US3101702A

US3101702A - Emergency shut-down gear for multi-cylinder compression ignition engines

Info

Publication number: US3101702A
Application number: US135995A
Authority: US
Inventors: Cushing Cyril Albert; Speaight John Henry William
Original assignee: English Electric Co Ltd
Current assignee: English Electric Co Ltd
Priority date: 1960-10-27
Filing date: 1961-09-05
Publication date: 1963-08-27
Anticipated expiration: 1980-08-27

Description

Aug- 27, 1963 c. A. cUsHlNG ETAL 3,101,702

EMERGENCY SHUT-'DOWN GEAR FOR MULTI-CYCLINDER COB/[PRESSION IGNITION ENGINES Filed Sept. 5, 1961 States Filed Sept. 5, 1961, Ser. No. 135,995 Claims priority, application Great Britain Oct. 27, 1960 2 Claims. (Cl. 12S-198) The present invention relates to an emergency shutdown gear for a multi-cylinder compression ignition engine.

According to the invention, emergency shut-down gear for a multi-cylinder compression-ignition engine comprises a source `of hydraulic pressure; a single speed-responsive tripping device driven by the engine; at least two fuel-injection pumps driven by said engine and delivering fuel to the cylinders thereof; at least two hydraulic `control valves each comprising a valve body having an inlet' port, an outlet port, and u, drain port, said inlet port being connected to said source of hydraulic pressure, a piston mounted -to slide in said body between a first position, in which the inlet port is connected to the outlet port and the drain port is blocked, and a second position, in which the drain port is connected to the outlet port and the inlet port is blocked, `and resilient means to bias said piston towards said second position; tension means connecting the piston of each said hydraulic control valve to said tripping device to oppose movement `of said piston due to `said resilient means; each said fuel-injection pump comprising a spragging pin housing having a bore, a spragging pin slidable in said bore, spring means to bias the spragging pin to lock the fuel pump, and the spragging pin having a surface acted on by the pressure in said `bore in the sense to over-ride said spring means; and duct means connecting said bore to the outlet port of a hydraulic control valve, whereby `on operation of said tripping device the pistons of said hydraulic control valves move substantially simultaneously under the influence of the resilient means to .their second positions, so that said bore of each Ifuel-injection pump is connected through the outlet port of a hydraulic control valve to the drain port thereof and the spragging pins of said fuel-injection pumps move substantially simultaneously, under the inuence `of the corresponding spring means, to lock the corresponding fuel-injection pumps, and thus to cause the delivery ofy fuel to the cylinders of the engine to be terminated substantially simultaneously.

This -arrangement is particularly suited to multi-cylinder engines where more than yone multi-element fuel pump is fitted, and where these pumps farearranged remote from one another, for instance on a V-engine with the pumps outboard. The emergency gear Iaccording to the invention ensures complete synchronisation of operation in such an engine.

The source of hydraulic pressure controlling the spragging pin may be derived from .the engine lubricating oil pressure system or from an independent closed hydraulic circuit.

The emergency shut-down gear Iaccording to the inpention fails safe in the failure of hydraulic pressure caused by leakage or any other breakdown will lock the fuel pump, and accordingly bring the internal combustion engine to a standstill, the same way as the action of the overspeed tripping device upon overspeeding.

An embodiment of the invention will now be described with reference to the accompanying drawing, which shows -a diagrammatic Iarrangement of emergency shut-down gear according to the invention.

In the drawing, the fuel pumps 1, 4, are controlled ate by an overspeed tripping device 2 by means of

piston valves

3, 5. Thepiston valve 3 is connected to fuel pump 1 and piston valve 5 to pump l4.

Each fuel pump comprises =a camshaft housing 111 wherein the engine-driven cam r12 is journalled, and the tappet assembly 13 of the pump plunger is mounted to slide perpendicularly to the axis Iof the camshaft, by which the plunger is reciprocated against the bias of a spring 14. A spragging pin 15 slidable in a lbore in its housing 17 is biased by a spring 16 towards the tappet assembly 13 in a direction perpendicular to both the `axis of said assembly and that `of thecam shaft. This spragging pin has -a shoulder 15a'capable of engaging in a recess 13a of the tappet assembly l13 in the uppermost or near uppermost position of the latter, but is normally Iheld back by hydraulic pressure applied to the surface on its lefthand side (as seen in the drawing) as will be explained hereinafter. The space behind the spragging pin 15 is connected to the camshaft housing 11 by Va relief bore 13, and the camshaft housing is connected to `drain by a The overspeed tripping device 2 comprises -a casing 20 wherein a trip latch 21 is pivotally mounted at 22. A lever 25 is mounted outside the casing 20* to rotate with a shaft 26, on which inside the casing a cam 27 is mounted which cooperates with a shoulder 21a of the trip latch 21. Normally the trip latch is biased clockwise and its arm 2lb abuts a stop 23 adjustably tted to the casing 20. In the event of overspeedng the trip latch 21 is swung `anti-clockwise by conventional overspeed tripping means (not shown) :and its shoulder 21a clears the cam 27. A bracket 28 attached .outside the casing 20 holds the sheaths of tension cables 29 yattached by Ia swivel joint 24 to the free end of the lever 25.

Each piston valve 3, 5 'comprises Ia casing 30 having an inlet port 31 connected to a supply of hydraulic pressure, an outlet port 32 connected by ,a pipe 33 to the pump 1, and a drain port 34. A piston 35, having an annular groove 36 connected by radial ports 37 to an inn-er bore 38, is mounted to slide in the casing 30, and is biased downward (as shown in the drawing) by a powerful pre-loaded compression spring 39.

The tension cables 29 are attached to the pistons 35, .and while the trip latch 21 keeps the lever 25 locked, these cables 29 hold the pistons 35 in la first position as shown, in which the inlet port 31 is connecten to the outlet port 32, and the drain port 34 is blocked. Hence hydraulic pressure is transmitted through the pipe 33 and the duct 133 is the casing of each fuel pump 1, 4 and acts on the surface of the spragging pin 15 to hold it back against the bias of spring 16.

However, when the trip latch 21 releases the cam 27, the spring 3-9 of each piston valve pushes the piston 35 downward to a second position, in which it blocks the inlet port 31, and connects the outlet port 32 to the drain port 34.

Following the closing of the inlet port 31 `and before the opening of the drain port 34, the piston 35, which has the form of a hollow plunger, displaces a ixed volurne of liquid which is equivalent to the volume of liquid in the bore `of the spragging pin housing 17 of the corresponding fuel pump. Accordingly the hydraulic pressure inside the bore of the housing 17 of the fuel pump drops at once, and the spragging pin 15 is pushed to the left by spring 16 and engages with its shoulder 15a kin a recess 13a of the respective tappet assembly 13 when the latter is in its maximum or near maximum lift position, and prevents it from following the cam 12 downward under Ithe bias of spring 14.

The fuel pumps 1, 4 are thus put out of action immediately Iand substantially simultaneously :and the internal combustion engine supplied by them is brought to a standstill at once.

When the overspeed trip device 2 is reset-by hand or otherwise-the piston 35 is returned -to its first position (as illustrated), hydraulic pressure is re-established in the bore of the housing 17 of the pumps 1, 4, the Spragging pin 15 is thereby withdrawn from the tappet assembly 13 against the bias of spring 16, and the fuel pumps 1, 4 are ready to resume operation.

The fail-safe elect of the arrangement will be noted: failure of hydraulic pressure for any reason will stop the fuel pumps 1, 4 in Ithe manner described, and they cannot then be restarted before the hydraulic pressure is restored.

Owing to the fact that the tappet assembly 13 is locked by the -spragging pin 15 lat `or near the maximum lift position, the cam 12 of each fuel pump 1, 4 is free to rotate clear of the tappet assembly until the associated spragging pin 15 is retracted under .re-established hydraulic pressure, this action being independent for each fuel pump.

What we claim as our invention and desire to secure by Letters Patent is:

l. Emergency shut-down gear for ya multi-cylinder compression-ignition engine, comprising =a source of hydraulic pressure; a single speed-responsive tripping device driven by the engine; at least two fuel-injection pumps ydriven by said engine and delivering fuel to the cylinders thereof; at least two hydraulic control valves eachy comprising a valve body having an inlet port, -an outlet pont, yand :a drain port, said inlet port being connected to said source of hydraulic pressure, a piston mounted to slide in said body between a irst position, in which the inlet port is connected to the outlet port and the drain port is blocked, and a second position, in which the drain port is connected to the outlet port and the inlet port is blocked, Iand resilient means to bias said piston towards said second position; tension means connecting the piston of each said hydraulic control valve to said tripping device to oppose movement `of said piston due to said reysilient means; each said fuel-injection pump comprising a spragging pin housing having a bore, a spragging pin slidable in said bore, spring means to bias the spragging pin to lock the vfuel pump, and the spragging pin having a surface acted on by lthe pressure in said bore in the sense to 4over-ride said spring means; land duct means connecting said bore `to the outlet port off a hydraulic control valve, whereby on operation of said tripping device the pistons of said hydraulic control valves move substantially simultaneously under the influence of the resilient means to their second positions, so that said bore of each fuel-injection pump is connected through the outlet port of a hydraulic control valve to the drain port thereof and the spragging pins of said fuel-injection pumps move substantially simultaneously, under the influence of the corresponding spring means, to lock the corresponding `fuel-injection pumps, fand thus to cause lthe delivery of rfuel to the cylinders of the engine to be terminated substantially simultaneously.

2. Emergency shut-down gear as claimed in claim 1 wherein each said piston has the form of a hollow plunger, the interior of which is in constant communication through said loutlet port and said duct means with said bore wherein the pressure acts on the surface of the spragging pin in the sense to -over-ride the spring means, whereby on movement of said piston from said `first piston to said second position, resulting trom yoperation of said overspeed trip device, la substantial volume `of liquid is -displaced 4from said bore along said duct means towards said hollow plunger, thereby facilitating movement of said spragging pin under the influence of its spring.

References Cited in the le of this patent UNITED STATES PATENTS '2,260,576 Maybach Oct. 28, 1941 2,840,064 Hofer June 24, 1958 FOREIGN PATENTS 7 68,732 Great Britain Feb. 20, 1957

Claims

1. EMERGENCY SHUT-DOWN GEAR FOR A MULTI-CYLINDER COMPRESSION-IGNITION ENGINE, COMPRISING A SOURCE OF HYDRAULIC PRESSURE; A SINGLE SPEED-RESPONSIVE TRIPPING DEVICE DRIVEN BY THE ENGINE; AT LEAST TWO FUEL-INJECTION PUMPS DRIVEN BY SAID ENGINE AND DELIVERING FUEL TO THE CYLINDERS THEREOF; AT LEAST TWO HYDRAULIC CONTROL VALVES EACH COMPRISING A VALVE BODY HAVING AN INLET PORT, AN OUTLET PORT, AND DRAIN PORT, SAID INLET PORT BEING CONNECTED TO SAID SOURCE OF HYDRAULIC PRESSURE, A PISTON MOUNTED TO SLIDE IN SAID BODY BETWEEN A FIRST POSITION, IN WHICH THE INLET PORT IS CONNECTED TO THE OUTLET PORT AND THE DRAIN PORT IS BLOCKED, AND A SECOND POSITION, IN WHICH THE DRAIN PORT IS CONNECTED, TO THE OUTLET PORT AND THE INLET PORT IS BLOCKED, AND RESILIENT MEANS TO BIAS SAID PISTON TOWARDS SAID SECOND POSITION; TENSION MEANS CONNECTING THE PISTON OF EACH SAID HYDRAULIC CONTROL VALVE TO SAID TRIPPING DEVICE TO OPPOSE MOVEMENT OF SAID PISTON DUE TO SAID RESILIENT MEANS; EACH SAID FUEL-INJECTION PUMP COMPRISING A SPRAGGING PIN HOUSING HAVING A BORE, A SPRAGGING PIN SLIDABLE IN SAID BORE, SPRING MEANS TO BIAS THE SPRAGGING PIN TO LOCK THE FUEL PUMP, AND THE SPRAGGING PIN HAVING A SURFACE ACTED ON BY THE PRESSURE IN SAID BORE IN THE SENSE TO OVER-RIDE SAID SPRING MEANS; AND DUCT MEANS CONNECTING SAID BORE TO THE OUTLET PORT OF A HYDRAULIC CONTROL VALVE, WHEREBY ON OPERATION OF SAID TRIPPING DEVICE THE PISTONS OF SAID HYDRAULIC CONTROL VALVES MOVE SUBSTAN-