A control device for an on-board compression-ignition engine in which partial compression-ignition combustion including spark ignition (SI) combustion performed by combusting a portion of mixture gas inside a cylinder by spark ignition followed by compression ignition (CI) combustion performed by causing the rest of the mixture gas inside the cylinder to self-ignite is executed within at least a part of an operating range of the engine, is provided. The device includes a detector configured to detect a parameter related to noise caused by the combustion inside the cylinder, and a combustion controller configured to control the combustion inside the cylinder during the partial compression-ignition combustion based on a combustion noise index value identified by the detected parameter of the detector and a given reference value defined as an upper limit of the combustion noise index value, the reference value increasing as a vehicle speed increases.

A control system for a compression-ignition engine is provided, which includes an engine having a combustion chamber, an injector, a spark plug, a swirl valve provided to an intake passage of the engine, and a controller connected to the injector, the spark plug, and the swirl valve to control them. The controller includes a processor configured to execute a swirl adjusting module to control an opening of the swirl valve so as to make the opening of the swirl valve smaller as an engine speed decreases and output a control signal to the injector to inject the fuel after the control of the swirl valve, and a combustion controlling module to output an ignition instruction to the spark plug so as to ignite at a given ignition timing after the EGR ratio adjustment, so that partial compression-ignition combustion is performed.

A control system of a compression-ignition engine includes an intake variable mechanism and a controller. In a second operating range, the controller controls the intake variable mechanism so that, while partial compression-ignition combustion is performed under an air-fuel ratio (A/F) lean environment, an intake valve open timing takes timing at an advanced side of an exhaust TDC. In a first operating range on a lower load side, the controller controls the intake variable mechanism so that, while the partial compression-ignition combustion is performed under the A/F lean environment, under the same engine speed condition, the intake valve close timing is more retarded within a range on a retarded side of an intake BDC as the engine load decreases, and an absolute value of a change rate of the intake valve close timing to the engine load becomes larger than in the second range.

A control system of a compression-ignition engine is provided, which includes an engine configured to cause combustion of a mixture gas inside the combustion chamber, an injector attached to the engine and configured to inject fuel into the combustion chamber, a spark plug disposed to be oriented into the combustion chamber and configured to ignite the mixture gas inside the combustion chamber, and a controller connected to the injector and the spark plug and configured to operate the engine by outputting a control signal to the injector and the spark plug, respectively. After the spark plug ignites the mixture gas to start combustion, unburned mixture gas combusts by self-ignition. The controller outputs the control signal to the injector so that a fuel injection timing is advanced when the engine operates at a high speed than at a low speed.

When the geometric compression ratio of an engine body is set to 13:1 or more and the engine body operates in a preset high load region, the effective compression ratio of the engine body is set to 12:1 or more with a difference from the geometric compression ratio being within 2, a gas to be introduced into a combustion chamber is supercharged by a supercharging system, fuel is injected at least in a compression stroke by an injector, and after the fuel injection is finished, an air-fuel mixture in the combustion chamber is ignited by an ignition device before the compression top dead center and is thus burned by flame propagation in the engine body, and then the unburned air-fuel mixture is burned by compression ignition.

A control apparatus for an engine includes an engine, an EGR system, a spark plug, a controller, and a supercharging system. While a supercharging system is performing supercharging and the EGR system is introducing burned gas into a combustion chamber, in response to a control signal from the controller, the spark plug ignites air-fuel mixture at predetermined timing so that unburned air-fuel mixture combusts by autoignition after the air-fuel mixture starts to combust by the ignition.

A compression self-ignition engine performs a SI combustion in which an air-fuel mixture is combusted due to flame propagation triggered by spark ignition, and a CI combustion in which the air-fuel mixture is combusted due to self-ignition induced by the flame propagation. An ECU comprises a first control means for controlling a SI ratio serving as an index relating to a ratio of a heat amount generated in the SI combustion with respect to a total heat amount generated in the SI and CI combustions or a heat amount generated in the CI combustion; and a second control means for controlling an in-cylinder temperature before the SI combustion. The ECU is configured to change a combustion state of each of the SI and CI combustions by both the first and second control means according to the operating state of the engine.

A control apparatus for a compression autoignition engine includes an engine, a state quantity setting device, a spark plug, and a controller. After the spark plug ignites air-fuel mixture to start combustion, unburned air-fuel mixture is combusted by autoignition. The controller changes, according to an operation state of the engine, a heat amount ratio that represents an index associated with a ratio of an amount of heat generated by air-fuel mixture being combusted by flame propagation, to a total amount of heat generated by air-fuel mixture in the combustion chamber being combusted.

A control apparatus for an engine includes an engine, a state quantity setting device, a spark plug, and a controller. After the spark plug ignites air-fuel mixture to start combustion, combustion of unburned air-fuel mixture is caused by autoignition. The controller outputs a control signal to the state quantity setting device such that, when a number of revolutions of the engine is high, a temperature in a combustion chamber before start of compression is higher than that when the number of revolutions of the engine is low.

A control apparatus for a compression autoignition engine controls compression autoignition by ignition. The control apparatus includes an injector, a spark plug, and a controller. The controller controls the injector so that fuel is injected by a plurality of divided injections, and thereafter, outputs a control signal to the spark plug at predetermined ignition timing so that, by ignition, unburned air-fuel mixture combusts by autoignition. Control is performed so that, when load on the engine is high, an amount of fuel injected at later timing among the plurality of injections becomes larger than when the load is low.