An intake passage includes: a main intake passage provided with a throttle valve and extending from one side toward the other side along a cylinder bank; and a bypass passage provided with an EGR valve and connected to a part of the main intake passage located toward the other side with respect to the throttle valve. The bypass passage extends from a branch of the main intake passage toward the one side and then turns back and extends toward the other side. The EGR valve is located in a part of the bypass passage extending toward the other side and overlapping with a part extending from the branch to the one side.

Methods of operation of liquid and gaseous multi-fuel compression ignition engines that may be operated on a gaseous fuel or a liquid fuel, or a combination of both a gaseous fuel and a liquid fuel at the same time and in some embodiments, in the same combustion event. Various embodiments are disclosed.

Methods of operation of liquid and gaseous multi-fuel compression ignition engines that may be operated on a gaseous fuel or a liquid fuel, or a combination of both a gaseous fuel and a liquid fuel at the same time and in some embodiments, in the same combustion event. Various embodiments are disclosed.

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.

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.

A control device for a compression-ignition engine is provided, which includes an engine having a plurality of cylinders, spark plug, a fuel injector, and a control unit connected to the spark plug and the fuel injector. The control unit causes the engine to perform an all-cylinder operation when the engine operates at a load above a given load, and perform a reduced-cylinder operation at a load below the given load. In the reduced-cylinder operation, the fuel injector injects fuel to one or some of the cylinders to generate mixture gas, the spark plug ignites the mixture gas, and the engine starts, at an air-fuel ratio larger than a stoichiometric air-fuel ratio and a large compression ratio, SI combustion in which the mixture gas is ignited to combust by flame propagation, and then perform CI combustion in which unburned mixture gas ignites by self-ignition.

A control device for a compression-ignition engine is provided, which includes an engine having a plurality of cylinders, spark plug, a fuel injector, and a control unit connected to the spark plug and the fuel injector. The control unit causes the engine to perform an all-cylinder operation when the engine operates at a load above a given load, and perform a reduced-cylinder operation at a load below the given load. In the reduced-cylinder operation, the fuel injector injects fuel to one or some of the cylinders to generate mixture gas, the spark plug ignites the mixture gas, and the engine starts, at an air-fuel ratio larger than a stoichiometric air-fuel ratio and a large compression ratio, SI combustion in which the mixture gas is ignited to combust by flame propagation, and then perform CI combustion in which unburned mixture gas ignites by self-ignition.

Fuel management system for efficient operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder of the engine. A fuel management microprocessor system controls injection of the anti-knock agent so as to control knock and minimize that amount of the anti-knock agent that is used in a drive cycle. It is preferred that the anti-knock agent is ethanol. The use of ethanol can be further minimized by injection in a non-uniform manner within a cylinder. The ethanol injection suppresses knock so that higher compression ratio and/or engine downsizing from increased turbocharging or supercharging can be used to increase the efficiency or the engine.