A control system for a compression-ignition engine is provided, which includes the engine, a spark plug, a fuel injection valve, an air-fuel ratio control valve, and a control unit. A geometric compression ratio of the engine is 14:1 or above. The control unit includes a processor configured to execute an air-fuel ratio controlling module for, when the engine being in a given operating state is detected, controlling the air-fuel ratio control valve to bring the air-fuel ratio of the entire mixture gas to a given lean air-fuel ratio that is larger than a stoichiometric air-fuel ratio, and an spark plug controlling module for, after this control, outputting the control signal to the spark plug to perform the ignition at a given ignition timing so that the mixture gas starts combustion by flame propagation and then unburned mixture gas self-ignites. The given ignition timing is stored in a memory.

A control system for a compression-ignition engine is provided, which includes an engine configured to combust a mixture gas inside a combustion chamber by compression ignition, a fuel injector attached to the engine, a state function adjusting part attached to the engine and configured to adjust at least introduction of fresh air into the combustion chamber, a three-way catalyst provided in an exhaust passage of the engine, a wall temperature acquiring part configured to acquire a parameter related to a temperature of a wall of the combustion chamber, and a controller. A swirl flow is generated inside the combustion chamber to circle along the wall. When the wall temperature of the combustion chamber is below a given wall temperature, the controller sets an air-fuel ratio of the mixture gas substantially to a stoichiometric air-fuel ratio so as to remain within a purification window of the three-way catalyst.

A control system for a pre-mixture compression-ignition engine is provided, configured such that in a first combustion mode, the control unit controls the fuel injection valve to have a fuel amount within a mixture gas in an outer circumferential portion of the combustion chamber larger than in the center portion, the swirl generating part to generate a swirl flow in the outer circumferential portion, and the spark plug to ignite the mixture gas in the center portion. In a second combustion mode, the control unit controls the fuel injection valve to start a fuel injection on intake stroke so that the mixture gas is formed in the entire combustion chamber, the swirl generating part so that a swirl flow becomes weaker than in the first combustion mode, and the spark plug to ignite the mixture gas before CTDC.

A lift amount variable mechanism is configured to switch a cam for driving an intake valve (drive cam) between two types of intake cams in lift amount (i.e. a large lift cam and a small lift cam). In a first embodiment of this disclosure, the lift amount variable mechanism is controlled by an ECU so that the small lift cam is selected as the drive cam for control that promotes activation of an exhaust gas cleaning catalyst (catalyst warm-up control).

A fuel injection valve capable of forming a homogeneous air-fuel mixture in homogeneous combustion at a low engine speed and a control device thereof are provided. According to the present invention, a fluid injection valve that is configured separately from a fuel injection valve and has a function of injecting a fluid is provided and a control device of the fuel injection valve includes a control unit that performs control such that fuel is injected from the fuel injection valve and then controls the fluid injection valve such that the fluid is injected from the fluid injection valve and the fuel injected from the fuel injection valve is stirred.

A control system of an engine is provided, which controls, by using a tumble flow, a behavior of fuel that is directly injected into a combustion chamber formed inside a cylinder of the engine. The control system includes a fuel injector for directly injecting the fuel into the combustion chamber, a tumble flow generator for generating the tumble flow within the combustion chamber, an ignition timing control module for controlling an ignition plug to ignite after a top dead center on compression stroke of the cylinder in a cold state of the engine, and a fuel injector control module for controlling the fuel injector to inject the fuel at an intake-stroke injection timing, a compression-stroke-early-half injection timing, and a compression-stroke-latter-half injection timing. The fuel injector control module controls the fuel injector to inject the fuel toward a vortex center of the tumble flow at the compression-stroke-early-half injection timing.

An engine control device controls a cylinder direct fuel injection type spark ignition engine provided with a fuel injection valve configured to directly inject fuel to a cylinder and an ignition plug configured to perform spark ignition for a gas mixture inside the cylinder. In a case where it is necessary to warm up an exhaust gas purifying catalyst disposed in an exhaust passage, the engine control device executes a catalyst warm-up operation in which a fuel is injected at a timing during the compression stroke, and at a timing when the fuel spray colliding with the piston crown surface moves toward the ignition plug along the shape of the piston crown surface, and in which the ignition timing is after compression top dead center. The engine control device advances the fuel injection timing in accordance with an increase in an estimation amount of a liquid fuel remaining on the top surface of the piston during execution of the catalyst warm-up operation.

A target first air amount for achieving a requested torque by an operation of an intake property variable actuator is calculated by using a first parameter. A target second air amount for achieving the requested torque by an operation of a turbocharging property variable actuator is calculated by using a second parameter. A value of a first parameter changes to a value that reduces a conversion efficiency of an air amount into torque in response to the requested torque decreasing to a first reference value or lower. Further, a value of the second parameter starts to change to a direction to reduce the conversion efficiency in response to the requested torque decreasing to a second reference value that is larger than the first reference value, or lower, and gradually changes to a direction to reduce the conversion efficiency in accordance with the requested torque further decreasing from the second reference value to the first reference value. The target air-fuel ratio is set at a first air-fuel ratio in a period in which the requested torque is larger than the first reference value, and is switched to a second air-fuel ratio which is leaner than the first air-fuel ratio in response to a decrease of the requested torque to the first reference value or lower.

Methods and systems are provided for fueling an engine of a vehicle during an exit from a deceleration fuel shut-off (DFSO) condition. In one example, a method may include fueling the engine using a compression stroke direct injection during the exit from the DFSO condition to reach a first engine torque threshold, and may further include increasing a separation between the compression stroke direct injection and a spark to gradually increase the engine torque to a second, higher engine torque threshold, and thereafter transitioning engine fueling from the compression stroke direct injection to an intake stroke direct injection. In this way, torque bumps may be reduced during DFSO exit.

A multicylinder engine includes a plurality of intake ports, a plurality of in-cylinder injectors, and an electronic control unit. The electronic control unit is configured to initially set a value of a control parameter of the multicylinder engine, individually for each of the cylinders, such that there is a common regularity between a distribution among the cylinders, of a difference of the value of the control parameter of each of the cylinders from the value of the control parameter of a reference cylinder, and a distribution among the cylinders, of a difference of the distance of a narrowed portion of each of the cylinders from the distance of the narrowed portion of a reference cylinder. The control parameter is a parameter that determines an air-fuel ratio of an air-fuel mixture around an ignition plug at a time of ignition in stratified charge combustion operation.