CN1114758C - Fuel injection device for reciprocating piston internal-combustion engine - Google Patents

Abstract

In order to form a defined quantity of fuel and bring it to the injection pressure, the device contains a metering piston designed as a pressure booster (1) with a stepped piston, in order to feed the fuel to one or more injector nozzles ( 5), the device has at least one control valve (3). The pressure booster (1) and the control valve are actuated by an electronically regulated hydraulic system, which is filled with operating oil at a low pressure substantially lower than the injection pressure by means of a pump. Individual injections are obtained by means of the control valve (3).

Description

Fuel injection devices for reciprocating piston internal combustion engines

                      

The present invention relates to a fuel injection device for a reciprocating piston internal combustion engine and a reciprocating piston internal combustion engine with such a device.

Background technique

In EP-A-0690222 a fuel injection device is described which has a metering piston filled with fuel by a fuel pump at a high pressure of up to 2000 bar and a control with a delivery member for delivering fuel piston. The control piston is moved between two end positions by means of an electrically regulated hydraulic system. The supplied fuel is conveyed from a fuel pump to the metering chamber via the conveying elements, or respectively from the metering chamber to the fuel injectors of the cylinders of a reciprocating piston internal combustion engine. The conveying elements are arranged in such a way that at either end position it is not possible to be connected both to the fuel pump and to a fuel injector of a cylinder at the same time.

Contents of the invention

The object of the present invention is to provide a fuel injection device for a reciprocating piston internal combustion engine, which can control the fuel injection nozzles one by one.

The device for injecting fuel according to the present invention comprises: a structure for supplying fuel, which has a metering piston for metering the amount of fuel injected, a control device for controlling the metering piston, a The supplied fuel quantity is delivered to a fuel injector control element and a hydraulic electric device for controlling the injection. In order to increase the fuel pressure to the injection pressure, the metering piston is designed as a pressure amplifier; the control element is designed as a The flow direction is set to the control valve after the pressure amplifier; the control device and the control valve are connected with the hydraulic electric device in order to control the injection process, the pressure amplifier is designed as a stepped piston; the structure for supplying fuel is charged into the In the working chamber of the small piston, the control device is designed as a control slider connected with the working chamber of the large piston.

The fuel supply is simplified by using a pressure booster, so that the fuel reservoir and the high pressure pump at pressures up to 2000 bar can be dispensed with. With this measure, the risk of leakage can be largely eliminated and the safety at work is increased. By means of the control valve, it is possible to deactivate the fuel injectors simultaneously and to produce intermittent injection and/or to close one or more injection valves of an internal combustion engine. When all fuel injectors of one cylinder of the internal combustion engine are disabled, the internal combustion engine can be operated at partial load by the remaining cylinders.

In partially clogged or flushed injectors, the injection volume can remain unchanged. Injection can be controlled in time when trajectory measurement is interrupted. If an ignition pressure measuring device is used, the injection device can be used to adjust the ignition pressure to a permissible value, so that the best fuel consumption can always be obtained.

Description of drawings

The drawing shows an embodiment of the device of the invention.

Detailed ways

The injection device comprises a pressure booster 1 and a control slide 2 movable between two end positions as well as a control valve 3 and a hydroelectric unit 4 . The pressure booster 1 is designed as a stepped piston with two pistons 7 , 8 of different diameters. The pistons 7, 8 are in any case movably arranged in a chamber 9, 10, the chamber 9 for the large piston 7 being connected to the control slide 2 via a channel 11, and the chamber 10 for the small piston 8 It is connected via a channel 12 to the control valve 3 and via a channel 13 to a structure 14 for supplying fuel oil, for example diesel or heavy oil. Arranged in the chamber 9 is an elastic means 15 which holds the pressure booster 1 in one end position. In this end position, the connecting channel 11 connected to the control slide 12 is blocked, but the connecting channels 12 and 13 connected to the control valve 3 and the fuel supply structure 14 respectively are open. The control slide 2 is arranged in a cylinder-shaped chamber 21 with a supply channel 22, connected to the consumer (consumer) channel 11 on the pressure amplifier 1, and a discharge channel 24 and a A channel 25 for the pressure device and a leakage channel 26 . A spring 27 is arranged in the cavity and keeps the control slide 2 in an end position while the channel 25 is closed. The control slide 2 is cylindrical and has two control edges 32 , 32 in order to control the flow of a medium. The control valve 3 has an on/off function and has a valve body 41 with a valve seat, a fuel supply channel 42, a return channel 43 and a user channel 44, a valve slide 45 with a valve cone 46 and A known drive 47 for the valve slide. The hydraulic power unit 4 includes a plurality of hydraulic pumps 51 (only one is shown), an oil reservoir 52, pre-control valves 53, 54 for controlling the slide 2 and the control valve 3, one for indicating the rotation angle and Angle sensor 55 for the crank position, a device 56 for sampling the position of the pressure booster and an electronic controller 57 connected in signal transmission to the pilot control valves 53 , 54 , angle sensor 55 and device 56 . The device 56 is preferably designed as an inductance measurement system. Of course it is also possible to use other measuring systems, for example capacitive, optical, magnetic or similar. To compensate dead time, an injection volume adjustment with suitable components is provided. In addition, a suitable adjustment of the start of injection is provided as a function of the rotational speed. The actual values of the speed and position of the metering piston can be detected and controlled by comparison with ideal values of the speed and position of the metering piston.

As shown in the figure, a plurality of lines 61 branch from the oil reservoir 52, which in any case provides a cylinder for a reciprocating piston internal combustion engine, so that the cylinder can have one or more injectors. Grease mouth. Line 61 is connected to control slide 2 and to supply channel 22 of pilot valves 53 , 54 . Line 62 is provided for each discharge valve (not shown). As already mentioned, the pressure booster 1 is connected to the control valve 3 .

As shown, a plurality of control valves 3 can be connected to the pressure amplifier 1 . This pressure booster fulfills two tasks, one is metering and the other is increasing the fuel pressure for each injection process. The metering of the fuel is carried out by means 56 which constantly determine the distance traveled and supply it as a signal to the electronic control unit 57 . The displaced volume can be determined by the cross-section and travel path of the small piston 8 of the pressure booster 1, so that a volumetric injection is achieved. Furthermore, for example a damaged injector can also be determined indirectly by means of a metering piston sensor, since in this case the speed of the metering piston is greater than usual during the injection process. Using this signal, the electronic device can suppress the injection of fuel into the cylinder by the defective injector, thus appropriately reducing the load on the entire motor and/or report the defect by the alarm device. The hydraulic pump further controls the supply of oil into the oil reservoir 52 at a pressure of about 100-300 bar. The energy contained in this oil is used to brake the device as described below.

The figure shows the device in the pre-injection state, in which the structure 14 supplies fuel at a pressure of about 10 bar to the pressure amplifier 1 and starts the injection, as described below. In short, before starting the injection, the pilot control valve 53 for the control slide 2 is braked by the electronic control unit 57 and the control slide is moved relatively slowly into the working position. Control oil flows into the larger chamber 9 of the pressure booster 1 and moves the stepped piston so the fuel present in the smaller chamber 10 moves. Since the small chamber 10 is blocked on the one hand by a non-return valve in the structure 14 and on the other hand by the closed control valve 3, a pressure corresponding to the surface ratio of the stepped piston builds up. During the pressure build-up, or after the valve slide 45 brakes, the control valve 3 opens, so that fuel flows into the injectors. In order to prevent low-pressure injection, the injection process ends very quickly.

After the injection process is over, the control slide 2 returns to its rest position, so that control oil can flow out of the large piston chamber 9 of the pressure booster 1 via the channels 11 and 24 . In this way, the recovery is supported by means 15 and the fuel newly flowing into the small piston chamber 10 of the pressure booster 1 .

In order to define a certain amount of fuel and bring it to the injection pressure, the device contains a metering piston designed as a pressure booster 1 with a stepped piston, for supplying fuel to one or more injector nozzles 5, the The device has at least one control valve 3 . The pressure booster 1 and the control valves are actuated by an electronically regulated hydraulic system, which is filled with operating oil at a low pressure substantially lower than the injection pressure by means of a pump. Individual injections can be achieved by means of the control valve 3 .

Claims (12)

1. A device for injecting fuel, comprising: a structure (14) for supplying fuel, which has a metering piston (1) for metering the amount of injected fuel, and a metering piston (1) for controlling the amount of fuel injected. A control device (2), a control member (3) for delivering the supplied fuel quantity to a fuel injection nozzle (5) and a hydraulic electric device (4) for controlling the injection, characterized in that: In order to increase the fuel pressure to the injection pressure, the metering piston is designed as a pressure booster (1); the control element is designed as a control valve (3) arranged downstream of the pressure booster in the flow direction; the control device (2) and control The valve (3) is connected with the hydraulic electric device (4) in order to control the injection process, the pressure amplifier is designed as a stepped piston (1); the structure for supplying fuel (14) fills the small piston (8) with fuel In the working chamber (10) of the large piston (7), the control device is designed as a control slider (2) connected to the working chamber (9) of the large piston (7). 2. The device according to claim 1, characterized in that: there is a sampling device (56) for detecting the current position of the pressure amplifier (1) and comparing the actual position of the pressure amplifier (1) with an ideal position . 3. The device according to claim 2, characterized in that it has a sampling device (56) for detecting the actual speed of the pressure amplifier (1) and comparing the actual speed of the pressure amplifier with an ideal speed. 4. The device according to any one of claims 1-3, characterized in that: there is a device with one or more oil reservoirs (52, 53) for supplying working oil and a plurality of oil reservoirs (52, 53) for each control slide Block and pre-control valves (53) for each control valve. 5. The device as claimed in claim 1, characterized in that there is a suitable regulating device (57) for regulating the start of the injection or the injection quantity according to the comparison between the corresponding actual value and the ideal value. 6. The device as claimed in claim 1, characterized in that there is a suitable regulating device (57) for regulating the start of the injection and the injection quantity according to the comparison between the respective actual and ideal values. 7. The device according to any one of claims 1, 2, 5 and 6, characterized in that in order to supply charge to a plurality of cylinders of an internal combustion engine or to supply fuel to a plurality of injectors of a cylinder, a plurality of control Valve (3) is connected to this pressure amplifier (1). 8. The device according to any one of claims 1, 2, 3, 5 and 6, characterized by means for injecting diesel or heavy oil into each cylinder of a reciprocating piston internal combustion engine. 9. A reciprocating piston internal combustion engine, said internal combustion engine is a two-stroke or four-stroke internal combustion engine, characterized in that it comprises the device described in any one of claims 1, 2, 3, 5 and 6. 10. A reciprocating piston internal combustion engine, said internal combustion engine is a two-stroke or four-stroke internal combustion engine, characterized in that it comprises any one of the devices in claim 4. 11. A reciprocating piston internal combustion engine, said internal combustion engine is a two-stroke or four-stroke internal combustion engine, characterized in that it comprises the device of any one of claim 7. 12. A reciprocating piston internal combustion engine, said internal combustion engine is a two-stroke or four-stroke internal combustion engine, characterized in that it comprises any one of the devices in claim 8.

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