Yanmar Power Technology Co., Inc.

Yanmar Co., Ltd.

Go Asai

Kazuhiro Yamada

Takashi Miyamoto

Hitoshi Adachi

Tomohiro Fukuda

Isao Takagawa

Hideyuki Ogawa

Gen Shibata

Kenji Yamazaki

An internal combustion engine including: an operating state detection unit that detects an operating state of the internal combustion engine; a fuel reforming unit configured to be supplied with a liquid fuel including hydrocarbon and generate a reformed fuel having an octane number larger than that of the supplied liquid fuel; a reformed fuel composition adjusting unit that adjusts the composition of the reformed fuel generated by the fuel reforming unit; and a control device that controls the composition of the reformed fuel by controlling the reformed fuel composition adjusting unit in accordance with the operating state detected by the operating state detection unit.

Internal combustion engine

An internal combustion engine including a fuel reformation unit that generates reformed fuel based on liquid fuel and higher in octane rating than the liquid fuel and introduces the generated reformed fuel to an output cylinder. The fuel reformation unit includes a first fuel reformer that includes a reciprocal mechanism where a piston reciprocates in a cylinder, a second fuel reformer that includes a reformation catalyst, and a reformed gas passage that connects the first and second fuel reformers together. First reformed gas discharged from the first fuel reformer is introduced to the second fuel reformer through the reformed gas passage.

An internal combustion engine in which a fuel reforming operation in a fuel reformation cylinder is not executed when a gas temperature of a fuel reformation chamber at a time point when a piston in the fuel reformation cylinder reaches a compression top dead point is estimated to fall short of a reforming operation allowable lower limit gas temperature set based on a lower limit value of a reforming reaction enabling temperature. For example, fuel is supplied from an injector so that an equivalence ratio in the fuel reformation chamber is less than 1. Alternatively, the fuel supply from an injector is stopped. This way, a supply of non-reformed fuel from the fuel reformation cylinder to an output cylinder can be avoided, and knocking in the output cylinder can be avoided.

Control device for internal combustion engine and control method for internal combustion engine

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 in which a fuel reforming operation in a fuel reformation cylinder is not executed and a warming operation for raising the temperature of the fuel reformation cylinder is executed, when a gas temperature of a fuel reformation chamber at a time point when a piston in the fuel reformation cylinder reaches a compression top dead point is estimated to fall short of a reforming operation allowable lower limit gas temperature. For example, EGR gas is introduced to the fuel reformation chamber without cooling the EGR gas. Further, during a predetermined period from the expansion stroke to an exhaust stroke of an output cylinder, exhaust gas warming fuel is supplied to a combustion chamber. Further, the fuel is combusted in the fuel reformation chamber.

An internal combustion engine in which when the gas temperature of a fuel reformation chamber when a piston in a fuel reformation cylinder reaches the compression top dead point is estimated to be equal to or higher than a soot generation lower limit temperature set according to an equivalence ratio of the fuel reformation chamber, a reaction gas temperature adjusting operation for suppressing or reducing an increase in the reaction gas temperature in the fuel reformation chamber is executed. Further, a closing timing of an air-intake valve is changed to reduce an effective compression ratio of the fuel reformation chamber.

A control device to be applied to an internal combustion engine having a fuel reformation cylinder and an output cylinder, wherein the compression end gas temperature of the fuel reformation cylinder is adjusted by changing an EGR gas amount, an effective compression ratio, or a polytropic number according to an equivalence ratio in the fuel reformation cylinder so as to achieve a target concentration of a specific gas component in reformed fuel generated in the fuel reformation cylinder. The target concentration is defined according to a required engine power.

An internal combustion engine in which a required reformed-fuel heat generation quantity (required output cylinder heat generation quantity) is calculated based on a required engine power and the thermal efficiency of an output cylinder. An estimated reformed fuel heat generation quantity is calculated based on the molar number of reformed fuel, mole fraction of each gas component in the reformed fuel, and heat generation quantity of each gas component in the reformed fuel. When a value resulting from subtracting the estimated reformed fuel heat generation quantity from the required reformed-fuel heat generation quantity is negative, a fuel reforming operation is not executed, assuming that there is a possibility that surplus reformed fuel may be generated. For example, a fuel supply from an injector to a fuel reformation chamber is stopped.

An internal combustion engine in which an output from a fuel reformation cylinder is obtained based on a cylinder internal pressure and a rotational speed of the fuel reformation cylinder, and an output adjusting operation for adjusting an output from an output cylinder is executed so that a sum of the output from the fuel reformation cylinder and the output from the output cylinder matches with a required engine power. In this output adjusting operation, during a transient operation in which the required engine power is increased, the output from the output cylinder is increased by increasing the fuel supply amount to a combustion chamber. Then, the fuel supply amount to a fuel reformation chamber is gradually increased while the fuel supply amount to the combustion chamber is gradually reduced, so that a heat source is shifted from the fuel to the reformed fuel.

An internal combustion engine in which when an ECU receives an engine stop command by an ON-operation of an engine stop switch, a supply of fuel from an injector to a fuel reformation chamber is stopped while a supply of fuel from an injector to a combustion chamber is continued, and the residual amount of a reformed fuel in passages is estimated, in this state. When the estimated residual amount reaches a predetermined amount or zero, the fuel supply from the injector to the combustion chamber is stopped, and an internal combustion engine is stopped.

The purpose of the present invention is to provide an engine with reforming cylinders which are fuel reforming devices capable of supplying a reformed fuel according to the outputs of outputting cylinders. The engine is provided with the outputting cylinders for burning the fuel and the reforming cylinders which are the fuel reforming devices for reforming the fuel through the reciprocating motions of pistons. The amount of reformed fuel supplied to all the outputting cylinders is changed according to the outputs of the outputting cylinders while maintaining the amount of supplied fuel and the amount of suctioned gas, which are supplied into one reforming cylinder.

Engine

An object is to provide an electronically controlled diesel engine capable of inhibiting the drastic increase of the fuel injection quantity from the fuel injection quantity before acceleration without the measurement of the relation between the number of revolutions of an engine, boost pressure, and the upper smoke limit of the fuel injection quantity. An electronically controlled diesel engine includes an judge part of an acceleration () that judges whether a control of acceleration is finished or not based on a difference between a target number of revolutions of the engine (Nset) and an actual number of revolutions of the engine (Ne). The electronically controlled diesel engine includes that the calculate part of a third upper limit of a fuel injection quantity () that is included in the calculate part of the upper limit of the fuel injection quantity () that sets an initial upper limit of a fuel injection quantity (Q) to a bigger injection quantity either of an injection quantity at the time of the judgment and a limit of a injection quantity based on the actual number of revolutions of the engine (Ne) at the time of the judgment when the judge part of an acceleration () determines that the condition of acceleration in the low speed area are satisfied and recover the limit value to the normal limit value until the judgment means of cancel of acceleration in the low speed area determines that the condition of cancel of acceleration in the low speed area are satisfied.

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Osaka, Japan

Go Asai