The present invention discloses a two-dimensional engine, including a driving device, a two-dimensional gas compressor, a gas outlet pipe, a refueling device, a safety device, an electric ignition device, an axial-flow gas compressor, and a crank connecting rod mechanism, wherein the electric ignition device is arranged on a left side of the gas outlet pipe; the crank connecting rod mechanism is arranged below the gas outlet pipe; the driving device includes a first motor, a first gear, a first dowel bar and a first rack that is arranged on the first dowel bar; the first rack is meshed with the first gear; and the two-dimensional gas compressor includes an upper pressure plate, a first cylindrical plate, a second cylindrical plate, a fixing rod, a first pressure-bearing plate, a second pressure-bearing plate and a shell. The present invention has the beneficial effects of simple structure and relatively high energy utilization rate.

A combustion system is applied to an engine. The combustion system includes an injection device that injects a fuel into a combustion chamber, a spark plug that ignites fuel in the combustion chamber, and a control device that controls the injection device and the spark plug. The control device includes a first control unit that executes predetermined first control. In the first control, control is performed such that, a total injection amount corresponding to all the fuel injected by the injection device in one combustion cycle of the engine is injected within a first period corresponding to a period from valve close timing which brings an intake valve into a closed state until a first half of a compression stroke of the engine ends.

In a catalyst warming-up control, a first time injection is performed by an injector in an intake stroke. A second time injection is performed with an amount smaller than the first time injection in an expansion stroke after a compression top dead center. In the catalyst warming-up control, an interval from the start of the ignition period of an spark plug to the completion of the second time injection is controlled by the ECU so that the initial flame generated from an air-fuel mixture containing the fuel spray injected by the first time injection is brought into contact with the fuel spray injected by the second time injection.

In a catalyst warming-up control, a first time injection is performed by an injector in an intake stroke. A second time injection is performed with an amount smaller than the first time injection in an expansion stroke after a compression top dead center. In the catalyst warming-up control, an interval from the start of the ignition period of an spark plug to the completion of the second time injection is controlled by the ECU so that the initial flame generated from an air-fuel mixture containing the fuel spray injected by the first time injection is brought into contact with the fuel spray injected by the second time injection.

A fuel injector is configured so that, when seen from a top view of a combustion chamber, a first fuel spray flux and a second fuel spray flux sandwich an electrode part of a spark plug, and the electrode part is located outside of contour surfaces of the two fuel spray fluxes. A first injection angle between a center line of the first fuel spray flux and a vertical line and a second injection angle between a center line of the second fuel spray flux and the vertical line are larger than an angle between a center line of any other fuel spray flux and the vertical line. The second injection angle is made smaller than the first injection angle so that a distance from the electrode part to the contour surface of the second fuel spray flux is larger than a distance from the electrode part to the contour surface of the first fuel spray flux.

An upper part of FIG. 7 represents a catalyst warming-up control when a normal fuel is used, and a lower part of FIG. 7 represents the catalyst warming-up control when a heavy fuel is used. As understood from a comparison between the upper part and the lower part of FIG. 7, the start timing of the ignition period and the total injection amount of the injector in each cycle when the heavy fuel is used are the same as those when the normal fuel is used, though the ratio of the intake stroke injection and the expansion stroke injection to the total injection amount of the injector is changed to increase the fuel amount of the expansion stroke injection as compared with the case where the normal fuel is used.

An upper part of FIG. 7 represents a catalyst warming-up control when a normal fuel is used, and a lower part of FIG. 7 represents the catalyst warming-up control when a heavy fuel is used. As understood from a comparison between the upper part and the lower part of FIG. 7, the start timing of the ignition period and the total injection amount of the injector in each cycle when the heavy fuel is used are the same as those when the normal fuel is used, though the ratio of the intake stroke injection and the expansion stroke injection to the total injection amount of the injector is changed to increase the fuel amount of the expansion stroke injection as compared with the case where the normal fuel is used.

An intake stroke injection and a compression stroke injection are performed during catalyst warm-up control (upper section in FIG. 7). During the catalyst warm-up control, a discharge period at an electrode portion is set on a retard side of compression top dead center, and an expansion stroke injection is performed during the discharge period. However, when a distance between a spray contour surface and the electrode portion increases, an additional injection (first injection) is performed in advance of the expansion stroke injection (second injection) (lower section in FIG. 7). The additional injection is performed at a timing that is on the retard side of compression top dead center and is on an advance side relative to a start timing of the discharge at the electrode portion.

A control device is configured to perform, when it is estimated that a combustion fluctuation increases, estimation related to an ignition delay for initial flame generated from a discharge spark and an air-fuel mixture containing fuel spray injected by intake stroke injection. When it is estimated that the ignition delay for the initial flame is increased from that before the increase in the combustion fluctuation, an injection amount in expansion stroke injection is reduced in a next time cycle. When it is estimated that the ignition delay for the initial flame is reduced from that before the increase in the combustion fluctuation, the injection amount in expansion stroke injection is increased in a next time cycle.

A cylinder head of an engine in which a thermal stress acting between a valve seat made of clad material and a base metal is reduced. The cylinder head comprises: an inner wall surface; a pair of intake ports arranged adjacent to each other; a valve seat formed of clad material around each intake port; a mask section formed within a predetermined range of a circumference of each intake port to protrude toward a combustion chamber; and a cavity formed between a pair of the mask sections by partially depressing the inner wall surface toward the combustion chamber.