An object is to achieve stable diesel combustion and improvement in the thermal efficiency of the diesel combustion in an internal combustion engine using a fuel having a relatively high self-ignition temperature. A control apparatus for an internal combustion engine includes a fuel injection valve capable of injecting fuel into a combustion chamber and an ignition device whose position relative to the fuel injection valve is set in such a way that it can ignite fuel spray directly. The apparatus performs pre-injection at a predetermined pre-injection time during the compression stroke and main injection at a predetermined injection start time after pre-spray formed by the pre-injection is ignited by the ignition device, thereby causing self-ignition to occur and causing at least a portion of the main-injected fuel to burn by diffusion combustion. When the quantity of the pre-injected fuel is increased, the pre-injection time is advanced responsive to the increase in the quantity of the pre-injected fuel.

An object of the invention is to reduce the amount of smoke generated and to improve the stability of diesel combustion in cases where an EGR apparatus is used in an internal combustion engine that performs diesel combustion using fuel having a relatively high self-ignition temperature. A control apparatus performs first injection at a first injection time during the compression stroke, causes spray guide combustion to occur, and starts to perform second injection at such a second injection time that causes combustion of injected fuel to be started by flame generated by the spray guide combustion, thereby causing self-ignition and diffusion combustion of fuel to occur. The apparatus changes the ratio of the first injected fuel quantity to the total fuel injection quantity and the ratio of the second injected fuel quantity to the total fuel injection quantity for the same total fuel injection quantity in one combustion cycle, based on the EGR rate in the intake air.

A control device of an engine is provided. The engine is operated at a high compression ratio, a geometric compression ratio of the engine being 14:1 or higher. The control device includes a fuel injection controller for controlling a fuel injector of the engine to start a fuel injection in a latter half of a compression stroke within an engine operating range where an engine speed is below a predetermined value and an engine load is above a predetermined value, and an ignition controller for controlling an ignition plug of the engine to retard an ignition timing when a timing for the fuel injection controller to start the fuel injection is on a retarding side of a predetermined timing, the ignition timing being retarded based on a retarding amount of the fuel injection start timing from the predetermined timing.

An object is to improve the combustion condition in an internal combustion engine equipped with a supercharger and performing diesel combustion using fuel having a relatively high self-ignition temperature in an operation state in which the engine load is increased or decreased. A control apparatus performs first injection during the compression stroke, causes spray guide combustion to occur, and starts to perform second injection at such a second injection time that combustion of injected fuel is started by flame generated by the spray guide combustion, thereby causing self-ignition and diffusion combustion of fuel to occur. During a response delay period in changing the boost pressure when changing the engine load of the internal combustion engine to a target engine load, the ratio of the quantity of fuel injected by the first injection to the total fuel injection quantity in one combustion cycle is made higher than the ratio of the quantity of fuel injected in the first injection to the total fuel injection quantity in one combustion cycle during the time when the engine load is equal to the target engine load and the actual boost pressure is equal to a target boost pressure corresponding to the target engine load.

A split cycle internal combustion engine comprising a compression cylinder accommodating a compression piston; a combustion cylinder accommodating a combustion piston; a crossover passage between the compression cylinder and the combustion cylinder arranged to provide working fluid to the combustion cylinder; a controller arranged to determine a peak temperature of combustion in the combustion cylinder based on a received indication of a peak temperature of combustion in the combustion cylinder; and a coolant system arranged to regulate a temperature of the working fluid supplied to the combustion cylinder; wherein, in response to determining that the peak temperature of combustion exceeds a selected threshold, the controller is configured to control the coolant system to regulate the temperature of the working fluid supplied to the combustion cylinder so that a peak temperature of combustion in the combustion cylinder is less than the selected threshold.

A control device for a compression ignition engine includes a controller configured to operate an engine body by compression ignition combustion when the engine body operates in a predetermined compression ignition range. When the engine body operates in a predetermined high load range of the compression ignition range, the controller maximizes a filling amount of the cylinder using a gas state adjustment system, and lowers an EGR ratio so that the air-fuel mixture in the cylinder is lean with an excess air ratio λ higher than 1 in a lower speed range, and maximizes the filling amount of the cylinder, and increases the EGR ratio so that the air-fuel mixture in the cylinder has the excess air ratio λ of 1 or lower in a higher speed range than the lower speed range.

An engine system includes an engine, a main combustion chamber formed by a cylinder head and a piston, an auxiliary chamber formed with a communicating hole communicating with the main combustion chamber, an injector configured to inject fuel into the main combustion chamber, an ignition plug provided to the auxiliary chamber and configured to ignite a mixture gas inside the auxiliary chamber, an accelerator opening sensor, and a control device. The control device controls the injector so that an air-fuel ratio of the mixture gas inside the auxiliary chamber becomes a first air-fuel ratio when an engine load range is a first range, and the air-fuel ratio of the mixture gas inside the auxiliary chamber becomes a second air-fuel ratio leaner than the first air-fuel ratio when the engine load range is a second range where the engine load is higher than in the first range.

An internal combustion engine (1) is provided with a turbocharger (2), and is configured to be switchable between a stoichiometric combustion mode having a theoretical air-fuel ratio as a target air-fuel ratio and a lean combustion mode having a lean air-fuel ratio as a target air-fuel ratio. An air bypass valve (20) is provided in an air bypass passage (19) communicating a collector (11a) on the downstream of a throttle valve (12) with the upstream side of a compressor (2b) in an intake passage (11). At the time of the shifting from the lean combustion mode to the stoichiometric mode, the throttle valve (12) is closed and the air bypass valve (20) is temporarily opened to decrease the pressure inside the collector (11a) quickly.

In an internal combustion engine, combustion stability is improved while exhaust gas emission is suppressed. For this purpose, a control device (1) for controlling an injector (103) is configured to include a control unit (21) that controls the injector (103) to perform a first fuel injection (1001) for injecting fuel at a first fuel pressure from the injector (103) in an intake stroke (S1) in one combustion cycle of an internal combustion engine (100) and a second fuel injection (1002) for injecting fuel at a second fuel pressure higher than the first fuel pressure from the injector (103) after the first fuel injection (1001) in the same one combustion cycle in the intake stroke (S1).

A fuel injection control device for an engine is provided. A swirl generator generates a swirl flow inside a combustion chamber. A fuel injector with multiple nozzle holes injects fuel into the combustion chamber, and forms a lean mixture gas inside the combustion chamber. A spark plug ignites the lean mixture gas to cause a portion of the mixture gas to start combustion accompanied by flame propagation, and then combusts by self-ignition. The fuel injector has first and second nozzle holes, and a first atomized fuel spray injected from the first nozzle hole and a second atomized fuel spray injected from the second nozzle hole separate from each other by the swirl flow. The fuel injector performs the fuel injection in an intake stroke, and retards a start timing of the injection when an engine load is high compared to that when the load is low.