FR2799505A1 - Cooling system for engine of motor vehicle, has multiple solenoid valves to provide finer control of flow of coolant to allow the engine to run at optimum temperatures under all driving conditions - Google Patents

Abstract

The cooling system has solenoid valves (14-18) in branches (4-8) of the cooling circuit (2), and has a data acquisition unit (22) to gather information on the operating conditions of the vehicle. The data acquisition unit is connected to a controller (19) that selectively operates the solenoid valves to control the flow of coolant to optimize the temperature of the engine.

Description

The present invention relates to a cooling system for a motor vehicle engine.

More particularly, the invention relates to a cooling system comprising a hydraulic circuit of heat transfer fluid associated with a main pump for circulation thereof through the engine of the vehicle and various branches of circuit, in which equipment is arranged. vehicle thermal.

knows that cooling systems are designed to guarantee engine resistance to thermomechanical stresses resulting from combustion.

additional functions are implemented in addition to the main cooling of the engine to improve overall performance or to provide and guarantee benefits to vehicle users, such as for example heating the passenger compartment thereof.

cooling systems are then dimensioned in relation to the most demanding operating conditions of the engine in thermally established phases, that is to say at maximum speed and at full load.

these critical conditions of thermally established phases - vehicle operation, represent only a tiny part of the most common use cases of a vehicle.

Indeed, statistical studies show that the majority of private vehicle journeys are made in urban areas and that over 55% of these journeys are less than 6 km long and less than 5 minutes long.

Under these conditions, the thermal operating parameters of the motors are not optimized, which results in a degradation of their performance, increased consumption, a high level of emission of pollutants and a reduction in the thermal and acoustic comfort of the vehicles.

The object of the invention is therefore to solve these problems.

To this end, the subject of the invention is a motor vehicle engine cooling system, of the type comprising a coolant hydraulic circuit, associated with a main pump for circulating it through the vehicle engine and various circuit branches. , in which are arranged thermal equipment of the vehicle, characterized in that at least some of the branches of the circuit are provided with solenoid valves for regulating the circulation of fluid therein and in that it comprises means for acquisition of information relating to the conditions of operation of the vehicle, connected to means for controlling the operation of solenoid valves to regulate the volume and the flow rate of fluid in circulation in the hydraulic circuit in order to optimize the operation of the engine.

The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to the appended drawing, represents a block diagram illustrating the structure and operation of a system according to the invention.

This figure shows a motor vehicle engine cooling system, which is designated by general reference 1.

This system comprises a hydraulic circuit designated by the general reference containing a heat transfer fluid, this circuit being associated with a main pump for circulating fluid in the engine 1 of the vehicle and in different branches of the circuit.

branches are for example five in number are designated by the references 4,5,6,7 and 8 in this figure.

thermal equipment is placed in these cir cuit branches, this equipment being designated by the references 9,10,11,12 and 13 respectively.

thermal equipment comprises, for example in a conventional manner, means forming an air heater for heating the passenger compartment of the vehicle, means forming a water / oil exchanger, means forming a direct fluid return, means forming a radiator and finally means forming a degassing box for that -this.

According to the invention, at least some of the branches of this circuit are provided with solenoid valves for regulating the circulation of fluid therein. Thus, for example, in this figure, each branch 4,5,6,7 and 8 equipped with a solenoid valve, respectively 14,15,16,17 and 18, the operation of which is controlled by a processing unit d 'information designated by the general reference 19 in this figure.

solenoid valves can be open / close solenoid valves or proportional solenoid valves.

operation of the main pump 3 can also be controlled by the information processing unit 19.

This information processing unit in fact comprises any appropriate computer designated by the general reference 20, associated for example with information storage means, designated by the general reference 21, and which will be described in more detail below.

This information processing unit is also connected to means for acquiring information relating to the operating conditions of the vehicle and which are designated by the general reference in this figure.

various information relating to the operating conditions of the vehicle is then analyzed by the computer to control the operation of the solenoid valves and possibly of the main pump, in order to regulate the volume and the flow rate of fluid in circulation in the hydraulic circuit to optimize the operation of the engine.

Indeed, such a structure makes it possible to optimize the operation of the engine cooling system to adapt it to thermal vehicle conditions in order to improve the benefits in terms of fuel consumption, pollution control and thermal and acoustic comfort of this vehicle. .

Such a structure in fact makes it possible to respond in the best possible way and in real time, to the needs in terms of thermal control of the engine and thermal comfort of the vehicle cabin and is based on a self-adapting architecture of the cooling system, controlled by a calculator.

Thus, for example, two types of thermal phases can be defined for the operation of an engine, namely a transient thermal phase when the engine is started and when the latter is running cold and an established thermal phase.

These phases can then be associated with engine cooling strategies based on the control of two physical parameters defining almost all of the functional part of the system, namely volume and the flow rate of fluid circulating in the circuit.

This allows for example to optimize the rise in temperature of the engine in order to optimize its operation.

The volume of fluid in the cooling circuit in fact contributes to the inertia of the system, that is to say to the time of rise in engine temperature. It is therefore possible to virtually reduce this inertia by reducing the volume of useful fluid during the temperature rise phases thereof.

This virtual reduction in the volume of fluid is done by closing the non-functional fluid circuit branches during the engine temperature rise phases, that is to say typically the branches in which the degassing means and the means forming the water exchanger are placed. / oil and the means forming the passenger compartment air heater when there is no demand for heating the passenger compartment of the vehicle for example.

fluid flow in the various branches of the circuit is today sized to meet the specifications for engine performance and optimized operation of the water / oil exchanger and radiator.

However, these specifications are defined in relation to the operating points at full load and at maximum speed in thermally established phase of the engine.

As indicated above, these points represent only a minority of the usual operating points for vehicle use and it is also possible to envisage reducing the flow rate in each branch of the circuit to further optimize the rise in temperature of the engine.

transient thermal phase of temperature rise of the engine, the internal flow of fluid in the circuit is then reduced to the maximum to promote the temperature rise of the walls of the combustion chamber of the lubricating oil, by direct contact with the jacket.

During these phases, the engine does not need to cool down.

On the other hand, during the thermally established phases, it is possible to regulate the flow of fluid in the water / oil exchanger and the radiator in order to optimize for all operating points, the temperature of the lubricating oil the temperature of the walls of the combustion chamber.

To reduce the flow in each of these branches and thus control the circulation of the fluid, it is then possible to control the solenoid valves 14 17 and 18 described above.

As indicated above, the computer 20 is connected to a certain number of information acquisition means.

These information acquisition means can include various sensors, including sensors for the temperature of the engine material, fluid leaving it, lubricating oil and vehicle cabin, etc.

Engine operating parameters sensors can also be used to read the engine operating speed, torque the vehicle speed.

Environmental parameters can also be useful, such as the outside air temperature.

Analysis of these different pieces of information enables the computer to determine the engine cooling requirements in order to adapt, in real time, the hydraulic architecture of the cooling circuit by controlling the volume and the flow rate of fluid circulating in it.

Thus, for example, information for controlling the various organs which have been described previously can be stored in the storage means 21 associated with the computer 20.

Of course, this computer can also be adapted to control a fan unit associated with the radiator, for example. It can therefore be seen that the regulation of the volume and of the flow rate of fluid circulating in the hydraulic circuit by piloting solenoid valves placed in different branches thereof and possibly of operation the main pump associated with this circuit, makes it possible to adapt in time how this cooling system works, to the needs in terms of engine cooling to facilitate the rise in temperature thereof and thus to optimize the operation thereof.

In addition, one or more auxiliary pumps can also be arranged in circuit branches as they have just been described above, this or these auxiliary pumps then being controlled by the calculator 20 of the control means 19.

Claims (6)

<B><U>REVENDICATIONS</U> </B> 1. Cooling system of a motor vehicle engine, of the type comprising a hydraulic circuit (2) of heat transfer fluid, associated with a main pump (3) for circulation thereof through the engine (1) of different vehicles branches (4,5,6,7,8) of circuit, in which are arranged thermal equipments (9,10,11,12,13) of the vehicle, characterized in that at least some of the branches (4,5 , 6,7,8) of the circuit are provided with solenoid valves 15,16,17,18) for regulating the circulation of fluid in them and in this comprises means (22) for acquiring information relating to operating conditions of the vehicle, connected to means (19) for controlling the operation of the solenoid valves (14, 15, 16, 17, 18) for regulating the volume and flow rate of fluid in circulation in the hydraulic circuit (2) in order to optimize engine operation (1). 2. System according to claim 1, characterized in that the hydraulic circuit (2) comprises branches in which are arranged means (9) forming cabin air heater, means (10) forming water / oil exchanger, means ( 11) forming direct fluid return, means 2) for radiator mant and means (13) forming degassing box. 3. System according to claim 1 or 2, characterized in that the information acquisition means (22) include sensors suitable for reading the temperature of the engine material, the temperature of the fluid leaving the engine, the oil temperature of the engine, the temperature in the passenger compartment of the vehicle, the engine operating speed, the torque and the vehicle speed and the outside air temperature. 4. System according to any one of the preceding claims, characterized in that the solenoid valves (14,15,16,17,18) comprise opening / closing solenoid valves and proportional solenoid valves. 5. System according to any one of the preceding claims, characterized in that at least one auxiliary pump controlled by the control means (19) is arranged in one of the branches of the hydraulic circuit 6. System according to any one of the preceding claims, characterized in that the main pump (3) is controlled by the piloting means (19).