GB2455339A - Temperature responsive flow control valve - Google Patents

Abstract

A temperature responsive valve 11 has two generally cylindrical valve members 28, 29 arranged concentrically within a valve chamber 27. The outer valve member 28 has an end flange 32 abutting an outer annular seat 45 adjacent a hot outlet 16 and is directly actuated by a thermostat capsule 24 via radial spokes 35. The capsule 24 reacts against a central column 26 which guides the inner valve member 29, the inner valve member 29 having an end flange 37 abutting an inner annular seat 38 also adjacent the hot outlet 16, while its other end has hooked castellations 39 engaging the capsule 24. The outer valve member 28 blocks flow from a hot inlet 14 when the temperature sensed by the capsule 24 is below 80{C. As the temperature rises, the outer valve member 28 moves so coolant can flow between the valve members 28, 29 back to the engine. With a further rise in temperature, the capsule 24 engages the castellations 39 to move the inner valve member 29 and allow flow through the hot outlet 16 to a radiator 17.

Description

Temperature responsive flow control valve for an engine cooling system This invention relates to a thermostatically controlled valves and in particular to temperature responsive control valves for use in engine cooling systems, particularly but not exclusively, of motor vehicles.

Typically, an engine cooling system has a pump to circulate coolant used to cool the engine, a radiator to cool the coolant and a bypass to allow coolant to circulate through the engine without being cooled by the radiator. In motor vehicles, a cabin heater is usually, provided so that the coolant warmed by the engine provides heating for any occupants of the vehicle. Additionally, the main engine coolant is often used to cool one or more additional heat exchangers or radiators such as a transmission oil cooler, a fuel cooler or an air-charge cooler. A temperature responsive control valve is provided to control the flow of coolant through the radiator and frequently also to control the flow of coolant through the bypass.

GB2401 166A describes a temperature responsive flow control valve in which a housing has a hot inlet for connection to a bypass receiving hot coolant from an engine, a cold inlet for connection to a radiator and an outlet for a pumped return to the engine. A thermostat capsule controls flow to substantially prevent coolant flow from the hot and cold inlets to the outlet when the temperature of the coolant sensed by the temperature responsive actuator is below a first predetermined temperature, to permit coolant flow only from the hot inlet to the outlet when the sensed temperature is between the first predetermined temperature and a second higher predetermined temperature, to permit coolant flow from both of the inlets to the outlet when the sensed temperature is between the second temperature and a third higher predetermined temperature and to permit coolant flow only from the cold inlet to the outlet when the sensed temperature exceeds the third temperature.

Although such a flow control valve works well when installed in a cooling system to control a return flow to the engine from a bypass and a radiator (a so-called bottom thermostat configuration), it is sometimes more convenient to install the valve as part of the engine in a so-called top thermostat configuration where flow to the radiator is connected to the engine at the thermostat.

It is an object of this invention to provide an improved temperature responsive control valve suitable for use in an engine cooling system in a top thermostat configuration..

According to the invention there is provided a temperature responsive control valve for use in an engine cooling system in which a pump circulates liquid coolant to an engine, coolant from the engine is returned to the pump through a radiator and a bypass arranged in parallel and the control valve controls flow as between the radiator and the bypass, the control valve having a housing defining a hot inlet which in use is connected to the engine to receive hot coolant therefrom, a hot outlet which in use is connected to the radiator to deliver hot coolant thereto, a return outlet which in use is connected to the pump for return to the engine, a valve chamber, a first generally cylindrical valve member in the valve chamber cooperating with a first valve seat and movable away from the first valve seat to control the flow of coolant from the hot inlet to the return outlet, a second generally cylindrical valve member cooperating with a first valve seat and arranged concentrically with the first valve member to define an annular bypass passage therebetween, the second valve member being movable away from the second valve seat to control coolant flow from the hot inlet to the hot outlet and a temperature responsive actuator to move the first and second valve members, the first valve member being operable to substantially prevent coolant flow from the hot inlet to the hot and return outlets when the temperature of the coolant sensed by the temperature responsive actuator is below a first predetermined temperature and the second valve member being operable to substantially prevent coolant flow from the hot inlet to the hot outlet through the bypass passage when the temperature of the coolant sensed by the temperature responsive actuator is below a second predetermined temperature higher than the first temperature.

Conveniently there is a lost motion connection between the actuator and the second valve member.

Preferably the first valve member cooperates with the housing to prevent coolant flow from the hot inlet to the return outlet through the bypass passage when the sensed temperature exceeds a third predetermined temperature higher than the second temperature.

The housing may also have a cold inlet which in use is connected to the radiator to receive cold coolant therefrom, the cold inlet being in direct communication with the return outlet, in which case flow from the cold inlet may be arranged to flow over at least part of the actuator to influence the temperature sensed by the actuator.

Preferably, housing has a main bore in which the first valve member is slidable which can provide direct communication between the hot inlet and the return outlet, a spring loaded pressure relief valve member blocking the direct communication until the pressure difference between the hot inlet and the return outlet exceeds a predetermined amount.

The invention will now be described by way of example with reference to the accompanying drawings, of which:-Fig.1 is cross-section through the temperature sensitive control valve according to the invention.

The temperature responsive flow control valve 11 shown in Fig.1 has a housing 12 which may be part of an engine 13. The housing 12 has a hot inlet 14 for connection to an engine outlet passage 15 receiving hot coolant from the engine 13, a hot outlet 16 connected to a radiator 17 through a top hose 18, a cold inlet 19 connected to the radiator 17 through a bottom hose 21 and a return outlet 22 for a pumped return to the engine 13 through an engine return passage 23. In the region of the hot outlet 16 the housing 12 includes an abutment column 26 which extends into a generally cylindrical valve chamber 27. A thermostat capsule 24 has a pushrod 25 which reacts against the abutment column 26.

The hot inlet 14, hot outlet 16, cold inlet 19 and return outlet 22 open into the valve chamber 27. However, flow of coolant from the hot inlet 14 to the return outlet 22 and to the hot outlet 16 is controlled by first and second generally cylindrical valve member 28, 29 arranged concentrically within the valve chamber 27. An annular bypass passage 46 is defined between the first or outer valve member 28 and the second or inner valve member 29, both of which would ordinarily be moulded in a plastics material.

The outer valve member 28 is guided in a main bore 31 of the valve chamber 27 by an end flange 32 and a guide flange 33, the end flange 32 abutting an outer annular seat 45 at the end of the main bore 31 adjacent the hot outlet 16. The capsule 24 has a flange 34 which is engaged by spokes 35 (e.g. four) which extend radially inwards from the tubular body of the outer valve member 28. An inner helical compression spring 36 reacts against the housing 12 in a blind end bore 44 adjacent the cold inlet 19 and the return outlet 22, this spring 36 holding the spokes 35 against the capsule flange 34.

The inner valve member 29 is at one of its ends guided on the abutment column by an end flange 37 abutting an inner annular seat 38 at the end of the main bore 31 adjacent the hot outlet 16 while at its other end there are hooked castellations 39 which extend axially past the capsule flange 34 and between the spokes 35. Typically there will be four castellations 39 to match the number of spokes 35. A step 41 in the main bore 31 between the hot inlet 14 and the return outlet 22 defines a seat for a pressure relief valve member in the form of a washer 42 which is urged against the step 41 by an outer helical compression spring 43.

When the temperature sensed by the thermostat capsule 24 is below 80°C, the outer valve member 28 is biased by the inner spring 36 acting through the spokes 35 such that the end flange 33 is on the outer annular seat 33, the end flange 33 preventing flow from the hot inlet 21 to the hot outlet 16 through the annular bypass passage 46 and the washer 42 preventing direct flow from the hot inlet 21 to the return outlet 22. Small leakages between the end flange 32 and the outer annular seat 45 and between the washer 42 and the outer valve member 28 (or through a small orifice in either the valve washer 42 or the outer valve member 28) can give sufficient flow of hot coolant for the capsule 24 to sense a temperature dominated by that in the hot inlet 14.

As the coolant temperature rises above 80°C the capsule flange 34 pushes against the spokes 35 such that the outer valve member 28 moves progressively away from the hot outlet 16. Initial movement of the outer valve member 28 allows flow past the outer annular seat 45 so that coolant can flow from the hot inlet 21, through the annular bypass passage 46 between the outer valve member 28 and the inner valve member 29, past the spokes 35 and through an annular gap between the outer valve member 28 and the capsule 24 to the return outlet 22. During this initial movement of the outer valve member 28, the inner valve member 29 remains in its initial position with its end flange 37 engaged with the inner annular seat 38. However, further movement of the capsule 24 causes the capsule flange 34 to abut the hooked castellations 39 which thus act as a lost motion connection between the capsule 34 and the inner valve member 29 to lift the end flange 37 of the inner valve member 29 away from the inner annular seat 38 and allow flow past the end flange 37 and through the hot outlet 16. Above 90°C, the outer valve member 28 cooperates with the housing 12 to prevent coolant flow from the hot inlet 14 to the return outlet 22 through the annular bypass passage 46. This is achieved by the outer valve member 28 having a plain cylindrical end remote from the end flange 32 which approaches and engages the end bore 44. It will be appreciated that the outer valve member 28 may have a plain cylindrical end which is always in engagement with the end bore 44 and is thus guided by it, there being a apertures in the outer valve member 28 adjacent the plain end which will allow the coolant -6.

flow from the annular bypass passage 46, the apertures being closed off at the higher coolant temperatures as previously described.

If the pump pressure becomes high, e.g. at higher engine speeds, and thus the pressure difference between the hot inlet and the return outlet exceeds a predetermined amount, the pressure relief valve washer 42 can lift away from the step 41 against the outer spring 43 to allow direct flow from the hot inlet 14 to the return outlet 22.

The cold inlet 19 provides a convenient return passage for cold flow from the radiator 17 to the engine and control valve 11 does not directly control the flow between the cold inlet 19 and the return outlet 22. However, while it would be feasible to select an alternative return passage into the engine, the cold flow from the radiator 17 can flow over at least part of the capsule 24 and thus influence the temperature sensed by the capsule 24 to give a correction for ambient temperature. This ambient compensation is explained more fully in GB2401 I 66A which is hereby incorporated by reference. Temperature responsive flow control valve for an engine cooling system This invention relates to a thermostatically controlled valves and in particular to temperature responsive control valves for use in engine cooling systems, particularly but not exclusively, of motor vehicles.

Typically, an engine cooling system has a pump to circulate coolant used to cool the engine, a radiator to cool the coolant and a bypass to allow coolant to circulate through the engine without being cooled by the radiator. In motor vehicles, a cabin heater is usually, provided so that the coolant warmed by the engine provides heating for any occupants of the vehicle. Additionally, the main engine coolant is often used to cool one or more additional heat exchangers or radiators such as a transmission oil cooler, a fuel cooler or an air-charge cooler. A temperature responsive control valve is provided to control the flow of coolant through the radiator and frequently also to control the flow of coolant through the bypass.

GB2401 166A describes a temperature responsive flow control valve in which a housing has a hot inlet for connection to a bypass receiving hot coolant from an engine, a cold inlet for connection to a radiator and an outlet for a pumped return to the engine. A thermostat capsule controls flow to substantially prevent coolant flow from the hot and cold inlets to the outlet when the temperature of the coolant sensed by the temperature responsive actuator is below a first predetermined temperature, to permit coolant flow only from the hot inlet to the outlet when the sensed temperature is between the first predetermined temperature and a second higher predetermined temperature, to permit coolant flow from both of the inlets to the outlet when the sensed temperature is between the second temperature and a third higher predetermined temperature and to permit coolant flow only from the cold inlet to the outlet when the sensed temperature exceeds the third temperature.

Although such a flow control valve works well when installed in a cooling system to control a return flow to the engine from a bypass and a radiator (a so-called bottom thermostat configuration), it is sometimes more convenient to install the valve as part of the engine in a so-called top thermostat configuration where flow to the radiator is connected to the engine at the thermostat.

It is an object of this invention to provide an improved temperature responsive control valve suitable for use in an engine cooling system in a top thermostat configuration..

According to the invention there is provided a temperature responsive control valve for use in an engine cooling system in which a pump circulates liquid coolant to an engine, coolant from the engine is returned to the pump through a radiator and a bypass arranged in parallel and the control valve controls flow as between the radiator and the bypass, the control valve having a housing defining a hot inlet which in use is connected to the engine to receive hot coolant therefrom, a hot outlet which in use is connected to the radiator to deliver hot coolant thereto, a return outlet which in use is connected to the pump for return to the engine, a valve chamber, a first generally cylindrical valve member in the valve chamber cooperating with a first valve seat and movable away from the first valve seat to control the flow of coolant from the hot inlet to the return outlet, a second generally cylindrical valve member cooperating with a first valve seat and arranged concentrically with the first valve member to define an annular bypass passage therebetween, the second valve member being movable away from the second valve seat to control coolant flow from the hot inlet to the hot outlet and a temperature responsive actuator to move the first and second valve members, the first valve member being operable to substantially prevent coolant flow from the hot inlet to the hot and return outlets when the temperature of the coolant sensed by the temperature responsive actuator is below a first predetermined temperature and the second valve member being operable to substantially prevent coolant flow from the hot inlet to the hot outlet through the bypass passage when the temperature of the coolant sensed by the temperature responsive actuator is below a second predetermined temperature higher than the first temperature.

Conveniently there is a lost motion connection between the actuator and the second valve member.

Preferably the first valve member cooperates with the housing to prevent coolant flow from the hot inlet to the return outlet through the bypass passage when the sensed temperature exceeds a third predetermined temperature higher than the second temperature.

The housing may also have a cold inlet which in use is connected to the radiator to receive cold coolant therefrom, the cold inlet being in direct communication with the return outlet, in which case flow from the cold inlet may be arranged to flow over at least part of the actuator to influence the temperature sensed by the actuator.

Preferably, housing has a main bore in which the first valve member is slidable which can provide direct communication between the hot inlet and the return outlet, a spring loaded pressure relief valve member blocking the direct communication until the pressure difference between the hot inlet and the return outlet exceeds a predetermined amount.

The invention will now be described by way of example with reference to the accompanying drawings, of which:-Fig.1 is cross-section through the temperature sensitive control valve according to the invention.

The temperature responsive flow control valve 11 shown in Fig.1 has a housing 12 which may be part of an engine 13. The housing 12 has a hot inlet 14 for connection to an engine outlet passage 15 receiving hot coolant from the engine 13, a hot outlet 16 connected to a radiator 17 through a top hose 18, a cold inlet 19 connected to the radiator 17 through a bottom hose 21 and a return outlet 22 for a pumped return to the engine 13 through an engine return passage 23. In the region of the hot outlet 16 the housing 12 includes an abutment column 26 which extends into a generally cylindrical valve chamber 27. A thermostat capsule 24 has a pushrod 25 which reacts against the abutment column 26.

The hot inlet 14, hot outlet 16, cold inlet 19 and return outlet 22 open into the valve chamber 27. However, flow of coolant from the hot inlet 14 to the return outlet 22 and to the hot outlet 16 is controlled by first and second generally cylindrical valve member 28, 29 arranged concentrically within the valve chamber 27. An annular bypass passage 46 is defined between the first or outer valve member 28 and the second or inner valve member 29, both of which would ordinarily be moulded in a plastics material.

The outer valve member 28 is guided in a main bore 31 of the valve chamber 27 by an end flange 32 and a guide flange 33, the end flange 32 abutting an outer annular seat 45 at the end of the main bore 31 adjacent the hot outlet 16. The capsule 24 has a flange 34 which is engaged by spokes 35 (e.g. four) which extend radially inwards from the tubular body of the outer valve member 28. An inner helical compression spring 36 reacts against the housing 12 in a blind end bore 44 adjacent the cold inlet 19 and the return outlet 22, this spring 36 holding the spokes 35 against the capsule flange 34.

The inner valve member 29 is at one of its ends guided on the abutment column by an end flange 37 abutting an inner annular seat 38 at the end of the main bore 31 adjacent the hot outlet 16 while at its other end there are hooked castellations 39 which extend axially past the capsule flange 34 and between the spokes 35. Typically there will be four castellations 39 to match the number of spokes 35. A step 41 in the main bore 31 between the hot inlet 14 and the return outlet 22 defines a seat for a pressure relief valve member in the form of a washer 42 which is urged against the step 41 by an outer helical compression spring 43.

When the temperature sensed by the thermostat capsule 24 is below 80°C, the outer valve member 28 is biased by the inner spring 36 acting through the spokes 35 such that the end flange 33 is on the outer annular seat 33, the end flange 33 preventing flow from the hot inlet 21 to the hot outlet 16 through the annular bypass passage 46 and the washer 42 preventing direct flow from the hot inlet 21 to the return outlet 22. Small leakages between the end flange 32 and the outer annular seat 45 and between the washer 42 and the outer valve member 28 (or through a small orifice in either the valve washer 42 or the outer valve member 28) can give sufficient flow of hot coolant for the capsule 24 to sense a temperature dominated by that in the hot inlet 14.

As the coolant temperature rises above 80°C the capsule flange 34 pushes against the spokes 35 such that the outer valve member 28 moves progressively away from the hot outlet 16. Initial movement of the outer valve member 28 allows flow past the outer annular seat 45 so that coolant can flow from the hot inlet 21, through the annular bypass passage 46 between the outer valve member 28 and the inner valve member 29, past the spokes 35 and through an annular gap between the outer valve member 28 and the capsule 24 to the return outlet 22. During this initial movement of the outer valve member 28, the inner valve member 29 remains in its initial position with its end flange 37 engaged with the inner annular seat 38. However, further movement of the capsule 24 causes the capsule flange 34 to abut the hooked castellations 39 which thus act as a lost motion connection between the capsule 34 and the inner valve member 29 to lift the end flange 37 of the inner valve member 29 away from the inner annular seat 38 and allow flow past the end flange 37 and through the hot outlet 16. Above 90°C, the outer valve member 28 cooperates with the housing 12 to prevent coolant flow from the hot inlet 14 to the return outlet 22 through the annular bypass passage 46. This is achieved by the outer valve member 28 having a plain cylindrical end remote from the end flange 32 which approaches and engages the end bore 44. It will be appreciated that the outer valve member 28 may have a plain cylindrical end which is always in engagement with the end bore 44 and is thus guided by it, there being a apertures in the outer valve member 28 adjacent the plain end which will allow the coolant -6.

flow from the annular bypass passage 46, the apertures being closed off at the higher coolant temperatures as previously described.

If the pump pressure becomes high, e.g. at higher engine speeds, and thus the pressure difference between the hot inlet and the return outlet exceeds a predetermined amount, the pressure relief valve washer 42 can lift away from the step 41 against the outer spring 43 to allow direct flow from the hot inlet 14 to the return outlet 22.

The cold inlet 19 provides a convenient return passage for cold flow from the radiator 17 to the engine and control valve 11 does not directly control the flow between the cold inlet 19 and the return outlet 22. However, while it would be feasible to select an alternative return passage into the engine, the cold flow from the radiator 17 can flow over at least part of the capsule 24 and thus influence the temperature sensed by the capsule 24 to give a correction for ambient temperature. This ambient compensation is explained more fully in GB2401 I 66A which is hereby incorporated by reference.

Claims (7)

1. A temperature responsive control valve for use in an engine cooling system in which a pump circulates liquid coolant to an engine, coolant from the engine is returned to the pump through a radiator and a bypass arranged in parallel and the control valve controls flow as between the radiator and the bypass, the control valve having a housing defining a hot inlet which in use is connected to the engine to receive hot coolant therefrom, a hot outlet which in use is connected to the radiator to deliver hot coolant thereto, a return outlet which in use is connected to the pump for return to the engine, a valve chamber, a first generally cylindrical valve member in the valve chamber cooperating with a first valve seat and movable away from the first valve seat to control the flow of coolant from the hot inlet to the return outlet, a second generally cylindrical valve member cooperating with a first valve seat and arranged concentrically with the first valve member to define an annular bypass passage therebetween, the second valve member being movable away from the second valve seat to control coolant flow from the hot inlet to the hot outlet and a temperature responsive actuator to move the first and second valve members, the first valve member being operable to substantially prevent coolant flow from the hot inlet to the hot and return outlets when the temperature of the coolant sensed by the temperature responsive actuator is below a first predetermined temperature and the second valve member being operable to substantially prevent coolant flow from the hot inlet to the hot outlet through the bypass passage when the temperature of the coolant sensed by the temperature responsive actuator is below a second predetermined temperature higher than the first temperature.
2. 2. A control valve according to claim I wherein there is a lost motion connection between the actuator and the second valve member.
3. 3. A control valve according to claim 1 or claim 2 wherein the first valve member cooperates with the housing to prevent coolant flow from the hot inlet to the return outlet through the bypass passage when the sensed temperature exceeds a third predetermined temperature higher than the second temperature.
4. 4. A control valve according to any preceding claim wherein the housing also has a cold inlet which in use is connected to the radiator to receive cold coolant therefrom, the cold inlet being in direct communication with the return outlet.
5. 5. A control valve according to claim 4 wherein flow from the cold inlet can flow over at least part of the actuator to influence the temperature sensed by the actuator.
6. 6. A control valve according to any preceding claim wherein the housing has a main bore in which the first valve member is slidable which can provide direct communication between the hot inlet and the return outlet, a spring loaded pressure relief valve member blocking the direct communication until the pressure difference between the hot inlet and the return outlet exceeds a predetermined amount.
7. 7. A temperature responsive flow control valve substantially as described herein with reference to the accompanying drawings.

   7. A temperature responsive flow control valve substantially as described herein with reference to the accompanying drawings.

   A temperature responsive control valve for use in an engine cooling system in which a pump circulates liquid coolant to an engine, coolant from the engine is returned to the pump through a radiator and a bypass arranged in parallel and the control valve controls flow as between the radiator and the bypass, the control valve having a housing defining a hot inlet which in use is connected to the engine to receive hot coolant therefrom, a hot outlet which in use is connected to the radiator to deliver hot coolant thereto, a return outlet which in use is connected to the pump for return to the engine, a valve chamber, a first generally cylindrical valve member in the valve chamber cooperating with a first valve seat and movable away from the first valve seat to control the flow of coolant from the hot inlet to the return outlet, a second generally cylindrical valve member cooperating with a first valve seat and arranged concentrically with the first valve member to define an annular bypass passage therebetween, the second valve member being movable away from the second valve seat to control coolant flow from the hot inlet to the hot outlet and a temperature responsive actuator to move the first and second valve members, the first valve member being operable to substantially prevent coolant flow from the hot inlet to the hot and return outlets when the temperature of the coolant sensed by the temperature responsive actuator is below a first predetermined temperature and the second valve member being operable to substantially prevent coolant flow from the hot inlet to the hot outlet through the bypass passage when the temperature of the coolant sensed by the temperature responsive actuator is below a second predetermined temperature higher than the first temperature.

   2. A control valve according to claim I wherein there is a lost motion connection between the actuator and the second valve member.

   3. A control valve according to claim 1 or claim 2 wherein the first valve member cooperates with the housing to prevent coolant flow from the hot inlet to the return outlet through the bypass passage when the sensed temperature exceeds a third predetermined temperature higher than the second temperature.

   4. A control valve according to any preceding claim wherein the housing also has a cold inlet which in use is connected to the radiator to receive cold coolant therefrom, the cold inlet being in direct communication with the return outlet.

   5. A control valve according to claim 4 wherein flow from the cold inlet can flow over at least part of the actuator to influence the temperature sensed by the actuator.

   6. A control valve according to any preceding claim wherein the housing has a main bore in which the first valve member is slidable which can provide direct communication between the hot inlet and the return outlet, a spring loaded pressure relief valve member blocking the direct communication until the pressure difference between the hot inlet and the return outlet exceeds a predetermined amount.