A method of predicting manifold air pressure in an internal combustion engine during idle comprising the steps of receiving an idle air control (IAC) duty cycle value from an idle air controller, receiving an atmospheric pressure, and predicting a manifold pressure in an engine control unit based on the IAC duty cycle value and the atmospheric pressure.

A target compression ratio ε(t+Tact) after a prescribed time Tact has expired from a current point of time is calculated from an intake air volume drawn into a cylinder after expiration of the prescribed time Tact from the current point of time. A control command to an electric motor that drives a variable compression ratio mechanism is calculated so as to bring an actual compression ratio εr(t+Tact) after the prescribed time Tact into accordance with the target compression ratio ε(t+Tact) after the prescribed time Tact. This enables the actual compression ratio to follow the target compression ratio accurately.

A learned neural network learned in weights using an engine load, an engine speed, and an intake pressure inside the engine intake passage downstream of the throttle valve (19) as input parameters of the neural network and using leakage of blow-by gas from a blow-by gas feed path (20) as a truth label is stored. At the time of operation of the vehicle, the learned neural network is used to detect the abnormality of leakage of blow-by gas from the blow-by gas feed path (20) from the above input parameters.

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).

A system and method for controlling an exhaust gas recirculation (EGR) system in a hybrid vehicle using an intrusive monitor include adjusting EGR flow through an EGR valve based on an average pressure difference between pressure measured from a manifold absolute pressure (MAP) sensor and inferred pressure determined from mass air flow (MAF) into an intake of an engine when engine speed, throttle and camshaft timing position change is below a corresponding threshold. The measured pressure and inferred pressure are determined when the EGR valve is in a closed position and an open position.

An engine system incorporating an engine, one or more sensors, and a controller. The controller may be connected to the one or more sensors and the engine. The one or more sensors may be configured to sense one or more parameters related to operation of the engine. The controller may incorporate an air-path state estimator configured to estimate one or more air-path state parameters in the engine based on values of one or more parameters sensed by the sensors. The controller may have an on-line and an off-line portion, where the on-line portion may incorporate the air-path state estimator and the off-line portion may configure and/or calibrate a model for the air-path state estimator.

A control device for an internal-combustion engine includes circuitry. The circuitry is configured to calculate, in accordance with an operating state of the internal-combustion engine, a basic supercharging pressure of intake gas generated by a supercharger provided in the internal-combustion engine. The circuitry is configured to acquire a flow rate change state parameter that correlates with a change state of the flow rate of the intake gas controlled by a flow rate control mechanism provided in the internal-combustion engine. The circuitry is configured to calculate a correction value in accordance with the flow rate change state parameter. The circuitry is configured to calculate an estimated supercharging pressure of the intake gas by correcting the basic supercharging pressure with the correction value. The circuitry is configured to control operation of the internal-combustion engine using the estimated supercharging pressure.

A system and method for improving the functioning of a turbocharged diesel engine equipped with a cylinder deactivation system includes detecting when the turbocharged diesel engine is at risk of compressor surge, and then delaying the implementation of the cylinder deactivation. The delay may be a set period of time, or it may be determined by performing a set of instructions effective for estimating changes in intake manifold pressures over time if cylinders are deactivated, and then comparing the intake manifold pressure estimates to acceptable intake manifold pressure information. A formula for performing the required estimates is provided.

Methods and systems are provided for determining an offset of a manifold pressure sensor. In one example, an engine method may include indicating degradation of the manifold pressure sensor based on a sensor offset, the sensor offset based on a manifold pressure measured at a first throttle angle, a barometric pressure at a second throttle angle, a reference manifold pressure at the first throttle angle and reference barometric pressure, and the reference barometric pressure. Further, the method may include adjusting an output of the manifold pressure sensor by the determined sensor offset.

An in-cylinder pressure sensor detecting in-cylinder pressure is provided. A first crank angle and a second crank angle in the adiabatic compression stroke are set using an in-cylinder-pressure-maximum crank angle as a baseline, and an absolute pressure correction value is calculated using the in-cylinder pressure and in-cylinder volume at each of these crank angles. A crank angle advanced from the in-cylinder-pressure-maximum crank angle is set as the second crank angle in a manner so as to be a timing in the adiabatic compression stroke on the retard side with respect to the spark timing, and is used for the absolute pressure correction.