Method for activating torque control functions of a heat engine according to a range of opening of a clutch device

Abstract

The invention relates to a method for controlling an engine (10) of a motor vehicle (1) having a manual gearbox (20), comprising: - a step of placing the clutch disc (310) in a retracted position relative to the flywheel (120), - a step of changing the gear ratio of the gearbox (20), - a step of moving the clutch disc (310) to an engagement position so as to enter a slipping phase, - said method further comprising: - a step of detecting a predetermined range of opening of the clutch device (30), and - a step of activating, during the slipping phase, a function of adding or limiting torque at the flywheel (120) with respect to a torque at the flywheel (120) that is desired by the driver only when the clutch device (30) is open over the predetermined range of opening.

Description

DESCRIPTION TITLE: METHOD FOR ACTIVATING TORQUE CONTROL FUNCTIONS OF AN INTERNAL COMBUSTION ENGINE ACCORDING TO A CLUTCH OPENING RANGE

[0001] The present invention claims priority from French application No. 2208622 filed on 29.08.2022, the content of which (text, drawings and claims) is incorporated herein by reference.

[0002] The present invention relates to a method for activating torque control functions of an internal combustion engine according to the opening range of a clutch device. The invention finds a particularly advantageous application in motor vehicles equipped with an internal combustion engine and a manual gearbox.

[0003] In a motor vehicle, the gearbox allows the power generated by the engine to be transmitted to the drive wheels of the vehicle by multiplying the rotational speed of a flywheel of the engine mechanically linked to the crankshaft.

[0004] In a vehicle with a manual transmission, the gearbox is connected to the flywheel via a primary drive shaft (called the "input shaft") and a clutch mechanism, and to the vehicle's drive wheels via a secondary drive shaft (called the "output shaft") and a transmission system. The primary and secondary shafts are connected by a series of gears that define a variety of gear ratios, allowing the torque transmitted from the primary shaft to the output shaft to be multiplied.

[0005] When the driver changes gears, they first release the accelerator pedal and then depress the clutch pedal. This disengages the engine's flywheel from the gearbox's input shaft by separating the clutch disc from the flywheel. The driver then changes gear using the gear lever and then releases the clutch pedal while simultaneously pressing the accelerator pedal again.

[0006] When the clutch pedal is released, the clutch disc re-enters contact with the flywheel in a phase known as "slipping," during which the disc slides on the flywheel until it reaches an engagement position (known as "sticking") in which the clutch disc is locked to the rotating flywheel. In other words, the torque on the gearbox input shaft is equal to the torque transmitted by the clutch during the entire slipping phase, and then equal to the torque transmitted by the engine to the clutch once the engagement position has been reached and the clutch mechanism is closed.

[0007] During an upshift, the torque of the flywheel, controlled by the accelerator pedal, can sometimes be significantly less than the torque supplied by the clutch disc. This torque discontinuity can generate a jolt followed by rebound in the drivetrain when the clutch disc engages with the flywheel. To address this issue, it is known to control the internal combustion engine to increase the flywheel torque relative to the torque requested by the driver via the accelerator pedal. It is also known to limit the flywheel torque during an upshift if the driver accelerates too rapidly before the drivetrain is fully engaged.

[0008] However, when the flywheel's torque-boosting function is activated during clutch disengagement, even when the clutch is slipping, a peak in engine speed and / or torque has been observed, which will be felt by the driver. Furthermore, an incorrect activation of the flywheel's torque-limiting function could cause a drop in torque during gear changes.

[0009] The invention aims to effectively remedy these drawbacks by proposing a method for controlling a motor vehicle engine with a gearbox. manual transmission, said engine comprising a flywheel connected to a primary shaft of the gearbox via a clutch device, said clutch device comprising a clutch disc whose movement is controlled by a clutch pedal, said method comprising: - a step of positioning the clutch disc in a retracted position relative to the flywheel by pressing the clutch pedal, - a gear change step in the gearbox, - a movement stage, by progressively releasing the clutch pedal, of the clutch disc towards an engagement position in order to enter a sliding phase, - said process further comprising: - a step for detecting a predetermined opening range of the clutch device, and - an activation step, during the sliding phase, of a function adding or limiting torque to the flywheel relative to a flywheel torque desired by the driver only when the clutch device is open over the predetermined opening range.

[0010] The invention thus improves driving comfort by automatically activating the flywheel's torque-adding or torque-limiting function during a re-engagement phase in which the clutch mechanism is within a predetermined opening range. In other words, the invention prevents the activation of the flywheel's torque-adding or torque-limiting function outside this opening range in areas of excessive opening or near-closure of the clutch mechanism that could lead to driving discomfort.

[0011] According to one embodiment of the invention, the predetermined opening range is detected when a clutch pedal depress level is between a first depress threshold and a second depress threshold.

[0012] According to one embodiment of the invention, the second penetration threshold is strictly greater than the first penetration threshold.

[0013] According to one embodiment of the invention, the first penetration threshold and the second penetration threshold are calibrable.

[0014] According to one embodiment of the invention, the first depressment threshold is between 30% and 40% of a clutch pedal depressment level and the second depressment threshold is between 90% and 99% of a clutch pedal depressment level.

[0015] According to one embodiment of the invention, the first sinking threshold and the second sinking threshold depend on at least one parameter chosen from: a temperature of the clutch device, a gear ratio previously engaged before the gear change, a speed of the motor vehicle.

[0016] According to one embodiment of the invention, the first indentation threshold (S1) and the second indentation threshold are subject to hysteresis.

[0017] The invention also relates to a control computer for a motor vehicle engine with a manual gearbox, said engine comprising a flywheel connected to a primary shaft of the gearbox via a clutch device, said clutch device comprising a clutch disc, said computer being configured to detect a predetermined opening range of the clutch device, and to activate a function of adding or limiting torque to the flywheel relative to a torque corresponding to a desire for acceleration by the driver during a slip phase only when the clutch device is open over the predetermined opening range.

[0018] According to one embodiment of the invention, the computer is configured to detect the predetermined opening range when the clutch pedal depress level is between a first depress threshold and a second depress threshold.

[0019] The invention further relates to a motor vehicle comprising a computer as previously defined.

[0020] The invention will be better understood upon reading the following description and examining the accompanying figures. These figures are given only to illustrate, but in no way limit, the invention.

[0021] [Fig. 1] Figure 1 is a schematic representation of a motor vehicle implementing the method according to the invention of activating torque control functions of a heat engine according to an opening range of a clutch device;

[0022] [Fig. 2] Figure 2 is a diagram of the steps of the method according to the invention of activating torque control functions of a heat engine according to an opening range of a clutch device;

[0023] [Fig. 3] Figure 3 is a time-dependent graph illustrating the activation of a flywheel torque addition or limitation function as a function of the clutch pedal depress level.

[0024] Figure 1 shows a vehicle 1 with an internal combustion engine 10 and a manual gearbox 20. The vehicle 1 also includes a clutch device 30, a transmission system 40, a plurality of wheels 50 and an engine control unit 60.

[0025] The engine 10 comprises an engine block 100 having a plurality of cylinders in each of which a mixture of fuel and air is burned in order to drive in rotation a crankshaft 110 which is mounted in a fixed manner with a flywheel 120.

[0026] The gearbox 20 includes a primary shaft 210 and a secondary shaft 220 connected by a plurality of gear sprockets 230 allowing the torque transmitted from the primary shaft 210 to the secondary shaft 220 to be multiplied. The selection of the sprocket, called the gear ratio, is carried out by the driver (not shown) of the vehicle 1 using a gear lever (not shown).

[0027] The clutch assembly 30 comprises a clutch disc 310, which is fixedly mounted to the input shaft 210 of the gearbox 20. The movement of the clutch disc is controlled by a clutch pedal 31 which can be operated by the driver of the vehicle 1. The clutch disc 310 is able to be moved between a position of engagement of the clutch disc 310 with the flywheel 120, when the driver does not press or presses little on the clutch pedal 31 (the clutch device 30 is then in the closed state), and a disengagement position in which the flywheel 120 is no longer in contact with the clutch disc 310, when the driver presses sufficiently on the clutch pedal 31 (the clutch device 30 is then in the open state).

[0028] When the clutch device 30 is engaged with the flywheel 120 (i.e. when the clutch disc 310 is in the engagement position), the torque generated by the engine 10 is transmitted to the primary shaft 210 via the crankshaft 110 and the clutch disc 310 and then multiplied via the gear sprockets 230 to the secondary shaft 220 which transmits it to the wheels 50 via the transmission system 40.

[0029] When the clutch disc 310 moves from a disengaged position to an engaged position and contacts the flywheel 120, the clutch disc 310 first slides on the flywheel 120 in a so-called "sliding" phase before reaching the engaged position. This occurs, in particular, when the driver releases the clutch pedal 31 during a re-engagement phase after a gear change.

[0030] The control unit 60 allows control of the engine 10, in particular the fuel injection into the engine cylinders 10. The control unit 60 is also capable of controlling the torque of the flywheel 120 of the engine 10 during a gear change. The control unit 60 is capable of implementing the method according to the invention for activating torque control functions of an internal combustion engine according to a clutch opening range 30. The method is described below with reference to Figure 2.

[0031] First, in step E1, when the driver wants to perform an upshift, he depresses the clutch pedal 31, this which has the effect of placing the clutch disc 310 in a position set back from the flywheel 120.

[0032] The driver uses the gear lever to change gear ratios in step E2. To do this, the driver manually disengages an initial gear ratio and then shifts to a target gear ratio higher than the initial gear ratio.

[0033] In a step E3, the driver gradually releases the clutch pedal 31 in order to re-engage the clutch disc 310 with the flywheel 120. In doing so, the clutch disc 310 first moves towards the engagement position so as to enter a sliding phase of the clutch disc 310 on the flywheel 120, before the clutch disc 310 reaches the engagement position on the flywheel 120.

[0034] In an E4 step, the computer 60 detects a predetermined Pemb opening range of the clutch device 30.

[0035] In an E5 step, the computer 60 activates, during the sliding phase, a function of adding or limiting the torque of the flywheel only when the clutch device 30 is open on the predetermined Pemb opening range.

[0036] The torque addition or limitation function consists of increasing or decreasing the torque of the 120 flywheel relative to a torque setting desired by the driver. The driver's desired 120 flywheel torque corresponds to the driver's acceleration input, determined by the accelerator pedal depress. This provides torque assistance to the 120 flywheel during gear changes, improving driving comfort by limiting the risk of excessive or insufficient torque.

[0037] The predetermined Pemb opening range is detected when a clutch pedal depress level Ne is between a first threshold a penetration threshold S1 and a second penetration threshold S2. The second threshold S2 is strictly greater than the first threshold S1.

[0038] The first threshold S1 and the second threshold S2 are exclusively between 0% and 100%. 0% depressment level corresponds to no pressure on the clutch pedal 31, i.e., the clutch disc 310 is in the engaged position and therefore the clutch assembly 30 is closed. 100% depressment level corresponds to the clutch pedal 31 being fully depressed to the end stop, i.e., the clutch disc 310 is in the disengaged position and therefore the clutch assembly 30 is open.

[0039] Advantageously, the first depressment threshold S1 and the second depressment threshold S2 are calibrable. The first depressment threshold S1 is preferably between 30% and 40% of a depressment level Ne of the clutch pedal 31 and the second depressment threshold S2 is preferably between 90% and 99% of a depressment level of the clutch pedal 31.

[0040] Figure 3 highlights that the function F for adding or limiting the torque of the flywheel 120 is: - deactivated (state 0) between times t1 and t2 because the depressed level Ne of the clutch pedal 31 is less than the threshold S1, - activated (state 1) between times t2 and t3 because the depressed level Ne of the clutch pedal 31 is between thresholds S1 and S2, - deactivated between times t3 and t4 because the depressed level Ne of the clutch pedal 31 is greater than the threshold S2, - activated between times t4 and t5 because the depressed level Ne of the clutch pedal 31 is between the thresholds S1 and S2, and - deactivated between times t5 and t6 because the level of depressment Ne of the clutch pedal 31 is less than the threshold S1.

[0041] In other words, the strategy makes it possible to inhibit the activation of the torque addition or limitation function in the event of an excessive opening of the clutch device 30 (the depressment of the clutch pedal 31 is greater than the threshold S2) or in case of closure of the clutch device 30 (the depressment of the clutch pedal 31 is less than the threshold S1).

[0042] The first sinking threshold S1 and the second sinking threshold S2 may depend on at least one parameter chosen from: a temperature of the clutch device 30, a gear ratio previously engaged before the gear change, a speed of the motor vehicle.

[0043] In order to avoid untimely activations and deactivations of the flywheel 120's torque addition or limitation function, the first indentation threshold S1 and the second indentation threshold S2 are subject to hysteresis.

[0044] As an output of this strategy, a boolean value is sent to the torque addition or limitation functions. These functions will be activated or deactivated depending on the value of the boolean output.

Claims

CLAIMS 1. Method for controlling an engine (10) of a motor vehicle (1) with a manual gearbox (20), said engine (10) comprising a flywheel (120) connected to a primary shaft (210) of the gearbox (20) via a clutch device (30), said clutch device (30) comprising a clutch disc (310) whose movement is controlled by a clutch pedal (31), said method comprising: - a step of placing (E1) the clutch disc (310) in a withdrawn position relative to the flywheel (120) by pressing the clutch pedal (31), - a step (E2) of changing the gear ratio of the gearbox (20), - a step of moving (E3), by progressively releasing the clutch pedal (31), the clutch disc (310) towards an engagement position so as to enter a sliding phase, characterized in that said method further comprises: - a step of detecting (E4) a predetermined opening range (Pemb) of the clutch device (30), and - a step of activating (E5), during the sliding phase, a function of adding or limiting torque to the flywheel (120) with respect to a torque of the flywheel (120) desired by the driver only when the clutch device (30) is open over the predetermined opening range (Pemb).

2. Method according to claim 1, characterized in that the predetermined opening range (Pemb) is detected when a depression level (Ne) of the clutch pedal (31) is between a first depression threshold (S1) and a second depression threshold (S2).

3. Method according to claim 2, characterized in that the second depression threshold (S2) is strictly greater than the first depression threshold (S1).

4. Method according to claim 2 or 3, characterized in that the first depression threshold (S1) and the second depression threshold (S2) are calibratable.

5. Method according to any one of claims 2 to 4, characterized in that the first depression threshold (S1) is between 30% and 40% of a depression level (Ne) of the clutch pedal (31) and the second depression threshold (S2) is between 90% and 99% of a depression level of the clutch pedal (31).

6. Method according to any one of claims 2 to 5, characterized in that the first depression threshold (S1) and the second depression threshold (S2) depend on at least one parameter chosen from: a temperature of the clutch device (30), a gear ratio previously engaged before the gear change, a speed of the motor vehicle.

7. Method according to any one of claims 2 to 6, characterized in that the first depression threshold (S1) and the second depression threshold (S2) are subject to hysteresis.

8. Computer (60) for controlling an engine (10) of a motor vehicle (1) with a manual gearbox (20), said engine (10) comprising a flywheel (120) connected to a primary shaft (210) of the gearbox (20) via a clutch device (30), said clutch device (30) comprising a clutch disc (310), said computer (60) being configured to detect a predetermined opening range (Pemb) of the clutch device (30), and to activate a function for adding or limiting torque to the flywheel (120) with respect to a torque corresponding to a desire for acceleration on the part of the driver during a slipping phase only when the clutch device (30) is open over the predetermined opening range (Pemb).

9. Calculator according to claim 8, characterized in that it is configured to detect the predetermined opening range (Pemb) when a depression level (Ne) of the clutch pedal (31) is between a first depression threshold (S1) and a second depression threshold (S2).

10. Motor vehicle (1) characterized in that it comprises a computer (60) defined according to claim 8 or 9.

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