METHOD FOR REGULATING THE MOTOR TORQUE OF AN INTERNAL COMBUSTION ENGINE TO PERFORM A GEAR RATIO CHANGE

Abstract

One aspect of the invention relates to a method 100 for regulating engine torque produced by an internal combustion engine of a powertrain equipped with a mechanical gearbox, a mechanical clutch, and control means. This method 100 is notable in that, during the acceleration phase of the powertrain, it comprises the steps, executed by the control means, of: Detecting 101 an intention to shift from a gear ratio N to a higher gear ratio N+n; and Degrading 102 the nominal ignition timing of the internal combustion engine so as to reduce the engine torque produced by the internal combustion engine. Figure to be published with the abbreviation: Figure 2

Description

Title of the invention: METHOD FOR REGULATING THE MOTOR TORQUE OF A MOTOR WITH INTERNAL COMBUSTION TO PERFORM A GEAR RATIO CHANGE TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a method for regulating engine torque produced by an internal combustion engine. The invention finds a particularly interesting, but not exclusive, application in the field of engine torque regulation of a two-wheeled vehicle. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] Two-wheeled vehicles equipped with an internal combustion engine are known to have a mechanical gearbox without an actuator and a mechanical clutch without an actuator.

[0003] On this type of vehicle, during acceleration, the driver can, without using the clutch, shift from a gear ratio N, for example equal to 2, to a higher gear ratio N+l, namely 3 in the example described.

[0004] In order to shift from a lower to a higher gear ratio, it is necessary to reduce the forces applied to the gearbox gears by reducing the engine torque produced by the internal combustion engine. To this end, engine control means control a shutdown of fuel injection into the cylinders of the internal combustion engine and / or a shutdown of spark production at the spark plugs of the internal combustion engine.

[0005] Thus, as illustrated in [Fig. 1] showing an engine torque profile 1, when a gear change is detected, a cut-off of fuel injection and / or spark production, indicated by point 2, occurs. This cut-off of fuel injection and / or spark production causes a sudden drop in the engine torque produced by the internal combustion engine. The engine torque then abruptly changes from a positive torque to a negative torque generated by the losses of the internal combustion engine, resulting in uncomfortable jolts for the driver. Summary of the invention

[0006] The invention offers a solution to the problem mentioned above, by proposing a method allowing, without operating a clutch, for a change in gear ratio that is more comfortable for the driver.

[0007] In this context, the invention, in its broadest sense, relates to a method for regulating engine torque produced by an internal combustion engine of a powertrain equipped with a mechanical gearbox, a mechanical clutch, and control means. The method according to this aspect of the invention is remarkable in that, during the acceleration phase of the powertrain, it comprises the steps, executed by the control means, of • Detect a desire to move from a speed ratio N to a higher speed ratio N+n; • Degrade the nominal ignition advances of the internal combustion engine so as to decrease the engine torque produced by the internal combustion engine.

[0008] Thus, by degrading the nominal ignition advances of the internal combustion engine, rather than abruptly cutting off the fuel injection into the cylinders of the internal combustion engine and / or cutting off the sparks at the spark plugs of the internal combustion engine, the engine torque is reduced so as to optimize the torque reduction to allow a gradual and smooth gear change.

[0009] In addition to the characteristics just mentioned in the preceding paragraph, the process according to this aspect of the invention may have one or more complementary characteristics from among the following, considered individually or according to all technically possible combinations.

[0010] According to a non-limiting aspect of the invention, the nominal ignition advances are degraded by applying an ignition advance regulation profile. Thus, the engine torque is reduced thanks to an adjustable ignition advance profile with which the torque reduction is optimized to allow for a smooth and progressive gear change.

[0011] According to a non-limiting aspect of the invention, the nominal ignition advances are degraded until the engine torque is between a minimum torque threshold and a maximum torque threshold. The engine torque is thus reduced to allow the disengagement of the gear ratio N and the re-engagement of the higher gear ratio N+n in a range around zero torque.

[0012] According to a non-limiting aspect of the invention, the minimum torque threshold is less than ONm and the maximum torque threshold is greater than ONm.

[0013] According to a non-limiting aspect of the invention, the ignition advance regulation profile comprises: • During an initial period of time, a sudden degradation of the nominal ignition advances; • During a second time window following the first time window, a progressive degradation ramp of said ignition advances until the engine torque is between the minimum torque threshold and the maximum torque threshold; • During a third time window successive to said second time window, an operating profile during which the motor torque is between the minimum torque threshold and the maximum torque threshold.

[0014] According to a non-limiting aspect of the invention, the ignition advance regulation profile includes, during a fourth time window successive to the third time window, a progressive catch-up ramp for the nominal ignition advances.

[0015] Another aspect of the invention relates to a vehicle comprising a powertrain equipped with an internal combustion engine, a mechanical gearbox, a mechanical clutch, and control means. The vehicle according to this aspect of the invention is remarkable in that the control means are arranged to perform the steps of the process according to any one of the aforementioned aspects of the invention.

[0016] Another non-limiting aspect of the invention relates to a computer program product downloadable from a communication network and / or recorded on a computer-readable medium and / or executable by a processor, said computer program product being notable in that it includes program code instructions for implementing the method according to any one of the aforementioned aspects of the invention, when the program is executed on a computer.

[0017] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0018] The figures are presented for illustrative purposes only and are in no way limiting of the invention.

[0019] [Fig. 1] illustrates a torque profile of an internal combustion engine according to the prior art.

[0020] [Fig.2] illustrates the steps of a method for regulating a motor torque according to a non-limiting aspect of the invention.

[0021] [Fig.3] illustrates an ignition advance regulation profile and a motor torque correlated to said ignition advance regulation profile according to a non-limiting aspect of the invention. DETAILED DESCRIPTION

[0022] Figure 2 shows a non-limiting example of an embodiment of a method 100 for regulating motor torque according to a non-limiting aspect of the invention.

[0023] This engine torque can be produced by an internal combustion engine of a two-wheeled vehicle's powertrain. This powertrain can also include a mechanical gearbox without an actuator, a mechanical clutch without an actuator, and means for controlling the powertrain.

[0024] During the acceleration phase of the powertrain and when a gear change is requested, in other words when the driver accelerates and operates his gear selector, the method 100 includes a first step, executed by the engine control means, of detecting 101 a desire to change from a gear ratio N, for example equal to two, to a higher gear ratio N+n, for example equal to three.

[0025] This desire to change gear ratio corresponds to pulling on the gear selector and can be identified by a position sensor of a gear selector included in the two-wheeled vehicle, then transmitted to the engine control means.

[0026] As soon as the intention to move from a speed ratio N to a higher speed ratio N+n is detected by the engine control means, the latter perform a step of degrading 102 the nominal ignition advances of the internal combustion engine.

[0027] The nominal ignition advances are determined by the manufacturer and correspond to an angle of a crankshaft before top dead center during which a spark is produced at the spark plug. Usually, this angle is between 15° and 45° before top dead center.

[0028] By reducing the nominal ignition timing, the engine torque produced by the internal combustion engine is decreased. The forces applied to the gears and shafts of the gearbox are therefore reduced, making gear changes easier.

[0029] According to a non-limiting example embodiment, the nominal ignition advances are degraded by applying an ignition advance control profile PI conforming to that illustrated in [Fig.3].

[0030] Figure 3 also shows an engine torque profile P2 correlated with the ignition advance regulation profile PL

[0031] According to the illustrated example, the ignition advance regulation profile PI models a sudden degradation of the nominal ignition advances during a first time window TL. This sudden degradation of the nominal ignition advances is almost instantaneous and results in a sudden reduction of engine torque.

[0032] This first time window T1 is followed by a second time window T2. During this second time window T2, a gradual degradation ramp of the ignition timing is applied. This degradation ramp continues until the engine torque falls between a minimum torque threshold S1 and a maximum torque threshold S2. Thus, compared to the prior art, the engine torque is reduced in two stages so as to diminish the jerking phenomenon present in the prior art.

[0033] In this non-limiting embodiment example, the minimum torque threshold SI is -5Nm and the maximum torque threshold S2 is +5Nm.

[0034] This second time window T2 is followed by a third time window T3. During this third time window T3, an operating profile is applied in which the motor torque is between the minimum torque threshold S1 and the maximum torque threshold S2.

[0035] According to a non-limiting example of an embodiment, the operating profile during which the engine torque is between the minimum torque threshold S1 and the maximum torque threshold S2 corresponds, for each cylinder of the internal combustion engine, to the production of a spark at the spark plug occurring between 0° and +15° after the top dead center of a piston of said cylinder.

[0036] Advantageously, during this operating profile, the engine torque is virtually stable and close to zero. The forces applied to the gears and shafts of the gearbox are reduced when the torque produced by the internal combustion engine is close to zero. Gear changes are therefore facilitated during this operating profile.

[0037] Finally, once the gear change has been made, the ignition advance regulation profile models a progressive recovery ramp of the nominal ignition advances during a fourth time window T4 successive to the third time window T3. Thus, the engine torque desired by the driver is again applied.

[0038] The various aspects of the aforementioned invention offer numerous advantages. Among these, we can mention: • Facilitate gear changes; • Improve driving comfort during gear changes; • Maintain high performance; and • Increase the lifespan of the gears and shafts of the gearbox.

Claims

Demands

1. Method (100) of regulating engine torque produced by an internal combustion engine of a powertrain equipped with a mechanical gearbox, a mechanical clutch and control means, said method (100) being characterized in that during the acceleration phase of said powertrain it comprises the steps, executed by said control means, of - Detecting (101) a desire to change from a speed ratio N to a higher speed ratio N+n; - Degrading (102) the nominal ignition advances of said internal combustion engine so as to decrease the engine torque produced by said internal combustion engine.

2. A method (100) according to the preceding claim, characterized in that the nominal ignition advances are degraded by applying an ignition advance regulation profile (IP).

3. A method (100) according to any one of the preceding claims, characterized in that the nominal ignition advances are degraded until the engine torque is between a minimum torque threshold (SI) and a maximum torque threshold (S2).

4. Method (100) according to the preceding claim, characterized in that the minimum torque threshold (SI) is less than ONm and the maximum torque threshold (S2) is greater than ONm.

5. A method (100) according to claim 2 and any one of claims 3 to 4, characterized in that the ignition advance regulation profile (PI) comprises: - During a first time window (T1), a sudden degradation of the nominal ignition advances; - During a second time window (T2) following said first time window (T1), a gradual degradation ramp of said ignition advances until the engine torque is between the minimum torque threshold (SI) and the maximum torque threshold (S2); - During a third time window (T3) following said second time window (T2), an operating profile during which the engine torque is between the minimum torque threshold (SI) and the maximum torque threshold (S2).

6. Method (100) according to the preceding claim, characterized in that the operating profile during which the engine torque is between the minimum torque threshold (SI) and the maximum torque threshold (S2) corresponds, for each cylinder of the internal combustion engine, to the production of a spark at the spark plug occurring between 0° and +15° after the top dead center of a piston of said cylinder.

7. Method (100) according to any one of claims 5 or 6, characterized in that the ignition advance regulation profile (PI) includes, during a fourth time window (T4) successive to the third time window (T3), a progressive catch-up ramp of the nominal ignition advances.

8. Vehicle comprising a powertrain equipped with an internal combustion engine, a mechanical gearbox, a mechanical clutch and control means, said vehicle being characterized in that said control means are arranged to carry out the steps of the process (100) according to any one of the preceding claims.

9. Product computer program downloadable from a communication network and / or recorded on a computer-readable medium and / or executable by a processor, characterized in that it includes program code instructions for implementing the method (100) according to any one of claims 1 to 7, when the program is executed on a computer.

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