Internal-combustion engines – Charge forming device – Fuel injection system
Patent
1990-05-17
1992-07-07
Miller, Carl S.
Internal-combustion engines
Charge forming device
Fuel injection system
123449, 123503, F02M 5702
Patent
active
051273810
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a fuel injection pump including a stepped plunger movable by a cam drive and having a reduced diameter portion for executing suction and delivery strokes and an end face for limiting the pump working space. The end face has a damping space connected with the suction space of the pump and whose volume can be changed. DE-OS 3,144,277 has already disclosed a fuel injection pump which, in order to increase the power by increasing the delivery rate of the pump plunger, has a hydraulic cushioning device in order to compliment the restoring forces required to decelerate the oscillating pump plunger, which restoring forces can no longer be produced by the helical springs which are supposed to hold the pump plunger in contact with the face cams. The known hydraulic cushioning device requires a restriction groove on the pump plunger in order to limit the outflow of the fuel from a damping space. The formation of the restriction groove on the pump plunger requires additional and, furthermore, cost-intensive operations since the restriction groove must usually be produced by erosion. Furthermore, the braking effect affects the majority of the pump plunger movement, with the result that the driving forces required are higher than necessary.
SUMMARY OF THE INVENTION
The object of the invention is a fuel injection pump in which a further increase in the velocity of the pump plunger and hence an increase in the power of the fuel injection pump is possible even though the hydraulic stop does not have an additional compensating groove and the braking effect occurs only partially in the region of the top dead centre of the pump plunger. The object of the invention is achieved by providing a damping face on the plunger portion having a larger diameter and which, at the end of the delivery stroke, is brought into the damping space and forms a throttle gap forming a connection with the suction space. It is advantageous to have the braking effect occur only in the event of the pump plunger or the camshaft driving the latter actually lifting off from the roller ring at high rotational operating speed. It is particularly advantageous here that the delivery stroke pressure and the braking pressure on the pump plunger occur temporally in succession and transverse forces, which can cause the jamming of the pump plunger, are thus avoided.
The present invention both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following detailed description of the preferred embodiment when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a simplified partially cross-sectional side view of a fuel injection pump, according to the invention and FIG. 2 shows in schematic partially cross-sectional view of a cylinder sleeve of the fuel injection pump according to the invention, with the pump plunger guided in the cylinder sleeve.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The drawing shows in FIG. 1, a simplified partially cross-sectional view of a distributor-type fuel injection pump in which a drive shaft 2 is mounted in a housing 1 and to which a lifting disc 3 arranged transversely to the drive shaft 2 is coupled: The lifting disc is provided with face cams 4 corresponding to the number of cylinders of the internal combustion engine which are to be supplied. The bearing surface of the lifting disc 3 runs on rollers 5, which are held in a fixed roller ring 6. At its driving-side end protruding into a fuel-filled suction space 26, a pump plunger 9, which slides in a bore 7 of a cylinder sleeve 8, has a collar 10, which is fixed to the lifting disc 3 for rotation therewith. To control the fuel injection quantity, a control slide 11 embracing the pump plunger 9 slides on the driving-side pump plunger portion, in which, for the purpose of controlled discharge of partial quantities of the fuel delivered, there is arranged a transverse bore 12 which is contro
REFERENCES:
patent: 3758241 (1973-09-01), Eheim
patent: 3908619 (1975-09-01), Bittelmeyer
patent: 4476835 (1984-10-01), Laufer
patent: 4711221 (1987-12-01), Laufer
patent: 4788959 (1988-12-01), Iiyama
patent: 4798186 (1989-01-01), Ganser
patent: 4969442 (1990-11-01), Taue
Kupzik Roland
Schunck Eberhard
Miller Carl S.
Robert & Bosch GmbH
Striker Michael J.
LandOfFree
Fuel injection pump for internal combustion engines does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fuel injection pump for internal combustion engines, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fuel injection pump for internal combustion engines will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1823702