WO2006056709A2

WO2006056709A2 - Device for deactivating internal combustion engine cylinders

Info

Publication number: WO2006056709A2
Application number: PCT/FR2005/050827
Authority: WO
Inventors: Saïd IZELFANANE
Original assignee: Peugeot Citroen Automobiles Sa
Priority date: 2004-11-26
Filing date: 2005-10-07
Publication date: 2006-06-01
Also published as: WO2006056709A3; FR2878570B1; FR2878570A1; EP1815111A2

Abstract

The invention relates to a device for deactivating at least one cylinder (17, 18) of a multicylinder-type internal combustion engine, including means (20, 21, 22, 23) for disabling exhaust or intake valves of said cylinder, actuatable by a pressurised fluid, a pressurised fluid supply circuit (15), a controlled solenoid valve (14) and a secondary circuit (5) connecting said solenoid valve (14) to said disabling means (20, 21, 22, 23), characterised in that said secondary circuit (5) co-operates with auxiliary supply means (1, 2, 3) for keeping said secondary circuit (5) filled with the fluid during periods when said disabling means (20, 21, 22, 23) are not actuated.

Description

Device for deactivating cylinders of an internal combustion engine.

The present invention relates to a method and a device for controlling the pressure of a feed ramp means that allow the shutdown or in service of the valves of a group of cylinders of an internal combustion engine.

Internal combustion engines and in particular engines fitted to motor vehicles or road vehicles are solicited most of the time at a fraction of their nominal power. In these phases of operation that do not claim to deliver a significant torque, the engines suffer pumping losses that affect their performance and which are at the origin of excessive fuel consumption. These pumping losses correspond to the work that must be provided to suck the air / fuel mixture that is in the intake manifold at a relatively low pressure and introduce it into the combustion chamber during the intake phase.

To reduce these pumping losses, it is known to inactivate a number of cylinders. These deactivated cylinders then see their intake and exhaust valves closed and they are no longer traversed by any flow of gas mixture. These deactivated cylinders generate almost no more pumping losses because they operate as pneumatic springs, their piston alternating the compression and decompression phases of the gaseous mixture trapped in these cylinders. As for the cylinders remaining active, they must produce a larger torque and therefore require a higher flow of intake air into the manifold which increases the pressure in the distributor and thus reduces the losses by pumping the engine.

The deactivation of the cylinders is conventionally operated by an appropriate mechanism acting on the distribution of the cylinders according to the operating conditions of the engine. In the case of a distribution by camshafts and pawls, it is thus known to associate with the hydraulic stops with catch-up play on which latches are based, such a mechanism for disengaging the stops when one wants to disable the cylinders. Disengagement of the stops is conventionally performed hydraulically by raising, in a ramp supplying the disengagement mechanism, the pressure above a calibrated threshold pressure. Patent FR2837871 illustrates an example of such a mechanism.

However, after several hours of non-operation of the engine, the ramp feeding such a mechanism is empty due to leakage generated at the disengaging mechanism. This is why, during the first cylinder deactivation action, it is first necessary to fill the feed ramp of the disengaging mechanism before being able to raise the pressure above the calibrated threshold pressure. As a result, the first deactivation action of the rolls has a drawback materialized by a very long response time.

Therefore, the present invention proposes to overcome this disadvantage by maintaining a minimum pressure in the feed ramp of the disengaging mechanism.

More specifically, the subject of the invention is a device for deactivating at least one cylinder of a multi-cylinder type internal combustion engine, comprising means for decommissioning the intake or exhaust valves of said cylinder. actuated by a fluid under pressure, a pressurized fluid supply circuit, a piloted solenoid valve and a secondary circuit connecting said solenoid valve to said means for decommissioning, characterized in that said secondary circuit cooperates with auxiliary power supply means intended to maintaining the fluid filling of said feed ramp outside the periods of operation of said decommissioning means.

According to other features, said secondary circuit comprises leakage passages of said fluid, in particular at the means of deactivation and / or at a nozzle provided in said secondary circuit and said auxiliary power supply means are shaped so that their feed rate compensates for the flow of the leakage passages.

According to other features, the intake or exhaust valves of said cylinder are actuated by means of hydraulic play-compensated stops fed by a feed ramp and said auxiliary supply means are formed by a calibrated bore ensuring the communication between the feed ramp and the secondary circuit.

According to other features, the auxiliary power supply means form a continuous communication with pressure drop between the feed ramp and the secondary circuit.

According to other features, the auxiliary power supply means consist of a Venturi effect duct communicating the feed ramp and the secondary circuit. According to other features, the venturi effect duct generates a pressure drop such that the pressure in the secondary circuit connecting the solenoid valve to the means of decommissioning the valves is less than a defined threshold pressure (Pseuil).

According to other features, the auxiliary power supply means consist of a conduit of constant section, provided with a plug pierced with an opening of dimension much smaller than the section of the conduit.

According to other features, the constant section conduit provided with a pierced plug generates a pressure drop such that the pressure in the secondary circuit connecting the solenoid valve to the means of decommissioning the valves is less than a threshold pressure. defined (Pseuil).

According to other features, the hydraulic play catchers incorporate the means for decommissioning the valves.

According to other features, the deactivation device comprises a filter upstream of the auxiliary power supply means, intended to limit the fouling of said auxiliary power supply means. FIG. 1 represents a schematic view of a device known from the prior art for deactivating two of the four cylinders of an internal combustion engine.

FIG. 2 represents a schematic view of a device for deactivating two of the four cylinders of an internal combustion engine, according to a first embodiment of the invention.

FIG. 3 represents a schematic view showing a schematic view of a device for deactivating two of the four cylinders of an internal combustion engine, according to a second embodiment of the invention.

Referring to Figures 1, 2, 3, there is shown the exhaust portion of a camshaft and latch distribution of an internal combustion engine having four cylinders in line 16, 17, 18, 19. classic, and not shown in the figure, the translational movement of a valve that alternates its opening and closing, operates through a lever, called latch. One of the ends of the pawl is in fact in contact with the valve stem and admits an oscillation movement as a function of the rotation of the cam carried by the camshaft. The other end of the pawl serves as a pivot point and rests on a stop.

So that the ends of the latches, not shown in the figure, remain in abutment on their abutment, it is advantageous to adjust the contact using hydraulic stops to compensate for play. The catch-up game is then fed by a fluid, in the occurrence of the oil, which is conveyed by the ramp 4.

According to FIGS. 1, 2 and 3, the hydraulic stops with catch-up clearance 8, 9, 10, 11 respectively comprise means of decommissioning (20, 21, 22, 23), also known as disengaging means, also powered. by a fluid, in this case oil, which is conveyed by the ramp 5. Thus, only the cylinders 17, 18 are deactivatable. The ramp 4 which feeds the hydraulic stops with play catch-up

6, 7, 8, 9, 10, 11, 12, 13 is maintained filled by means of a feed ramp 15, which itself is fed by the main oil feed ramp of the engine cylinder head, not shown on FIG. the figures.

The ramp 5, which supplies the clutch mechanisms 20, 21, 22, 23, is intermittently powered by means of a communication 14 with the ramp 4. Advantageously, the communication 14 is a solenoid valve. More specifically, when it is necessary to disable the valves, the solenoid valve 14 opens so as to let the oil from the ramp 4 to the ramp 5, where the pressure is initially lower. When the pressure in the ramp 5 exceeds a calibrated threshold pressure Pseuil, the clutch mechanisms 20, 21, 22, 23 are activated so as to disengage the hydraulic catch-up stops (8, 9, 10, 11). In this way, the valves are rendered inactive.

When it is necessary to reactivate the valves, the solenoid valve 14 closes in such a way that the pressure in the ramp 5 descends below that of the calibrated threshold Pseuil so that the clutch mechanisms 20, 21, 22, 23 are no longer enabled. Note that the pressure drop is induced by the leaks existing at the disengaging mechanisms 20, 21, 22, 23 and at a nozzle 24 which serves to degass the fluid circuit in the ramp 5.

In order to overcome the leaks existing at the disengaging mechanisms 20, 21, 22, 23 and the nozzle 24, the invention consists in maintaining a continuous communication between the ramps 4 and 5, while controlling the flow rate of the oil from ramp 4 to ramp 5.

According to a first embodiment, the communication can be carried out by means of a Venturi effect duct 1, dimensioned according to the maximum pressure in the ramp 4 and the calibrated pressure Pseuil in the ramp 5, so that the oil which is flows continuously through the conduit 1 in the ramp 5, does not increase the pressure beyond the calibrated pressure Pseuil. According to a second embodiment, the communication can be achieved by means of a duct 3 of constant section, provided with a plug 2 pierced with an opening of much smaller size than the section of the duct 3, so that the oil which flows through the conduit 3, does not increase the pressure in the ramp 5 beyond the calibrated pressure Pseuil.

In addition, whatever the auxiliary power supply means chosen, it is advantageous to have upstream of said auxiliary supply means a filter 25 for filtering the liquid under pressure. Thus, whether it is the conduit 3 provided with a plug 2 or the duct venturi effect 1, the risk of fouling will be very much reduced.

Therefore, the invention makes it possible, with few constraints, to maintain a minimum pressure in the feed ramp of the clutch mechanism and consequently to reduce the response time during the first deactivation of the cylinders. .

Claims

1. Device for deactivating at least one cylinder (17, 18) of a multi-cylinder type internal combustion engine, comprising means for decommissioning (20, 21, 22, 23) of the intake valves or exhausting said cylinder operable by a pressurized fluid, a pressurized fluid supply circuit (15), a controlled solenoid valve (14) and a secondary circuit (5) connecting said solenoid valve (14) to said disengaging means service (20, 21, 22, 23), characterized in that said secondary circuit (5) cooperates with auxiliary supply means (1; 2, 3) for maintaining the fluid filling of said secondary circuit (5) by outside the periods of operation of said decommissioning means (20, 21, 22, 23).

2. Deactivation device according to the preceding claim, characterized in that the secondary circuit (5) comprises leakage passages of said fluid, in particular at the means of decommissioning (20, 21, 22, 23) and / or at the a level of a nozzle (24) provided in the secondary circuit (5), and in that said auxiliary supply means (1; 2, 3) are shaped so that their feed rate compensates for the flow of the leakage passages .

3. Device according to any one of the preceding claims, characterized in that the intake or exhaust valves of said cylinder (17, 18) are actuated by means of hydraulic stops with clearance adjustment (8, 9, 10, 11) fed by a ramp (4) and in that said auxiliary supply means (1; 2, 3) are formed by a calibrated bore providing communication between the feed ramp (4) and the secondary circuit (5). ).

4. Device according to claim 3, characterized in that the auxiliary supply means (1) form a continuous communication with pressure drop between the ramp (4) and the secondary circuit (5).

5. Device according to claims 3 or 4, characterized in that the means (1) consist of a Venturi effect duct communicating the ramp (4) and the secondary circuit (5).

6. Device according to claim 5, characterized in that the Venturi effect duct (1) generates a pressure drop such that the pressure in the secondary circuit (5) is less than a defined threshold pressure (Pseuil).

7. Device according to claim 3, characterized in that the means (1) consist of a duct (3) of constant section, provided with a plug (2) pierced with an opening of dimension much smaller than the section of the duct (3).

8. Device according to claim 7, characterized in that the conduit (3) of constant section and provided with a plug (2) pierced, generates a pressure drop such that the pressure in the secondary circuit (5) is less than a defined threshold pressure (Pseuil).

9. Device according to any one of claims 3 to 8, characterized in that the hydraulic stops catch-up play (8,

9, 10, 11) integrate the means for decommissioning (20, 21, 22, 23) of the valves.

10. Device according to any one of the preceding claims, characterized in that it comprises a filter (25) upstream of the auxiliary supply means (1; 2, 3) for limiting the fouling of said auxiliary means d 'food.