The present disclosure provides a method for adjusting the operation of an internal combustion engine comprising: determining a gradient of an overrun-air line based on an ambient condition and a current operating point; determining a value for a cylinder air mass situated in a cylinder after closure of the gas exchange valves; and using the determined cylinder air mass to adjust one or more operating parameters of the internal combustion engine. The overrun-air line may correspond to an air mass situated in the respective cylinder after closure of the gas exchange valves at predefined operating temperature for the engine, when the engine is operated briefly without fuel metering and combustion. Determining a cylinder air mass may be based at least in part on the current operating point and the current ambient value of the at least one ambient variable.

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.

The speed of a turbocharger may be estimated using data from sensors that are readily available in most engine management systems. In some cases, a pressure measurement from a MAP sensor may be used, in combination with one or more computational models, to provide an efficient, lower cost estimate of turbo speed that can be used to control operation of the engine and/or the turbocharger.

In an EGR system, a quantity of exhaust gas passing through an EGR valve is computed by an EGR valve model simulating a behavior of the recirculated exhaust gas passing through the EGR valve. An exhaust gas quantity flowing into a cylinder is computed by an EGR-gas-delay model simulating a behavior of the exhaust gas passing through the EGR valve and the throttle valve and then flows into a cylinder. The EGR-gas-delay model includes a confluent-delay model simulating a behavior of EGR gas passing thorough the EGR valve and flowing into the intake passage upstream of the throttle valve; an intake-pipe-delay model simulating a behavior of EGR gas flowing in the intake passage and passing through the throttle valve; and an intake-manifold-delay model simulating a behavior of EGR gas which passes through the throttle valve and then flows into the intake passage downstream of the throttle valve.

Provided is a cylinder intake air amount estimation apparatus for an internal combustion engine, which is capable of highly precisely calculating a cylinder intake air amount based on an AFS intake air amount in a control system for an engine including a supercharger. A cylinder intake air amount calculation part calculates the cylinder intake air amount based on an intake opening intake air amount by using a physical model of an intake system derived based on a volume efficiency acquired by considering an intake manifold as a reference, which is a volume efficiency of air entering a cylinder from the intake manifold, a virtual intake manifold volume, and a stroke volume per cylinder, the physical model being adapted to the control system for an engine including a supercharger.

An intake air mass estimation unit is provided that sets predetermined degrees of crank angle to an angle that can divide an intake stroke into a plurality of sections, measures at every the predetermined degrees of crank angle the pressure downstream of the throttle valve and the time taken for the predetermined degrees of crank angle rotation, estimates the intake air mass flowing from the upstream to downstream of the throttle valve at every the predetermined degrees of crank angle, using the pressure downstream of the throttle valve and the time taken for the predetermined degrees of crank angle rotation measured at every the predetermined degrees of crank angle, and integrates the intake air mass at every the predetermined degrees of crank angle for 720 degrees of crank angle rotation, thereby estimating the intake air mass needed for one combustion.

A control system and a control method for an internal combustion engine, which are capable of accurately calculating an in-cylinder gas amount and an EGR ratio by a relatively simple method even in a case where an in-cylinder gas temperature is changed by execution of internal EGR, and properly controlling the engine using the EGR ratio thus calculated. An in-cylinder gas amount Gact actually filled in the cylinder is calculated by correcting an ideal in-cylinder gas amount Gth, which is an amount of gases filled in a cylinder in an ideal state in which it is assumed that no exhaust gases of the engine are recirculated into the cylinder, using an ideal in-cylinder gas temperature Tcylth according to an in-cylinder gas temperature Tcyl, and an EGR ratio REGRT is calculated using the in-cylinder gas amount Gact and an intake air amount Gaircyl.

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 method for an internal combustion engine, the internal combustion engine including a valve timing control mechanism on at least an intake side and configured to control an operation of the valve timing control mechanism on the intake side during acceleration, the method including, calculating a relational expression between an intake valve timing, the intake valve timing being an operation timing of an intake valve, and a cylinder air charge amount in a range in which the intake valve timing can be advanced or retarded within a predetermined calculation cycle from a current value, calculating a target air charge amount, the target air charge amount being a target value of the cylinder air charge amount during the acceleration, based on an operating state of the internal combustion engine, calculating a target value of the intake valve timing corresponding to the target air charge amount from the relational expression for each calculation cycle, and setting a command signal for the valve timing control mechanism on the intake side based on a calculated target value of the intake valve timing.

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.