FR2953889A1 - Coolant calories exchanging circuit for heat engine of motor vehicle, has derivation branch arranged in parallel with heater, and selection units permitting orientation of coolant in selective manner in heater or derivation branch - Google Patents

Abstract

The circuit (1) has a gas/liquid exchanger (3) arranged downstream of a heat engine (2), in which the exhaust gas from internal combustion of the heat engine provide caloric energy to a coolant and a unit heater (4) arranged downstream of the gas/liquid exchanger. A liquid/oil heat exchanger (5) is arranged downstream of the heater and upstream of the engine. A derivation branch (6) is arranged in parallel with the heater, and selection units (7) comprising three-way electric valves permit orientation of the coolant in a selective manner in the heater or the derivation branch. An independent claim is also included for a method for regulating heat of a coolant circulating in a calories exchanging circuit.

Description

CALORIE EXCHANGE CIRCUIT AND METHOD FOR THERMALLY REGULATING CIRCULATING HEAT PUMP FLUID IN A THERMAL MOTOR OF A MOTOR VEHICLE Technical Field:

The invention relates to the field of heat exchange of a heat transfer fluid circulating in a motor vehicle engine with ancillary organs such as gas / water type heat exchangers for heating the passenger compartment of a motor vehicle also designated by the term air heater, or water / oil exchangers to improve the temperature rise of the engine when the engine is cold.

The invention more particularly relates to a heat exchange circuit making it possible to improve both the motor heating speed in order to reduce the overconsumption during the temperature rise phases and to improve the heating speed of the passenger compartment if necessary.

PRIOR ART Generally speaking, it is known to use a gas / water type exchanger placed on the exhaust line so as to transmit heat to the heat transfer fluids circulating in the engine. Such a type of circuit has in particular been described in the document FR 2 921 866.

However, in this case, it is not possible to selectively carry out the heating of the compartment of the motor vehicle and the supply of calories to the engine oil by means of the heat transfer fluid.

Thus, the object of the invention is to enable the circulation of the coolant 30 to be adapted on the one hand, as a function of the heating requirements in the compartment, and on the other hand to optimize the consumption during a start-up at cold engine.

The invention therefore relates to a heat exchange circuit of a heat transfer fluid circulating in a motor vehicle engine, such a circuit comprising: a gas / water exchanger arranged downstream of the engine, and wherein the exhaust gases from the internal combustion of the heat engine supply heat energy to the heat transfer fluid; • A heater arranged downstream of the gas / water heat exchanger, and wherein the heat transfer fluid provides heat energy to the air to achieve heating of the passenger compartment of the vehicle; • A water / oil exchanger arranged downstream of the heater, and upstream of the engine, and wherein the coolant exchanges heat with the engine lubricating oil;

According to the invention, this circuit is characterized in that it comprises a first branch branch arranged in parallel with the heater and selection means for directing the coolant selectively either in the heater or in the first branch of derivation.

In other words, the heat transfer fluid can either be oriented inside the heater to allow air to be reheated later to the vehicle interior, or be oriented within the first branch of derivation to no longer be used to heat the cabin but to directly transmit its calories to the engine lubricating oil by means of the liquid / oil exchanger arranged downstream of the heater.

Advantageously, the circuit may comprise a second branch branch arranged in parallel with the motor.

In this case, it is possible to close the engine cooling circuit and thus the coolant can warm the cabin by means of the heater and / or heat the engine via the water / oil heat exchanger.

The heat transfer fluid can then take this second bypass branch to return to the gas / liquid exchanger and again receive calories from the exhaust gas. In practice, the motor can be arranged in series with a two-way valve that will allow or stop the circulation of heat transfer fluid in the engine.

Such a valve thus makes it possible to improve the rise in temperature of the engine. Indeed, until the engine has reached its normal operating temperature the valve remains closed and the heat transfer fluid does not circulate in the engine.

When the valve is opened, the circulation of the heat transfer fluid is reversed inside the second branch branch. The heat transfer fluid can then pass through the radiator of the vehicle so as to transmit its calories to the outside environment if necessary.

According to a particular embodiment, the second branch branch can be arranged in parallel with the motor and the two-way valve.

Thus, when the two-way valve is closed, the heat transfer fluid can pass through the second bypass branch and avoid the motor to return directly towards the gas / water heat exchanger.

In contrast, when the two-way valve is open, the heat transfer fluid passes into the engine and then into the two-way valve and can then return to the second bypass branch when in particular there is no need to heat the fuel. interior of the motor vehicle.

Advantageously, the circuit may comprise an additional electric pump arranged upstream of the gas / liquid exchanger and downstream of a connection between the second bypass branch and the two-way valve.

Thus, the electric pump makes it possible to circulate the heat transfer fluid inside the circuit when, in particular, the two-way valve is closed and that consequently the heat-transfer fluid pump of the engine is not activated. This pump can also be activated if the engine pump does not provide sufficient flow to cool the engine and to warm the passenger compartment of the motor vehicle. .

In practice, the circuit may include an electronic unit controlling the selection means according to the temperature information provided by an outdoor air temperature sensor.

In this way, it is preferable to warm up the engine when the temperature of the outside air is greater than or equal to a predetermined threshold and, consequently, the selection means direct the coolant in the first branch branch.

In this way, there is no hot source within the dashboard in which the heater is integrated and in the case of a vehicle equipped with an air-conditioning system of the passenger compartment, this makes it possible to do not generate a warm atmosphere inside the cabin.

Indeed, the heater no longer having internal water circulation, it no longer radiates on the evaporator of the air conditioning circuit and the temperature of the air blown out of the dashboard can be reduced by 5 ° C.

The invention also relates to a method of thermal regulation of a heat transfer fluid circulating in a heat exchange circuit as previously described according to the invention.

It is characterized in that, when the engine is started, the temperature of the outside air is measured and the heat transfer fluid is oriented in the first bypass branch when the outside air temperature is higher than a predetermined value. In other words, when for example the air temperature is greater than 15 ° C, it is therefore not necessary to circulate the heat transfer fluid inside the heater and therefore the selection means allow to orienting the coolant inside the first bypass branch of the circuit. Brief description of the figures.

The manner of carrying out the invention as well as the advantages resulting therefrom, will emerge clearly from the following embodiment, given by way of indication, but not by way of limitation, in support of the appended figures in which FIGS. 1 to 6 represent different operating modes of the circuit.

How to realize the invention As already mentioned, the invention relates to a heat exchange circuit of a heat transfer fluid flowing in a heat engine.

As shown in FIG. 1, the heat transfer fluid of the circuit (1) is mainly used to cool the heat engine (2) when it has reached its operating temperature.

To do this, after having cooled the engine (2), the coolant passes into the fluid / air exchanger (13), also referred to as the radiator.

Such a circuit (1) also comprises a gas / liquid type exchanger (3) for transmitting the calories of the exhaust gas to the heat transfer fluid in order to improve its rise in temperature during the starting phases.

Indeed, this rapid rise in temperature is important so as to allow rapid heating of the vehicle compartment but also to reduce the engine consumption during cold start phases.

Thus, the circuit (1) also comprises a heater (4) for heating the compartment. It also comprises a liquid / oil exchanger (5) in which the heat transfer fluid transmits its calories to the engine lubricating oil.

As shown, the circuit (1) has selection means (7) which can be fully realized by means of a three-way electric valve. This valve is, in this case, controlled by an electronic control unit (20), receiving information on the outside air temperature by means of a temperature sensor (21). Indeed, depending on the outside temperature, it is possible to orient the heat transfer fluid either in the heater (4) or in a first shunt portion (6).

Thus, as represented by FIG. 1, the coolant is oriented in the heater 10 (4) by the selection means (7). This position of selection means (7) can in particular be controlled when the outside temperature is below 15 ° C.

The circuit also comprises a two-way valve (9) for controlling or closing the circulation of the coolant inside the engine. A mechanical water pump (10) is also positioned in series with the engine (2) so as to allow the circulation of the coolant in the motor circuit (2).

The circuit (1) also has a second branch (8) for closing the circuit on itself when the two-way valve (9) is closed.

In this case, an additional electric pump (14) can be arranged upstream of the gas / liquid exchanger (3) to circulate the coolant.

This arrangement of the circuit (1) therefore operates in the start-up phases when it is not necessary to cool the motor but on the contrary to rapidly increase its temperature in order to limit the overconsumption.

Likewise, as shown in FIG. 2, when it is not necessary to supply calories to the heater (4), the selection means (7) can direct the heat transfer fluid inside the heater. first branch branch (6).

This can especially be the case when the outside temperature is higher than a threshold value such as 15 ° C. In this case, the heat transfer fluid serves only to transmit its heat captured at the gas / liquid exchanger (3) to the engine oil at the liquid / oil exchanger (5). .

The additional electric pump (14) operates and allows the circulation of the coolant in the circuit (1).

As shown in Figure 3, the circuit (1) may be devoid of a second branch branch, and therefore in this case, the heat transfer fluid passes through the motor 10 constantly. The additional electric pump (14) can operate in this case, but can also depend on the speed of the engine, and therefore the speed of the mechanical water pump (10).

For example, for an engine speed lower than 2500 rpm and during a request for cabin heating, the additional electric pump (14) can operate. Without request for heating the passenger compartment, and for a higher engine speed 2500 rpm, the additional electric pump (14) can be stopped.

As shown in FIG. 4, when the outside temperature is greater than a predetermined threshold value, the selection means (7) can orient the coolant in the first branch branch (6).

In this case, it is not necessary to operate the additional electric pump (14). As shown in FIG. 5, once the set temperature of the passenger compartment and the normal operating temperature of the heat engine have been reached, the circuit (1) goes into cooling mode of the heat engine.

To do this, the two-way valve (9) is open and the heat transfer fluid then passes through the second branch branch in the opposite direction to that of FIG. 1.

For an outdoor air temperature of less than 15 ° C, the thermal regulation mode is activated while continuing to require heating in the passenger compartment. Thus, the heat engine can maintain a normal operating temperature of between 90 and 115 ° C.

As shown in FIG. 6, in the cooling phase and without the request for heating the passenger compartment, for example for an outside air temperature greater than 15 ° C., the selection means (7) direct the coolant to inside the first branch branch (6).

In this case, no hot source within the dashboard is generated by the heater.

Thus, a vehicle equipped with an air conditioning system of the passenger compartment will not generate a warm atmosphere for thermal comfort.

Indeed, the heater no longer having water circulation within it, it no longer radiates on the evaporator of the air conditioning circuit and the air temperature blown out of the dashboard can be reduced by 5. degrees C.

It follows from the foregoing that a circulation circuit and a circulation method according to the invention have many advantages and in particular:

they make it possible to reduce the consumption of the thermal engines during the phases of temperature rise;

They allow rapid heating of the passenger compartment;

- Such a circuit has a limited number of elements and their operation allows for an architecture with a minimum of connections between the different elements.

Claims (7)

REVENDICATIONS1. Circuit (1) for exchanging calories of a coolant circulating in a heat engine (2) of a motor vehicle, said circuit (1) comprising: a gas / liquid exchanger (3) arranged downstream of the engine, and wherein the exhaust gases from the internal combustion of the heat engine (2) supply heat energy to said heat transfer fluid; a heater (4) arranged downstream of said gas / liquid exchanger (3), and wherein the heat transfer fluid provides heat energy to the air to heat the passenger compartment of the vehicle; a liquid / oil exchanger (5) arranged downstream of the heater (4), and upstream of the engine (2), and wherein the coolant exchanges heat with the lubricating engine oil; characterized in that it comprises a first branch branch (6) arranged in parallel with the heater (4) and selection means (7) for selectively directing the heat transfer fluid in the heater (4). ), or in the first branch branch (6). 2. Calorie exchange circuit according to claim 1, characterized in that it comprises a second branch branch (8) arranged in parallel with the motor (2). 3. Calorie exchange circuit according to claim 1, characterized in that the motor (2) is arranged in series with a two-way valve (9) adapted to allow or stop the circulation of heat transfer fluid in the engine (2). ). 4. Calorie exchange circuit according to claims 2 and 3, characterized in that the second branch branch (8) is arranged in parallel with the motor (2) and the two-way valve (9). 5. Calorie exchange circuit according to claim 4, characterized in that it comprises an additional electric pump (14) arranged upstream of the gas / liquid exchanger (3) and downstream of a connection (15). between the second bypass branch (8) and the two-way valve (9). 35 2953889 - 10 - 6. Calorie exchange circuit according to claim 4, characterized in that it comprises an electronic unit (20) controlling the selection means (7) as a function of temperature information provided by a temperature sensor (21). outside air. 5 7. A method of thermal regulation of the heat transfer fluid circulating in a heat exchange circuit according to one of the preceding claims, characterized in that, when the engine is started, the temperature of the outside air is measured, and one orients the heat transfer fluid in the first bypass branch (6) when the temperature of the outside air is greater than a predetermined value.