An internal combustion engine variable operation system includes: an intake-side variable valve mechanism for controlling an opening timing and a closing timing of an intake valve of an internal combustion engine; an exhaust-side variable valve mechanism for controlling an opening timing and a closing timing of an exhaust valve of the internal combustion engine. At a cold start of the internal combustion engine, the exhaust-side variable valve mechanism sets the opening timing of the exhaust valve advanced at or close to a midpoint between top dead center and bottom dead center, and sets the closing timing of the exhaust valve advanced at a first preset advance-side point before top dead center, and the intake-side variable valve mechanism sets the opening timing of the intake valve retarded at a first preset retard-side point after top dead center.

The invention relates to a method for operating an internal combustion engine during any driving operation and in particular during a defined testing cycle which determines compliance with regulations. The internal combustion engine has at least one exhaust gas aftertreatment device with an adjustable degree of efficiency (for example by changing the reduction agent) or an exhaust gas recirculation device or alternative variables for changing the raw engine emissions. At least one monitoring window is assigned to the active profile. The aim of the invention is to allow strict exhaust gas regulations to be met in particular during real driving operations while simultaneously allowing a low fuel consumption. This is achieved in that at least one main monitoring window of the driving profile and a sub-monitoring window (F2) with a starting point and an end point are defined within a driving profile or test cycle. During the sub-monitoring window (F2), a predictive and quantitative estimation of at least one observed emission (E) for the main monitoring window F3 is carried out before reaching the end point of another main monitoring window F3, and the estimated emission quantity is compared with a defined maximum emission quantity. In the event of a large deviation of the maximum emission quantity, at least one control parameter of the internal combustion engine or the exhaust gas aftertreatment process is adaptively modified such that the quantity of the monitored emission (E) approximates the specified target value as much as possible and the consumption of operating resources is optimized.

The invention relates to a method for operating an internal combustion engine during any driving operation and in particular during a defined testing cycle which determines compliance with regulations. The internal combustion engine has at least one exhaust gas aftertreatment device with an adjustable degree of efficiency (for example by changing the reduction agent) or an exhaust gas recirculation device or alternative variables for changing the raw engine emissions. At least one monitoring window is assigned to the active profile. The aim of the invention is to allow strict exhaust gas regulations to be met in particular during real driving operations while simultaneously allowing a low fuel consumption. This is achieved in that at least one main monitoring window of the driving profile and a sub-monitoring window (F2) with a starting point and an end point are defined within a driving profile or test cycle. During the sub-monitoring window (F2), a predictive and quantitative estimation of at least one observed emission (E) for the main monitoring window F3 is carried out before reaching the end point of another main monitoring window F3, and the estimated emission quantity is compared with a defined maximum emission quantity. In the event of a large deviation of the maximum emission quantity, at least one control parameter of the internal combustion engine or the exhaust gas aftertreatment process is adaptively modified such that the quantity of the monitored emission (E) approximates the specified target value as much as possible and the consumption of operating resources is optimized.

This engine system is provided with: an engine; an injector; a super charger (including a compressor); an electronic throttle device provided in an air intake passage, the compressor being provided in the air intake passage upstream of the electronic throttle device; an evaporated fuel treatment apparatus (including a canister, a purge passage, and a purge valve), an outlet of the purge passage being connected to the air intake passage upstream of the compressor; and an electronic control unit (ECU). The ECU controls the purge valve in order to perform a purge cut of the vapor from the purge passage toward the air intake passage when determining that the engine has started to decelerate, and thereafter controls the injector in order to perform fuel cut to the engine.

This engine system is provided with: an engine; an injector; a super charger (including a compressor); an electronic throttle device provided in an air intake passage, the compressor being provided in the air intake passage upstream of the electronic throttle device; an evaporated fuel treatment apparatus (including a canister, a purge passage, and a purge valve), an outlet of the purge passage being connected to the air intake passage upstream of the compressor; and an electronic control unit (ECU). The ECU controls the purge valve in order to perform a purge cut of the vapor from the purge passage toward the air intake passage when determining that the engine has started to decelerate, and thereafter controls the injector in order to perform fuel cut to the engine.

The present invention suppresses the worsening of stability due to a variation in EGR amounts between cylinders in a spark ignition engine. An engine control device for controlling a spark ignition engine equipped with an EGR means for recirculating exhaust gas in a combustion chamber and an air-fuel-ratio detection means for detecting the air-fuel ratio in each cylinder, the engine control device being characterized by being equipped with a means for changing the parameters for ignition control of a rich cylinder, when the air-fuel ratio of cylinders varies and there are richer cylinders and leaner cylinders relative to a prescribed air-fuel ratio during the execution of exhaust gas recirculation by the EGR means.

The present invention suppresses the worsening of stability due to a variation in EGR amounts between cylinders in a spark ignition engine. An engine control device for controlling a spark ignition engine equipped with an EGR means for recirculating exhaust gas in a combustion chamber and an air-fuel-ratio detection means for detecting the air-fuel ratio in each cylinder, the engine control device being characterized by being equipped with a means for changing the parameters for ignition control of a rich cylinder, when the air-fuel ratio of cylinders varies and there are richer cylinders and leaner cylinders relative to a prescribed air-fuel ratio during the execution of exhaust gas recirculation by the EGR means.

Provided is a device that detects a rotational speed variation amount of a multi-cylinder four-cycle engine, a rotation signal corresponding to each of the cylinders are generated once per one rotation of a crankshaft, an amount of time elapsed from a previous generation to a current generation of the rotation signal corresponding to each of the cylinders is detected as a rotation signal generation interval for each of the cylinders every time the rotation signal is newly generated, a difference between newly detected rotation signal generation interval for each of the cylinders and previously detected rotation signal generation interval for the same cylinders is calculated as a rotation signal generation interval change amount every time the rotation signal generation interval is detected, and a rotational speed variation amount of the engine is detected on the basis of the rotation signal generation interval change amount.

An internal combustion engine includes an ignition plug and an electronic control unit. The electronic control unit is configured to: (i) execute a lean-burn operation in a first operation region, (ii) execute an operation in a second operation region at an air-fuel ratio lower than an air-fuel ratio during the lean-burn operation, and (iii) control a gas flow in a cylinder so that a ratio of a change in a gas flow speed around the ignition plug during ignition to a change in an engine rotation speed in a first engine rotation speed region within the first operation region is smaller than the ratio in a second engine rotation speed region within the second operation region.

An internal combustion engine includes an ignition plug and an electronic control unit. The electronic control unit is configured to: (i) execute a lean-burn operation in a first operation region, (ii) execute an operation in a second operation region at an air-fuel ratio lower than an air-fuel ratio during the lean-burn operation, and (iii) control a gas flow in a cylinder so that a ratio of a change in a gas flow speed around the ignition plug during ignition to a change in an engine rotation speed in a first engine rotation speed region within the first operation region is smaller than the ratio in a second engine rotation speed region within the second operation region.