JP2534138Y2 - Fuel supply device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a fuel supply device for an internal combustion engine that injects fuel into an intake pipe of the internal combustion engine.

[Conventional technology]

A conventional fuel supply system for an internal combustion engine is disclosed in, for example,
As disclosed in JP-A-6663 or JP-A-63-41664, when the key switch is turned on, the difference between the pressure pumped fuel from the fuel tank by the fuel pump and the pressure in the intake pipe of the internal combustion engine is determined by the pressure regulator. The pressure is regulated so that the pressure becomes constant, and the regulated fuel is distributed from the fuel delivery pipe to the same number of fuel injectors as the number of cylinders of the internal combustion engine (hereinafter referred to as injectors) to open the injectors. This injects and supplies fuel into the intake pipe of the internal combustion engine. On the other hand, surplus fuel after pressure regulation is returned to the fuel tank through a pipe. At this time, the fuel is configured to lower the fuel temperature, for example, through a cooling medium passage provided in parallel with the fuel delivery pipe. When the key switch is turned off, the power supply of the fuel supply system is normally turned off, and the fuel is not circulated as described above. The control of the injector and the like is performed by an electronic control unit (hereinafter, referred to as an ECU) including a microcomputer.

[Problems to be solved by the invention]

Since the conventional fuel supply device for an internal combustion engine is configured as described above, when the internal combustion engine is stopped, left in a high temperature state, and then restarted, the fuel evaporates due to the high temperature and the pressure increases. As a result, the flow rate becomes lower than an appropriate state, and the mixing ratio of fuel and air supplied into the intake pipe becomes lean, which causes problems such as inability to start or impair operability.

The present invention has been made to solve the above-described problems, and has as its object to provide a fuel supply device for an internal combustion engine that can be easily started even in a high temperature state and does not impair operability.

[Means for solving the problem]

The fuel supply device for an internal combustion engine according to the present invention travels over a certain distance where the fuel temperature does not immediately decrease after the key switch is turned off, and any one of the fuel temperature, the cooling water temperature, and the intake air temperature exceeds the threshold temperature. In this case, the fuel pump is operated only for a fixed time after the key switch is turned off.

[Action]

The fuel supply device for an internal combustion engine according to the present invention has a high fuel temperature when the conditions of the fuel temperature, the cooling water temperature, the intake air temperature, and the traveling distance are all the same. The fuel is circulated to lower the fuel temperature in advance.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing a system of the entire engine unit, and FIG. 2 is a schematic flow chart showing a main operation flow. In the figure, 1 is a well-known internal combustion engine mounted on a vehicle, 2 is an intake pipe of the internal combustion engine 1, 3 is an injector arranged for each cylinder of the internal combustion engine 1, and 4 is the temperature of the cooling water of the internal combustion engine 1. , A cooling water temperature sensor, which is disposed in the intake pipe 2 and detects the temperature of the intake air of the engine 1, and a fuel passage 6 having, for example, a cooling medium passage. , A fuel temperature sensor 8, a fuel delivery pipe 9 to which the injector 3 is attached, and a pressure regulator 10 for adjusting a fuel pressure by introducing a negative pressure of the intake pipe 2.
Are provided in order. Numeral 11 denotes a fuel tank for storing fuel, which is connected to the most upstream side and the most downstream side of the fuel passage 6. 12 is a traveling distance detecting means for detecting the traveling distance of the vehicle, 13 is a timer, a ROM storing the flow of the main part of FIG. 2 as a program, a RAM as a work memory, and performs calculation, determination and control. As a well-known ECU composed of a CPU and the like. Reference numerals 4, 5, 8, and
Each detection element indicated by 12 is connected, and an injector 3 and a fuel pump 7 are connected to an output port thereof. Further, the microcomputer 13 is directly connected to the (+) terminal of the battery 14 having the (-) terminal grounded via the key switch 15 and not through the key switch 15.

Next, the operation will be described. Now, it is assumed that the vehicle is running while the internal combustion engine 1 in which the key switch 15 is turned on is operating. The traveling distance of the vehicle is detected by the traveling distance detecting means 12. Further, the fuel in the fuel tank 11 is pressure-fed in the direction indicated by the arrow in the drawing by the operation of the fuel pump 7, the pressure is regulated by the pressure regulator 10, the fuel is returned to the fuel tank 11 through the fuel delivery pipe 9,
When fuel is supplied, a part of the fuel is injected and supplied into the intake pipe 2 by temporarily opening the injector 3. The temperature of the fuel is detected by a fuel temperature sensor 8. At the time of intake, the internal combustion engine 1 sucks a mixture of the fuel and the intake air supplied into the intake pipe 2. The temperature of the intake air is detected by an intake air temperature sensor 5. The cooling water temperature of the internal combustion engine 1 is detected by a cooling water temperature sensor 4. On the other hand, the microcomputer 13
Compares the magnitude of the output signal of the traveling distance detection means 12 with a predetermined threshold value to determine whether the vehicle has traveled a predetermined distance or more. Then, the magnitude of each output signal of the fuel temperature sensor 8 and the threshold value preset for each of them is compared to determine whether at least one of them has reached a predetermined temperature or higher.

Then, the microcomputer 13 travels over a certain distance where the fuel temperature does not immediately decrease after the key switch is turned off, and when any of the fuel temperature, the cooling water temperature and the intake air temperature becomes higher than the threshold temperature. Flag only if it is determined that

Thereafter, the engine 1 is stopped. If the flag is set at that time, the microcomputer 13 drives the fuel pump 7 for a fixed time to circulate the fuel even after the key switch 15 is turned off. As a result, the fuel circulates through the cooling medium passage of the fuel passage 6 to lower the fuel temperature in advance by, for example, self-cooling. If the flag is not set, the process is terminated immediately after the key switch 15 is turned off.

[Effect of the invention]

As described above, according to the present invention, after the key switch is turned off, the vehicle travels over a certain distance where the fuel temperature does not immediately decrease, and any one of the fuel temperature, the cooling water temperature, and the intake air temperature exceeds the predetermined temperature. In this case, the fuel is circulated only for a predetermined time after the engine is stopped, so even if the key switch is turned off and the device is left in a high temperature state, the fuel temperature can be lowered in advance to prevent fuel evaporation due to the high temperature. This makes it possible to prevent the engine from being unable to start at the time of restarting and to prevent the driving performance from being deteriorated.

According to the present invention, in addition to the fuel temperature, the cooling water temperature and the intake air temperature are taken in parallel as elements for grasping the occurrence of vaporization of the fuel by the first detection means, and one of these three elements is determined to be a predetermined one. By setting the temperature to be higher than or equal to the temperature, in addition to heat transfer in the fuel line, the radiant heat from the engine and the radiant heat from the cooling water pipe can be taken into the determination of fuel vaporization. An effect that more accurate determination can be obtained is obtained.

Further, according to the present invention, the fuel temperature after the key switch is turned off is close to the threshold value by the second detecting means that the fuel temperature after the key switch is turned off travels a certain distance or more that does not immediately decrease. In this case, even when the fuel pump is operated by the first detection means, the fuel temperature after the key switch is turned off may immediately decrease depending on the running conditions (distance) before the key switch is turned off. In this case, the fuel pump is not operated, so that an unnecessary operation of the fuel pump can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system of the entire engine unit according to an embodiment of the present invention, and FIG. 2 is a schematic flowchart showing a main operation flow. In the figure, 1 ... internal combustion engine, 2 ... intake pipe, 3 ... injector, 4 ... cooling water temperature sensor, 5 ... intake air temperature sensor, 6 ... fuel passage, 7 ... fuel pump, 8 ... ... Fuel temperature sensor, 9 ... Fuel delivery pipe, 10 ... Pressure regulator, 11 ... Fuel tank, 12 ... Driving distance detecting means, 13 ... Microcomputer, 14 ... Battery, 15 ... Key switch.

Claims (1)

(57) [Scope of request for utility model registration] When a key switch is turned on, a fuel pump is operated to supply fuel to a fuel injection valve to circulate the fuel, and the fuel is cooled by the circulation. First detection means for detecting that one of the temperature of the cooling water of the internal combustion engine and the temperature of the intake air of the internal combustion engine has become equal to or higher than a preset threshold temperature; and The second detecting means for detecting that the vehicle has traveled a predetermined distance or more that does not immediately descend, and when both of the first and second detecting means detect the vehicle, the key switch is turned off for a predetermined time. Operating means for operating a fuel pump. A fuel supply device for an internal combustion engine, comprising: