GB2069056A - Preventing damage to i.c. engines through failure of lubricant supply - Google Patents

Abstract

A fuel valve A is held in the open position only when the pressure of lubricating oil on diaphragm B is sufficient to overcome the force exerted by spring D. A small diameter diaphragm C isolates diaphragm B from the effect of fuel pressure, which would tend to close the fuel valve. Alternatively the rod connecting diaphragm B and valve A may carry o- ring seals. <IMAGE>

Description

SPECIFICATION Lubfail-stop The invention, as shown in drawing 1 consists of a valve 'A' introduced into the fuel flow of a diesel or internal combustion engine. This valve is normally in the closed position but, when the engine is running the lubrication oil pressure, acting on the primary diaphragm B keeps the valve in the open position.

When the oil pressure fails, either through lack of lubricating oil or because of mechanical failure of the pressure circuit and pumping mechanism, the spring D, closes valve A thus stopping the engine before major damage can be caused.

There is no requirement and no provision for bypassing the device for starting purposes, as such provision may lead, whether by accident or design, to the device being in-operative in stopping an internal combustion engine whose lubricating oil pressure is insufficient for it's effective operation.

Starting the engine prior to oil pressure being available is assured by setting the Spring D to allow operation of the diaphragm B and valve A at a pressure low enough to be achieved by the operation of the starting mechanism.

As the fuel injection pumps on many internal combustion engines are capable of exerting a suction greater than the pressure required to activate the diaphragm B it is therefore necessary to introduce a smaller diaphragm C to contain the fuel within the body of the valve.

In the case of the lubricating oil pressure failing, whilst the engine is running the suction created by the fuel injection pump will, because of the smaller diameter of diaphragm C, not be able to overcome the force exerted by spring D and the valve will close, stopping the engine.

Drawing 2 shows an alternative method of achieving the same result by using small O-Rings "E" to contain the fuel oil and to avoid any suction to be exerted on the upper surface of diaphragm D.

1. A cut-out device for the protection of diesel engines against lubricating oil pressure failure comprising of a body member incorporating a diaphragm "B" which when raised by lubricating oil pressure will in turn open a spring loaded fuel valve thus allowing the engine to run.

2. A cut-out device according to Claim 1., which operates and opens the fuel valve "A" at lubricating oil pressures, low enough to be obtained by using normal starting procedures, such as electrical, mechanical or compressed air starters.

3. A cut-out device according to Claim 1. a 2., which incorporates a second diaphragm "C" between the oil pressure diaphragm "B" anOthe fuel shutoff valve "A".

4. A cut-out device according to Claim 1., 2. S 3., where the second diaphragm "C" described in Claim 3., is substantially smaller than the first diaphragm "B" described in Claim 1., so that the spring loaded valve "A" requires a much higher Ibs/sq.in. pressure or suction on diaphragm "C" to operate the valve against the ibs/sq.in. pressure on diaphragm "B".

5. A cut-out device according to Claim 1. to 4., where the relative pressure between the two diaphragms "B" and "C" and the valve spring are so balanced that the valve will open at the low lubricating oil pressure achieved by the starting process, thus avoiding the necessity of bypassing the device for starting and yet allow the valve to close when lubricating oil pressure fails instead of permitting the suction created by the fuel injection pump to hold the fuel valve in the open position.

6. A cut-out device according to Claims 1. to 5., where the body section between the two diaphragms "B" and "C" has a vent hole/leak off to atmosphere so as not to have interaction between the two diaphragms. This design also ensures that in the unlikely circumstance that either diaphragm "B" or "C" fails, fuel oil and lubricating oil cannot mix and such failure if it occurs, is immediately visible.

7. A cut-out device as described in Claims 1. to 6., fitted into the fuel lines of a diesel engine immediateiy prior to the fuel injection pump and connected to the lubricating oil pressure system by means of a suitable pipe to the underside of the diaphragm "B", thus allowing it to be raised by the lubricating oil pressure.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Lubfail-stop The invention, as shown in drawing 1 consists of a valve 'A' introduced into the fuel flow of a diesel or internal combustion engine. This valve is normally in the closed position but, when the engine is running the lubrication oil pressure, acting on the primary diaphragm B keeps the valve in the open position. When the oil pressure fails, either through lack of lubricating oil or because of mechanical failure of the pressure circuit and pumping mechanism, the spring D, closes valve A thus stopping the engine before major damage can be caused. There is no requirement and no provision for bypassing the device for starting purposes, as such provision may lead, whether by accident or design, to the device being in-operative in stopping an internal combustion engine whose lubricating oil pressure is insufficient for it's effective operation. Starting the engine prior to oil pressure being available is assured by setting the Spring D to allow operation of the diaphragm B and valve A at a pressure low enough to be achieved by the operation of the starting mechanism. As the fuel injection pumps on many internal combustion engines are capable of exerting a suction greater than the pressure required to activate the diaphragm B it is therefore necessary to introduce a smaller diaphragm C to contain the fuel within the body of the valve. In the case of the lubricating oil pressure failing, whilst the engine is running the suction created by the fuel injection pump will, because of the smaller diameter of diaphragm C, not be able to overcome the force exerted by spring D and the valve will close, stopping the engine. Drawing 2 shows an alternative method of achieving the same result by using small O-Rings "E" to contain the fuel oil and to avoid any suction to be exerted on the upper surface of diaphragm D. CLAIMS

1. A cut-out device for the protection of diesel engines against lubricating oil pressure failure comprising of a body member incorporating a diaphragm "B" which when raised by lubricating oil pressure will in turn open a spring loaded fuel valve thus allowing the engine to run.

2. A cut-out device according to Claim 1., which operates and opens the fuel valve "A" at lubricating oil pressures, low enough to be obtained by using normal starting procedures, such as electrical, mechanical or compressed air starters.

3. A cut-out device according to Claim 1. a 2., which incorporates a second diaphragm "C" between the oil pressure diaphragm "B" anOthe fuel shutoff valve "A".

4. A cut-out device according to Claim 1., 2. S 3., where the second diaphragm "C" described in Claim 3., is substantially smaller than the first diaphragm "B" described in Claim 1., so that the spring loaded valve "A" requires a much higher Ibs/sq.in. pressure or suction on diaphragm "C" to operate the valve against the ibs/sq.in. pressure on diaphragm "B".

5. A cut-out device according to Claim 1. to 4., where the relative pressure between the two diaphragms "B" and "C" and the valve spring are so balanced that the valve will open at the low lubricating oil pressure achieved by the starting process, thus avoiding the necessity of bypassing the device for starting and yet allow the valve to close when lubricating oil pressure fails instead of permitting the suction created by the fuel injection pump to hold the fuel valve in the open position.

6. A cut-out device according to Claims 1. to 5., where the body section between the two diaphragms "B" and "C" has a vent hole/leak off to atmosphere so as not to have interaction between the two diaphragms. This design also ensures that in the unlikely circumstance that either diaphragm "B" or "C" fails, fuel oil and lubricating oil cannot mix and such failure if it occurs, is immediately visible.

7. A cut-out device as described in Claims 1. to 6., fitted into the fuel lines of a diesel engine immediateiy prior to the fuel injection pump and connected to the lubricating oil pressure system by means of a suitable pipe to the underside of the diaphragm "B", thus allowing it to be raised by the lubricating oil pressure.