JPS6172868A - Temperature controlling method of fuel injection valve and device thereof - Google Patents

Abstract

PURPOSE:To aim at vapor lock prevention in time of restarting at high temperature and the acceleration of fuel atomization in time of starting at low temperature, by installing an electronic heat pump in and around a fuel passage of a fuel injection valve, while heating or cooling the fuel injection valve in selection of an electric current to the electronic heat pump. CONSTITUTION:An injection valve 34 is nothing but a solenoid valve, having a valve body 50 housing a solenoid 48. And, at a lower part of this valve body 50, there is provided with an injection nozzle 56 consisting of a nozzle body 52 and a needle valve 54. At the above-mentioned, an electronic heat pump 62 is fitted in a circumference of the nozzle body 52, while a connector 68 installed in the lead wire 66 is connected to a power source via a switch. In addition, a temperature sensor 70 is installed in the valve body 50, and the signal is inputted into an ECU46 via a lead wire 72. And, fuel temperature inside the injection valve 34 is detected by the temperature sensor 70, and if the detected fuel temperature is, for example, lower than the specified value, heat is absorbed from an injection nozzle 56 by the electronic heat pump 62, cooling the fuel, thus a vapor lock phenomenon is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electronically controlled fuel injection system (hereinafter referred to as EF) for an internal combustion engine.
The present invention relates to a fuel injection valve (referred to as T system), and more particularly to a temperature control method and apparatus for a fuel injection valve.

[Conventional technology]

As is well known, the fuel injection valve of the EFI system is a solenoid valve that supplies fuel to the engine intake system by energizing a solenoid and opening an injection nozzle using an electronic control circuit (ECU).

During engine operation, the fuel injection valve generates heat by itself due to repeated energization of the solenoid, and is also heated by heat transmitted or radiated from the engine body.

When the engine is restarted in a high temperature state after being stopped, the fuel inside the injection valve and the fuel supply pipe upstream thereof reaches a high temperature, causing vapor lock, resulting in engine malfunction and restart failure. Therefore, in the prior art, the injection valve is covered with a heat insulating cover (Japanese Unexamined Patent Publication No. 56-85556), or a heat insulating material is placed between the intake manifold and the injection valve (Japanese Unexamined Utility Model Publication No. 58-44480). No. Publication, Utility Model Publication No. 58-116
Publication No. 759). Engines are also known in which a fan for cooling the injection valves is specially installed.

On the other hand, when the engine is started at a low temperature, the injection valve and the fuel are cooled, so the fuel is not sufficiently atomized.

For this reason, the reality is that a cold start injector is installed separately to facilitate starting.

[Problem that the invention seeks to solve]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and apparatus for controlling the temperature of a fuel injection valve, which can avoid the vapor lock described above during a high temperature restart and improve fuel atomization during a low temperature restart.

[Means for solving problems]

The present invention provides a fuel injection valve with fuel i+ of an injection nozzle.
An electronic heat pump is provided around path 11, and the injection nozzle is heated or cooled by switching the current to the electronic heat pump.

An electronic heat pump is defined as a device that generates or absorbs heat based on the Mertier effect (a phenomenon in which heat, such as Joule heat, is generated or absorbed at the contact surface when an electric current flows through the contact surface of dissimilar metals). An example of such an electronic heat pump is one that utilizes an n-type semiconductor and a p-type semiconductor.

〔Example〕

Next, the present invention will be described in detail with reference to the accompanying drawings. First, we will give an overview of the EFT system using Figure 2.
10 is an engine, 12 is an air cleaner, 14 is an intake temperature sensor, 16 is a throttle body, 18 is a throttle valve,
20 is a throttle sensor linked to a throttle valve, 22
24 is a surge tank, 24 is an intake pressure sensor, 26 is a throttle bypass, 28 is an air valve, 30 is an intake pipe, 32 is a fuel distribution pipe, 34 is an injection valve of the present invention, 36 is an injection valve 34
38 is a water temperature sensor, 40 is a distributor, 42 is a crank angle sensor, 44 is a rotation speed sensor, and 46 is an ECU. The ECU 46 calculates the fuel injection pulse width based on the signals from each sensor in a well-known manner and drives the injection valve 34 through the conductor 36.

FIG. 1 shows an injection valve 34 of the present invention. The injection valve 34 is a solenoid valve and has a valve body 50 that houses a solenoid 48. An injection nozzle 56 consisting of a nozzle body 52 and a needle valve 54 is provided at the lower part of the valve body 5o.The needle valve 54 is connected to a plunger 58, and opens when the solenoid 48 is energized. This allows pressurized fuel to flow into the intake pipe.

An electronic heat pump 62 is fitted into the valve body 50 on the outer periphery of the nozzle body 52 of the injection nozzle 56 . A radiation fin 64 is provided on the outer periphery of the electronic heat pump 62. A connector 68 provided on the conductor 66 of the electronic heat pump 62 can be connected to a power source via a switch as described below. Valve body 50 is provided with a temperature sensor 70 whose signal is input to ECII 46 via conductor 72 . In the illustrated example, the temperature sensor 70 protrudes near the plunger 58, but it may also protrude into the fuel passage 60 of the injection nozzle 56.

FIG. 3 shows the configuration of the electronic heat pump 62 and its drive circuit. The electronic heat pump 62 has electrode plates 74A, 7
An n-type semiconductor 76 and a p-type semiconductor 78 are sandwiched between the outer cylinder 84 and the inner cylinder 86 via a pair of electrically insulating and heat conductive holding members 80 and 82. Retained. The inner cylinder 86 is attached to the outer periphery of the nozzle body 52. Between the electrode plates 74B and 74C, ECII
4-way switch 9 controlled by 46 through conductor 88
Direct current is selectively applied from the battery 92 in either the forward or reverse direction through the DC current.

A control program shown in the flowchart of FIG. 4 is programmed into the memory (ROM) of the EcU 46. This control program is executed at predetermined time intervals. In step 101, the fuel temperature T inside the injection valve is detected based on a signal from the temperature sensor of the injection valve 34.

In step 102, it is determined whether the temperature T is greater than a first set value TI (for example, 70°C).T>T1
If it is 1, in step 103, the switch 90 is switched to energize the electronic heat pump 62 in the direction in which it operates in the cooling mode, and this program ends. As a result of this energization, the electronic heat pump takes heat from the injection nozzle 56 and radiates it from the heat radiation fins 64 due to the Beltier effect.
The fuel in fuel passage 1?360 is cooled. This results in
Paper lock is prevented from occurring.

T>Tl! If not, the process proceeds to step 104, where it is determined whether the temperature T is smaller than the second set value TL (for example, 0° C.). If T<TL, the switch 90 is switched in step 105 to operate the electronic heat pump 62 in the heating mode to heat the fuel in the fuel passage 60. Therefore, atomization of the injected fuel is promoted.

If the fuel temperature T is between the two set values Tll and TL, the program ends without operating the electronic heat pump.

〔Effect of the invention〕

As shown on J22, an electronic heat pump is installed in the injection valve to heat or cool the injection valve depending on the temperature, so
When restarting at a high temperature, cooling prevents paper locks in the fuel passages and fuel supply pipes, improving the high-temperature startability and stability of the engine, and when starting at a low temperature, heating promotes fuel atomization. Low-temperature startability and stability can be improved. Moreover, since an electronic heat pump is used, heating/cooling can be extremely easily selected by simply switching the current direction. Furthermore, the injection valve can be cooled more reliably and effectively than conventional heat insulating covers and cooling fans. Furthermore, since the injection valve is heated at low temperatures, the conventional cold start injector can be eliminated, and fuel consumption can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway side view of the fuel injection valve of the present invention, Fig. 2 is an overall view of the EFI system, Fig. 3 shows the configuration and drive circuit of the electronic heat pump, and Fig. 4 shows the temperature control program. It is a flowchart. 34--Fuel injection valve, 56-Injection nozzle, 60-Fuel passage, 62-Electronic heat pump, 76--N type semiconductor, 7 [-N type semiconductor, 90--... Changeover switch. Figure 3 Figure 4

Claims (1)

[Claims] 1. In a fuel injection valve of an electronically controlled fuel injection device for an internal combustion engine, an electronic heat pump is provided around the fuel passage of the fuel injection valve, and the fuel injection valve is heated or heated by switching current to the electronic heat pump. A temperature control device for a fuel injection valve, characterized in that it is capable of cooling. 2. In a fuel injection valve equipped with an electronic heat pump around the fuel passage, a temperature sensor provided in the fuel injection valve detects the temperature of the fuel inside the fuel injection valve, and when the temperature is equal to or higher than a first set value, the electronic heat pump is activated. A method for controlling the temperature of a fuel injection valve, comprising operating the electronic heat pump in a cooling mode, and operating the electronic heat pump in a heating mode when the temperature is below a second set value.