An engine with a vertically oriented parallel valve and stem arrangement accommodating tumble flow to support spark-ignited fuel usage. The engine may be provided in a configuration generally suited for swirl flow, compression combustion fuel usage. However, the introduction of a unique, replaceable valve head assembly may be utilized to induce tumble flow within a combustion chamber of the engine. Thus, spark-ignited fuel may be utilized without requiring vast overhaul of the engine to accommodate such fuels. Notably, with the addition of such an assembly, diesel fuel may be replaced with natural gas on large scale equipment without the requirement of impractically burdensome or expensive measures.

The present invention relates to a control apparatus and method for an internal combustion engine including two fuel injection valves in the intake port of each cylinder. In the present invention, fuel injection from a first fuel injection valve is activated while fuel injection from a second fuel injection valve is temporarily stopped at the resumption of fuel injection from the deceleration fuel cut-off state in response to a decrease in the engine rotation speed. The amount of minimum fuel injection to each cylinder that ensures the accuracy of fuel measurement can be reduced, and fuel is injected from the first fuel injection valve in an amount equal to or greater than the amount of minimum fuel injection. Thus, fuel injection can be resumed at a lower engine speed than when fuel injection is resumed from the two fuel injection valves.

The present invention relates to a control apparatus and method for an internal combustion engine including two fuel injection valves in the intake port of each cylinder. In the present invention, fuel injection from a first fuel injection valve is activated while fuel injection from a second fuel injection valve is temporarily stopped at the resumption of fuel injection from the deceleration fuel cut-off state in response to a decrease in the engine rotation speed. The amount of minimum fuel injection to each cylinder that ensures the accuracy of fuel measurement can be reduced, and fuel is injected from the first fuel injection valve in an amount equal to or greater than the amount of minimum fuel injection. Thus, fuel injection can be resumed at a lower engine speed than when fuel injection is resumed from the two fuel injection valves.

An engine capable of reducing the content of hydrocarbon in exhaust gas is provided. When viewed parallel to cylinder center axes, tangential virtual lines extending from endpoints of curved port central axes along tangent lines of the endpoints pass intake valve ports, straight port central axes extending from the endpoints of the curved port central axes are further away from a partition wall than the tangential virtual lines, and intake air bent through curved ports passes straight ports and is sucked through the intake valve ports along the wall between the cylinders.

An engine capable of reducing the content of hydrocarbon in exhaust gas is provided. When viewed parallel to cylinder center axes, tangential virtual lines extending from endpoints of curved port central axes along tangent lines of the endpoints pass intake valve ports, straight port central axes extending from the endpoints of the curved port central axes are further away from a partition wall than the tangential virtual lines, and intake air bent through curved ports passes straight ports and is sucked through the intake valve ports along the wall between the cylinders.

One exemplary embodiment of the present disclosure relates to an engine intake port structure. According to the engine intake port structure of the exemplary embodiment of the present disclosure, a chamfer is formed to be offset to either side from an end corner of an intake port. Accordingly, the inflow of a fuel gas is concentrated on a side in which an opening width of the chamfer is wide at the beginning of an opening stage when the intake port is opened/closed by a valve unit, and after the intake port is opened, the opening width is formed to be similar at four sides of the valve unit such that swirls formed in the fuel gas is weakened. That is, complete combustion of the fuel can be anticipated since the length of time during which the fuel gas remains in a combustion chamber is extended.

An engine with a vertically oriented parallel valve and stem arrangement accommodating tumble flow to support spark-ignited fuel usage. The engine may be provided in a configuration generally suited for swirl flow, compression combustion fuel usage. However, the introduction of a unique, replaceable valve head assembly may be utilized to induce tumble flow within a combustion chamber of the engine. Thus, spark-ignited fuel may be utilized without requiring vast overhaul of the engine to accommodate such fuels. Notably, with the addition of such an assembly, diesel fuel may be replaced with natural gas on large scale equipment without the requirement of impractically burdensome or expensive measures.

An internal combustion engine includes including a fuel reformation cylinder for reforming a fuel and an output cylinder for yielding an engine power by combusting a fuel or a reformed fuel, wherein at least a part of the surfaces constituting a volume-variable reaction chamber of the fuel reformation cylinder has a highly heat-insulative material.

An internal combustion engine includes including a fuel reformation cylinder for reforming a fuel and an output cylinder for yielding an engine power by combusting a fuel or a reformed fuel, wherein at least a part of the surfaces constituting a volume-variable reaction chamber of the fuel reformation cylinder has a highly heat-insulative material.

An internal combustion engine including a fuel reformation cylinder for reforming a fuel and an output cylinder for yielding an engine power by combusting a fuel or a reformed fuel, wherein at least a part of the surfaces constituting a volume-variable reaction chamber of the fuel reformation cylinder has a highly heat-insulative material.