A combustion system is provided for an internal combustion engine including a cylinder head and a piston. In one example, a combustion system may include a cylinder head with a second cylinder surface angled relative to a first cylinder surface, an intake port coupled to the first cylinder surface, an exhaust port coupled to the second cylinder surface, and a piston with a first piston surface parallel to the first cylinder surface and a second piston surface parallel to the second cylinder surface.

An electronic control unit of an internal combustion engine is configured to control the fuel injection valve and to control a spark plug if necessary such that fuel is combusted by pre-mixture compression ignition combustion or flame propagation combustion. The electronic control unit is configured to perform homogeneous combustion in a flame ignition operation range when switching failure has not occurred, the homogeneous combustion being combustion in which fuel homogeneously diffused into the combustion chamber is ignited using the spark plug and is combusted by flame propagation combustion. The electronic control unit is configured to perform spray-guided stratified combustion in a second operation range when the switching failure has occurred, the spray-guided stratified combustion being combustion in which fuel in the fuel injection path is ignited using the spark plug and is combusted by the flame propagation combustion.

An internal combustion engine includes a combustion chamber with a cylinder head, a cylinder, and a piston. The internal combustion engine also includes at least one intake valve and at least one exhaust valve that are connected to the combustion chamber, a fuel injector that injects fuel into the combustion chamber, at least two ignition devices arranged in the combustion chamber, and control means that control the valves, the injector, and the ignition means. The control means operate the engine according to different combustion modes including a controlled ignition combustion mode, a compression ignition combustion mode, and an assisted compression ignition combustion mode. The control means activate the ignition means in the assisted compression ignition combustion mode.

A fuel property determination apparatus for an internal combustion engine is applied to an internal combustion engine that is equipped with an ignition plug and an ignition timing controller. An electronic control unit provided in the fuel property determination apparatus executes a determination process of making a determination on a property of a fuel supplied to the internal combustion engine based on an ignition sufficiency ratio, during a predetermined period after startup of the internal combustion engine. The electronic control unit is configured to determine that the property of the fuel is heavy when a determination index value that is obtained by subjecting the ignition sufficiency ratio to a smoothing process is equal to or larger than a predetermined threshold. The electronic control unit is configured to set a smoothing coefficient to a value corresponding to each of a first period, a second period, and a third period.

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 ignition apparatus for an internal combustion engine includes: a spark plug; a first ignition coil and a second ignition coil; a battery; a booster circuit that boosts a voltage supplied from the battery; a power transistor that conducts and interrupts a primary current flowing to a primary coil included in the first ignition coil; a MOSFET that applies and interrupts the voltage boosted by the booster circuit to a primary coil included in the second ignition coil; and an ECU that starts electric discharge by the spark plug by controlling the power transistor, and repeatedly applies and interrupts the voltage boosted by the booster circuit by the MOSFET so that the electric discharge that is started is maintained.

An ignition apparatus for an internal combustion engine includes: a spark plug; a first ignition coil and a second ignition coil; a battery; a booster circuit that boosts a voltage supplied from the battery; a power transistor that conducts and interrupts a primary current flowing to a primary coil included in the first ignition coil; a MOSFET that applies and interrupts the voltage boosted by the booster circuit to a primary coil included in the second ignition coil; and an ECU that starts electric discharge by the spark plug by controlling the power transistor, and repeatedly applies and interrupts the voltage boosted by the booster circuit by the MOSFET so that the electric discharge that is started is maintained.

An internal combustion engine includes a spark plug which protrudes into a combustion chamber. The spark plug has a central electrode and a ground electrode, and is configured such that a spark is generated between the central electrode and the ground electrode by electrical discharge. The spark plug has a vortex generator that separates an air flow near the ground electrode from the ground electrode and generates a vortex at a downstream side. The central electrode and the ground electrode are placed in a manner such that a spark or a flame deformed by an air flow flowing between the central electrode and the ground electrode enters the trailing vortex, or the spark penetrates through the inside of the trailing vortex.

An engine-knock controlling system for a carburetor-based engine includes one or more cylinders in which combustion occurs, wherein the system also includes a plurality of knock sensors coupled to an engine block, a first wiring harness, a first control unit, a second wiring harness, and a second control unit or an intermediate control unit, or a second control unit and intermediate control unit. The knock sensor(s) detects threatening engine-knock noise as an audible signal and transmits a signal through the wiring harnesses and control units to generate an ignition retarding action to correct the engine misfire and eliminate the knock/ping. Once the engine knock event is resolved, the processor of the first control unit transmits via the second wiring harness a signal to the second control unit or to the intermediate control unit, or to the second control unit and the intermediate control unit, to allow full-advance of ignition timing.

An internal combustion engine control apparatus includes: an ignition coil including a primary coil and a secondary coil that are magnetically coupled to each other; a first switch element for turning on and off a current to the primary coil; and a spark plug, for igniting an air-fuel mixture in an internal combustion engine by using a spark discharge caused by switching the first switch element from the ON state to the OFF state. The internal combustion engine control apparatus is configured to: determine occurrence of one of an abnormality in a discharge voltage and a misfire of the spark plug, when the calculated time duration in which a voltage of the primary coil after the switching of the first switch element from the ON state to the OFF state is above a predetermined comparison reference voltage does not fall within an allowable range.