplug ignition channel or the afterburner sparkplug ignition channel.

A wheelie suppressing device comprises a wheelie determiner section which detects a wheelie state; and a wheelie suppressing section which performs a wheelie suppressing control for suppressing an engine output when the wheelie determiner section has detected the wheelie state, wherein the wheelie suppressing control includes a first suppressing control for suppressing the engine output while performing fuel feeding and an ignition operation, and a second suppressing control for suppressing the engine output by performing the fuel feeding or the ignition operation at a reduced rate.

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.

Methods and systems are described for monitoring air/fuel imbalance in cylinders of an engine. Engine speed signals are sampled and then run through a notch filter set to the sampling frequency. Based on a first frequency content of the resulting filtered engine speed, cylinder imbalance is detected and addressed.

A method for controlling an engine which comprises a combustion pressure sensor includes receiving a combustion pressure signal from the combustion pressure sensor. An Indicated mean effective pressure (IMEP) deviation for each cylinder and an IMEP deviation for each driving cycle for the engine are calculated based on a combustion pressure according to the received combustion pressure signal. A main injection timing is set based on a difference between the calculated IMEP deviations for the each cylinder and a difference between the calculated IMEP deviations for the each driving cycle. The engine runs by injecting a fuel according to the set main injection timing.