JPS61250376A - Compression-ignition type internal combustion engine - Google Patents

Abstract

PURPOSE:To obtain an efficient heating function for fuel and air, by constituting a hot spot, provided in a predetermined position in a combustion chamber for injected fuel to pass through, of a heat generating unit, which is electrically heated, and a heat generated unit of large thermal capacity brought into contact with the heat generating unit. CONSTITUTION:A cylindrical member 7, mounted by a thread to a cylinder head, mounts a heat generated bottom end of the member 7 inserted into a combustion chamber, and this hot spot 2, comprising the heat generated unit 8 and a heat generating unit 9 arranged along the internal peripheral surface of the heat generated unit 8, screws the point end part of a fuel injection valve 1 to be fitted to an upper end part of the cylindrical member 7. The heat generated unit 8, consisting of ceramics of alumina or the like with a large thermal capacity further with excellence in insulation resistance, etc., forms space communicating with internal space of the cylindrical member 7 while a hole 8a communicating with inside the combustion chamber 3. While the heat generating unit 9, consisting of an electric resistance material, is arranged along the internal peripheral surface of the heat generated unit 8, and the heat generating unit 9 is coated on the upper with an insulating protective layer 11.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a compression ignition internal combustion engine.

(Prior Art) As a compression ignition internal combustion engine, a diesel engine or a broiled engine is conventionally known. The former compresses the inhaled air to high temperature and pressure, injects fuel near top dead center, and performs combustion through spontaneous ignition. The latter has a broiled ball inside the combustion chamber, which is preheated from outside the combustion chamber with a heavy oil burner to aid in ignition.

In the above-mentioned conventional diesel engine, since it uses a spontaneous ignition system, the temperature of the air compressed in the cylinder must reach the ignition temperature of the fuel, so the compression ratio is high, and the maximum combustion chamber pressure is equal to that of a gasoline engine. It's about double that.

As a result, the structure of the engine needs to be made stronger, the maximum rotational speed of the engine is limited, and problems such as a decrease in specific output and engine vibration and noise arise.

Furthermore, the above-mentioned hot-pot engine is currently used only in small ships, its heating mechanism is primitive, and its efficiency is currently significantly inferior to that of internal combustion engines.

In order to overcome these drawbacks, Japanese Patent Application Laid-Open No. 58-352
An internal combustion engine as shown in Publication No. 72 has been proposed, and in the internal combustion engine shown in this publication, fuel is vaporized by a hot spot, and the air around the hot spot is heated by the heat generating part of the hot spot. Since the compression action and the heating action promote the temperature increase of the air-fuel mixture, spontaneous ignition can be achieved at a compression ratio lower than that of conventional compression ratios, and the various problems associated with diesel engines described above can be improved.

(Problems to be Solved by the Invention) However, the heat generated by the heating element in the hot spot portion shown in the above publication and the heated body heated by the heating element do not sufficiently contribute to heating the fuel and air, making it ineffective. The problem was that it was not functioning.

Therefore, in view of the above problems, an object of the present invention is to provide a highly efficient compression ignition internal combustion engine equipped with a hot spot 7) having an efficient heating function for fuel and air.

(Means for Solving the Problems) In order to solve the above-mentioned problems, in the present invention, the liquid fuel injected from the injection valve of the compression ignition internal combustion engine is placed at a predetermined position in the combustion chamber through which the liquid fuel is heated. In the compression ignition internal combustion engine, the hot spot has a heating element that is electrically heated and a heating element having a large heat capacity that contacts the heating element, and the hot spot has a hot spot that is controlled. The hot spot is mounted with a suppressing means for suppressing the heat of the hot spot from being transmitted to the compression ignition internal combustion engine, and the injected fuel is directly directed to the heat generating part and the heat generating body. This is a compression ignition internal combustion engine characterized by being configured so as to be in contact with the engine.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is an overall configuration diagram showing the configuration of this embodiment. In this figure, fuel is injected from an injection valve 1 by an injection pump 4 near the end of the compression stroke of the engine. At this time, the injected fuel hits a hot spot 2 provided at the tip of the injection valve 1, is heated and vaporized by the hot spot 2, and flows into the combustion chamber 3. A heating element provided at the hot spot 2 generates heat in response to electricity, and power is supplied to this heating element from a power source 6 via a current control circuit 5.

FIG. 2(a) is a cross-sectional view showing the structure of the tip of the injection valve 1 and the hot spot 2 in FIG.
A hollow cylindrical member 7, which is a mounting member for mounting and fixing the injection valve 1 to the engine, is screwed into this male threaded portion 1a.

That is, a female threaded portion 7a is formed on the inner periphery of one end of the cylindrical member 7. A flat threaded portion 7b for fixing to the engine is formed on a part of the outer periphery of the cylindrical member 7, and a heated body 8 of the hot spot 2 is formed on the inner periphery of the other end of the cylindrical member 7. A female screw portion 7C to be screwed is formed.

The hot spot 2 is composed of the heating element 8 and the heating element 9. The heating element 8 is made of alumina (A IgO) which has a large heat capacity and is excellent in insulation resistance, high temperature strength, thermal shock resistance, etc. or silicon nitride (Si3N*
), etc., and a space communicating with the internal space of the cylindrical member 7 and a combustion chamber 3 as shown in FIG. 2(b).
A hole 8a communicating inside is formed. Furthermore, a male threaded part 8b is formed at the end of the heated body 8, and is screwed into the female threaded part 7C of the cylindrical member 7, and a heat insulating material 10 such as asbestos is interposed at the part where both 7 and 8 are joined. has been done.

The heating element 9 is made of an electrical resistor made of platinum, nickel, nickel-chromium alloy, tungsten, etc., and is arranged along the inner peripheral surface of the heating element 8.
An insulating protective layer 11 is coated thereon. And an electrical resistor forming the heating element 9 and an insulating protective layer 11
is wired and coated along the inner circumferential surface of the heating element 8 before sintering, and is sintered and molded as one piece.

Note that a lead wire 12 for supplying power from the power source 6 to the heating element 9 is provided inside the cylindrical member 7, and is connected to a conductor wiring 13 formed on the inner peripheral surface of the cylindrical member 7. Power is supplied to the heating element 9 via the conductor wiring I3. The electric power supplied by the current control circuit 5 is then controlled.

The wiring pattern of the electric resistor of the heating element 9 may be wired in series as shown in FIG. Therefore, it is preferable to wire in parallel as shown in (B) and (C) of the same figure.If wired in parallel like this, 1
The heat generating function can be maintained even if the wire is broken in some places.

In the compression ignition internal combustion engine equipped with the above-described injection valve 1 and hot spot 2, when high-pressure fuel is injected from the injection valve 1 near the end of the compression stroke, the injected fuel first reaches the inner wall portion of the hot spot 2. The heat generating part of the hot spot 2 (heating element 9
．． It will float around the heated body 8). On the other hand, the air around hot spot 2 is already at a sufficiently high temperature due to the temperature rise due to adiabatic compression and further heating by the heat generating part of hot spot 2, and the air is already at a sufficiently high temperature that it is mixed with the vaporized fuel. A high-temperature gas mixture is formed, and combustion proceeds sequentially from the region where ignition conditions are met.

At this time, the high temperature of the compressed air required for spontaneous ignition is obtained by the heating action of the hot spot 2 and the adiabatic compression action, so the compression ratio can be lowered compared to a conventional diesel engine that relies only on adiabatic compression. is possible. As a result, the maximum combustion pressure is lower, requirements for strength and rigidity are relaxed, resulting in a lightweight structure, environmental problems such as engine noise and vibration are alleviated, and from a performance standpoint, high-speed operation is possible.
It is also advantageous in terms of ignition delay.

Furthermore, as mentioned above, the hot spot 2 of this embodiment can be externally controlled to a desired temperature, so it can be used with fuels having various ignition temperatures, and can also be controlled depending on the operating conditions such as engine speed. It is also possible to improve efficiency by varying the temperature accordingly. For example, at the time of starting, the injected fuel is ignited by increasing the power supplied to the heating element 9 and controlling the heating element 9 to a high temperature, and after starting, the injected fuel is ignited by the heated element that has become high temperature due to combustion heat. to reduce the power supplied to the heating element 9. As a result, the amount of power supplied to the heating element 9 can be saved, and the internal combustion engine can be operated efficiently and with good starting and non-starting conditions.

Further, since the heat insulating material 10 is provided at the joint between the cylindrical member 7 and the hot spot 2, the heat at the hot spot 2 is not transmitted to the cylindrical member 7 and to the internal combustion engine via the cylindrical member 7. The heat of the hot spot 2 is suppressed and efficiently contributes to the heating of the fuel and air, thus making it possible to reduce the power supplied to the heating element 9.

Furthermore, by arranging the wiring patterns of the electric resistors forming the heating element 9 in parallel, it is possible to ensure electricity supply even if a part of the wiring is disconnected, so that the heating function of the heating element 9 can be maintained. Improves reliability.

Furthermore, the heated element 8 of the hot spot 2 is made of a ceramic material and can be molded integrally with the electric resistor forming the heating element 9, so that it can be manufactured easily.

Next, another embodiment of the present invention will be described using FIG. 4.

The configuration of this embodiment is substantially the same as the configuration of the previous embodiment, and the same parts are denoted by the same reference numerals and the explanation thereof will be omitted.

In the embodiment described above, the heated body 8 of the hot spot 2 was screwed into the cylindrical member 7 to connect the two, but in this embodiment, a concave groove is formed at the end of the heated body 8,
The tip of the cylindrical member 7 is fitted into this concave groove portion via the heat insulating material 1, and a plurality of bottles 14 are provided that penetrate through both at this fitting portion, thereby making the cylindrical member 7 a hot spot. 2 are definitely connected. Note that a heat insulating material is also provided between the pin 14 and the heat generating element 8.

By doing so, the shape of the connecting portion between the two becomes extremely simple, making manufacturing even easier.

Further, in each of the above embodiments, the cylindrical member 7 and the heated body 8
However, if this heat insulating material 11 is eliminated and the cylindrical member 7 is made of a material with low thermal conductivity, the heat from the hot spot 2 will be difficult to escape to the engine side. Therefore, the same effects as in each of the above embodiments can be obtained.

Further, in each of the above embodiments, an example is shown in which the present invention is applied to a direct injection type internal combustion engine, but the present invention may also be applied to a preheating chamber of a preheating chamber type internal combustion engine.

(Effects of the Invention) As described above, according to the present invention, the compression ignition internal combustion engine has a hot spot whose temperature is controlled at a predetermined position in the combustion chamber through which liquid fuel injected from the injection valve of a compression ignition internal combustion engine passes. In the ignition type internal combustion engine, the hot spot has a heating element that is electrically heated and a heating element having a large heat capacity in contact with the heating element, and the hot spot is installed in the compression ignition type internal combustion engine in part. A suppressing means for suppressing heat from the hot spot from being transmitted to the compression ignition internal combustion engine is interposed, and the injected fuel is configured to directly contact the heat generating element and the heated body. Since it is a compression ignition internal combustion engine, the transfer of heat from hot spots to the internal combustion engine is suppressed, so the heat from hot spots efficiently contributes to heating the fuel and air. The power supplied to the heating element can be sufficiently reduced, and the heat in the hot spot is efficiently transferred to the fuel and air, and the injected fuel comes into direct contact with the heating element and the heated element, so the fuel and air are sufficient. As a result, the internal combustion engine can lower the compression ratio without losing efficiency, reducing noise and vibration, enabling high-speed circuits, and improving the phenomenon of ignition delay. In addition, it is possible to use various fuels with different ignition temperatures, and lean combustion is also possible, which has the effect of reducing harmful exhaust gas emissions.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing the configuration of an embodiment of the present invention, FIG. 2(a) is a configuration diagram showing the configuration of the hot spot in FIG. 1 and members in its vicinity, and FIG. 2(b) is shown in Figure 2 (
A-A sectional view of a), Figure 3 (A), (B),
(C) is the wiring pattern of the electric resistor forming the heating element, the fourth
The figure is a configuration diagram showing the configuration of a hot spot and members in its vicinity in another embodiment of the present invention. 1...Injection valve, 2...Hot spot, 3...Combustion chamber. 4... Injection pump, 5... Current control circuit, 6...
power supply. 7... Cylindrical member, 8... Heated element, 9... Heating element, 10... Heat insulator, 11... Insulating protective layer.

Claims (3)

[Claims] (1) In a compression ignition internal combustion engine that has a hot spot whose temperature is controlled at a predetermined position in a combustion chamber through which liquid fuel injected from an injection valve passes, the hot spot is electrically heated. The hot spot is attached to the compression ignition internal combustion engine, and the heat from the hot spot is transferred to the compression ignition internal combustion engine side. 1. A compression ignition internal combustion engine, characterized in that a suppressing means for suppressing transmission is interposed so that the injected fuel directly contacts the heating element and the heated element. (2) In the compression ignition internal combustion engine according to claim 1, the heating element electrically heated at the hot spot is composed of a plurality of electrical resistors connected in parallel. Compression ignition internal combustion engine. (3) In the compression ignition internal combustion engine according to claim 1, the heating element of the hot spot is made of a ceramic material, and an electric resistor forming the heating element is placed on a surface that is in contact with the injected fuel. A compression ignition internal combustion engine characterized by being arranged and integrally sintered and molded.