EP2796677A1 - Internal combution engine with cylinder deactivation - Google Patents

Abstract

The invention relates to a motor vehicle combustion engine comprising a plurality of valve behavior modification actuators and a distributor (110, 120) configured to be rotated by the engine so that it delivers pressure to different ones of said plurality of actuators. actuators during engine rotation.

Description

The invention relates to engines for motor vehicles with multiple combustion cylinders and more particularly the systems for deactivating certain cylinders, in particular by deactivating the distribution for certain valves of the engine.

Partially loaded cylinder deactivation systems have been available for many years on V6 and V8 engines, and more recently on four-cylinder in-line gasoline engines.

A known system is to actuate valves using a cam mounted on a sliding sleeve. The cam is adjoined by a circular portion of the sleeve so that after sliding of the sleeve, an actuating rod of the valve cooperates only with the circular portion and the movement of the valve is neutralized. The sliding of the sleeve is implemented using an electromagnetic actuator.

It was also proposed in the document FR 2 975 133 , controlling the opening of a fluid outlet valve of a hydraulic chamber of the hydraulic abutment. The fluid outlet valve then constitutes a valve deactivation actuator. In FR 2 975 133 , the control of the valve is itself a hydraulic control, controlled by a shut-off valve.

These deactivation systems, as they are currently thought, make it possible to deactivate half of the cylinders of an engine having an even number of cylinders, the deactivated cylinders being always the same. This deactivation is allowed and possible only on stabilized operating points and weakly loaded motor field. This gives access to a mode of deactivation equivalent to 50% of the load that can produce the engine in conventional operating mode. This unique mode of deactivation makes it possible to access consumption gains by improving the efficiency of the engine, by operating in more virtuous engine performance zones and by reducing pumping losses, ie by lesser use. throttle valve to regulate the load.

Additional gains in terms of reducing carbon dioxide emissions are available if we consider that we can control the engine load by additional deactivation modes to those at 50% load. Thus solutions exist to disable otherwise by proceeding to a so-called "rotating" cylinder deactivation. In other words, on the same engine cycle and from one engine cycle to another, it is not always the same cylinder that is deactivated.

The invention aims to enable the implementation of a rotating deactivation of the cylinders of a motor vehicle engine which deactivation is reliable and inexpensive by using essentially mechanical actuators.

This object is achieved according to the invention by means of a combustion engine of a motor vehicle comprising several actuators for modifying the behavior of respective cylinder valves which actuators take a position of modification or non-modification of the valve behavior of a respective cylinder in a function of a pressure in a respective pipe for transmitting fluid pressure to the actuator in question, the device comprising a fluidic pressure tap capable of delivering or not a fluid pressure to at least one of said plurality of actuators according to the position of the pressure valve, characterized in that the pressure tap is a distributor configured to be rotated by the motor so that it delivers pressure to different actuators among said plurality of actuators during engine rotation.

Advantageously, the actuators are valve deactivation actuators and the actuators take a position of modification or non-modification of valve behavior which are respectively a deactivation position and a valve activation position.

Advantageously, the dispenser is a rotary distributor.

Advantageously, the distributor has a stator and a rotor, and a plurality of pressure transmission lines emanating from the stator, the rotor being configured so that an oil pressure is transmitted to a different transmission line depending on the position of the rotor relative to the stator.

Advantageously, the stator is a jacket surrounding the rotor and the rotor has at least one peripheral mouthpiece supplied with pressurized oil, the stator having a series of peripheral openings which are connected with different pressure transmission lines, the mouthpiece rotor peripheral and peripheral openings of the stator being arranged so that the peripheral mouth is successively facing different peripheral openings during the rotation of the rotor in the stator.

Advantageously, the motor has a plurality of pressure transmission lines disposed substantially at the same angular position in the direction of rotating the rotor, so that said plurality of pipes are opposite the peripheral mouth of the rotor simultaneously during the rotation of the rotor.

Advantageously, said plurality of pipes located opposite the peripheral mouth of the rotor simultaneously comprise a pipe transmitting pressure to an actuator for modifying the behavior of the intake valve of an engine combustion cylinder and a pipe transmitting pressure to an exhaust valve behavior modification actuator of the same combustion cylinder.

Advantageously, the rotor has at least one peripheral fluid collector connected to a fluid discharge pipe, the collector being arranged to face the pressure transmission pipes during the movement of the rotor so that the fluid in a The pressure transmission line is depressurized by fluid flow in the discharge line when the manifold faces such a pressure transmission line.

Advantageously, the fluid peripheral manifold has an extent such that it simultaneously faces a plurality of pressure transmission lines which are connected to actuators for modifying the behavior of valves of different combustion cylinders.

Advantageously, the rotor has a central cavity connected to the fluid discharge pipe.

• la figure 1 représente une butée hydraulique selon un mode de réalisation de l'invention,
• la figure 2 est une vue en coupe longitudinale d'un distributeur hydraulique selon un mode de réalisation de l'invention,
• la figure 3 est une vue de dessus d'un rotor de ce même distributeur hydraulique,
• la figure 4 est une vue en coupe transversale de ce même distributeur hydraulique.

Other features, objects and advantages of the invention will appear on reading the description which follows, with reference to the appended figures in which:

• the figure 1 represents a hydraulic stop according to one embodiment of the invention,
• the figure 2 is a longitudinal sectional view of a hydraulic distributor according to one embodiment of the invention,
• the figure 3 is a top view of a rotor of the same hydraulic distributor,
• the figure 4 is a cross-sectional view of the same hydraulic distributor.

The system proposed here for turning cylinder deactivation is a hydraulic system in which the engine oil pressure is used. The present system comprises a solenoid valve, a rotary distributor and an actuator by intake and exhaust valve.

Such an actuator is for example an actuator for opening a hydraulic chamber or at high pressure of a hydraulic stop of a valve actuating device with latch, as proposed for example in the document FR 2 975 133 . according to a variant, such an actuator has the shape of a hydraulically controlled ring to disable a hydraulic stop as shown on the figure 1 .

The hydraulic stop represented on the figure 1 is composed of a body 1 in which slides an axis 2 forming at its upper end a fulcrum for a pawl 3 simultaneously forming a ball 4 with the latter.

The axis 2 constitutes a hydraulic piston and the body 1 forms a hydraulic chamber in which circulates a hydraulic piston constituted by the axis 2.

The axis 2 has an internal cavity which serves as a low-pressure reservoir supplied with oil by a channel 5 which opens out in the axis 2 after passing laterally through the body 1. The channel 5 allows both to lubricate the ball joint. end of the axis 2 as well as to feed the high pressure chamber formed in the body 1, via a ball valve 6 connecting the low pressure reservoir formed by the axis 2 and the high pressure chamber formed by the body 1. In order to keep the assembly in contact and to return the axis 2 to the initial position in deactivated mode, a spring 7 is installed in the high-pressure chamber.

A ring 8 surrounds the body of the hydraulic stop, which ring is freely mounted in displacement in a direction of longitudinal sliding to the hydraulic stop. An oil discharge channel 9 is formed at the edge of the hydraulic chamber and closed or released by the ring 8 according to the position thereof. Thus, the ring 8 can take here an erased position which comes to put the hydraulic chamber at high pressure in communication with the oil discharge channel 9 or a closed position which closes the channel 9 and confines the oil under pressure in the hydraulic chamber. For this, the ring 8 here has a lateral bore which comes opposite the channel 9 and a corresponding hole in the chamber 1 when the ring is moved to its erased position, thereby setting the chamber 1 and the channel discharge 9 in hydraulic connection. Thus the activation and deactivation of the hydraulic stop are controlled by the displacement of the ring 8.

The ring 8 controls the leakage of the pressure chamber by acting on the body 1 of the stop and not on the axis 2. The ring 8 is preferably designed to operate with two precise positions: low position with sealing, and position high with stop leakage. In the high position, the pressure chamber of the stop can be filled with oil at the same time by the channels 5 and 9. When a volume variation of the oil is made in the pressure chamber, this volume is directed towards the circuit of high pressure oil with oil supply stops, the channels 9 and 5 being connected.

A channel 10 opens at the bottom of the ring 8 and applies an oil pressure on a lower end thereof, which oil pressure causes a displacement of the ring 8 upwards. Thus the ring 8 is here controlled in opening by the oil pressure from the channel 10. A spring 11 is disposed between the ring 8 and a flange of the body 1 so that the spring 11 recalls the ring 8 downwards in closure of the channel 9 when the pressure in the channel 10 is suppressed. A pipe 12 is disposed at the lower end of the body 1 and a pipe 13 is disposed in the upper part of the ring 8 to allow the oil to be evacuated which could accumulate respectively at the bottom of the housing of the hydraulic abutment and above the ring 8 and thus braking the ring 8 in its movements.

The transition from one mode to another is done by controlling the pressure in the channel 10. In activated mode, the channel 10 is at atmospheric pressure. The ring 8 is thus kept in the closed position by the spring 11.

When the cam presses on the pawl 3, the hydraulic chamber formed by the body 1 rises in pressure and thus prevents the present hydraulic stop from sinking. When the pawl returns to its position where it cooperates with the back of the cam, the valve 6 opens to fill the hydraulic chamber which has weakly emptied due to leaks in various connections of the hydraulic chamber.

In the deactivated mode, the channel 10 is put under the pressure of the engine oil circuit. The calibration of the spring 11 is such that under this pressure the ring 8 slides and communicates the hydraulic chamber with the channel 9. If it is at atmospheric pressure, then there is an opening of the valve 6 and therefore a consumption of unnecessary oil. This is why it is more interesting to connect the channel 9 with the pressurized circuit of the engine and thus with the channel 5. When the cam comes to press on the pawl 3, the hydraulic chamber no longer rises in pressure and therefore the hydraulic stop sinks. It is then returned to the initial position by the return spring 7. When the pawl 3 returns to the position where it is in contact with the back of the cam, the valve 6 can open to fill the hydraulic chamber in addition to the return oil through the channel 9.

In the present embodiment, a sliding ring is thus used which makes it possible to close the hydraulic chamber or high pressure chamber of the present hydraulic abutment or to open the hydraulic chamber and respectively activate or deactivate it.

The described ring makes it possible, by its draining efficiency and rapidity of actuation, to deactivate a rotating type of cylinder, that is to say one in which the deactivated cylinder or cylinders are variable according to the successive cycles of the engine. It also makes it possible to implement a greater number of deactivations and activations of cylinders and to get rid of the maximum aeration of the oil by placing the opening of the high-pressure chamber as close to this one.

The displacement of this ring can be achieved as in the present example by an oil pressure, this oil pressure being controlled for example by a control valve. In this way, a largest possible drain section is obtained in a hydraulic chamber volume dimensioned just as necessary.

The distributor rotates at half the speed of the camshafts. The invention does not require an angular setting variation device. The invention indirectly controls the leakage of the oil at the pressure chamber through the position of the ring 8 in the abutment. A change in the condition of the hydraulic stop is made once every two turns of the camshaft only if the pressure chamber 121, 124 is pressurized. A control solenoid valve is used to supply the pressure distributor. Three functions are thus performed by the distributor: pressurization of the pressure chamber under the control ring 124, sealing of the pressure chamber under the control ring 120 and discharge of the pressure chamber under the control ring 129

The ring described here is an axial displacement ring. Alternatively, the communication between the hydraulic chamber and the channel 9 can be closed or released by a ring movable in rotation about the main axis of the hydraulic stop.

The distributor supplying the various cylinder deactivation actuators will now be described, the deactivation actuators being here such movable rings for deactivating a respective hydraulic abutment.

A solenoid valve, not shown, which is arranged upstream of the distributor, makes it possible to supply oil or not with the deactivation circuit. In normal operation mode, that is without cylinder deactivation, the solenoid valve is closed. The distributor is not supplied with oil and the hydraulic stops then function as conventional hydraulic stops. In operating mode with rotating cylinder deactivation, the solenoid valve opens, the distributor is supplied with oil.

The distributor will be described now with reference to the figure 2 .

The distributor makes it possible to cyclically control each of the actuators. Such a distributor is driven by the vehicle engine, here by a gear system or alternatively by a belt or chain, which system is here in conjunction with the camshaft of the engine. The speed of the dispenser is determined by this connection. In the present example the distributor is rotated at a rotational speed four times slower than the crankshaft, to obtain a motor operation at 50% load. The engine load in the deactivation mode is obtained by summing the number of effective combustions on the total number of potential combustions with all the active cylinders.

The present dispenser is composed of a liner 110 and a rotor 120 mounted in the liner 110. The rotor 120 is supplied with oil when the solenoid valve is open. The supply of the rotor 120 is here carried out by an inlet of the pressurized oil within a circumferential groove 121 of the latter, which surrounds it centrally with reference to the axial extent of the rotor 120. such oil inlet is for example made in the form of a pipe passing through the liner 110 to the right of the circumferential groove 121. As shown in FIG. figure 3 , the rotor 120 has two flats 122 and 123 disposed on either side of the circumferential groove 121 which form a spacing 124 between the rotor 120 and the inner wall of the liner 110. The oil under pressure arriving in the circumferential groove 121 also circulates in the spacing delimited by the flats 122 and 123.

As shown on the longitudinal section of the figure 2 , the liner 110 has through holes 112, 113 substantially radial. The liner 110 has such holes distributed in pairs so that the bores of the same pair are substantially in the same angular position around the axis of rotation of the rotor 120. Thus, on the figure 4 two holes 114 and 115 are shown which belong to two other pairs of such bores. Within each pair of bores, a bore is connected to an actuator for deactivating an intake valve and a bore is connected to an actuator for deactivating an exhaust valve of a given cylinder. In the case of the hydraulic stop of the figure 1 , such a deactivation actuator is constituted by the ring 8. For this oil pressure transmission lines extend from each bore to the associated actuator.

Thus, within the pair of holes 112, 113 shown in FIG. figure 2 , the hole 112 is associated with the actuator for deactivating the inlet valve of a given cylinder and the hole 113 is associated with an actuator for deactivating the exhaust valve of the same cylinder. Thus, when the spacing 124 defined by the flats 122 and 123 is opposite a given pair of bores, it feeds pressurized oil the two actuators respectively associated with these bores.

The flats 122 and 123 of the distributor are thus made to put in communication the arrival of oil and the actuators via the oil pressure transmission lines. The lines transmit oil under pressure to the deactivation actuators to deactivate an intake valve or an exhaust valve. Each pipe can alternatively control several actuators. The machining of the flats 122 and 123 has an angular extent corresponding to the desired duration for the deactivation command sent by the distributor.

The rotor 120 has a cavity 125 at its center. Of this cavity 125 extend radial passages of which two are represented under the references 126 and 127 on the figure 2 and two are represented as 127 and 128 on the figure 4 . These radial passages 126, 127, 128 open out at the periphery of the rotor 120. The radial passages 126, 127, 128 are arranged in such a way that they join the pressure transmission holes 112, 113 of the actuators during the rotation of the rotor. rotor. The central cavity 125 is in communication with an oil discharge circuit. Thus, when a radial passage 126, 127, 128 comes opposite a pressure transmission bore, there is a depressurization of the corresponding pressure transmission line by circulation of oil to the central cavity. 125 then to the evacuation circuit. More specifically, in the present embodiment, the radial passages 126, 127, 128 open at the periphery of the rotor 120 in a groove 129 which extends in an arc around the axis of rotation of the rotor 120 on an angular extent of about 180 degrees. This groove 129 forms a manifold whose extent is such that a pressure transmission pipe remains in connection with the central cavity 125 and the evacuation circuit via this groove 129 for about half a turn of the rotor 120, thus ensuring a holding in the activation position of the hydraulic stop and the corresponding actuator during this half-turn. In order to further improve the depressurization of the duct (s) opening into the groove 129 during this half-turn, two radial passages connecting the groove 129 to the central cavity 125, here passages 127 and 128, are adopted here. Radial passages 127 and 128 are separated from each other by an angle of about 120 degrees.

Thus, when the rotor 120 is rotating, it cyclically communicates the pressure transmission lines with either the pressurized oil inlet or the discharge circuit, independently between these pipes. The configurations of the flats 122 and 123 and the groove 129 determine the control sequence of the actuators in a manner subject to the motor cycle.

Thus, a deactivation phase of a cylinder is here the following. The first four-stroke cycle is in normal operation mode, then the second cycle is in deactivation mode. The exhaust valve opens and the valve feeds the intake valve deactivation actuator. The intake valves then remain closed. The injection and ignition of the candle are then deactivated. After the deactivation phase, the cylinder concerned resumes its normal cycle.

Thanks to the configuration of the rotor and the hydraulic control itself of the hydraulic stop or more generally the hydraulic control of the actuator for modifying the behavior of the valve, other actions on the distribution can be implemented besides the maintenance. in the open position or in the closed position of a valve. Thus, such a device makes it possible to control a partial opening of the valve, a double valve lift, a variation of the opening or closing angle of the valve, or an alternative valve actuation law.

Such an embodiment allows the cylinder to be deactivated with a 50% mode (or other modes: by varying the position of the orifices on the manifold liner (stator) and the speed of rotation of the rotor relative to at the rotational speed of the camshafts, it is possible to obtain other modes of cyclic deactivation - in this case, the 50% mode consists in having the speed of rotation of the distributor (rotor) equal to half of the rotational speed of the camshafts) on engines having an odd number of cylinders such as three-cylinder engines, without major problem of acyclism. It also makes it possible to deactivate all the cylinders, to gain additional gains in terms of carbon dioxide emissions by controlling the engine load by additional deactivation modes in the 50% mode, making it possible to reduce the pumping losses due to reduced use of the throttle valve. Such an embodiment also makes it possible to keep a cylinder head architecture of low height, and not to modify the distribution facade of the engine.

Claims (10)

Motor vehicle combustion engine comprising a plurality of respective cylinder valve behavior modifying actuators (8) which actuators (8) assume a position of modifying or non-changing the valve behavior of a respective cylinder according to a pressure in a respective fluidic pressure transmission line (10) to the actuator (8) in question, the device comprising a fluidic pressure tap (110, 120) able to deliver or not a fluid pressure to at least one actuator (8) among said plurality of actuators (8) according to the position of the pressure tap (110, 120), characterized in that the pressure tap is a distributor (110, 120) configured to be rotated by the motor so that it delivers pressure to actuators (8) different from said plurality of actuators (8) during the rotation of the motor. Combustion engine according to Claim 1, characterized in that the actuators (8) are valve deactivation actuators and the actuators (8) assume a position of modification or non-modification of the valve behavior which are respectively a deactivation position. and a valve activation position. Combustion engine according to Claim 1 or Claim 2, characterized in that the distributor (110, 120) is a rotary distributor. Combustion engine according to one of the preceding claims, characterized in that the distributor (110, 120) has a stator (110) and a rotor (120), and a plurality of pressure transmission lines (112, 113, 114, 115) emanating from the stator ( 110), the rotor (120) being configured so that an oil pressure is transmitted to a different transmission line (112, 113, 114, 115) depending on the position of the rotor relative to the stator. Combustion engine according to the preceding claim, characterized in that the stator (110) is a jacket surrounding the rotor (120) and the rotor (120) has at least one peripheral mouth (122, 123, 124) supplied with oil under pressure, the stator ( 110) having a series of peripheral openings (112, 113, 114, 115) which are connected to different pressure transmission lines (112, 113, 114, 115), the peripheral mouth of the rotor (122, 123, 124) and the peripheral openings of the stator (112, 113, 114, 115) being arranged in such a way so that the peripheral mouth (122,123,124) successively faces peripheral openings (112,113,114,115) different during the rotation of the rotor (120) in the stator (110). Combustion engine according to the preceding claim, characterized in that it has a plurality of pressure transmission lines (112,113,114,115) arranged substantially at the same angular position in the direction of rotation of the rotor (120), so that said plurality of conduits (112,113,114,115 ) are opposite the peripheral mouth (122, 123, 124) of the rotor (120) simultaneously during the rotation of the rotor (120). Combustion engine according to the preceding claim, characterized in that said plurality of conduits (112,113,114,115) located opposite the peripheral mouth (122,123,124) of the rotor (120) simultaneously comprise a pipe (112,113,114,115) transmitting a pressure to an intake valve behavior modification actuator of a combustion engine cylinder and a pipe (112,113,114,115) transmitting pressure to an exhaust valve behavior modification actuator of the same combustion cylinder. Combustion engine according to one of the preceding claims, characterized in that the rotor (120) has at least one peripheral fluid collector (129) connected to a fluid discharge line (125), the collector (129) being arranged to face the pressure transmission lines (112,113,114,115) during the movement of the rotor (120) so that the fluid in a pressure transmission line (112,113,114,115) is depressurized by fluid flow in the fluid line. discharge (125) when the collector (129) faces such a pressure transmission line (112,113,114,115). Combustion engine according to the preceding claim, characterized in that the peripheral fluid collector (129) has an extent such that it simultaneously faces a plurality of pressure transmission lines (112,113,114,115) which are connected to behavior modification actuators. different combustion cylinder valves. Combustion engine according to claim 8 or claim 9, characterized in that the rotor (120) has a central cavity (125) connected to the fluid discharge conduit.

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