JPS634018B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic accumulator fuel system for use in internal combustion engines, particularly diesel engines.

The electronic pressure accumulation type fuel injection system for internal combustion engines is equipped with an electronic control unit (hereinafter referred to as "ECU"), and this ECU
The injector is activated by command signals determined based on signals sent from various sensors that detect engine operating conditions such as engine speed and engine load, and the fuel injection amount and injection timing are adjusted. . used in such fuel injection devices.
ECUs are mainly composed of microcomputers and have complex circuit configurations and wiring, making them prone to failures. If a failure occurs in the ECU, the engine cannot be operated until the ECU is repaired, and especially in the case of engines such as vehicles and ships, there may be situations where the vehicle has to be abandoned during operation.
Therefore, some injection devices equipped with conventional ECUs have double or triple safety circuits inside the ECU.
(Unexamined Japanese Patent Application Publication No.
55-119955).

However, even with such a safety circuit,
Since failure of the ECU cannot be completely avoided, there was a desire for a fuel injection system that would enable temporary operation in the event of an emergency until the electrical system surrounding the ECU could be repaired.

Therefore, in the present invention, the ECU performs highly accurate electronically controlled fuel injection under normal conditions, and when a failure related to the ECU occurs, the fuel injection control system that does not depend on the ECU is used to control the fuel injection in the vehicle. The purpose of the present invention is to provide a fuel injection device that enables such operations. For this purpose, the present invention has a valve body formed with a pressure receiving surface in the middle part and a needle valve at one end, which is biased in the needle valve closing direction by a spring, and inserted into the valve body housing hole of the nozzle holder. The valve body storage hole is arranged to be slidable against a spring force, and has a first pressurized space in the needle valve corresponding part, a second pressurized space in the pressure receiving surface corresponding part, and a non-needle An injection nozzle device is provided with a third pressurized space in a portion corresponding to the valve side end, and an injection port communicating with the first pressurized space, and a large piston head is provided at one end and a large diameter piston head is provided at the other end. A double-headed piston is provided, each having a small-diameter piston head, and the reciprocating motion of the piston defines a first pressure chamber by the large-diameter piston head, a second pressure chamber by the small-diameter piston head, and a second pressure chamber by the small-diameter piston head. The pressure chamber is connected to a first pressurizing space of the injection nozzle device and a pressure intensifier connected to the third pressurizing space via a first stop valve; Supplying electronically controlled hydraulic oil through the switching valve device and the second stop valve, and electronically controlled operation via the second switching valve device to the second pressurized space of the injection nozzle device. a hydraulic oil supply device that supplies oil; a fuel supply device that supplies electronically controlled fuel oil to a second pressure chamber of the pressure booster via a check valve; 1 switching valve device, 2nd switching valve device, 1st stop valve,
an electronic control device that supplies a command signal to a second stop valve; a first pump that is driven by the engine and supplies hydraulic oil to the first pressure chamber of the pressure booster via the third stop valve; the second of said pressure intensifier
A second pump that supplies fuel oil to the pressure chamber via a fourth stop valve, and a speed governor connected to the first pump and the second pump, and when the electronic control device is activated, the third and fourth pumps are connected to each other. Closing the stop valve and supplying hydraulic oil and fuel oil from the hydraulic oil supply device and the fuel oil supply device to the pressure booster, respectively;
While controlling the oil pressure supplied to the second pressurized space to control fuel injection, when the electronic control device is inactive, the first stop valve is closed and the third and fourth stop valves are opened to control the first pump. and a second pump supplies hydraulic oil and fuel oil to the pressure intensifier, respectively, and closes a second stop valve to supply pressurized fuel only to the first pressurized space, The present invention provides an electronic pressure accumulation type fuel injection device that can perform fuel injection with injection timing control by a first pump and injection amount control by a second pump corresponding to the operation.

Hereinafter, one embodiment of a fuel injection device according to the present invention will be described with reference to the drawings.

The drawing shows an overall view of a fuel injection device according to the present invention, and includes an injection nozzle device A that injects fuel, a pressure booster B that pumps pressurized fuel to the injection nozzle device A, and a pressure booster B and the injection nozzle device A. a hydraulic oil supply device C that supplies hydraulic oil; a first switching valve device V1 provided between the pressure booster B and the hydraulic oil supply device C;
The second switching valve device V2 provided between the injection nozzle device A and the hydraulic oil supply device C, the fuel supply device D that supplies fuel to the pressure booster B, and the first and second switching valve devices V1 and V2 are connected to the engine. an electronic control unit (hereinafter referred to as "ECU") E that supplies command signals according to the operating state of pump G
, a speed governor H connected to the first pump and the second pump, and a pressure intensifier B are connected to a communication path that communicates with the injection nozzle device A, the hydraulic oil supply device C, the first pump F, and the second pump G, respectively. The first, second, third,
It is provided with fourth stop valves V3, V4, V5, and V6.

The injection nozzle device A includes a nozzle holder A1, a valve body A3 slidably housed in a valve body housing hole A2 formed in the nozzle holder A1, and a spring A4 that biases the valve body A3 in the valve closing direction. The valve body A3 is composed of a small diameter portion A3a at both ends, a needle valve A3b, and a large diameter portion A3c at an intermediate portion. The valve body storage hole A2 accommodates the small diameter part, large diameter part, and needle valve A3 of the valve body A3.
It has a diameter corresponding to the diameter of A, A3c, and A3b, respectively, and is formed to allow the valve body to slide,
The large diameter part A3c storage part A2c is formed longer on the small diameter part A3a side than the large diameter part A3c, and stores the spring A4 in that space. is embedded. In the valve body storage hole A2, a first pressurized space A2b is provided at a portion corresponding to the tip of the needle valve A3b, and a large diameter portion A3 is provided.
A second pressurized space A2c is provided in a portion corresponding to the end on the needle valve side.
A third pressurized space A2d is formed in a portion corresponding to the tip on the side opposite to the needle valve of the small diameter portion A3a, and the first pressurized space
A nozzle A2e is formed in the end wall of A2b.
Further, the first pressurized space A2b is directly connected to the pressure intensifier B, the third pressurized space A2d is connected to the pressure intensifier B via the first stop valve V3, and the second pressurized space A2c is connected to the second switching valve device V.
It is connected to the hydraulic oil supply device C via 2.
Further, the third pressurized space A2d is communicated with the relief tank T via a fifth stop valve V7 that is opened in conjunction with the closing of the first stop valve V3.

The pressure intensifier B is provided with a double-headed piston B1 having a large diameter piston head at one end and a small diameter piston head at the other end so as to be able to reciprocate. A first pressure chamber B2 is defined by the piston head, and a second pressure chamber B3 is defined by the small diameter piston head. 1st
The pressure chamber B2 has a first switching valve device V1 and a second stop valve V
4 to the hydraulic oil supply device C, and also to the first pump F via the third stop valve V5. The second pressure chamber B3 is communicated with the fuel oil supply device D via the check valve V11, and the second pump G via the check valve V12 and the fourth stop valve V6, and is connected to the injection nozzle device A. First pressurized space A
2b and the third pressurized space A2d directly and via the first stop valve V3, respectively. Furthermore, a gap B4 defined by the movement of the piston on the second pressure chamber B3 side of the hole that accommodates the piston head of the large tube is connected to the first pressure chamber B2 via the first relief valve V8 and the hydraulic oil supply. It is communicated with a communication path with device C. The first relief valve V8 is an electromagnetic switching valve, and the operating spring V8b is connected to the ECU E.
A solenoid V8a is provided to adjust the set load.

The hydraulic oil supply device C basically consists of a hydraulic oil tank C1 and a pump C2 that is attached to the output shaft EGa of the engine EG and pumps up the hydraulic oil from the tank C1.
2, via the filter C3, the second relief valve V9 and the accumulator C4, on the other hand directly the second
first and second oil passages C5, which communicate with the switching valve device V2;
They are connected to C6 and C6', respectively. The second relief valve V9 is a solenoid valve like the first relief valve V8, and bypasses the pump C2.
It is connected to ECU E with a solenoid V8a that adjusts the set load of actuating spring V9b.

The first switching valve device V1 consists of a 4-port 2-position electromagnetic valve, and when the solenoid V1a is energized, it is switched to position I, and the first pressure chamber B2 of the pressure intensifier B and the first communicate with oil passage C5,
When the solenoid V1a is deenergized, it is switched to a position to communicate the first pressure chamber B2 and the second oil passage C6.

The second switching valve device V2 is also configured in the same manner as the first switching valve device V1, and when the solenoid V2a is energized, it is switched to the position where the second pressurized space A2c of the injection nozzle device A and the first oil passage C5 are connected. When the solenoid V2a is deenergized, the position is switched to communicate the second pressurized space A2c and the second oil passage C6'.

The fuel supply device D is basically a fuel tank D1.
and a pump D that pumps fuel oil from the tank D1.
2 and a motor D3 that drives the pump D2, the tank D1 is connected to the second pressure chamber B3 of the pressure intensifier B via the pump D2, a third relief valve V10 that bypasses the pump D2, a filter D4, and a check valve V11. is communicated with. In addition, the third relief valve V1
0 is a solenoid valve like the first and second relief valves V8 and V9, and is provided with a solenoid V10a connected to the ECU E.

The ECU E includes, on the one hand, a rotation speed sensor S1 provided close to the outer periphery of the output shaft EGa of the engine EG, a top dead center position sensor S2, an accelerator S3 that determines the engine load, and a sensor S4 that detects the lift of the needle valve A3b.
and various sensors attached to the engine, and on the other hand, it is connected to the aforementioned solenoids V1a, V2a, V8a, V9a, and V10a. Incidentally, a predetermined number of teeth EGa' are protruded on the outer peripheral surface of the output shaft EGa of the engine EG at equal intervals over the entire circumference, and as the output shaft EGa rotates, sensors S1 and S2 consisting of electromagnetic pickups are activated. The number of passing teeth is detected by these sensors.

The first pump F is equipped with a plunger F2 that is slidable in a plunger valve F1 that has a through hole F1a in the side wall, and the plunger F2 is in contact with a cam J1 of a camshaft J of the engine at its lower end. The plunger barrel F1 is reciprocated in the axial direction as the camshaft J rotates, and is engaged with an adjusting rod F3 connected to the speed governor H and displaced in response to the operation of the speed governor H. It is rotated by the displacement of B. The upper end of plunger F2 is notched,
A band-shaped circumferential protrusion F2a having a constant width is formed along the circumference and extending at an angle with respect to the axis, and the circumferential protrusion F2a and the through hole F1a are formed during reciprocating movement of the plunger barrel F2. The timing of matching is changed depending on the rotation angle of the plunger barrel. A through hole F1b provided in the end wall of the plunger barrel F1 and communicating with the pump chamber within the plunger barrel communicates with the first pressure chamber B2 of the pressure intensifier B via the third stop valve V5.

The second pump G has the same configuration as the first pump, but the plunger G2 has an inclined notch G2a whose width gradually increases at its upper end, and is provided on the end wall of the plunger barrel G1. The through hole G1b, which communicates with the pump chamber in the pressure intensifier B, is connected to the second
It communicates with pressure chamber B3. The lower end of the plunger G2 is in contact with the cam J2 of the camshaft J, but by providing a phase difference between the cams J1 and J2, a time difference is created in the upward movement timing of the plunger F2 and the plunger G2, and the second pump The first pump starts injecting hydraulic fluid at the same time as the first pump finishes injecting fuel.

The third and fourth stop valves V5 and V6 open in conjunction with the closing of the second stop valve V4, and the speed governor closes the third and fourth stop valves V by appropriate means (not shown).
5. It starts operating as soon as V6 is opened.

To explain the operation of the fuel injection system configured as described above, first, when the ECU E is in normal operation, the third, fourth, and fifth stop valves V5, V6, and V7 are respectively closed, and the second stop valve V4 is closed. When the first pressure chamber B2 of the pressure intensifier B is opened, hydraulic oil is supplied from the hydraulic oil supply device C, and fuel oil is supplied to the second pressure chamber B3 from the fuel supply device D. The first switching valve device V1 is switched to supply and return hydraulic oil by energizing and deenergizing the solenoid V1a, so a fixed amount of hydraulic oil is always supplied to the first pressure chamber B2 at a fixed timing. Ru. This oil pressure presses the large-diameter piston head, and the hydraulic oil in the gap B4 is released to the second oil passage C6 of the hydraulic oil supply device C through the first relief valve V8, so that the piston B1 of the pressure intensifier Second pressure chamber B3
It descends to compress the fuel in the first pressure chamber B.
The fuel is pressure-fed from the second pressure chamber B3 with increased pressure according to the pressure-receiving area ratio of the large-diameter piston head of No. 2 and the small-diameter piston head of the second pressure chamber B3.
In addition, the first, second, third relief valves V8, V9, V
10 is a solenoid V8a controlled by the ECU,
Each operating spring V8 is activated by V9a and V10a.
The relief pressure is variably controlled by changing the set loads of V, V9b, and V10b.

The fuel oil pressure-fed from the second pressure chamber B in this way is then sent to the injection nozzle device A, but the first stop valve V3 disposed in the communication passage leading to the third pressurized space A2d is opened. , the pressurized fuel is supplied to the third pressurized space A2d as well as the first pressurized space A2b. Therefore, the third pressurized space A2d and the first pressurized space A2b have substantially the same hydraulic pressure to press the valve body A2 from both ends, but the spring A4 urges the valve body A2 toward the injection port A2e. Therefore, the injection port A2e
is closed by needle valve A3b. Injection port A
In order to open 2e, that is, to perform injection, the ECU E energizes the solenoid V2a of the second switching valve device V2 and switches the valve position to the position to open the hydraulic oil supply device C. Hydraulic oil is sent from the tank C1 to the second pressurized space A2c, and the hydraulic pressure applied to the bottom of the large diameter part of the valve body is used to move the valve body A2 to the spring A2.
Push up against the pressure of step 4. On the other hand, when the solenoid V7a is deenergized and switched to the second position,
The pressurized space A2c is communicated with the second oil passage C6', the hydraulic oil in the second pressurized space A2c is returned to the tank C1, and the needle valve A3b is lowered to close the injection port A2e and the injection ends. Therefore, the second switching valve device V2
The switching timing and valve opening time determine the opening/closing timing and opening time of the injection port A2e, and the fuel injection timing and injection amount depend solely on the operation of the ECU E that sends a command signal to the solenoid V2a. are doing.

The ECU E detects each of the rotation speed sensor S1 arranged around the output shaft of the engine, the top dead center position sensor S2, the accelerator S3 that determines the engine load, and the needle valve lift sensor S4 attached to the injection nozzle device A. The second switching valve device V2 is supplied with signals and according to a preset program based on those values.
A command signal is supplied to the solenoid V2a.

Next, if a failure occurs in ECU E or its wiring system, ECU E
No command signal is provided from E, so these solenoids are always deenergized. At this time, an appropriate fault display device (not shown) linked to the operation of ECU E indicates manual operation by the driver of the vehicle or ECU.
The first and second stop valves V3 and V4 are closed by suitable automatic switching means (not shown) which is activated in the event of a failure of E. When these stop valves V3 and V4 are closed, the third, fourth, and fifth stop valves V5 and V that operate in conjunction with these stop valves V3 and V4 are closed.
6, V7 is opened, and the oil pressure in the third pressurized space A2d of the injection nozzle device A is reduced to the relief tank T under low pressure.
The pressure is reduced to the oil pressure of , and the pressure intensifier B is supplied with hydraulic oil from the first pump F and fuel oil from the second pump G, respectively. 3rd and 4th stop valve V
5. At the same time as V6 is opened, the speed governor H that communicates with these starts operating, and the adjustment rod F3 of the first pump connected to the speed governor H is displaced and the plunger F2
is rotated, the timing at which the through hole F1a and the circumferential protrusion F2a match is changed, and therefore the timing at which hydraulic oil is supplied from the through hole F1b to the pressure intensifier B is variably controlled. Similarly, the adjusting rod G3 of the second pump G is displaced and the plunger G2 is rotated, and the notch G2a is formed so that the width thereof gradually increases. is changed, and the amount of fuel oil supplied from the through hole G1b to the pressure booster B is variably controlled. Therefore, the pressure booster B is supplied with hydraulic oil and fuel oil controlled by the speed governor H, and performs a fuel pressure boosting action, and the fuel pressure boosted in this way is supplied to the first pressurized space of the injection nozzle device A. Spring A with its hydraulic pressure is sent to A2b.
The valve body A2 is pushed up against the pressing force of 4 and is injected.

That is, when the ECU is in operation, the opening timing and opening time of the injection port A2e are controlled by adjusting the hydraulic pressure in the second pressurized space A2c in response to the spring force of the spring A4. At times, it becomes impossible to adjust the oil pressure in the second pressurized space A2c, so the first stop valve V3 is closed, and the fifth stop valve V7 is opened, so that the third pressurized space A2
The oil supply from pressure intensifier B to d is cut off to lower the oil pressure in the third pressurized space A2d, so that only spring A
The valve body A2 is urged in the valve closing direction by the pressing force of 4, and the injection port A2e is opened and closed by the force relationship between the oil pressure of the fuel supplied to the first pressurized space A2b and the pressing force of the spring A4. It was designed to be carried out in a timely manner.

As described above, according to the present invention, during normal times, the ECU
In addition, when the ECU is inoperative due to a malfunction, the control is switched to the governor, and fuel injection control that does not depend on the ECU is performed. Thus, it is possible to provide a highly reliable electronic pressure accumulation type fuel injection device that can ensure at least the minimum driving ability without making it impossible to drive a vehicle due to a failure of the ECU or the like.

[Brief explanation of the drawing]

FIG. 1 shows an overall view of an embodiment of a fuel injection device according to the present invention. A... Injection nozzle device, A2b... First pressurized space, A2c... Second pressurized space, A2d... Third pressurized space, A2e... Injection port, B... Pressure intensifier, B2...
First pressure chamber, B3... Second pressure chamber, C... Hydraulic oil supply device, C5... First oil path, C6, C6'...
2nd oil passage, D... fuel supply device, E... ECU,
F...First pump, G...Second pump, S1, S
2, S4...Sensor, V1, V2...Switching valve device, V3, V4, V5, V6, V7...Stop valve,
V8, V9, V10...Relief valve, V11, V
12...Check valve.

Claims (1)

[Claims] 1. Slide the valve body, which has a pressure receiving surface in the middle part and a needle valve at one end and is biased in the needle valve closing direction by a spring, into the valve body storage hole of the nozzle holder against the spring force. The valve body housing hole has a first pressurized space in the part corresponding to the needle valve, a second pressurized space in the part corresponding to the pressure receiving surface, and a third pressurized space in the part corresponding to the end opposite to the needle valve. A double-headed injection nozzle device each having a pressurized space and an injection port communicating with the first pressurized space, and a large-diameter piston head at one end and a small-diameter piston head at the other end. A type piston is provided, and the reciprocating movement of the piston defines a first pressure chamber therein by a large-diameter piston head and a second pressure chamber by a small-diameter piston head, and the second pressure chamber is defined by the injection nozzle device. a pressure intensifier connected to a first pressurized space and connected to the third pressurized space via a first stop valve; a first switching valve device and a second stop valve in the first pressure chamber of the pressure intensifier; A hydraulic oil supply device that supplies electronically controlled hydraulic oil through a second switching valve device and supplies electronically controlled hydraulic oil to a second pressurized space of the injection nozzle device via a second switching valve device. a fuel supply device that supplies electronically controlled fuel oil to a second pressure chamber of the pressure booster via a check valve; Valve device, first stop valve,
an electronic control device that supplies a command signal to a second stop valve; a first pump that is driven by the engine and supplies hydraulic oil to the first pressure chamber of the pressure booster via the third stop valve; the second of said pressure intensifier
A second pump that supplies fuel oil to the pressure chamber via a fourth stop valve, and a speed governor connected to the first pump and the second pump, and when the electronic control device is activated, the third and fourth pumps are connected to each other. Closing the stop valve and supplying hydraulic oil and fuel oil from the hydraulic oil supply device and the fuel oil supply device to the pressure booster, respectively;
While controlling the oil pressure supplied to the second pressurized space to control fuel injection, when the electronic control device is inactive, the first stop valve is closed and the third and fourth stop valves are opened to control the first pump. and a second pump supplies hydraulic oil and fuel oil to the pressure intensifier, respectively, and closes a second stop valve to supply pressurized fuel only to the first pressurized space, 1. An electronic pressure accumulation type fuel injection device for an internal combustion engine, characterized in that fuel injection is performed by controlling the injection timing by a first pump and controlling the injection amount by a second pump in accordance with the operation.