Device for controlling supply of a system with a fluid

A system for cooling internal combustion engine pistons comprising an oil pump driven by the engine, jets projecting oil on the pistons, and a control device (2) interposed between the oil pump and the jets, where the control device comprises a valve (14) positioned between an oil inlet pipe (8) connected to the pressurised oil pump and a jet supply pipe (10), where said valve allows the oil to flow out from the pump to the jets when the oil pressure is at least equal to a threshold pressure, and where the device also comprises a solenoid valve (22) capable of causing the valve (14) to close by permitting the pressurised oil to be brought into contact with the closure member (16), in a direction of closure of the valve (14).

DESCRIPTION

Technical Field and Prior Art

The present invention relates to a device for controlling the supply of a system with a fluid, for example the supply of jets cooling the pistons of an internal combustion engine with oil.

The cooling jets enable a cooling fluid such as oil to be projected against the bases of the pistons.

The cooling fluid is conveyed under pressure to the jets which vaporise this fluid when it is projected against the pistons. Pressurisation is obtained by means of a hydraulic pump, which is driven directly by the engine.

Such jets are of two types:a first type of jet permanently projects oil against the bases of the pistons, independently of the engine's operating conditions,a second type of jet contains a valve which opens only when the pressure of the cooling fluid reaches a given threshold value. The valve is formed by a piston and a spring, where the piston cooperates with a seat in order to block the passage of the fluid. Thus, when the engine is operating at low speed the pressure of the cooling fluid is less than the valve opening pressure, and the jets are not supplied. When the engine is operating at high speed the pressure of the cooling fluid increases until it exceeds the valve opening threshold value. The valve opens, allowing the jets to be supplied and the cooling fluid to be projected against the piston. The supply of cooling fluid can be interrupted only by reducing the pressure of the cooling fluid so that it once again falls below the threshold value. This threshold value is determined by the motor vehicle manufacturer. This value may, notably, be adjusted by modifying the load of the spring. This type of jet has the advantage that it reduces consumption of cooling fluid compared to the jet of the first type.

And reductions of this consumption of cooling fluid are constantly sought.

Accordingly it is one aim of the present invention to offer a device for controlling the supply of cooling fluid, enabling fluid consumption to be reduced still further, and generally it is one aim of the present invention to offer a device for controlling the supply of a system with a fluid.

BRIEF DESCRIPTION OF THE INVENTION

The above aim is met by a device comprising a valve allowing a fluid to pass from a fluid tank to at least one jet when the fluid is at a pressure higher than a given pressure, and a solenoid valve able to allow said fluid under pressure to be injected so as to cause the valve to close.

In other words, a single-direction valve controlled solely by pressure is associated with an electrically controlled valve to enable the single-direction valve to be closed regardless of the pressure of the fluid.

By means of the invention, interruption of the fluid supply is particularly simple and can be achieved at all pressure levels; a reduction of the fluid consumption can then be obtained.

Furthermore, this device is of a simple and robust design and can be adapted for all configurations. In the event of failure the fluid supply continues. As a consequence, in the case of the supply of jets to cool internal combustion engine pistons, the cooling of the pistons continues.

The subject-matter of the present invention is then principally a device for controlling the supply of a system from a fluid under pressure source comprising a valve intended to be positioned between a fluid under pressure inlet pipe and a supply pipe of said system, said valve allowing the fluid under pressure to flow out from the source to the system when the pressure of the fluid is at least equal to a threshold pressure, the valve having a closure member and an elastic means of return movement supported on a second face of the closure member, a first face of the closure member opposite the second face being intended to receive an effort from the fluid under pressure to cause the opening of the valve, and wherein the device also comprises a solenoid valve intended to be installed in a control pipe connected to the fluid under pressure inlet pipe and conveying the fluid under pressure to the second face of the closure member, said solenoid valve controlling the contact of the second face of the closure member with the fluid under pressure, and the solenoid valve being closed if there is no electrical power.

Advantageously, the valve comprises a sleeve for guiding the elastic means, wherein said sleeve is immobile, also forming a stop for the closure member in its maximum opening position, and where the sleeve comprises a recess receiving one end of the elastic means. The closure member may be a piston, and comprise a recess in its second face receiving another end of the elastic means.

The fluid under pressure reaches the second face of the closure member for example through the sleeve.

The solenoid valve is, for example, a proportional or “on-off” solenoid valve.

The valve may comprise at least one spur leading to a chamber formed by the closure member of the side of the second face of the closure member, to allow the outflow of the fluid trapped in this chamber when the valve is opened, said spur being intended to be connected to a low-pressure tank, and the dimensions of said spur being such that they allow pressure to be established in said chamber when the solenoid valve is opened.

For example, the solenoid valve has a mobile core in a coil and a magnetic circuit guiding the magnetic field able to be generated by the coil, an elastic means interposed between a magnetic stop and the core pushing the latter to the outside of the coil, a closure member pressed against a seat by the elastic means through the core, and the core being attracted inside the coil when a magnetic field is generated by the coil, allowing the closure member to become separated from the seat.

The elastic means of the solenoid valve is advantageously supported between the magnetic stop and a shoulder of the core, a part of the core being surrounded by the elastic means such that, when the core abuts a stop against the magnetic stop the elastic means is not completely compressed.

Advantageously, the control device according to the invention can comprise a casing in which the valve and the solenoid valve are installed so as to form a secure assembly intended to be installed in a housing comprising the inlet, supply and control pipes.

The subject-matter of the present invention is a system for cooling at least one internal combustion engine piston comprising an oil pump driven by the engine, at least one oil jet on the piston, said jet being supplied by the oil pump, a control device according to the present invention interposed between the oil pump and the jet, the control device being installed on a housing in which are installed the pressurised oil inlet pipe connected to the oil pump, the supply pipe connected to the jet, and the control pipe connected to the pressurised oil inlet pipe.

DETAILED DESCRIPTION OF THE INVENTION

In the following description the example used to explain the invention will be that of the supply of the cooling jets; however, the present invention applies to all fields using fluids and requiring their supply to be controlled.

Moreover, for purposes of simplification, we shall use the term “oil” to speak of the hydraulic cooling fluid. However, it should be noted that the present invention is not limited to the use of oil, and that all hydraulic fluids able to reduce the temperature of the pistons may be suitable.

InFIGS. 1 to 3Bit is possible to see an example embodiment of a control device according to the present invention.

The control device2according to the present invention is intended to be positioned between a pressurised oil source3(represented symbolically inFIG. 4) and at least one oil jet4(represented symbolically inFIG. 4) intended to project oil against the bases of the pistons (unrepresented) of an internal combustion engine. The control device2controls the pressurised oil supply of several jets, at least one per piston.

In the case of the control of the jets' oil supply, the control device is intended to be installed on an engine block7.

The engine block7has a pressurised oil inlet pipe8, a pipe10for supplying the pressurised oil jets and a pipe12for controlling the interruption of the jets' supply of oil.

The oil inlet pipe8is connected to the jet supply pipe10and to the control pipe12.

InFIG. 1it is possible to see the control device2according to the invention comprising a valve14positioned in the oil outflow path between the oil inlet pipe8and the jet supply pipe10, and a solenoid valve22interrupting or permitting the passage of pressurised oil from the control pipe12to the valve14.

The solenoid valve22is intended to be connected to an electronic control unit (unrepresented) sending orders to open or close the solenoid valve22.

InFIG. 3A, the valve14can be seen represented alone; it comprises a mobile closure member16, a valve seat18with which the mobile closure member16cooperates, and an elastic means20opposing the movement of the mobile closure member16.

According to the invention, the control pipe12is such that it conveys a part of the pressurised oil coming from the inlet pipe8on a second face16.2of the mobile closure member16of the valve14, facing a first face16.1receiving the oil directly from the inlet pipe8.

The first face16.1is an opening control face, and the second face16.2is a closure control face.

The valve14comprises a cylindrical body23, pierced by a through-bore24. The through-bore24comprises a first part of larger diameter24.1and a second part of smaller diameter24.2connected by an annular bearing forming the valve seat18, where the part of smaller diameter24.2is directed towards the inlet pipe8.

When the control device2is put in position on the engine block7, the valve body23is assembled in sealed fashion in a bore36of the engine block7, where the bore36connects the inlet pipe8and the jet supply pipe10.

The valve body23comprises a first radial spur25connecting the bore24with the supply pipe10.

The mobile closure member16, which is formed, in this example embodiment, by a piston, is installed sliding in the part of larger diameter24.1.

The first face16.1of the piston is supported by the valve seat18.

The spring20is installed under compression between the second face16.2of the piston16and the valve body23.

In the represented example a guide element26is assembled in the bore24, formed by a sleeve installed immobile in the bore24, for example installed by force in the bore24. The sleeve26comprises an axial recess28receiving one end of the spring20, holding the spring20.

The piston16also advantageously comprises a central recess29to receive one end of the spring20, improving its holding.

The sleeve26comprises, in its base, an axial spur30allowing the oil to flow out of the control pipe12to the piston16.

Advantageously, the sleeve26forms a piston opening stop, enabling the maximum stroke of the piston to be adjusted easily. In addition, the structure of the spring mounting20between the piston16and the sleeve26allows the compression of the spring20to be restricted, and thus the risks of damage to the latter to be reduced.

The valve14is normally closed, i.e. the valve14is closed when the oil pressure is lower than the threshold pressure. In this case, the piston16is supported on the valve seat18and prevents supply of the jets. In this configuration, the piston16is separated from the sleeve26by the spring20.

The body23comprises a second radial spur32opening on to the bore24in a chamber27formed by the piston and the sleeve26. The second spur32forms a vent to evacuate any oil located in the chamber27, when the piston16moves in the bore24in the direction of the sleeve26. The radial spur32is connected to a low-pressure tank33represented inFIG. 4, such that the oil pressure in the chamber27does not oppose the movement of the piston16, when the solenoid valve22is closed.

The valve14is assembled in the bore26such that the first radial spur25is located opposite the supply pipe10, and the second radial spur32is positioned opposite a vent pipe38constructed in the engine block7.

In an advantageous variant embodiment, annular grooves are provided on the outer periphery of the valve body23into which open the radial spurs25and32respectively, where these grooves allow the outflow of the oil to the supply pipe10and the vent pipe38respectively, whatever the orientation of the radial spurs. This embodiment helps facilitate assembly, since it is no longer required that the valve body is oriented precisely relative to the pipe10and of the engine block7, during installation of the control device in the engine block7.

We shall now describe the solenoid valve22in detail.

The solenoid valve is, for example, of the two-way, two-position type. The solenoid valve may be of the proportional type or of the “on-off” type.

The solenoid valve22is received in a casing39.

InFIG. 3B, the electromagnet controlling the opening and closing of the solenoid valve is represented in isolated fashion.

The electromagnet comprises a core40forming a magnetic mass, installed in unfixed fashion in a coil43, and is capable of generating a magnetic field when traversed by a current. The coil is received in a housing42of the casing39.

The casing39is advantageously made from a soft ferromagnetic material, channelling the magnetic field generated by the coil43, forming a magnetic circuit with the mobile core40. A magnetic stop45is installed at one end of the coil43to close the magnetic circuit. Advantageously, plastic over-moulding is applied around the coil43and the magnetic stop45, enabling them to be secured easily, and to facilitate their installation in the casing39.

An elastic means46, in the represented example a helical spring, is installed under compression between the core40and the magnetic stop45, tending to push the core40towards the outside of the housing42.

Advantageously, the core40comprises a shoulder49, on which one end of the spring46is supported; thus the spring46surrounds a part of the core40. When the core40moves back under the effect of the magnetic field it abuts against the magnetic stop45. Firstly, this stop restricts the stroke of the core40, and secondly this prevents the spring46from being compressed completely; this construction reduces the risks of damage to the spring.

When the coil43generates a magnetic field the core40is attracted inside the coil against the magnetic stop45, against the effort exerted by the spring46.

The control pipe12is extended in the casing39by a pipe54.

The solenoid valve22also comprises a closure member48formed, in the represented example, by a ball able to be supported on a seat50. The position of the ball48is determined by the core40, through a rod52connecting the ball48and the core40. It is understood that this example is in no sense restrictive, and that every type of solenoid valve may be suitable.

The seat50is formed between a part of larger diameter54.1and a part of smaller diameter54.2of the pipe54, where the ball48is housed in the part of larger diameter54.1.

The control pipe12is connected to the bore24of the valve in the area of the part of larger diameter54.1of the pipe54by means of a radial spur56, opposite the axial spur30of the sleeve, where the radial spur56is located beyond the ball48in the oil outflow direction.

The solenoid valve, particularly the ball48, the spring46and the channels are dimensioned such that the ball48remains pressed against the seat50whatever the pressure of the oil, until an opening order is given.

The casing39of the solenoid valve is installed in a sealed fashion on the engine block7; more particularly sealing is applied in the area of the junction between the control pipe12and the pipe54, and in the area of the junction between the axial spur30and the radial spur56.

Furthermore, sealing is applied between the electromagnet and the casing39to prevent leakage of oil originating from the control pipe12.

In a particularly advantageous manner, the valve14, the solenoid valve22and the casing39are produced as a secure assembly, which is added to the engine block7on to which it is attached, for example by means of screws or any other system.

To this end, the valve may be attached in the casing39, for example by mounting in force of one end of the valve body23in a bore58made in the casing39, and into which the radial spur56opens. By this means an integral assembly is produced which is easy to handle for its installation on the engine block7.

We shall now explain the operation of the control device according to the present invention.

The pressurised oil flows out in the inlet pipe8and in the control pipe12. The pressure of the oil is applied on to the first face16.1of the piston16. While the oil pressure is below the threshold pressure the valve14remains closed and the jets are not supplied (unrepresented position). No fluid is consumed by the jets and it therefore remains available for other uses in the pipe10which is extended by the pipe11.

If no current is applied to the coil43, the ball48of the solenoid valve22is pressed on to the seat50due to the effort exerted by the spring46on the core40. The solenoid valve22is therefore closed until an opening order is sent to it; the solenoid valve22therefore blocks the control pipe12and isolates the second face16.2of the piston16; this face16.2therefore “does not experience” any pressure. We recall that the chamber27is connected to a low-pressure tank.

As can be seen inFIG. 1, when the oil pressure reaches the threshold pressure the piston16is moved in the direction of the sleeve26against the spring20; the first face16.1of the piston16is separated from its seat18and allows the oil to flow out towards the jets, and the latter are then supplied. The oil contained in the chamber27between the piston16and the sleeve26is evacuated by the second radial spur32, which is connected to a low-pressure zone.

The valve14closes again when the oil pressure becomes lower than the threshold pressure, or after a command is given to the solenoid valve22.

When it is desired to discontinue the supply of the jets, an order to open the solenoid valve is given by the control unit, an electric current traverses the coil43, which generates a magnetic field, tending to move the core towards the inside of the housing42against the spring46pressed against the magnetic stop45. The rod52no longer exerts any effort on the ball48which, under the action of the pressure of the oil in the control pipe12upstream from the solenoid valve, becomes separated from its seat50, as can be seen inFIG. 2A. The oil then flows out in the radial spur56, and then in the axial spur30, traverses the sleeve26, fills the chamber27between the sleeve26and the piston16, and exerts an effort on the second face16.2of the piston16in the same direction as the spring20of valve14. The piston16then moves in the direction of the seat18of the valve. InFIG. 2Ait is possible to see the closure member16moving in the direction of its seat18.

The closure member slides until it is resting against the latter (FIG. 2B). The valve14is then closed and the jets are no longer supplied.

The diameter of the spurs, notably of the second radial spur32, is determined so as not to create too large a leak, which would prevent the rise in pressure in the chamber27, and would prevent the oil originating from the control pipe12from acting on the second face16.2of the piston16. The diameter of the spur32is also determined so as to allow a leak of sufficient size for the oil presented in the chamber27not to oppose the opening of the valve14.

When the solenoid valve is closed the oil contained in the chamber27is evacuated through the radial spur32. If the pressure conditions are still met the valve opens again; otherwise it remains closed.

The control device according to the invention allows the supply of the jets to be permitted or discontinued in a simple manner. Advantageously, it is manufactured in the form of an assembly which is easy to handle, formed by the valve, the solenoid valve and the casing39.

In addition, this closure is very rapid, and is possible at all pressures. This is therefore a device with a very broad range of uses. It enables the oil consumption to be reduced; the capacity of the oil pump can then be reduced. Since the latter is driven directly by the engine a reduction of fuel consumption can therefore be obtained.

It is understood that the relative positioning of the solenoid valve and of the valve inFIGS. 1,2A and2B is absolutely not restrictive, and all other positionings may be suitable, allowing great freedom in the manufacture of the device.

It is understood that an embodiment in the form of an assembly to be added on to the engine block is under no circumstances restrictive, and that all other configurations may be conceived.

In addition, this device requires little power to operate, which is particularly advantageous in the case of motor vehicles. Since the electromagnet can be small in size the power required to operate the solenoid valve is small.

This control device is particularly adaptable and can be manufactured taking account of the closure requirements, of the encumbrance and of the imposed production costs.

In addition, this device is extremely safe, even when operating in degraded mode. Indeed, if the solenoid valve22malfunctions the ball48remains pressed against the seat50. Indeed, the closure member of the valve14is subjected only to the oil pressure on its first face16.1. The oil is supplied as in the traditional devices and the pistons are consequently always cooled.

InFIG. 4a schematic diagram of the invention can be seen comprising the oil inlet pipe8, the jet supply pipe10and the control pipe12, the valve14between the oil inlet pipe8and the supply pipe and the solenoid valve22between the control pipe and the valve14. The arrows indicate the fluid's outflow direction.

It is understood that the control device according to the invention is not restricted to the supply of jets for cooling internal combustion engine pistons, but applies to all systems in which it is desired to control in simple fashion the supply of hydraulic or pneumatic fluid.