JPS5888457A - Fuel injection device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To reduce the cost of a captioned device by providing a switch valve mechanism interlocked with a fuel pressure-supply mechanism in a passage to release a high-pressure fluid introduced into a spool operation oil chamber to the low-pressure side for reducing the necessary number of solenoid valves. CONSTITUTION:When the first solenoid valve 11 is opened, the fuel from a pressure source 3 is supplied to an oil chamber 14, and a spool 5 is shifted to the right against a spring 17. Consequently, an oil chamber 18 is connected to a pressure source 2 via a port 19, and the fuel in a fuel chamber 23 is jetted out from a nozzle 10 as being intensified in its pressure by areas of a piston 8 and a plunger 9. At this stage, when the piston 8 is brought near to the bottom dead center, and edge 8a of its annular groove is laid on an annular groove 27 of a bore 6 composing a main part of a switch valve mechanism together with an annular groove 26, and annular grooves 26 and 27 are mutually connected. Thereby, the fuel in the oil chamber 14 is discharged to a tank 16 via a pipe 25, and annular grooves 26 and 27, and the spool 5 is returned to the left. Then, when the second solenoid valve 13 is opened, fuel is supplied to the fuel chamber 23.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wet type fuel injection device for an internal combustion engine that injects fuel by driving a plunger by the hydraulic pressure of a fluid flowing through a spool valve.

In conventional fuel injection systems of this type, an 8-position, 8-port solenoid valve is used to control the movement of the spool valve, and another 2-position, 2-port, 0-port solenoid valve is used for accurate metering. I was using it. Or 8. Two Kg position 8 boat solenoid valves were used instead of the position 8 boat solenoid valve.

In this conventional system, a total of eight valves, one each of a Z position 8-bow F solenoid valve and a 2-position 2-bot solenoid valve, were required, or eight FZ position 8-bot solenoid valves were required. At times, eight-boat boats had the disadvantage that they were complex in structure and large in size, and were often difficult to manufacture. i again! &-) If the 8th position is used, 8 units are required, which increases the cost. In this case, 1 out of 8
It has been proposed to construct the valve with p-Tary pulp, but this also requires a cost comparable to that of a solenoid valve, and currently does not provide sufficient heat rays.

In order to eliminate the drawbacks of the above conventional configuration, the present invention company,
The return function of the spool is not controlled externally by a solenoid valve, etc., but is instead controlled by the opening/closing valve mechanism of the annular groove provided on the piston (or plunger).
11m17)! It is an object of the present invention to provide a fuel injection device which can be performed using a boat S-position solenoid valve, and which can be made smaller by reducing the number of parts, reduce costs, and simplify a control circuit by reducing the number of welfare solenoid valves.

The present invention will be explained below with reference to embodiments shown in the drawings.

In the first NK, l indicates the injector, and 2 indicates the sFi hydraulic pressure source as a whole. A spool valve consisting of an injector l#i bore 6, a spool b and a spring lf that freely slide within it, and an integrated large-diameter piston 8 and plunger 9 that slide within the bore 6 and 7, respectively. A fuel compression means configured, a normal fuel injection nozzle 10 negative by dneIO&, and an 11th and 8th! for controlling these! It has a single 8-boat solenoid valve 1113. Fuel chamber B8Fi check valve 84 formed by the lower end surface of plunger 9 and bore 7, second solenoid valve 1
8 to supply pressure #8 and at the same time directly to nozzle IO. On the other hand, the hydraulic oil chamber 14 formed by the left end surface of the Subur 5 and the bore noise is connected to the supply pressure source 8 via the first passage 15 and the first solenoid valve 11, and is also connected to the second passage w! Annular tI4 provided in bore 6 via r25
26 will be contacted.

Another annular groove 2te provided in the i-arrow is connected to a low-pressure fuel tank 16. The two annular grooves 86 and 27 cooperate with an annular groove provided in the piston 8 and having eight edges ga and Bb to perform a valve function. Furthermore, one boat 20 of the spool valve is connected to the supply pressure source 2 by a set of pipes gl, and the other boat 20 is connected to the fuel tank 16 via a throttle #)ggt. Piston 8 top surface and bore 6
The actuation 711 chamber 18 formed by the two bows) 1
9. Either one of go will be contacted. supply pressure source 2,
Filter g08. from SFi fuel tanks 16', 16'.
Pump 201, +3014c pumps fuel through 808, pressure regulating valve 801! , 808 and accumulator g04.8
04 to control the pressure to a constant value. 80, eight solenoid valves 11, based on signals from sensors 81 to 81, which will be described later
1B's TT-control controller. Note that the number of injectors l is the same as the number of cylinders of the engine (not shown).

The 3rd WJ is Senna & ~8i1 controller 80° solenoid valve 11,1! FIG. 11 shows a Puka diagram related to IK.

8M detects the engine rotation speed, 8T detects the amount of accelerator pedal depression, S, Q engine temperature, 184IIi engine cylinder mark, 86Fi detects emergency situations such as fuel leaks from piping and engine overrun. It's Senna.

In the controller 280, PI is the injection amount setting circuit, r
1 is an injection start timing setting circuit, MU1 is a calculation circuit that determines the injection amount based on the signals of SEN 9B Otori and 8g, and MU 5lfi Senna 8. ~8. This is a calculation circuit that determines the injection start timing based on the signal, and a MusVi output amplification circuit. Specifically, the company
Calculated IgI circuit I is energized to the eighth solenoid valve 18 by 1
The calculation circuit Mutomi calculates the deviation of the start time of energization to the first electromagnetic valve 11 with respect to the cylinder mark. In addition, the output amplifying circuit 1 determines the crank position mr and uses the solenoid valve (11) of the necessary cylinder.
The first solenoid valve 11 is normally energized for a certain period of time.

The operation will be explained next. In the state shown in FIG. 1, by bringing the two boats of the first solenoid valve 11 into a conductive state (hereinafter referred to as "open"), fuel is forced from the supply pressure source 8 to the hydraulic oil chamber 14, and the spool 6, it overcomes the force of spring 17 and is displaced to the right. At this time, communication is made between the annular groove g6 and the pin 8 as shown in the enlarged view of Figure 8.
It is. By displacing the spool b to the right, the boat 19 is opened one by one φ). As a result, the working wJ oil chamber 18 is brought into communication with the pressure source 2 via the bow 19, the pressure is increased to the area ratio of the piston 8 and the plunger 9, and the fuel in the fuel chamber 28 is injected from the nozzle 10. At this time, the compressed fuel is prevented from being returned to the pressure source 8 by the check valve B1.

Here, after the spool 5 is displaced to the right, the first solenoid valve l
ik closed. There is a certain time delay and the piston 8ti is displaced downward, but when the piston 8 comes close to the bottom dead center, the edge 8 of the annular groove of the piston is aligned with the annular groove 8 of the bore 6.
This overlaps with 7 and will be communicated. Even if the piston is at the bottom dead center, the edge 8b is prevented from blocking the annular groove 16 (at the top dead center position shown in FIG. 8, m >'1).
>j*) From this point on, the annular groove 26.2 will be in communication up to the bottom dead center position shown in the diagram. In this state, the fuel in the hydraulic oil chamber No. 1 is discharged into the tank 16 through the pipe 86 and the annular groove 86.27, and the spool b is returned to the left by the force of the spring 17. Port 19 due to displacement of spool b
is closed and then boat -8O is opened. Then, the fuel in the hydraulic oil chamber 18 is discharged into the tank 16 via the cylinder 86. Subsequently, while the eighth solenoid valve 18t is opened, as the fuel in the hydraulic oil chamber 18 is released, the fuel chamber 2
Piston 8 and plunger 9 are pushed back upwards by pressure crab 8, and from pressure fi8, check valve! After 4 km, the next fuel to be injected is guided to the fuel chamber B8. A second solenoid valve 18 is installed so that fuel commensurate with the planned injection amount is guided here.
control the opening time.

When metering is completed in this way, the piston 8, the plunger 9#i, and the pressures in the hydraulic oil chamber 18 and the fuel chamber 88 are kept balanced and stopped. The aperture ggFi has the effect of prolonging the metering time, which allows for more accurate metering.

Then, by opening the first electromagnetic valve 11 again, fuel is injected, and by repeating this, fuel can be supplied to an internal combustion engine (not shown).

- Eleventh second solenoid valve 11.1 from controller 80
If we explain the signal to B in chronological order, the first solenoid valve 11 opens at time tm in Figure 2 and the injection operation starts.
After the spool 5 moves to the right end, the first solenoid valve 11 is closed at time fiB. Thereafter, at time C, the annular grooves go and g7 open, so the spool b returns and the pupil becomes open for metering.Next, when the eighth solenoid valve 18 is opened at time 'LD, the piston 8 and plunger 9 return, and the metering becomes possible. is started, and at time E, the solenoid valve is closed to complete metering. Here, communication between the annular grooves go and g7 is cut off immediately after the clock is set due to the rise of the piston 8. Then, the timing is variably controlled based on the signals from sensor 8I, etc. to optimize the timing, and sensor S
, , S, the time DEN is variably controlled to perform metering.

In addition, since the current needs to be supplied only when the first solenoid valve 11tJ is opened, power can be saved compared to a conventional two-position eight-boat solenoid valve.

In the above embodiment #i annular groove 16, gs, edges sa, s
It is clear that b may be constructed as the plunger 9 of this company, or that it may be constructed with a hole and an annular groove instead of three annular grooves.

Furthermore, by providing a spill mechanism in one langeer to determine the end of injection, it is possible to accurately determine the injection path and spool return tying from the design value of the opening lift.

Furthermore, although only one cylinder is shown in FIG. 1, this does not mean that multiple cylinders can be used. Although FIG. 1 shows a normal nozzle 8 loaded by a spring, a nozzle loaded by hydraulic pressure or the like may also be used. In addition, the pressure source is metered, spool 1
The movements may be separated, or conversely, everything including the piston drive may be constructed from one pressure source, and the pressure medium may be other than fuel except for metering.

It goes without saying that either one constructed from Controller's analog circuits or one constructed from digital circuits is fine.

As described above, the present inventor installed a valve mechanism between the spool hydraulic oil chamber and the fuel tank that opens and closes in conjunction with the pressure feeding mechanism to control the return stroke of the spool, and also connects the spool hydraulic oil chamber and the pressure source. By installing an electromagnetic on-off valve between them, the control of the spool's forward stroke and injection timing can be achieved.
Furthermore, by installing an electromagnetic on-off valve between the pump chamber and the pressure source, the number of electromagnetic valves can be reduced, and the structure is simple and inexpensive. If the injector can be provided, the effect of saving operating energy can be achieved.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram showing one embodiment of the present invention, Fig. 8 is a block diagram of the sensor, controller, and solenoid valve shown in Fig. 1, and Figs. 8 and 4 are drive diagrams shown in Fig. 1. Enlarged view of the piston section showing the top dead center and bottom dead center states, No. bF
! ! i is a timing diagram used to explain the operation of the present invention. l・-injector, 2.3...pressure source, b...spool, 8...piston, 9...plunger, 10
...fuel injection nozzle, ll...first solenoid valve, 13
...Second solenoid valve, 16...by Spool IE! 1 Oil chamber, 16...-Fuel tank, SS・°・Fuel chamber, 26.
2?・-・Annular groove formed by the main part t′ of the opening/closing valve mechanism, 80・
··controller. Representative Patent Attorney 14th Department Takashi

Claims (1)

[Claims] A supply pressure source that pumps relatively high-pressure fluid, a piston that receives the hydraulic pressure of this fluid, a plunger that works in conjunction with the piston and compresses fuel when the piston receives hydraulic pressure, and injects the compressed fuel. and a spool valve that applies hydraulic pressure to the piston when the high-pressure fluid is introduced into the spool hydraulic oil chamber in order to apply hydraulic pressure to the piston. An on-off valve that opens and closes in conjunction with the operation of the pressure feeding mechanism consisting of the piston and plunger, which is installed in a passage for releasing high-pressure fluid introduced into the spool hydraulic oil chamber to the low-pressure side.
1. A fuel injection device for an internal combustion engine, comprising: