DD205217A1 - FOUNDER DEVICE FOR EQUAL PRESSURE INJECTION SYSTEMS OF INTERNAL COMBUSTION ENGINES - Google Patents

Abstract

The inventive Foerdereinrichtung is intended for injection quantities with constantly pressurized, but separately controlled injectors, especially for motor vehicle engines. It includes a motor-driven high-pressure pump and pump, the latter feeding the suction side of the high-pressure pump. The object is to design the Foerdereinrichtung so that before the start of the engine, the injection system is operational. Erfindungsgemaess this is achieved in that the conveyor pump is coupled on the one hand to an output shaft of the engine with the interposition of a one-way clutch and on the other hand with the interposition of another one-way clutch an auxiliary motor is connected, wherein by means of a switching valve, the pressure side of the delivery pump to the high pressure circuit or after reaching the target form to the suction side of the high pressure pump is connectable. In a further advantageous variant, the alternator can serve as an auxiliary engine.

Description

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Title of the invention:

Conveyor for constant pressure injection systems of internal combustion engines

Field of application of the invention;

The invention relates to the conveyor of constant pressure injection systems with constantly pressurized, but separately controlled injectors for internal combustion engines and driven by the engine high pressure and delivery pump for the fuel, the pressure side of the pump is completed in the operating state to the suction side of the high pressure pump. The invention is particularly intended for conveyors of constant pressure injection systems on automotive internal combustion engines.

Characteristic of the Prior Art:

Previously known is a conveyor of the initially described. very high genus for high-pressure storage injection systems by the DD-PS 126 713 "The high-pressure pump is acted upon suction side with the interposition of a filter from a feed pump and feeds the injection circuit with the high-pressure accumulator.

Furthermore, it is known in an above-described conveyor for use in marine diesel engines to provide an additional, not by the internal combustion engine, but by a • electric motor driven pre-pressure pump before

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the start of the high-pressure accumulator of the injection circuit is applied to a minimum pressure, but is turned off during the rest of the engine operation; Document: "SKL ~ Engines - electrically controlled injection system on the diesel engine 6VDS 26/20 ALE-2", published by: VEB Schwermaschinenbau Karl Liebknecht Magdeburg, 1981. The above-described conveyors are the cranking conditions of a motor vehicle diesel engine do not do justice. In the first version it is necessary to use the starter to drive the diesel engine and the high-pressure and delivery pump until a minimum accumulator pressure in the injection circuit for the fuel has been established. The disadvantage is that a larger amount of energy from the starter battery must be removed to the readiness of the fuel injection quantity.

In the further embodiment, a separate smaller externally driven high-pressure pump is required, which has to fulfill any function during normal operation · Previously also injection systems according to DE-OS 26 17 841, in which the injection quantities are conveyed via a pressurized by a variable-pressure pump pressure transducer · These systems have a fuel delivery pump that feeds both the high pressure pump and the injection circuit of the pressure transducer. The pressure side of the fuel supply pump is connected via a respective check valve with the injection circuit of the pressure transducer and the inlet of the high pressure pump · Previously known by DE-OS 20 53 140 and conveyors for low-pressure injection, the hydraulically connected in series each have a delivery and pressure pump, wherein both pumps are electrically driven * These solutions offer because of the different injection systems no suggestion for the present invention associated task »

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Object of the invention %

In storage fuel injection systems of the type mentioned is to be achieved that the starting process by means of starter time as short as possible and with rapid pressure build-up in the high pressure circuit and minimal energy extraction from the starter batteries »In addition, no starting energy for preparing the operational readiness of the storage injection system for the internal combustion engine expended during the starting process become·

Explanation of the essence of the invention:

The invention has for its object to provide a conveyor, which inevitably ensures an immediately ready-to-operate injection system at starter function for the internal combustion engine and is also used in the usual engine operation.

According to the invention the object is achieved by using the usual in automotive internal combustion engines alternator in such a way that the feed pump is coupled on the one hand to an output shaft of the engine with the interposition of a one-way clutch and on the other hand verbund with a switchable as an auxiliary alternator is the, by means of a pressure-controlled changeover valve the pressure side of the feed pump can be connected to the high pressure circuit or to the suction side of the high pressure pump.

According to the invention, it is also possible that the feed pump is coupled on the one hand to an output shaft of the internal combustion engine with the interposition of a one-way clutch and on the other hand connected with the interposition of another one-way clutch with an auxiliary motor, wherein by means of a switching valve, the pressure side of the delivery pump to the high pressure circuit or after Reaching the desired admission pressure can be connected to the suction side of the high-pressure pump.

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Both versions ensure that the conveyor can serve both as a Vordruckerzeuger for the high pressure circuit and for feeding the high pressure pump.

In the first described embodiment, moreover, the alternator is advantageously used as an auxiliary motor, so that a separate auxiliary motor as in the second embodiment can be omitted.

It is advantageous that the switching valve is directly or indirectly - z · B, electrically driven by a pre-pressure switch - driven by the high pressure circuit and after reaching the target form in the high pressure circuit, the pressure side of the feed pump from the high pressure circuit is disconnected, but connected to the suction side of the high pressure pump.

This embodiment and also the next embodiment brings advantages for both mentioned erfindungsge-. proper solutions «ν

To inevitably secure the operational readiness of the injection system before the starter operation, it is advantageous that the starter circuit is controlled by means of a pressurized from the high pressure circuit Vordrucksehalters and turned on only after reaching the form in the high pressure circuit.

In the above-described conveyor, in which the alternator serves as an auxiliary motor, it is advantageous if the alternator by means of a switch directly from the starter switch and a directly or indirectly controlled switch / regulator as a motor or as a generator to the electrical system is connectable, wherein a circuit on . Engine operation is then set when the starter switch is actuated and the pressure in the high-pressure circuit is less than the nominal pre-pressure «

It is expedient that the form pressure switch assigned to the switching valve and actuated by the actuating organs of the switching tventiles.

This design results in a simple electrical and hydraulic ^ switching device with only one actuator.

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Embodiment:

With reference to a drawing, embodiments of the invention will be described. It shows:

Fig. 1 shows a conveyor according to the invention to an internal combustion engine with a DC alternator

Fig. 2 shows a conveyor according to the invention with an electric auxiliary motor. .

Schematically, FIG. 1 shows an internal combustion engine with a "constant pressure injection system" using electromagnetically controlled injection valves. For feeding the high-pressure circuit 1 with the pressure accumulator 2 of the injection system driven by the engine high-pressure pump 3 is provided. This high-pressure pump 3 is conveyed on the suction side 3s of the fuel from a pump 4 sucking from the fuel tank 4 via the pressure side 5d with the interposition of a switching valve 6. On the one hand, the non-return valve 62 is connected to the pressure side 5d of the feed pump 5, which on the other hand leads to the high-pressure circuit 1. "Also, the directional control valve 61 to the pressure side 5d of the feed pump 5 is connected, whereby it blocks the flow at too low pressurization of the high pressure circuit 1 - under target pressure - and at higher pressure than the target form the flow to the suction side 3s of the high pressure pump 3 opens. A pressure relief valve 16 limits the filling pressure at the suction side 3s of the high-pressure pump 3 to a much lower pressure level of 0.015-0.03 MPa. This results in the following operation: At lower pressure than the target pressure on the high pressure side 1 · the directional control valve 61 is locked. The feed pump 5 acts on the check valve 62, the high pressure side 1, wherein the form is constantly increasing «.

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When the setpoint pressure on the high-pressure side 1 is exceeded, the hydraulically actuated directional control valve 61 opens and the delivery rate of the delivery pump 5 flows to the suction side 3s at the substantially lower pressure level. The check valve 62 remains closed due to the self-adjusting low delivery pressure of the feed pump 5 against the target i on the high pressure side 1 · The described function of the switching valve 6 allows the feed pump 5 both for form pressure in the high pressure circuit 1 before the start of the engine and to supply the high-pressure pump 3 during engine operation «

The switching valve 6 could also be indirectly controlled by the high-pressure circuit 1. Mechanically, the drive of the feed pump 5 is connected on the one hand with the interposition of a one-way clutch 7 with a secondary drive shaft of the internal combustion engine and on the other hand with an auxiliary motor 8; 10 coupled to the drive during the starting phase.

Substituting a conventional DC generator by appropriate electrical wiring as an auxiliary motor 8, so there can be a direct coupling to the feed pump 5 of FIG. The use of a three-phase alternator as a motor requires a separate circuit, which is not content of this application.

The one-way clutch 7 allows that only the feed pump 5 can be driven by the DC motor 8 connected as a motor before the starting process of the internal combustion engine until the admission pressure in the high pressure ^ circle 1 is reached. The one-way clutch 7 acts as a freewheel in this case. From the start of the internal combustion engine with the starter 9, both the high-pressure pump 3 and the one-way clutch 7, the feed pump 5, and the DC generator 8 is driven by the secondary engine of the internal combustion engine. By electrical switching measures, which will be described later, j

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after reaching the target pressure in the high pressure circuit 1 of the DC generator connected as such to the electrical system and the starter turned on.

If an embodiment according to FIG. 2 is provided with a separate auxiliary engine 10 which is intended to drive the delivery pump 5 only before starting the internal combustion engine, then a further one-way clutch 11 must be arranged between the delivery pump 5 and the auxiliary engine 10. This one-way clutch 11 acts as a freewheel when the feed pump 5 is driven by the internal combustion engine via the secondary drive shaft and the one-way clutch 7 ·

In order to ensure an appropriate function of the conveying device according to the invention under different operating conditions, a number of electrical circuit measures are provided.

At the high pressure circuit 1 a pressurized by this form pressure switch 12 is arranged, which closes the starter circuit 13 only after reaching the desired form. He is in line with the starter switch 14

When using a DC generator as an auxiliary motor 8 for the feed pump 5, the form pressure switch 12 is designed as a switch, depending on the pressure ratios higher or lower than the desired form in the high-pressure circuit 1 alternatively when the starter switch 14, the auxiliary motor 8 via the switch / controller 15 or the Starter 9 turns on · The switch / controller 15 closes the DC generator appropriately as an auxiliary engine 8 or alternator to the electrical system of the vehicle with the internal combustion engine. It is also possible to use the actuators of the change-over valve 6 to actuate the form pressure switch 12, since they also react when exceeding or falling below the form in Hochdrückkreis. The result is a compact hydraulic and electrical switching unit with only one connected to the high-pressure circuit, hydraulic-mechanical control system * The acted upon by the high-pressure circuit 1 injectors are driven by the control electronics 17 «.

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Claims (5)

Invention claim: 1, conveying device for constant pressure injection systems with constantly pressurized, but separately controlled injection valves for internal combustion engines and driven by the engine high-pressure pump, generator and pump whose pressure side is connected in the operating state to the suction side of the high-pressure pump, characterized in that the delivery pump (5) is coupled, on the one hand, to an output shaft of the internal combustion engine with the interposition of a one-way clutch (7) and, on the other hand, connected to an alternator as an auxiliary engine (8), wherein the pressure side (5d) of the delivery pump is provided by means of a pressure-controlled change-over valve (6) (5) can be connected to the high-pressure circuit (1) or to the suction side (3a) of the high-pressure pump (3), 2. conveying device for constant pressure injection systems with constantly pressurized, but separately controlled injection valves for internal combustion engines and driven by the engine high pressure and delivery pump for the fuel, the pressure side of the feed pump is connected in the operating state to the suction side of the high pressure pump, characterized characterized that the feed pump (5) is coupled on the one hand to an output shaft of the internal combustion engine with the interposition of a one-way clutch (7) and on the other hand with the interposition of a further one-way clutch (11) with an auxiliary motor (10) is connected, wherein by means of a switching valve (6) the pressure side (5d) -9- 240065 2 the delivery pump (5) to the high-pressure circuit (1) or after reaching the target form to the suction side (3s) of the high-pressure pump (3) is connectable. 3. Conveying device according to item 1 or 2, characterized by that the switching valve (6) directly or indirectly -. B · is electrically controlled by a pre-pressure switch - from the high pressure circuit (1) and after reaching the desired form in the high pressure circuit (1) the pressure side (5d) of the feed pump (5) from the high pressure circuit (1) separated, but to the suction side (3s) the high-pressure pump (3) is connected, 4. conveying device according to item 1 or 2, characterized by in that the starter circuit (13) is controlled by means of a pre-pressure switch (12) acted upon by the high-pressure circuit (1) and is switched on only after reaching the admission pressure in the high-pressure circuit (1). Conveyor according to item 1,
characterized by in that the alternator can be switched on as an engine or as a generator to the vehicle electrical system by means of a switch (14) and a directly or indirectly controlled by the high-pressure circuit, wherein a circuit is set to motor operation when the starter switch (14) operated and in the high-pressure circuit (1) the pressure is less than the desired form. 6. Conveyor according to point 3 »
characterized by in that the admission pressure switch (12) is assigned to the changeover valve (6) and can be actuated by the actuators of the changeover valve (6) » 2 sheets of drawings,