Transmission shocks and idling defects such as engine racing and rough idling due to aging of a throttle opening area are prevented from occurring. An internal combustion engine control apparatus for controlling an internal combustion engine that has an air flow rate sensor for measuring a rate of air represented as an actual air rate, the air flowing into a cylinder, and a throttle valve for adjusting the rate of air, includes a throttle valve controlling section for controlling a throttle opening of the throttle valve to reach a preset throttle opening set depending on a target air rate for realizing a demand torque, and a throttle opening correcting section for correcting the preset throttle opening on the basis of the target air rate upon fuel cutoff that stops a fuel from being supplied to the internal combustion engine and of an actual air rate measured by the air flow rate sensor.

Various methods and systems are provided for controlling emissions. In one example, a controller is configured to respond to a sensed exhaust oxygen concentration by changing a fuel injection timing to maintain particulate matter (PM) within a range, and then adjusting an exhaust gas recirculation (EGR) amount based on NOx sensor output and based on the change in fuel injection timing.

The invention relates to a method for determining the pressure P.sub.avcm upstream of a mechanical compressor (3) equipped with a double supercharging circuit of a combustion engine. The pressure P.sub.avcm is determined by a dynamic model based on a law of conservation of flow rate in the volume upstream of the mechanical compressor. The model links the pressure P.sub.avcm upstream of the mechanical compressor (3) to a temperature T.sub.avcm upstream of the mechanical compressor (3), to a boost pressure P.sub.sural and boost temperature T.sub.sural on the intake side of the engine, and to an openness Bypass of the bypass valve (4).

Systems, methods and apparatus for controlling operation of dual fuel engines are disclosed that regulate the fuelling amounts provided by a first fuel and a second fuel during operation of the engine. The first fuel can be a liquid fuel and the second fuel can be a gaseous fuel. The fuelling amounts are controlled to improve operational outcomes of the duel fuel engine.

Methods and systems are provided for operating a fuel system configured to deliver a gaseous fuel to an engine. While the engine is shutdown, diagnostic routines may be performed to identify fuel system leaks or breaches. When the engine is subsequently restarted, fuel rail pre-priming is adjusted based on the presence of fuel system leaks.

Methods and systems are presented for diagnosing operation of passive grade vent valves of a fuel system. The methods and systems include adjusting a position of a vehicle so that fuel in a fuel tank may cause a first grade vent valve to open and a second grade vent valve to close.

An injection control device includes: an instruction output unit outputting an instruction energization time that is an instruction value of an energization time of a fuel injection valve corresponding to a target injection amount; an energization controller controlling energization of the fuel injection valve based on the instruction energization time; an area corrector correcting an area of an electric current flowing through the fuel injection valve when the fuel injection valve is driven by the electric current, calculating a correction time of the energization time, and correcting the instruction energization time; an abnormality determiner determining that an abnormality related to the area correction has occurred when the correction time reaches a predetermined upper limit value; and a normal-return determiner executing, after the abnormality determiner determines that the abnormality related to the area correction has occurred, a normal-return determination at an execution timing of when a degree of influence of the abnormality on an emission becomes equal to or less than a predetermined value, for determining whether or not an abnormal state in which the abnormality related to the area correction has been caused has returned to a normal state.

On the basis of absolute values α and β of variations, before and after actuation of an exhaust brake, of fuel-injection and intake-air amounts, respectively, an exhaust brake is determined to normally operate when the absolute values α and β of the variations of the fuel-injection and intake-air amounts are not less than fuel-injection and intake-air variation thresholds, respectively; the exhaust brake is determined to have failure when the absolute values α and β of the variations of the fuel-injection and intake-air amounts are less than the fuel-injection and intake-air variation thresholds, respectively.

A pre-overheat system for minimizing engine damage due to overheating includes a temperature sensor and a warning system that alerts the vehicle's operator (using light, sound, vibration, etc.) if temperatures exceed steady-state temperatures and/or reach higher pre-overheat temperatures. Steady-state temperatures are measurable when the vehicle is functioning normally (especially its cooling system) and is running in normal environmental conditions, but is lower than a redzone overheat temperature for the particular vehicle. When the redzone overheat temperature is reached, the vehicle has gotten too hot and is likely to sustain irreparable damage. The operator can reduce or prevent damage to the vehicle by taking corrective action (such as stopping and checking coolant level and clearing debris from clogged vents and screens) before the vehicle is overheated. A shutdown mechanism can shut off the vehicle before the redzone overheat temperatures are reached.

Methods and systems are provided for reducing hot fuel vapor formation in a port injection fuel rail. In one example, a method may include operating a dual fuel injection system with at least a calibrated minimum amount of port fuel injection over a wide range of engine operating conditions, even as conditions change. A direct fuel injection amount is adjusted in accordance.