GB2195471A - A fuel injection pump for a diesel engine in a motor vehicle - Google Patents
A fuel injection pump for a diesel engine in a motor vehicle Download PDFInfo
- Publication number
- GB2195471A GB2195471A GB08722514A GB8722514A GB2195471A GB 2195471 A GB2195471 A GB 2195471A GB 08722514 A GB08722514 A GB 08722514A GB 8722514 A GB8722514 A GB 8722514A GB 2195471 A GB2195471 A GB 2195471A
- Authority
- GB
- United Kingdom
- Prior art keywords
- fuel
- adjusting
- fuel injection
- pump
- injection pump
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M41/00—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor
- F02M41/08—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined
- F02M41/10—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor
- F02M41/12—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor
- F02M41/123—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor characterised by means for varying fuel delivery or injection timing
- F02M41/125—Variably-timed valves controlling fuel passages
- F02M41/126—Variably-timed valves controlling fuel passages valves being mechanically or electrically adjustable sleeves slidably mounted on rotary piston
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D1/00—Controlling fuel-injection pumps, e.g. of high pressure injection type
- F02D1/02—Controlling fuel-injection pumps, e.g. of high pressure injection type not restricted to adjustment of injection timing, e.g. varying amount of fuel delivered
- F02D1/08—Transmission of control impulse to pump control, e.g. with power drive or power assistance
- F02D1/10—Transmission of control impulse to pump control, e.g. with power drive or power assistance mechanical
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
- F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
- F02M59/447—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston means specially adapted to limit fuel delivery or to supply excess of fuel temporarily, e.g. for starting of the engine
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B3/00—Engines characterised by air compression and subsequent fuel addition
- F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- High-Pressure Fuel Injection Pump Control (AREA)
Abstract
A fuel injection pump for a motor vehicle diesel engine has a pump (2 to 4), which is supplied with fuel by a pre-supply pump (12) under speed- dependent pressure, and a fuel quantity-adjusting member (16), which is adjusted by an adjusting device having an adjusting lever (18). The adjusting device is acted upon by an arbitrarily tensioned governor spring arrangement (24) and by a centrifugal adjuster (30). In order to ensure that residual quantities are supplied during overrun operation of the internal combustion engine, the adjusting device is associated with a stop (54), the position of which is adjustable in dependence upon the engine speed. This stop (54) is part of a hydraulic cylinder (50) whose piston (52) is acted upon by both a pressure spring (57) and, by the pressure from the pre-supply pump (12). <IMAGE>
Description
SPECIFICATION
A fuel injection pump for a diesel engine in a motor vehicle
The present invention relates to a fuel injection pump for a diesel engine in a motor vehicle.
In known fuel injection pumps the quantity of injected fuel delivered is reduced to zero when the internal combustion engine is in overrun operation, that is, given full deceleration, for example when running downhill or braking. Because of the higher compression work in diesel engines, there is, as a result, substantially greater drag power in diesel engines than in spark-ignition engines. On subsequent acceleration, the correspondingly high drag moment leads to an abrupt application of load and possibly causes the motor vehicle to jolt.
According to the present invention there is provided a fuel injection pump for a diesel internal combustion engine in a motor vehicle comprising a pump unit for delivering quantities of fuel, an adjusting member for determining the quantity of fuel delivered under injection by the pump unit, a pre-supply device for suppiying the pump unit with fuel under speed-dependent pre-supply pressure, an adjusting device which has an adjusting lever for actuating the adjusting member and upon which both an arbitrarily stressed governor spring arrangement and a centrifugal adjuster act, wherein the adjusting device is associated with a stop, which is adjustable by the speeddependent presupply pressure and which limits the position of the adjusting device for minimum fuel delivery quantities in dependence upon the engine speed.
The fuel injection pump according to the present invention has the advantage that a speed-dependent limitation of the residual delivery quantity substantially improves the travelling behaviour of the motor vehicle, particularly since the magnitude of the residual fuel quantity is dependent upon speed.
The invention is described further hereinafter, by way of example only, with reference to the accompanying drawings, in which:
Fig. 1 is a simplified section through a first embodiment of a fuel injection pump in accordance with the present invention having a device for limiting residual delivery quantities; and
Fig. 2 is a simplified side view of a second embodiment of a device for limiting residual quantities in accordance with the present invention.
A pump piston 3 operates in a cylinder bore 2 in a housing 1 of a fuel injection pump and is moved in a reciprocating and simultaneously rotating manner by a drive (not shown). The pump working chamber 4 of the pump unit is provided with fuel from a suction chamber 7 in the housing 1 during the suction stroke of the pump piston 3 by way of longitudinal grooves 5 disposed in the outer surface of the pump piston 3 and by way of a passage 5 in the housing 1.During the compression stroke of the pump piston 3, fuel is delivered from the working chamber 4 into a longitudinal passage 8 in the pump piston 3, from where it is fed by way of a distributor-type longitudinal groove 10 according to the angular position of the pump piston 3 into one of the delivery lines 11, which are disposed about the periphery of the cylinder bore 2 in correspondence with the number of cylinders to be supplied in the internal combustion engine. Fuel is made available in the suction chamber 7 by a pre-supply pump 12 which delivers fuel from a storage tank 13 under pressure into the suction chamber 7.A known pressure-control valve 14, which is connected in parallel with the pre-supply pump 12, adjusts the pressure in the suction chamber 7 in dependence upon the rotational speed of the injection pump in such a way that said pressure increases with increasing rotational speed.
An annular control spool 16 is displaceably mounted on the pump piston 3 and opens a radial bore 17, which is connected to the longitudinal passage 8, during the compression stroke of the pump piston 3, thus producing a direct connection between the working chamber 4 and the suction chamber 7, such that, from the instant of opening, none of the remainder of the fuel delivered by the pump piston 3 is fed to the delivery lines 11. In dependence on the position of the control spool 16, the connection to the suction chamber 7 is opened following variable travel of the pump piston 3, and the delivery of fuel is interrupted. The further the control spool 16 is moved towards the top of the pump piston 3, the greater the quantity of fuel delivered by the pump piston into the delivery lines 11 and to the injection nozzles (not shown).
The position of the control spool 16 is adjusted by a two-arm adjusting lever 18, which is pivotable about an axle 19 and which has a head 20 on one of its ends which projects into a recess 21 in the control spool 16. A one-arm governor lever 22 is also pivotable about the axle 19. This governor lever 22 is acted upon following a certain idle travel by a governor spring 24, one end of which is attached to a speed-adjusting lever 26, the other end passing through a bore 26 on the outer end of the governor lever 22 and being provided with a stop disc 27. An adjusting sleeve 29 of a centrifugal adjuster 30 acts on the governor lever 22 in the opposite direction to the action of the governor spring 24. The centrifugal adjuster 30 is driven by a transmission (not shown) in accordance with the rotational speed of the pump piston drive.It has a plurality of flyweights 33, which are located in a housing 32 and which have lugs 34 which act upon the lower edge of the adjusting sleeve 29 which is displaceable on an axle 36 in the longitudinal direction. A stop 36, which is fixed to the housing, limits the pivoting motion of the governor lever 22 in the direction of the centrifugal adjuster 30.
The second arm 40 of the adjusting lever
18 extends alongside the governor lever 22.
On its side facing the governor 22, it has a stop 41 which, when the fuel injection pump is at a standstill, is at a distance from the governor lever 22. The end of the arm 40 forks into two parts 42, 43. An idling spring 44, which is weaker than the governor spring 24, is attached to one part 42. The other end of the idling spring 44 is attached to an adjusting lever 45 which is rotatably mounted in the housing 1 and which can be used to adjust the idling speed.
A hydraulic adjusting cylinder 50 is disposed close to the end of the arm 40 of the adjusting lever 18, which cylinder has a piston 52 which is displaceable in a bore 51 and a piston rod 53 which is directed into the pivotal range of the part 43 of the adjusting lever 18.
The end 54 of the piston rod 53 remote from the piston 52, forms a movable stop for the adjusting lever 18. This stop is used in a speed-dependent manner to limit the pivoting range of the adjusting lever 18 towards the position where the quantity delivered is zero.
A pressure spring 57 located in a chamber 56, which is divided by the piston 52 in the bore 51 and is pressure-relieved through a line 55 and which is supported on the end of the cylinder 50, presses the piston 51 against a stop 58 located in an opposite pressure chamber 59. When the piston 52 is in abutment with the stop 58, the end 54 of the piston rod 53 allows the adjusting lever 18 to move through its largest possible pivotal range. As pressure increases in the pressure chamber 59, which is connected by way of a passage 60 to the suction chamber 7, the piston 52 is displaced against the force of the compression spring 57, and the end 54 of the piston rod 53 reduces the pivoting range of the adjusting lever 18.
The adjusting device and the device for limiting the residual delivery quantity of the above-described fuel injection pump operate as follows: On starting, the adjusting device for the control spool 16 and the adjusting cylinder 50 of the device for delimiting the residual delivery quantity take up the position shown in Fig. 1. The lever 22 abuts against the adjusting sleeve 29 and is loosely held by the governor spring 24 such that it is at a distance b from the stop disc 27 and at a distance a from the stop 41 of the adjusting lever 18. the adjusting lever 18 is held by the idling spring 44 in a position in which the control spool 16 is in its highest position, which corresponds to the maximum quantity of fuel being injected.Following starting, the adjusting sleeve 29 is displaced, with increasing engine speed, so that the lever 22 comes into abutment with the stop 41 of the adjusting lever 18. As the speed continues to increase, the idling speed 44 abutting against the adjusting lever 18 begins to control the lever movement.
It counterbalances the force generated by the centrifugal adjuster 30, whereby the control spool 16 is held in a position determining the idling speed. At speeds above the idling range, the lever 22 moves through the distance b to the stop disc 27 so that the lever 22 is in abutment against the stop disc 27 of the governor spring 24, so that, under the action of the force of the idling spring 44 and the governor spring 24, the governor lever 22 and adjusting lever 18 form a composite lever.
In dependence on the tension of the governor spring 24, which is adjusted by the speedadjusting lever 25, and the position of the adjusting sleeve 29, which is regulated by the centrifugal adjuster 30, the governor lever 22 and adjusting lever 18 move the control spool 16 into a position which corresponds to a particular quantity of fuel to be injected.
If, in the event of engine deceleration, for example when driving downhill, and hence when the governor spring 24 is relieved, the internal combustion engine is driven by the motor vehicle (overrun operation), the flyweights 33 press the adjusting sleeve 29 against the governor lever 22 and the adjusting lever 18. Both levers change position and displace the control spool 16 towards a position which results in a smaller quantity of fuel being delivered, until a smaller fuel delivery quantity has been established at a new state of load. In order to avoid a situation in which no fuel is delivered, the end 54 of the piston rod 53 of the adjusting cylinder 50 limits the pivotal range of the adjusting lever 18 and the displacement of the control spool 16.Due to the pressure in the suction chamber 7 and the pressure chamber 59 of the adjusting cylinder 50, which is controlled in dependence upon the rotational speed of the injection pump, this limitation of the pivotal range is dependent upon that rotational speed. As pressure increases in the pressure chamber 59, the piston 52 is displaced against the force of the compression spring 57 and then against the adjusting lever 18, whereby, depending on the pressure in the chamber 59, the end 54 of the piston rod 53 acts as a stop to limit the pivotal travel of the adjusting lever 18 towards a position in which a smaller quantity of fuel is delivered. When the internal combustion engine is in overrun operation, this residual delivery quantity, which has been matched to the speed, prevents the internal combustion engine being braked too hard and avoids an abrupt application of load on reaccleration.
In the embodiment of the device as shown in Fig. 2, which is constructed in substantially the same way as the one described above, the piston rod 53 of the adjusting cylinder 50 is provided with a safety mechanism which ensures that, in the event of faulty operation, the maximum permitted speed is not exceeded. The safety mechanism comprises a flexible member 60 which is disposed on the end 54 of the piston rod 53 and acts as a stop for the adjusting lever 18. The flexible member 60 comprises a sleeve 61, which is displaceably mounted on the piston rod 53 and which is biassed away from the piston rod 53 by a compression spring 62. The compression spring 62 acts such that, despite the piston 52 being fully advanced into the chamber 7, when the maximum permissible speed is exceeded, the force of the centrifugal adjuster 30 is able to overcome the force of the compression spring 62 such that, despite the adjusting lever 18 being in abutment against the sleeve 61, it is possible for the adjusting lever 18 to pivot towards a position in which a smaller quantity of fuel is delivered.
Claims (5)
1. A fuel injection pump for a diesel internal combustion engine in a motor vehicle comprising a pump unit for delivering quantities of fuel, an adjusting member for determining the quantity of fuel delivered under injection by the pump unit, a pre-supply device for supplying the pump unit with fuel under speed-dependent pre-supply pressure, an adjusting device which has an adjusting lever for actuating the adjusting member and upon which both an arbitrarily stressed governor spring arrangement and a centrifugal adjuster act, wherein the adjusting device is associated with a stop, which is adjustable by the speed-dependent presupply pressure and which limits the position of the adjusting device for minimum fuel delivery quantities in dependence upon the engine speed.
2. A fuel injection pump as claimed in claim 1, wherein the adjustable stop forms part of a hydraulic cylinder, which is subjected to the pre-supply pressure and which acts against a spring.
3. A fuel injection pump as claimed in claim 2, wherein the hydraulic cylinder includes a piston rod which limits the travel of the adjusting lever of the adjusting device.
4 A fuel injection pump as claimed in claim 3, wherein a flexible stop is disposed on the piston rod.
5. A fuel injection pump substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19863632540 DE3632540A1 (en) | 1986-09-25 | 1986-09-25 | FUEL INJECTION PUMP FOR A DIESEL INTERNAL COMBUSTION ENGINE IN A MOTOR VEHICLE |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8722514D0 GB8722514D0 (en) | 1987-10-28 |
| GB2195471A true GB2195471A (en) | 1988-04-07 |
| GB2195471B GB2195471B (en) | 1990-08-22 |
Family
ID=6310299
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8722514A Expired - Lifetime GB2195471B (en) | 1986-09-25 | 1987-09-24 | A fuel injection pump for a diesel engine in a motor vehicle |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS6388230A (en) |
| DE (1) | DE3632540A1 (en) |
| FR (1) | FR2604485B1 (en) |
| GB (1) | GB2195471B (en) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3146132A1 (en) * | 1981-11-21 | 1983-06-01 | Robert Bosch Gmbh, 7000 Stuttgart | FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES |
| DE3147701A1 (en) * | 1981-12-02 | 1983-06-16 | Robert Bosch Gmbh, 7000 Stuttgart | CONTROL DEVICE FOR A FUEL FLOW ADJUSTMENT MEMBER OF A FUEL INJECTION PUMP |
| DE3322214A1 (en) * | 1983-06-21 | 1985-01-10 | Robert Bosch Gmbh, 7000 Stuttgart | Injection pump for internal-combustion engines |
| DE3418437A1 (en) * | 1984-05-18 | 1985-11-21 | Robert Bosch Gmbh, 7000 Stuttgart | FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES |
-
1986
- 1986-09-25 DE DE19863632540 patent/DE3632540A1/en not_active Ceased
-
1987
- 1987-05-29 JP JP13196287A patent/JPS6388230A/en active Pending
- 1987-06-02 FR FR8707687A patent/FR2604485B1/en not_active Expired - Fee Related
- 1987-09-24 GB GB8722514A patent/GB2195471B/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| GB2195471B (en) | 1990-08-22 |
| JPS6388230A (en) | 1988-04-19 |
| GB8722514D0 (en) | 1987-10-28 |
| FR2604485A1 (en) | 1988-04-01 |
| FR2604485B1 (en) | 1993-08-13 |
| DE3632540A1 (en) | 1988-03-31 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19950924 |