GB2085965A

GB2085965A - Fuel injection pump delivery quantity and timing regulator

Info

Publication number: GB2085965A
Application number: GB8129318A
Authority: GB
Original assignee: Friedmann and Maier AG
Current assignee: Friedmann and Maier AG
Priority date: 1980-10-24
Filing date: 1981-09-29
Publication date: 1982-05-06
Also published as: GB2085965B; ATA526180A; AT367170B; DE3140838A1

Abstract

The axial position of cams 10 and 15 which respectively determine fuel injection quantity and timing is set by a capsule 21 responsive to an engine load dependent pressure. The capsule 21 engages an abutment 25 carried by the core of a solenoid 22. When the solenoid 22 is energised the core abutment 28 engages an engine coolant temperature responsive abutment 23 to permit increased fuel delivery for starting with appropriate timing of the beginning of injection. The angular position of the cams 10 and 15 is set by a rack and pinion 12, 13 operated by a speed governor mechanism (2, 3). Fig. 1 (not shown). <IMAGE>

Description

SPECIFICATION Fuel injection pump regulator The invention relates to apparatus for regulating the commencement of injection and the injection quantity of a fuel injection pump for an internal combustion engine in dependence upon operating parameters, in which the injection quantity is increased for starting, by means of an electro-magnet, and both the injection quantity and the instant of commencement of injection i.e. injection timing, are adjusted in dependence at least upon the engine load.

When the adjustment of the commencement of injection is performed by means of a by-pass piston, a different commencement of injection is obtained dependently upon the stroke of the by-pass piston. The stroke of such a by-pass piston is controlled by a separate regulator rod, and the control of this regulator rod as well as the control of the regulator rod which determines the quantity conveyed, are to be effected in dependence upon various influencing factors or operating parameters of the internal combustion engine.

The control rods provided for the adjustment of the commencement of injection and the injection quantity, respectively, may be displaced in this case by means of separate linkages which are preferably formed by displaceable and rotatable three dimensional cams hereintermed space cams, respectively.

It is already known to arrange the cams or space cams in a displaceable and/or rotatable manner in dependence upon operating parameters, the cams for the regulator of the commencement of injection as well as the cams for the regulation of the injection quantity being arranged in a displaceable and rotatable manner on the same shaft.

Furthermore it is also known already to increase the injection quantity for the start of the internal combustion engine beyond the maximum injection quantity permissible in operation. For the purpose of providing such an excess starting quantity electro-magnets have previously been proposed, and furthermore it has already been proposed to limit the maximum excess starting quantity in dependence upon an abutment which is adjustable by an operating temperature.

The invention seeks to provide a constructional form which can be built particularly simply and compactly and in which the number of movable parts is at the same time kept as low as possible.

According to the present invention, there is provided apparatus for regulating the commencement of injection and the injection quantity of a fuel injection pump for an internal combustion engine in dependence upon operating parameters, wherein the injection quantity is increased for starting by means of an electro magnet and both the injection quantity and the injection timing are regulated in dependence upon at least a load dependent pressure, and wherein a capsule for measuring the load dependent pressure is arranged to act in series with the core of the electromagnet to adjust the position of regulating members for the injection quantity and the injection timing by way of a common transmission linkage.

Owing to the fact that the core of the electro-magnet is arranged in the effective line of action of the load dependent pressure measuring capsule, the displacement movements effected by the pressure measuring capsule, may effect, e.g. by way of a common lever the adjustment of case, or spatial cams, for the adjustment of the regulating member for the injection quantity and the instant of injection, without a mutual interference occurring.

The electro-magnet is effective solely at starting and at this instant of time a load dependent pressure has not yet been built up. After starting the electro-magnet is de-energised again and the signals of the pressure measuring capsule can set on the regulating member for the injection quantity and the injection instant in an unaffected manner, In this case a co-axial arrangement of the electro-magnet and the pressure measuring capsule leads to a particularly small and compact assembly which, according to a preferred feature of the invention, may be embodied in a common module and preferably cooperates by way of a two-armed lever on the regulating member, in particular by way of respective space cams.

By means of the two-armed lever, further shortening of the constructural length may be obtained.

According to a preferred further development of the subject of the invention the construction is made such that a temperaturedependent abutment, for example an expansion element, for the temperature-dependent limitation of the excess starting quantity is arranged co-axially with the core of the electro-magnet for delivery of the excess starting quantity. The additional temperature-dependent abutment may also be grouped together with the pressure measuring capsule and the electro-magnet to form a common constuctional unit, resulting in small constructional dimensions.

The invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic illustration of a regulator viewed in the axial direction of the shaft common to the adjuster cams, and Figure 2 is a diagrammatic illustration of the apparatus according to the invention, in plan.

Referring to the drawings, rotary speed measuring mechanism 2 and a limit idling speed measuring mechanism 3 are arranged on a rotary shaft 1. A regulator rod 5 for regulating the injection quantity is displaced by means of a spring-loaded socket 4 by by a lever 6, The lever 6 itself may be manually displaced by means of a selector lever 7 between a ful load position and no load position. The regulator rod 5 is connected to an arm 8 which is moved by a cam follower roller 9 in contact with a space cam 10 for the purpose of regulation of the injection quantity.

A sleeve 11 of the rotary speed measuring mechanism 2 is connected to a pinion 1 3 by means of a toothed rack 1 2. The pinion 1 3 adjusts the rotary position of a shaft 14 on which are mounted the space cams 10 effective for the quantity adjustment of the injection time. The cams 10 and 1 5 can slide on the shaft 14 but are revented from rotating relative to the shaft by splines or keys.

Since very rotary speed of the shaft 1 is associated with a certain sleeve position 11 by way of the rotary speed measuring mechanism 2, a rotary position proportional to the rotary speed, of the shaft 14 is obtained by means of the toothed rack 1 2 and the pinion 1 3. The space cam 1 5 co-operates with a follower roller 1 6 of a regulator rod 1 7 which effects the regulation of the injection timing.

Thus, by rotation of the shaft 14, the injection quantity and the injection instant are adjusted in dependence upon the low determined by the contours of space cams 10 and 1 5.

The space cams 10 and 1 5 are located on a common slider sleeve 1 8 which may be displaced in dependence upon the load dependkent pressure for example the induction mainfold pressure. For this purpose the end of the slider sleeve 1 8 is connected to the pressure sensing device 20 by means of a lever 19.

The pressure sensing device 20 which comprises a barometer capsule 21 is arranged coaxially with an electro-magnet 22 and a temperature-controlled abutment 23. Therefore, actuation of the electromagnet 22 effects displacement of the sleeve 1 8 to the extent limited by the temperature-dependent abutment, for the purpose of delivering the starting quantity. The pressure sensing device 20 comprises an inlet 24 for loading the barometer capsule 21 with the load pressure.The change in length which results from compression of the barometer capsule is transmitted to the slider sleeve 1 8 by the lever 1 9. Since the maifold pressure of a motor under load extends over the complete middle pressure rotary speed range of a motor, the combination of the pressure adjustment and the rotary speed adjustment by means of the space cam 1 5 realises any desired injection adjustment in the entire characteristic motor field by means of the follower roller 1 6 and the regulator rod 1 7. The common attachment to the slider sleeve 18 of the space cams 10 and 1 5 permits in this case on the one hand any desired full load quantity and on the other hand any desired injection adjustment.

The barometer capsule 21 is supported on the abutment 25 of the core of the electromagnet 22. At starting, the abutment 25 is lifted off the barometer capsule 21, overcoming the force of the spring 26. The spring 27 displaces the barometer capsule until it lies again against the abutment 25, and the change in position resulting therefrom is transmitted to the slider sleeve 1 8. As the engine is not yet turning, a defined position of the space cams 10 and 15 results in this case, and the corresponding starting quantity and the corresponding injection commencement for the starting process can be obtained at once.

The other end of the core of the electromagnet 22 comprises an abutment 28 which, upon actuation of the electro-magnet 22 cooperates with the temperature-dependent limiter abutment 23. Depending upon the temperature of the cooling water the abutment 23 changes the position of its abutment surface, so that the maximum displacement of the abutment 28 controls the starting quantity and the injection position at the starting process as a function of the temperature of the motor.

The pressure sensing-device 20, the electromagnet 22 and the temperature-dependent abutment 23 are combined to a common constructional unit. In cases in which in the axial direction of the slider sleeve 1 8 sufficient space is available, this constructional unit can be coaxially connected directly to the slider sleeve without interposition of the lever 1 9.

Claims

1. Apparatus for regulating the commencement of injection and the injection quantity of a fuel injection pump for an internal combustion engine in dependence upon operating parameters, wherein the injection quantity is increased for starting by means of an electro-magnet and both the injection quantity and the injection timing are regulated in dependence upon at least a load dependent pressure, and wherein a capsule for measuring the load dependent pressure is arranged to act in series with the core of the electromagnet to adjust the position of regulating members for the injection quantity and the injection timing by way of a common transmission linkage.

2. Apparatus as claimed in Claim 1, wherein the capsule for measuring the load dependent pressure is arranged coaxially with the core of the electro-magnet.

3. Apparatus as claimed in Claim 1 or Claim 2, wherein the increased injection quantity on starting is dependent upon a prevailing operating temperature of the engine.

4. Apparatus as claimed in Claim 3, wherein a temperature dependent abutment is provided to limit the displacement of the core of the electro-magnet in dependence upon the operating temperature, the abutment being arranged coaxially with the core of the electromagnet.

5. Apparatus as claimed in Claim 1 or Claim 2, wherein the electro-magnet and the pressure measuring capsule are combined to form a single structural unit.

6. Apparatus as claimed in Claim 3 or Claim 4, wherein the electro-magnet, the pressure measuring capsule and the temperature dependent abutment are combined to form a single structural unit.

7. Apparatus as claimed in Claim 5 or Claim 6, in which the structural unit is arranged to act on the regulating members for the injection quantity and the injection timing by way of a transmission linkage which includes a straight lever arm pivoted at a point intermediate its ends.

8. Apparatus as claimed in Claim 7, wherein the transmission linkage additionally comprises three-dimensional cams for regulating the injection quantity and the injection timing respectively.

9. Apparatus for regulating the commencement of an injection and the injection quantity of a fuel injection pump constructed, arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.