JPS5937259A - Control apparatus for cooling fuel used in vehicle - Google Patents

Abstract

PURPOSE:To prevent occurrence of vapor-lock, by driving a fuel pump driving motor intermittently for a prescribed while when the fuel temperature is raised at the time when an engine is not in operation. CONSTITUTION:When the fuel temperature (t) is raised along a characteristic curve A after the time (m0) when operation of an engine is stopped and reaches a set temperature (te), a timer circuit T is set into operation at a time (m1) and a transistor Tr1 is energized. Resultantly, an intermittent driving circuit IN is set into operation and a transistor Tr2 is energized intermittently, which causes intermittent opening and closing of a contact (a2) of a relay RL2, so that a fuel pump driving motor M is operated intermittently. Thus, since the fuel temperature is lowered rapidly as shown by a characteristic curve B, it is enabled to prevent occurrence of vapor-lock.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for controlling the temperature of fuel in the fuel circulation system of an automobile in air and air. When the temperature is high, the fuel is circulated intermittently to increase the cooling effect of the fuel in the circulation system and to suppress an increase in the humidity of the fuel.

If the temperature of the fuel supplied to the engine rises above this value, vapor lock may occur in the injector, making it impossible to restart the engine. Especially when gasohol is used as the fuel, the critical hot water temperature will decrease. Therefore, it is necessary to suppress the fuel temperature rise to a lower level. As a countermeasure to the above problem, there is a blower installed to cool the injector, and after the engine has stopped, the blower is rotated by a motor to cool it down.
Since the blower is provided separately, it is expensive, and there are also problems such as being unable to install it due to space constraints.

This invention attempts to cool the fuel by circulating it, and when the ignition switch is turned off, the temperature switch becomes functional, detects the temperature of the fuel supplied to the injector, and sets this temperature in advance. If the upper limit value has been reached, the temperature switch is activated to operate the IJJ drive circuit, and the drive circuit limits the drive time and operates the fuel pump motor intermittently within the limited time. The fuel is intermittently circulated in the circulation system through the fuel tank, and when the fuel is stopped, the fuel absorbs heat from the heating section, and when it is circulating, the fuel is dissipated in the 14 circulation systems including the fuel tank. It is designed to efficiently exchange heat by repeating the heat exchange.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, relay RL is its coil OL.

is connected to the ignition contact IG of the ignition switch FJ'A't. When the common contact co and the ignition contact IG are connected, the coil cL1 is energized by the battery "m source E, and at this time the normally open relay contact IL+ is closed, activating the ignition circuit load and closing it normally. The relay contact is set to open.

Note that the contact OFi'' is a song number contact.

Contacts AOO and ST are accessory contacts and starter contacts, respectively, and their connection circuits are omitted. The timer circuit T is connected in series with the normally open first temperature switch v, , and when the relay contact is closed,
First temperature switch S'W? When + is closed, it receives the power supply Elr and operates for a certain period of time, during which time the transistor T
It is designed to run rl. The first temperature switch SW, t: closes when the temperature of the fuel supplied to the injector (not shown) reaches a preset upper limit, and opens when the humidity drops below the upper limit by a predetermined humidity. Adjust so that The intermittent drive circuit IN operates while the transistor Tr+ is operating to intermittently operate the transistor T, and is made of, for example, a multivibrator circuit, and operates for several minutes for the transistor Tr2, and then for several minutes. make it inoperable,
The idea is to repeat it.

The relay RLt has a coil cLt as a relay contact, and a second
Temperature switch gW-t, ? Nigeki switch 8W...
) is connected in series with the transistor 2, and when these are in a conductive state, the normally open relay contact a is closed, and the fuel pump motor M is connected to the power source E via the diode D.
It is designed to be driven by

Therefore, the drive cycle is +a+ of the intermittent drive circuit IN.
It is based on the absenteeism and its duration is determined by the set time of the timer circuit T. The motor drive circuit DV is shown surrounded by a chain line, and the intermittent drive circuit INN of the timer circuit T1 is
) Yin register Tr,, Tr! It becomes more.

Second temperature switch history, 2 is first temperature switch SW□
It is a normally open switch that is linked to the other hand, and it is also called a withdrawal switch. is a normally closed switch that operates for safety by detecting abnormal strikes such as collisions. In addition, the fuel pump motor M is also connected in parallel with the ignition circuit load without going through a diode D etc. in order to perform normal operation during engine operation. Explain the operation.

When the common contact C0 of the ignition switch sW is connected to the ignition contact IO, the relay, rt
The contact a1 of L is closed and the contact A1 is open, the fuel pump motor λ1 is continuously operated, the ignition circuit is energized, and the engine is put into operation. Ignitsushi from this state. When the common contact C8 of the on switch 8Wr is switched to the open contact OFF, the contact a of the relay RL,
1 is opened as shown in Figure 1, and contact 1b is closed, the ignition circuit load LG is de-energized, the engine stops, and the fuel pump motor M stops, temporarily stopping fuel supply and circulation. Stop at. Here, if the fuel pump motor M remains stopped, the fuel humidity t of the injector increases as time passes, as shown by the humidity characteristic A in FIG. In the present invention, in order to lower the reached humidity, the temperature switch history v H+ 5Wtt in Fig. 1 is closed when the injector fuel temperature t in Fig. 2 reaches the set temperature to. Therefore, after m0 when the engine is stopped, the temperature characteristic A
When the temperature t rises and reaches the set temperature te, the timer circuit T operates at time m, and the transistor T
rI becomes conductive. The intermittent drive circuit IN is operated by the conduction of the transistor Trl, the transistor Tr2 is intermittently made conductive, the contact a2 of the relay RL2 is intermittently opened and closed, and the fuel pump motor M is intermittently driven. Due to the intermittent drive, cooled fuel is supplied from the fuel tank at the beginning of the drive, so the humidity drops rapidly as shown in humidity characteristic B.
After that, it becomes almost constant. During the stop period, the humidity increases in the same manner as in the humidity characteristic A, and this process is repeated. The timer circuit T determines the elapsed time m from time m so that this can be repeated a necessary number of times, for example, several times.

is set, and when the fuel circulation is stopped, the fuel absorbs enough heat from the injector, and then it is dissipated in the fuel tank, and when it circulates, these fuels replace each other, so heat exchange is efficient. The reached flow rate is considerably lower than that in temperature characteristic A, and there is no danger of vapor build-up.

As described above, according to the present invention, an efficient cooling effect can be obtained by an electric circuit without adding a mechanical part as a fuel cooling device, and therefore, an effective and easy means to prevent vapor lock can be provided.

[Brief explanation of drawings]

FIG. 1 is a control circuit diagram showing an embodiment of the present invention, and FIG. 2 is a humidity increase characteristic diagram. So-y H, 9,, 1 (1/mountain 1 degree switch, DV...
Motor drive circuit, M...Motor for fuel pump.

Claims (1)

[Claims] A temperature switch, which is a switch element that functions under the condition that the engine is stopped, and which operates upon sensing that the temperature of fuel supplied to the engine has reached a set upper limit; and operation of the humidity switch. 1. A fuel cooling control device for a vehicle, comprising: a motor drive circuit that operates inside the circuit to intermittently drive a fuel pump motor for a predetermined period of time VC.