GB2027872A

GB2027872A - Cooling devices for internal combustion engines

Info

Publication number: GB2027872A
Application number: GB7926552A
Authority: GB
Original assignee: Unic SAS
Current assignee: Unic SAS
Priority date: 1978-08-07
Filing date: 1979-07-31
Publication date: 1980-02-27
Also published as: LU81568A1; IE48533B1; IT1119123B; DE2931821A1; DK148605C; GB2027872B; IT7968622A0; DK148605B; IE791421L; DE2931821C2; BE878122A; FR2433101A1; NL7905937A; DK329679A; FR2433101B1

Abstract

A cooling device for internal combustion engines, comprises a radiator 4 which is connected respectively to the cooling chamber of the engine and to a circulation pump 6 itself connected to a cooling liquid expansion chamber 8, in which is maintained an air pressure greater than atmospheric pressure, wherein the expansion chamber 8 is connected to an air pump 10 generating a pulsated air pressure, said pump 10 being driven by means of an auxiliary member of the internal combustion engine. <IMAGE>

Description

SPECIFICATION Improvements in cooling devices for internal combustion engines The present invention relates to an improvement in cooling devices for internal combustion engines.

In the cooling devices for internal combustion engines, particularly for Diesel engines, it is well known to maintain under pressure the cooling circuit employing liquid, in order to avoid the risk of the formation of steam at determined spots, particularly in the header tank of the engine and to avoid the phenomena of cavitation which lead, in common with chemical influences, to corrosions of determined parts of the cooling chambers.

Devices are also known in which the pressurization is obtained by connecting the expansion chamber directly to the general compressed air circuit supplying the different members of the vehicle.

However, these devices are not entirely satisfactory as it is desirable to isolate the cooling circuit of the engine from the general compressed air supply circuit.

According to the present invention, the expansion chamber is connected to an air pump generating a pulsated air pressure, said pump being driven by an auxiliary member of the internal combustion engine.

According to a feature of the invention, the device for pressurizing the circuit is actuated by a pressure variation of one of the auxiliary members of the engine and particularly the pressure pulsation at the inlet of the braking air compressor; the conditioning of such a device is very rapid and especially does not depend on the rise in temperature of the water leading to its expansion and consequently the establishment of pressure.

The defects in tightness of the filler caps with calibrated valve are less important, as the device is always in a position to establish the pressure and compensate the leakages.

The invention will be more readily understood on reading the following description with reference to the accompanying drawings, in which: Figure 1 is a schematic view of the cooling circuit of an internal combustion engine improved according to the invention; Figure 2 is a view in section of an embodiment of the air pump with membrane.

Referring now to the drawings, Fig. 1 shows an internal combustion engine 1 of which the cooling liquid circuit comprises, at the outlet of the cooling jacket of the engine, a manifold 2 which is connected by a conduit 3, to the upper part of a radiator 4 via a thermostatic valve 5 capable of short circuiting the passage towards the radiator and of connecting the conduit 3 directly to a circulation pump 6 which is connected to the inlet port of the cooling jacket of the engine 1.

At its lower part, the radiator 4 is also connected to the inlet port of the pump 6 by a conduit 7; similarly, an expansion chamber or service tank 8 of cooling liquid is connected by a conduit 9 to the suction of the pump 6.

To ensure overpressure in the expansion chamber 8 in the space located above the cooling liquid, said chamber is connected to the delivery port 1 2 of an air pump 10 by a conduit 11, said pump being connected to the atmosphere by a suction port 1 3.

In conduit 11, between the delivery of the air pump 10 and the expansion chamber 8, there is disposed a non-return valve 1 4 avoiding a possible return of the water in the air pump. The air pump 10, shown in greater detail in Fig. 2, is constituted by a body divided into two chambers 1 5 and 1 6 by a supple membrane 1 7 of which the equilibrium is obtained by its own rigidity and by the action of a spring 1 8 in abutment on the bottom of the chamber 16.

The chamber 1 5 is connected to atmosphere by the port 1 3 of which the opening is controlled by a suction valve 1 8 and to the expansion chamber 8 by the port 1 2 of which the opening is controlled by a delivery valve 19.

The other so-called drive chamber 1 6 is connected by a port 20 and a conduit 21 to an air suction pipe 22 for the general supply of compressed air, the suction pipe 22 of the compressor itself being connected to an air inlet manifold 24 of the engine supplied from a conduit 25 connected to atmosphere via an air filter 26.

The pressure pulsations produced in the suction pipe 22 of the compressor 23 are transmitted through the conduit 21 to inside the chamber 1 6 of the pump 10 thus provoking a reciprocating displacement of the membrane 1 7 against the spring 1 8. The displacement of the membrane 1 7 brings about a variation in volume of the air chamber 15, hence a variation in pressure results, bringing about a displacement of the valves 1 8 and 19, so that the atmospheric air drawn through the pipe 1 3 is delivered through pipe 1 2 towards the expansion chamber 8 by the conduit 11 and through the non-return valve 1 4. The calibration of the spring 1 8 enables a predetermined level of pressurization to be obtained.

As a variant, it would be possible to control the membrane 1 7 by a mechanical means connected to a drive member of the internal combustion engine.

1. A cooling device for internal combustion engines, comprising a radiator which is connected respectively to the cooling chamber of the engine and to a circulation pump itself

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in cooling devices for internal combustion engines The present invention relates to an improvement in cooling devices for internal combustion engines. In the cooling devices for internal combustion engines, particularly for Diesel engines, it is well known to maintain under pressure the cooling circuit employing liquid, in order to avoid the risk of the formation of steam at determined spots, particularly in the header tank of the engine and to avoid the phenomena of cavitation which lead, in common with chemical influences, to corrosions of determined parts of the cooling chambers. Devices are also known in which the pressurization is obtained by connecting the expansion chamber directly to the general compressed air circuit supplying the different members of the vehicle. However, these devices are not entirely satisfactory as it is desirable to isolate the cooling circuit of the engine from the general compressed air supply circuit. According to the present invention, the expansion chamber is connected to an air pump generating a pulsated air pressure, said pump being driven by an auxiliary member of the internal combustion engine. According to a feature of the invention, the device for pressurizing the circuit is actuated by a pressure variation of one of the auxiliary members of the engine and particularly the pressure pulsation at the inlet of the braking air compressor; the conditioning of such a device is very rapid and especially does not depend on the rise in temperature of the water leading to its expansion and consequently the establishment of pressure. The defects in tightness of the filler caps with calibrated valve are less important, as the device is always in a position to establish the pressure and compensate the leakages. The invention will be more readily understood on reading the following description with reference to the accompanying drawings, in which: Figure 1 is a schematic view of the cooling circuit of an internal combustion engine improved according to the invention; Figure 2 is a view in section of an embodiment of the air pump with membrane. Referring now to the drawings, Fig. 1 shows an internal combustion engine 1 of which the cooling liquid circuit comprises, at the outlet of the cooling jacket of the engine, a manifold 2 which is connected by a conduit 3, to the upper part of a radiator 4 via a thermostatic valve 5 capable of short circuiting the passage towards the radiator and of connecting the conduit 3 directly to a circulation pump 6 which is connected to the inlet port of the cooling jacket of the engine 1. At its lower part, the radiator 4 is also connected to the inlet port of the pump 6 by a conduit 7; similarly, an expansion chamber or service tank 8 of cooling liquid is connected by a conduit 9 to the suction of the pump 6. To ensure overpressure in the expansion chamber 8 in the space located above the cooling liquid, said chamber is connected to the delivery port 1 2 of an air pump 10 by a conduit 11, said pump being connected to the atmosphere by a suction port 1 3. In conduit 11, between the delivery of the air pump 10 and the expansion chamber 8, there is disposed a non-return valve 1 4 avoiding a possible return of the water in the air pump. The air pump 10, shown in greater detail in Fig. 2, is constituted by a body divided into two chambers 1 5 and 1 6 by a supple membrane 1 7 of which the equilibrium is obtained by its own rigidity and by the action of a spring 1 8 in abutment on the bottom of the chamber 16. The chamber 1 5 is connected to atmosphere by the port 1 3 of which the opening is controlled by a suction valve 1 8 and to the expansion chamber 8 by the port 1 2 of which the opening is controlled by a delivery valve 19. The other so-called drive chamber 1 6 is connected by a port 20 and a conduit 21 to an air suction pipe 22 for the general supply of compressed air, the suction pipe 22 of the compressor itself being connected to an air inlet manifold 24 of the engine supplied from a conduit 25 connected to atmosphere via an air filter 26. The pressure pulsations produced in the suction pipe 22 of the compressor 23 are transmitted through the conduit 21 to inside the chamber 1 6 of the pump 10 thus provoking a reciprocating displacement of the membrane 1 7 against the spring 1 8. The displacement of the membrane 1 7 brings about a variation in volume of the air chamber 15, hence a variation in pressure results, bringing about a displacement of the valves 1 8 and 19, so that the atmospheric air drawn through the pipe 1 3 is delivered through pipe 1 2 towards the expansion chamber 8 by the conduit 11 and through the non-return valve 1 4. The calibration of the spring 1 8 enables a predetermined level of pressurization to be obtained. As a variant, it would be possible to control the membrane 1 7 by a mechanical means connected to a drive member of the internal combustion engine. CLAIMS

1. A cooling device for internal combustion engines, comprising a radiator which is connected respectively to the cooling chamber of the engine and to a circulation pump itself connected to a cooling liquid expansion chamber, in which is maintained an air pressure greater than atmospheric pressure, wherein the expansion chamber is connected to an air pump generating a pulsated air pressure, said pump being driven by an auxiliary member of the internal combustion engine.

2. A cooling device as claimed in Claim 1, wherein the air pump is constituted by a body separated by a membrane into two chambers, one of which is connected to the suction of an air compressor supplying the general compressed air circuit of the vehicle and of which the other comprises suction and delivery ports provided with valves which are respectively connected to atmosphere and to the expansion chamber.

3. A cooling device as claimed in Claim 2 wherein the membrane is subjected on one- of its faces to the action of an elastic member disposed in the drive chamber connected to the suction of the compressor, said elastic member being calibrated in order to present á predetermined level of pressurization.

4. A cooling device as claimed in Claims 1 and 2, wherein a non-return valve is disposed in the conduit connecting the delivery of the air pump and the expansion chamber.

5. A cooling device as claimed in Claims 1 and 2, wherein the control of the membrane is ensured by a mechanical means connected to a drive member of the internal combustion engine.

6. A cooling device for internal combustion engines, substantially as described hereinabove and illustrated in the accompanying drawing.