GB2261260A

GB2261260A - Control of fuel feed to an i.c. engine injection pump.

Info

Publication number: GB2261260A
Application number: GB9221897A
Authority: GB
Inventors: Christoph Burckhardt
Original assignee: Daimler Benz AG; Mercedes Benz AG
Current assignee: Daimler Benz AG
Priority date: 1991-11-07
Filing date: 1992-10-19
Publication date: 1993-05-12
Anticipated expiration: 2012-10-19
Also published as: IT1258891B; ITRM920798A1; FR2683592A1; FR2683592B1; DE4136626C1; GB9221897D0; ITRM920798A0; GB2261260B

Description

1 A control.device for deactivating an internal combustion engine ) -, S.'

' - C- # -)J The invention relates to a control device for deactivating an internal combustion engine, particularly but not exclusively, an electronically controlled diesel internal combustion engine with an in-line type injection PUMP.

In an electronic diesel control with in-line type injection pump, in the event of a fault there is the problem of redundant fuel shut-off, e.g. in the case of the control rod jamming, in the case of the actuator jamming or in the case of the element piston seizing. However, due to the high accumulator volume and the self induction by the element pistons a satisfactory measure by interrupting the supply of fuel to the inlet chamber of the injection pump cannot be achieved.

However, EP 0 124 504 Al discloses a control device with which rapid deactivation of the internal combustion engine by means of a control valve arrangement is possible, the two directional control valves of which arrangement are switched over to extraction. Thus, the feed pump does not take any fuel in f rom the fuel tank but rather f rom the inlet chamber of the injection pump via a first electromagnetically actuable 4/3 directional control valve and also does not f eed the fuel to the inlet chamber of this injection pump but rather to the fuel tank via a second electromagnetic 3/2 directional control valve.

The design of the line arrangement and the control valve arrangement are constructionally complex.

The present invention seeks to achieve, using simple means, an extremely compact and space-saving embodiment for deactivating an internal combustion engine in the event of fault.

According to the present invention there is provided control device for deactivating an internal combustion 2 engine with an in-line type injection pump, having a control valve arrangement which has a delivery position and a switched-off position and is intermediately connected in a inlet line leading from a fuel tank to a delivery pump and in a delivery line leading from the delivery pump to an inlet chamber of the injection pump and, in the switc4ed-off position, connects the inlet chamber to the fuel tank via the delivery pump, wherein the control valve arrangement comprises a controllable rotary disc valve mounted in a valve housing which has all the connections for the respective flow connections and brings about a flow reversal in the delivery line section located between the rotary disc valve and the inlet chamber and in the inlet line section extending between the rotary disc valve and the fuel tank.

By using a rotary disc valve as control valve f or the necessary f low connections, an economical and compact design is obtained. In addition, the extent of line branching is simplified, since the existing line to the injection pump serves not only as a f eed or delivery line but also as an outlet or inlet line when the fuel supply is interrupted. The same applies also f or the line from the fuel tank to the control valve, which acts on the one hand as a inlet line and on the other as a return line.

Thus, it the event of a fault in the electronics, a rapid interruption in delivery is realised.

An embodiment of the invention is illustrated in the drawing and explained in greater detail below with reference to the drawing in which:

Fig. 1 shows an embodiment according to the invention in a diagrammatic view Fig. 2 shows the control valve in section in an enlarged view and Fig. 3 shows the control valve which is f lange-connected to the injection pump.

Fig. I shows a control device 1 which is intended for a diesel internal combustion engine with electronic fuel control.

3 The control device 1 is composed of a 2-bladed rotary disc valve 2 as control valve in a pot-like valve housing 3. An inlet line designated by 4 leads from a fuel tank 5 via the control valve to a delivery pump 6 f rom which a delivery line 7 starts and via the control valve to the inlet chamber 8 of an in-line type injection pump 9.

The pot-like valve housing 3 is flange-connected onto the side of the inline injection pump 9 and provided with two approximately half -moonshaped housing segments 10, 11 which are located symmetrically with respect to one another and have radially extending channels 12, 13 which open into an intermediate space 14 formed between the housing segments 10, 11, in which space the rotary disc valve 2 is mounted. The channel 12 is connected to an inlet line section 4b which leads to the delivery pump 6 and the channel 13 is connected to a delivery line section 7a which leads away from the delivery pump 6.

The intermediate space 14 is divided into two chambers 14a, 14b by the rotary disc valve 2 constructed as a dividing wall, control bores 15, 16 which open into the chambers interacting with the blades 2a, 2b of the rotary disc valve. The control bore 15 which penetrates the floor 3a of the valve housing 3 is connected to the inlet line section 4a which starts from the fuel tank 5. The control bore 16 is located in the housing 17 of the in-line injection pump 9 and connects the inlet chamber 8 of this in-line injection pump 9 to a chamber 14b of the valve housing 3 and to the delivery pump 6 via the delivery line sections 7b. The base 3a is the running or sliding surface for one side of the rotary disc valve 2, whilst the milled surface on the side of the in-line type injection pump 9 is the running or sliding surface for the other side of the rotary disc valve 2.

Provided in the valve housing 3 are two pole shoes 18, 19 which are located diametrically opposite one another, interact with the blades 2a, 2b and., when a triggerable electromagnet 20 is energised, hold the rotary disc valve 2, 4 constructed as a magnet armature, in the delivery position with a flow connection on the one hand between the fuel tank 5 and the deliver pump 6 and on the other hand between the deliver pump 6 and the injection pump 9. The delivery pump 6 takes in fuel from the container 5 through the inlet line 4 (inlet line section 4a - control bore 15 chamber 14a channel 12 - inlet line section 4b) and delivers it through the deliver line 7 (delivery line section 7a - fuel filter 22 - channel 13 chamber 14b - control bore 16 - delivery line section 7b inlet chamber 8) which leads to the inlet chamber 8 of the injection pump 9. This rotary disc valve position is illustrated in Fig. 1.

In the event of a f ault in the electronics, the electromagnet 20 is deactivated and the rotary disc valve 2 is transferred by the restoring spring 21 into its switchedoff position shown in Fig. 2. Here, the blades of the rotary disc valve 2 pass over the control bores 15, 16 and produce a new flow connection. The delivery line section 7b becomes the return or inlet line whilst the inlet line section 4a likewise becomes the return line.

With a valve housing 3 embodied as a die-cast component, the electromagnet 20, with plug and yoke 23, for actuating the rotary disc valve 2 can be integrated into said die-cast component.

claims 1. A control device for deactivating an internal combustion engine with an in-line type injection pump, having a control valve arrangement which has a delivery position and a switched-off position and is intermediately connected in a inlet line leading from a fuel tank to a delivery pump and in a delivery line leading from the delivery pump to an inlet chamber of the injection pump and, in the switched-off position, connects the inlet chamber to the fuel tank via the delivery pump, wherein the control valve arrangement comprises a controllable rotary disc valve mounted in a valve housing which has all the connections for the respective flow connections and brings about a flow reversal in the delivery line section located between the rotary disc valve and the inlet chamber and in the inlet line section extending between the rotary disc valve and the fuel tank.

Claims

2. A control device according to Claim 1, wherein the valve housing is of

pot-like construction and has two half-moon-shaped housing segments which are located symmetrically with respect to one another and between which an intermediate space is formed as bearing for the rotary disc valve which is of two-bladed construction and divides the intermediate space into two chambers into which control bores open.

3. A control device according to Claim 2, wherein each housing segment has an at least approximately radially extending channel which runs into the respective chamber, one of which channels is connected to the inlet side of the delivery pump and the other to the delivery side of the delivery pump, whilst one control bore (15) is connected to the fuel tank and the other control bore is connected to the inlet chamber of the injection pump.

6 4. A control device according to Claim 1, 2 or 3, wherein, in the delivery position of the rotary disc valve, there is a f low connection between the fuel tank and the delivery pump and a f low connection between the delivery pump and the inlet chamber in each case with intermediate connection of the control valve,, and in the switched-of f position, the rotary disc valve which is rotated by a restoring spring produces a f low connection between the inlet chamber and the delivery pump and a f low connection between the delivery pump and the f low container in each case with intermediate connection of this control valve.

5. A control device according to any one of the preceding claims, wherein the rotary disc valve comprises a magnet armature, and in the valve housing, the blades of the rotary disc valve are assigned pole shoes which hold the rotary disc valve in the delivery position counter to the force of the restoring spring when the electromagnet is energised.

6. A control device according to any one of Claims 1 to 5, wherein the valve housing is flange-connected to the injection pump as an attachment in such a way that the injection pump-side contact face is at the same time the running face for the rotary disc valve.

7. A control device according to any one of the preceding claims wherein the engine comprises an electronically controlled diesel internal combustion engine.

8. A control device for deactivating an internal combustion engine with an in-line type injection pump, substantially as described herein with reference to and as illustrated in the accompanying drawings.