JPH0240075A - Fuel injection system for engine - Google Patents

Abstract

PURPOSE:To make improvements in restartability by installing a refrigerant passage in a position proximate to a fuel injection valve, while winding a thermoelectric cooling element, emitting heat of the fuel injection valve to the refrigerant passage as long as the specified period after engine stoppage, on this fuel injection valve. CONSTITUTION:A fuel injection valve 8 with a pressure air feeding means 7 is attached to an immediate housing 5, while a refrigerant passage in which oil is passed through as a refrigerant is installed in a position proximate to the fuel injection valve 8. In addition, a thermoelectric cooling element 10 is rolled on a tip nozzle part of the fuel injection valve 8. When the tip nozzle part of the fuel injection valve 8 comes to receive heat from a heated engine after engine stoppage as well as when an electric current is made to flow from an N side terminal 105 to a P side terminal 106, heat of the nozzle part is absorbed by a metallic piece 103 in the inner part of the element 10 owing to a Peltier effect, thereby cooling the nozzle part. Consequently, such a possibility that fuel left over in a fuel passage 81 of the tip nozzle part might be evaporated as receiving the engine heat is thus prevented from occurring. In this connection, heat in the metallic piece 103 is emitted to the refrigerant passage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a fuel injection device for an engine, in which a fuel injection valve is attached to the housing of the engine and injects fuel directly into a combustion chamber.

[Conventional technology]

BACKGROUND ART Conventionally, it has been known that a method of directly injecting fuel into a combustion chamber is effective in improving fuel efficiency and emission performance.

Therefore, as shown in Japanese Patent Application Laid-open No. 54-69607, for example, a fuel injection valve for an engine is provided in which a fuel injection valve is attached to the casing (housing) of the engine, and fuel is injected directly into the combustion chamber from this fuel injection valve. A device has been developed.

Recently, in order to further improve fuel efficiency and emission performance, a low-pressure fuel injection valve is used as a fuel injection valve attached to the casing, and the fuel is injected from this fuel injection valve into pressurized air (assist air). A system has been developed in which the fuel is atomized and the mixture is injected into the combustion chamber as a mixture of fuel and air.

[Problems to be Solved by the Invention] In the fuel injection device in which the fuel injection valve is attached to the casing of the engine, the tip nozzle portion of the fuel injection valve is passed from outside the casing into the casing, and the injection valve provided at the tip is inserted into the casing. The tip nozzle part of the fuel injection valve must be made long in order to make the nozzle part face the spray hole formed in the wall of the combustion chamber. As described above, in the above fuel injection device, the fuel injection valve is attached to the casing of the engine, and the tip nozzle portion of the fuel injection valve is elongated, so that the fuel injection valve easily receives heat from the engine. For this reason, the above-mentioned fuel injection device has the following problem after the engine is stopped.

In other words, while the engine is running, fuel is injected from the fuel injection valve one after another, so there is no problem even if the fuel injection valve receives heat from the engine, but if the engine is stopped afterwards, , the fuel is no longer injected from the fuel injection valve, and the fuel remaining in the fuel passage at the nozzle at the tip of the fuel injection valve receives heat from the engine and evaporates, and the fuel that becomes steam is supplied into the combustion chamber. A situation occurred in which the combustion chamber was filled with fuel that had turned into steam.

For this reason, there is a problem in that it becomes difficult to start the engine during warm restart.

In view of the above circumstances, it is an object of the present invention to provide a fuel injection device for an engine that can improve restartability.

[Means to solve the problem]

The fuel injection device for an engine according to the present invention is a fuel injection device for an engine in which a fuel injection valve is attached to a housing of the engine. The fuel injection valve is wrapped with a thermoelectric cooling element that releases the heat of the fuel injection valve into the refrigerant passage for a predetermined period of time after the engine is stopped.

[Operation] According to the above configuration, even if the fuel injection valve starts receiving heat from the engine after the engine has stopped, the heat received from the engine is absorbed by the thermal cooling element, and the absorbed heat is transferred to the refrigerant passage. This means that it can be released.

(Example) Figs. 1 to 3 show a small two-cylinder low-crisis 1-engine equipped with an embodiment of the fuel injection device according to the present invention. In these figures, 1.2 indicates the adjacent A pair of matching cylinders (Freon 1 to cylinder and rear cylinder),
A rotor housing 11.21, each having a trochoidal inner circumferential surface, a side housing 12.22 disposed on the side thereof, and a top portion supported by an eccentric shaft 3.4 and having an inner circumferential surface of the rotor housing 11.21. It is provided with a substantially triangular rotor 13.23 that rotates planetarily while contacting the surface of the rotor 13. An ink mezzo eight housing 5 is interposed between the pair of cylinders 1 and 2.
and rotor housing 11.21 and side housing 12
．． 22 constitute a casing (housing) 6. Three working chambers 14.24 are formed for each cylinder between the casing 6 and each flank of the rotor 13.23. As the rotor 13.23 rotates, suction, compression, explosion, and exhaust strokes are performed in sequence.

In addition, the casing 6 includes an intake port 15 that takes air into the working chamber 14.24, an exhaust boat 16 that exhausts air from the working chamber 14.24, and an ignition port for the air-fuel mixture in the working chambers 14, 24. The spark plug 17.18 that performs
They are arranged in a manner known in general rotary piston engines.

A fuel injection valve 8 with a pressurized air supply means 7 is attached to the intermediate housing 5, and
A refrigerant passage 9 through which oil passes as a refrigerant is a fuel injection valve 8
It is located close to the

The fuel injection valve 8 has a main body that protrudes outside the casing G,
The tip nozzle portion is inserted into the inlet media 1-housing 5. The tip nozzle portion of the fuel injection valve 8 has a double pipe structure having a fuel passage 81 on the inside and an air passage 82 on the outside, and has an injection portion facing the spray hole 51 formed in the intermezoate housing 5. 83 at the tip.

As shown in detail in FIG. 4, the injection part 83 has an air injection hole 84 formed through the outer tube wall and a fuel injection hole 85 formed through the inner tube wall.

The air nozzle hole 84 is always open, and the fuel nozzle hole 85 is closed to the valve body 86.
It is designed to be opened and closed by. This valve body 86 is urged to close the fuel injection hole 85 by the spring force of a coil spring 87 when fuel is not injected from the fuel injection valve 8 . However, when fuel starts to be injected from the fuel injection valve 8, the pressure inside the fuel passage 81 increases, and when this pressure is applied to the valve body 86, the valve body 86
resists the spring force of the coil spring 87, and the arrow [1] appears in the figure.
] You will be moved in eight directions. When this happens,
The fuel injection holes 85 are spaced apart, and the fuel in the fuel passage 81 is discharged from the fuel injection holes 85 into the air passage 82. Pressurized air is flowed into the air passage 82 from the pressurized air supply means 7 at the timing when fuel is discharged from the fuel injection hole 85. Therefore, when the fuel is discharged into the air passage 82, the fuel is mixed with the pressurized air passing through the air passage 82, and is discharged from the air injection hole 84 as a mixture. The air-fuel mixture discharged from the air nozzle hole 84 is
The spray is discharged from the spray hole 51 into the working chamber 14.24.

A thermal lightning cooling element 10 is wrapped around the tip nozzle portion of the fuel injection valve 8 . As shown in FIG. 5, this thermoelectric cooling element 10 includes an n-type semiconductor element 101 and an n-type semiconductor element 10.
2, which are alternately joined with metal pieces 103 and 104. A power supply 107 and an energization control circuit 108 are connected to the n-side and n-side terminals 105 and 106 of the thermoelectric cooling element 10, and the ρ-side terminal 1 is connected from the n-side terminal 105 to the ρ-side terminal 1.
06/\It is possible to flow a current, or to change the direction of the current with the current flow control circuit 108 to flow the current from the n-side terminal 106 to the n-side terminal 105.

According to the configuration of this thermoelectric cooling element 10, when a current flows from the n(lIII terminal 105 to the n-side terminal 106), the inner metal piece 103 absorbs heat due to the Peltier effect, and the outer metal piece 104 generates heat. .In addition, conversely, the n-side terminal 10
6 to the n-side terminal 105, the outer metal piece 1
04 absorbs heat, and the inner metal piece 103 generates heat. Therefore, if the tip nozzle part of the fuel injection valve 8 receives heat from the warmed engine after the engine has stopped, by flowing current from the n-side terminal 105 to the n-side terminal 106, the engine can inject fuel. The heat received by the tip nozzle portion of the fuel injection valve 8 can be absorbed by the metal piece 103 inside the thermoelectric cooling element 10, thereby cooling the tip nozzle portion of the fuel injection valve 8. Therefore, the fuel remaining in the fuel passage 81 at the tip nozzle portion of the fuel injection valve 8 is prevented from receiving heat from the engine and evaporating. Note that since the refrigerant passage 9 is provided near the thermoelectric cooling element 10, the heat absorbed by the metal piece 103 inside the thermoelectric cooling element 10 is released from the outside metal piece 104 to the refrigerant passage 9. Become.

The energization control circuit 108 controls the direction of the current flowing through the thermoelectric cooling element 10 as described above, and also controls the oil temperature in the refrigerant passage 9 to a predetermined temperature (for example, after the fuel injection valve 8 is turned off, that is, after the engine is stopped). , 60[deg.] C.) or below. Note that instead of detecting the oil temperature in the refrigerant passage 9 by controlling the energization time, the temperature in the fuel passage 81 at the tip nozzle portion of the fuel injection valve 8 may be detected. In addition, the method of controlling the energization time is as follows.
It is also possible to control the energization time using a timer after the engine has stopped. Furthermore, it may be combined with a method of controlling the current value of energization based on the detected temperature to suppress power consumption.

Further, in the embodiment, the n-side terminal 10 is
6 to the n-side terminal 105, the inner metal piece 10
3 may be made to generate heat.

In this way, the fuel in the fuel passage 81 at the tip nozzle portion of the fuel injection valve 8 is warmed during a cold start, and fuel atomization during a cold start can be improved. In this case, the oil temperature in the refrigerant passage 9 is detected, and when the temperature is below a predetermined temperature (for example, 20°C), the thermoelectric cooling element 1
The energization time is controlled so that the current is applied to 0.

In the above embodiment, the fuel injection valve 8 is attached to the intake media 1 to the housing 5, but the rotor housing 11.21 or the side housing 12 is attached to the fuel injection valve 8.
．． The present invention may be used when the fuel injection valve 8 is attached to the fuel injection valve 22. However, if the fuel injection valve 8 is attached to the intermediate housing 5, this 11
If the rotor housing 11, 21 or This is particularly effective because the fuel injection valve 8 receives more heat from the engine than when the fuel injection valve 8 is attached to the side housing 12.22. The refrigerant passed through the refrigerant passage 9 may be cooling water. Further, the thermoelectric cooling element 10 may be energized to cool the fuel injection valve 8 not only after the engine is stopped but also during engine operation. moreover,
The present invention may be applied to a reciprocating engine.

〔Effect of the invention〕

The fuel injection device for an engine according to the present invention absorbs the heat received from the engine by the thermal cooling element even if the fuel injection valve starts receiving heat from the engine after the engine is stopped, and the absorbed heat is used to inject the fuel. The refrigerant can be released into a refrigerant passage located close to the valve. Therefore, restartability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a two-cylinder rotary piston engine equipped with an embodiment of the fuel injection device according to the present invention;
3 is a sectional view taken along the line ■--■ in FIG. 1, FIG. 4 is a detailed view of section D in FIG. 3, and FIG. 5 is a schematic structural diagram of the thermal lightning cooling element. 6... Housing, 8... Fuel injection valve, 9... Refrigerant passage, 10... Thermoelectric cooling element. Patent Applicant Mazda Co., Ltd. Representative Patent Attorney Etsushi Kotani Patent Attorney Chief 1) Masamukai Patent Attorney Takao Ito Figure

Claims (1)

[Claims] 1. In a fuel injection device for an engine in which a fuel injection valve is attached to the engine housing, a refrigerant passage is provided in a position close to the fuel injection valve, and a refrigerant passage is provided in a position close to the fuel injection valve, and the heat of the fuel injection valve is transferred to the fuel injection valve. A fuel injection device for an engine, characterized in that a thermoelectric cooling element is wrapped around the refrigerant passage for a predetermined period of time after the engine is stopped.