EP2090763B1 - Engine cooling circuit - Google Patents

Description

The invention relates to the cooling circuits of motor vehicle engines, and in particular the structure of coolant outlet housings receiving the heated coolant from the engine and provided with means for measuring a temperature of the liquid located in the engine. The box.

It is known to use valves to completely cut the engine internal water flow during startup phases. Thus, the thermal inertia of the engine is reduced and it reaches as quickly as possible its optimum operating temperature. When the engine reaches a sufficient temperature, the circulation of coolant is gradually restored.

The document FR 2 903 143 discloses a motor vehicle engine cooling circuit. This circuit comprises a water outlet housing provided with a temperature sensor and a thermostat. The housing comprises an outlet main pipe for transporting water to a radiator whose function is to cool said water, the cooled water being then conveyed by means of a pipe to the inlet of a water pump located upstream of the engine. The pump helps to circulate the cooled water in the engine and the heated water is then recovered in the housing. The housing comprises a first secondary water outlet pipe for supplying a heater with water and whose function is to create heating in the passenger compartment of the motor vehicle. The water recovered at the outlet of the heater is routed to the pump inlet for re-injection into the engine cooling circuit. The circulation of water in this first secondary pipe is controlled by means of a first solenoid valve placed between the housing and the heater. The housing has a second secondary outlet pipe which connects directly to the pipe connecting the radiator to the inlet of the pump, and constituting a bypass portion bypassing the radiator. The circulation of water in the second secondary pipe is controlled by means of a second solenoid valve, more precisely a proportional solenoid valve placed between the housing and the inlet of the pump. This bypass portion is used to directly send the heated water from the engine to the upstream portion of the cooling circuit positioned before said motor, through the housing. A 4 mm diameter branch tubing connects the housing part where the temperature sensor is installed to the pump inlet. The tubing has no means of closure and remains permanently open and thus ensures a low flow of water near the probe when the cooling circuit has been cut.

Such a cooling circuit has drawbacks. On the one hand, in the event of a probe failure, the water temperature measured by the thermostat is not very representative of the engine water temperature. Therefore, when the engine overheats, the thermostat will not necessarily open or too late to allow water to reach the radiator and participate in cooling the engine. Furthermore, this circuit requires an additional bypass line between the water outlet housing and the pump to provide reliable temperature measurement at the probe.

The invention aims to solve one or more of these disadvantages. The invention thus relates to a cooling circuit of an internal combustion engine of a motor vehicle, comprising a coolant outlet housing adapted to receive coolant from the engine; a pipe permanently conveying coolant from the outlet box to the engine; a cooling radiator adapted to receive coolant from the outlet housing; a temperature probe placed in the housing; a thermostatic valve closing the flow of coolant between the outlet box and the radiator; a deflector disposed in the housing and guiding a flow of coolant to the pipe, the temperature sensor and the thermostatic valve being disposed in this flow.

According to one variant, the thermostatic valve is disposed close to the temperature probe.

According to another variant, the thermostatic valve comprises a fuse membrane, the melting of this membrane releasing the flow between the housing and the radiator.

According to another variant, the thermostatic valve comprises a member whose thermal expansion displaces a seal and releases the flow between the outlet box and the radiator beyond a predefined temperature.

According to yet another variant, the body is made of wax.

According to a variant, said pipe has an inlet of which a portion is free of closure, the portion to which the baffle guides the flow.

According to another variant, the circuit comprises a device connected in the pipe between the output box and the motor, and comprises a shutter adapted to selectively close the inlet of the pipe except for said portion.

According to yet another variant, said device is a heater.

Alternatively, the shutter is slidably mounted in the housing between an open position of the inlet of the pipe and a closed position of the inlet of the pipe except for said portion.

According to yet another variant, the circuit comprises a pump for circulating the coolant in the circuit and connected between the output housing and the motor.

According to another variant, the deflector is disposed vis-à-vis the temperature sensor and the thermostatic valve.

• ■ la figure 1 est une représentation schématique d'un circuit de refroidissement de véhicule automobile ;
• ■ la figure 2 est une vue en coupe d'un boîtier de sortie de liquide de refroidissement d'un circuit selon l'invention.

Other characteristics and advantages of the invention will emerge clearly from the description which is given hereinafter, by way of indication and in no way limitative, with reference to the appended drawings, in which:

• ■ the figure 1 is a schematic representation of a motor vehicle cooling circuit;
• ■ the figure 2 is a sectional view of a coolant outlet housing of a circuit according to the invention.

The invention proposes a cooling circuit provided with an outlet box and a pipe permanently conveying coolant from the outlet box to the engine. A deflector disposed in the housing guides a flow of coolant to the pipe, a thermostatic valve closing the connection to the radiator and a temperature sensor being disposed in this flow.

Thus, the temperature probe and the thermostatic valve will be subjected to a temperature representative of the engine temperature. Thus, the engine control will have a more reliable temperature measurement and the risk of overheating of the engine will be reduced due to an opening of the valve when the coolant reaches its target temperature.

The figure 1 illustrates a cooling circuit 1 of an internal combustion engine 2. The circuit 1 comprises a casing 3 of coolant outlet. A temperature sensor 4 and a thermostatic valve 5 are arranged in the outlet housing 3. The thermostatic valve 5 selectively closes the flow of liquid between the outlet housing 3 and a radiator 7 below a predetermined temperature. The function of the radiator 7 is to cool the coolant, in this case water, flowing in the cooling circuit 1. The thermostatic valve 5 closes one end of a duct 6 joining the outlet housing 3 and the radiator 7. A duct 9 returns the radiator cooling liquid 7 to a pump 8. The pump 8 delivers the cooling liquid into the engine pipes 2. After passing through these pipes, the coolant is received in the outlet housing 3. Part of the coolant discharged into these pipes passes through a water / oil radiator 20. A conduit 19 discharges the coolant from the radiator water / oil 20 in the outlet housing 3.

The cooling circuit 1 further comprises a first secondary pipe 10 connecting the outlet housing 3 to the pump 8. The circuit comprises a peripheral connected in the secondary pipe 10, in this case a heater 11. The cooling circuit 1 comprises a second secondary duct 13 connecting the outlet housing 3 to the duct 9 via a proportional solenoid valve 14. This secondary duct 13 makes it possible to directly send heated water from the engine 2 to the pump 8, so that coolant reaches the pump 8 with a lower pressure drop than that generated by the heater 11 in the secondary pipe 10. The solenoid valve 14 is in particular open during the engine 2 startup phases to accelerate its rate of warming.

In the cooling circuit 1 according to the invention, a pipe permanently conveys liquid from the outlet housing 3 to the engine 2. The figure 2 is a schematic sectional view of the outlet housing 3. In this case, the secondary pipe 10 is used to convey the liquid permanently to the engine 2. The use of a pipe for feeding a device allows avoid using a pipe dedicated to the maintenance of the flow when all the valves are closed.

A portion of the secondary pipe 10 is free of closure. A shutter 31 is able to selectively close the inlet of the pipe 10, with the exception of a portion intended to convey the cooling liquid permanently to the engine 2. The shutter 31 is slidably mounted in the housing 3 between an open position of the inlet of the pipe 10 and a closed position of this inlet with the exception of the portion intended for the permanent flow. The junction between the pipe 10 and the outlet housing 3 may also have a protrusion not closed by the shutter 31. The permanent passage portion may for example comprise a section between 8 and 20 mm ² .

A deflector 32 is disposed in the housing 3 and guides a coolant flow (illustrated by the dashed arrow) to the closed portion. The deflector 32 is arranged so that the thermostatic valve 5 and the temperature sensor 4 are arranged in this flow. The deflector 32 will advantageously be arranged vis-à-vis the temperature sensor 4 and the thermostatic valve 5, to better guide the flow on these components.

Thus, the temperature sensor 4 and the thermostatic valve 5 will be subjected to a coolant temperature representative of the engine temperature. In order to reduce the size required for the deflector 32, the probe 4 and the valve 5 are advantageously arranged close to each other. The deflector 32 illustrated has a rectilinear section. However, a deflector according to the invention may have any suitable forms for guiding the flow as a function of the geometry of the coolant outlet box 3

Different types of thermostatic valves 5, known to those skilled in the art, may be used. The thermostatic valve may in particular comprise a member 51 whose thermal expansion displaces a seal and thus releases the flow in the conduit 6 between the outlet housing 3 and the radiator 7 beyond a predefined temperature. The dilation member 51 may in particular be made of wax. Other thermostatic valves may have a fusible membrane melting at a safety temperature in order to connect the outlet housing 3 with the radiator 7. Other thermostatic valves 5 may in particular include a thermomechanical closure member.

Claims (11)

1. Internal combustion engine cooling circuit (1) comprising a coolant outlet box (3) able to receive coolant from the engine (2); a line (10) permanently carrying coolant from the outlet box (3) to the engine (2); a cooling radiator (7) able to receive coolant from the outlet box; a temperature sensor (4) positioned in the box (3); a thermostatic valve (5) shutting off the flow of coolant between the outlet box and the radiator; characterized in that it further comprises a deflector (32) positioned in the box (3) and guiding a flow of coolant to the line, the temperature sensor (4) and the thermostatic valve (5) being positioned in this flow.
2. Cooling circuit according to Claim 1, in which the deflector (32) is positioned facing the temperature sensor (4) and the thermostatic valve (5).
3. Cooling circuit according to Claim 1 or 2, in which the thermostatic valve (5) is positioned near the temperature sensor (4).
4. Cooling circuit according to Claim 1 or 2, in which the thermostatic valve (5) comprises a meltable membrane, the melting of this membrane opening the flow between the box and the radiator.
5. Cooling circuit according to Claim 1 or 2, in which the thermostatic valve comprises a member (51) the thermal expansion of which moves a seal and opens the flow between the outlet box (3) and the radiator (7) when the temperature surpasses a predefined temperature.
6. Cooling circuit according to Claim 5, in which the said member (51) is made of wax.
7. Cooling circuit according to any one of the preceding claims, in which the line (10) has an inlet one portion of which is unclosed, towards which portion the deflector guides the flow.
8. Cooling circuit according to Claim 7, comprising a peripheral (11) connected in the line between the outlet box and the engine, and comprising a shut-up member (31) capable selectively of closing the entry to the line (10) with the exception of the said portion.
9. Cooling circuit according to Claim 8, in which the said peripheral is a unit heater (11).
10. Cooling circuit according to Claim 8 or 9, in which the said shut-off member (31) is mounted in the box such that it can slide between a position in which the entrance to the line is open and a position in which the entrance to the line is closed with the exception of the said portion.
11. Cooling circuit according to any one of the preceding claims, comprising a pump (8) for circulating the coolant around the circuit and which is connected between the outlet box (3) and the engine (2).

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