FR3000993A1 - METHOD FOR DETERMINING A MOTOR SPEED CORRECTION CORRECTION TORQUE OF A MOTOR PUMPS GROUP - Google Patents

Abstract

The invention relates to a method for determining an engine speed oscillation correction torque of a powertrain comprising a heat engine and a transmission, in which, following a torque request: the evolution of the engine speed is examined; engine speed, -on selects a calibration establishing a phase shift and an amplitude according to operating parameters of the powertrain, - the oscillation of the engine speed is isolated from the evolution of the engine speed by filtering the evolution of the engine speed by the application of the phase shift, the correction torque is determined by applying amplitude to the motor speed oscillation, in which process a type of acceleration (A) is identified following the torque demand, that the calibration establishing the phase shift and amplitude is selected from a separate calibration set with each type of acceleration (A) identified.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for determining a motor speed oscillation correction torque of a motor-speed oscillation correction torque. power train comprising a heat engine and a transmission. The invention applies to the field of control control of vehicles equipped with a gasoline or diesel powertrain (GMP) with a manual gearbox (BVM), automated (BVA), piloted (BVMP) or double clutch (DCT). Background Art Figure 1 schematically shows powertrain equipping a vehicle. The power train comprises a heat engine 1. In Figure 1, the heat engine is connected to a transmission 2 typically comprising a gearbox and a clutch device of which only a connecting element with the engine 1 is shown. The engine can be gasoline or diesel. The gearbox can be manual (BVM), automated (BVA), pilot (BVMP) or double clutch (DCT). The transmission 2 ensures the transfer of a torque generated by the engine to the wheels, not shown. The heat engine 1 is typically placed on shims 3 engine. Motor games are called the torsion phenomenon 4 of the transmission elements 2 between the moment when the heat engine 1 lands on its shims 3 and the moment when the heat engine drives the wheels during the acceleration transients. In other words, the engine games are the tilting of the engine 1 on its shims 3 during acceleration transients. There is always a tilting of the motor when applying torque when there was none, for example during a request for acceleration from a situation known as a raised foot, that is to say without pressing the accelerator pedal, or when decelerating when the foot is fully raised. The engine sets thus correspond to the applied torque for which neither the engine nor the wheel train with each other during a transient phase of acceleration.

There are two types of accelerations: A first type of acceleration called "with passage of games": the engine rocks on its holds during the acceleration phase. This life situation is encountered, for example, during an acceleration of starting following a stop.

A second type of acceleration called "without crossing the games" or "since stabilized": it is an acceleration accompanied, that is to say that the driver in a first phase slightly presses on the accelerator this which allows the engine to land on its holds, then in a second phase it really accelerates. This life situation occurs for example, when doubling a car.

As now illustrated in FIG. 2, the engine 1 and the transmission 2 are each the source of characteristic speed oscillations 1 'and 2'. An acceleration called "without traversing the games" generates only oscillations 2 'related to the transmission 2, while a so-called acceleration "with crossing games" is a composition 5 oscillations 1' related to the movement of the engine 1 and oscillations 2 'related to the movement of the transmission 2. Such vehicles are equipped with a computer to automatically adapt the operating point of each of the vehicle components, in particular the heat engine, in order to respect the will of the driver in terms of the requested torque and obtain a particular driving license. In order to obtain optimum driving pleasure, the computer typically uses two types of filtering of the torque requested by the driver made using a first filtering module said to be preventive of the engine torque and a second filtering module of the engine. engine torque says healing. The first preventive filtering module ensures a filtering of a set torque corresponding to the will of the driver in order to pass the engine games by limiting the jolts of the traction chain as much as possible. Figure 3 shows an example of preventive filtering of the motor torque. FIG. 3 shows the evolution of a setpoint Cc of engine torque corresponding to a request for engine torque, therefore of acceleration, at time t0 by a driver. In response to this torque request, the first filter module converts the setpoint torque Cc as a function of time into a so-called preventive motor torque Cp that provides a transition to the setpoint torque. The curve Cp comprises in particular during the rise in torque Cp, between the moment t1 when the engine begins to land on its holds and the time t2 when the tilting of the engine is completed, a smaller slope of torque rise which makes it possible to ensure a smooth tilting of the motor and thus to reduce transmission surges.

The second curative filter module makes it possible to attenuate any oscillations in the engine speed resulting from the passage of the engine games in acceleration and deceleration. For this purpose, it generates a corrective torque built by applying to the engine speed oscillation a phase shift with respect to said oscillation and an amplitude corresponding to a coefficient of proportionality between the amplitude of the steady state oscillation, expressed for example in rpm, and the intensity of the correction torque conventionally expressed in Nm In the existing methods of attenuating the oscillations of the engine speed via the curative approval module, the computer applies the same correction for all the accelerations. However, the tilting of the engine generates a surge in instantaneous speed greater than when the engine is already placed on its holds, followed by rebounds related to the torsion of the transmission elements. Focusing can then be done according to two principles: - either the focusing is oriented on the acceleration without crossing the games: in this case, the shock generated by the crossing of the games is not amortized, and bounces accentuated persist. The approval of the vehicle is bad and the number of customer complaints increases. - The focus is focused on accelerations with crossing games: in this case, the applied correction will be too strong and out of phase with respect to the need for all acceleration without passing games. In this case again the approval of the vehicle is bad.

This development is complex and long to achieve because of the compromises that must be made to satisfy most accelerations. Therefore, the problem underlying the invention is to have an improved driveability on most accelerations, whether traversed games or not.35 An object of the present invention is to provide a method engine torque determination which allows to have an improved driving license relative to the prior art on most accelerations, whether traversed games or not.

To achieve this objective, there is provided according to the invention a method for determining a correction torque (Ccor) of engine speed oscillation of a power unit comprising a heat engine and a transmission, in which, following a torque demand: - the evolution of the engine speed is monitored, - a calibration is selected which establishes a phase shift and an amplitude according to operating parameters of the powertrain, - the oscillation of the speed is isolated from the evolution of the engine speed. motor by filtering the evolution of the engine speed by the application of the phase shift, - the correction torque is determined by applying to the engine speed oscillation the amplitude, the method being characterized in that one identifies a type of acceleration following the torque request, in that the calibration establishing the phase shift and the amplitude is selected from a separate calibration set for each type of ac identified celeration.

In a variant where the heat engine is placed on shims, the type of acceleration is identified between a first type of acceleration during which the tilting of the heat engine on its shims takes place and a second type of acceleration during which the tilting the engine on its holds does not take place. Preferably, the type of acceleration is determined from the engine speed gradient. More preferably, the engine speed gradient is compared to an engine speed gradient threshold. More preferably, the engine speed gradient threshold is of the order of 100tr / min / s. In a variant, when the second type of acceleration is identified, a tilting time of the heat engine on its shims is determined and the correction torque is determined from the calibration selected for the first type of acceleration only during the determined tipping time. Preferably, when the tilting time of the engine on its shims is exceeded, the correction torque is determined from the calibration selected for the second type of acceleration.

In a variant, in which the transmission comprises a gearbox, the tilting time is determined from a mapping establishing a correspondence between the tilting time and a data pair composed of the engine speed and a gearbox ratio. speed engaged.

In another variant, the phase shift and the amplitude are determined from a mapping establishing a correspondence between the phase shift and the amplitude and a data pair composed of the engine speed and gearbox ratio engaged. The subject of the invention is also a vehicle equipped with a power unit comprising a heat engine and a transmission, characterized in that it comprises means for determining an engine speed oscillation correction torque comprising the required instructions. to implement the method according to one of the previously described variants.

BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages will appear on reading the following description of a particular embodiment, not limiting of the invention, with reference to the figures in which: - Figure 1 is a representation schematic of a heat engine connected to a transmission element. - Figure 2 schematically shows a comparison of the engine speed oscillations following a so-called acceleration without traversing engine games or a so-called acceleration with traversing engine games. FIG. 3 shows an exemplary preventive filtering strategy of a torque setpoint resulting from an acceleration request by a driver. - Figure 4 illustrates two examples of ramp up with and without crossing engine games, readings without torque filtering. - Figure 5 shows a management system of the torque control of a heat engine. FIG. 6 presents a diagram of the steps of the filtering method of a motor setpoint torque according to the invention implemented with the system of FIG. 5.

DETAILED DESCRIPTION FIG. 4 shows, for a powertrain fitted to a vehicle as shown in FIG. 1, two examples of engine revolutions N as a function of time. The axis of abscissa of the times is in this case translated in passage to the top dead center, PMH. The first example, illustrated by the curve 31, represents a rise in speed with an acceleration of the first type, called "with crossing games," thus implying a tilting of the engine on its holds, starting at time t1 from a regime of 2000 rpm at full load. The second example, illustrated by the curve 32, represents a rise in speed with an acceleration of the second type, called "without crossing the games", so with a motor having already tilted on these wedges, the acceleration also starting at t1, at 2000 rpm at full load. In this example, the two revs were measured without preventive filtering or curative filtering. Note for each of the two revs, 31, 32, the presence of a first bump regime, respectively Bl, B2. We then note these first bumps Bl, B2, on the one hand, that the revving is faster (Al slope) in the case of the revving 31, with an acceleration "with crossing games In the case of the ramp-up 32, with an acceleration without clearance crossing (slope A2), on the other hand, the temporal phase shift and the amplitude of these first two bumps of regime B1, B2, identified here by the respective positioning P1, P2 of their maximum speed, is not the same on both mounted in regime 31, 32.

FIG. 5 now presents determination means such as a calculator 10 which embeds the instructions required for carrying out the method of the invention described in detail below. This system comprises a driver interpretation module 11, a preventive approval module 12, a module 13 for detecting the type of acceleration and a module 14 for curative approval. Specifically, as shown in Figure 6, the module 11 determines in a step 101, a set torque motor, Cc from a torque request of the driver. The torque demand of the driver is interpreted according to the engine speed N, the ratio of gearbox, Rv, engaged, and the position, Pa, of the accelerator pedal actuated by the driver.

The reference motor torque Cc is then filtered using the preventive approval module 12 during a step 102 in order to minimize jolts during the passage of the first speed bump.

For this purpose, the module 12 firstly determines a so-called preventive engine torque, Cp, which is then translated into the indicated engine torque, Ci, taking into account the engine losses. Thus, the indicated engine torque, Ci, is equal to the sum of the preventive engine torque Cp and a motor loss torque, Cpm, in other words Ci = Cp + Cpm. The engine loss torque, Cpm, is the torque needed by the engine to drive the vehicle forward. The engine loss torque, Cpm, notably takes into account the friction of the engine as well as the losses related to accessories such as the alternator. Thus, as already shown in FIG. 3, the preventive motor torque, Cp, constitutes a motor torque of transition to the target motor torque, Cc, to be reached. This transition makes it possible to limit the gradient of the motor torque response and therefore the jolts of the traction chain. The module 12 also determines a type of acceleration, A, directly following the torque request by the driver, which makes it possible to distinguish between the second type of acceleration, which is said to be without passing through games, thus an acceleration during which the tilting occurs. the thermal engine on its holds does not take place and the first type of acceleration known as crossing games, so an acceleration during which the tilting of the engine on its holds takes place. The type of acceleration, A, may be a Boolean indicator taking a first value when the engine is being tilted and a second value when the engine is not tilting. The type of acceleration can be determined from the value of the engine RPM, AN, directly following the driver's torque request. To determine the type of acceleration, the engine speed gradient AN is compared with a threshold Sg of the engine speed gradient. According to one embodiment, this threshold, Sg is for example 100 revolutions / min / s. If the engine speed gradient, AN, is greater than the threshold Sg, it is considered that the acceleration is of the first type, with crossing of games. In the opposite case, if the engine speed gradient, AN, is lower than the threshold Sg, it is considered that the acceleration is of the second type, without crossing games. The acceleration type indicator A can be determined in a separate module from the value of the engine revving following the torque request by the driver.

The acceleration type detection module 13 continuously receives the transition motor torque, Cp, and the value of the acceleration type indicator A. Thus, in a step 301, the evolution of the transition motor torque, Cp, to determine in step 302 whether the driver is accelerating or decelerating. For example, step 302 is carried out by examining the sign of the transition motor torque gradient, Cp. If the sign is negative (NO branch between step 302 and 303), step 303 is concluded at a deceleration. If the sign is positive, it is concluded at step 304 that it is an acceleration and the value of the acceleration type indicator A, set to the preventive approval module 12 is scanned. In step 305, it is checked whether the acceleration type indicator, A, indicates the first type of acceleration called "with passing games": When an acceleration with passage of games is detected (branch YES from of step 305), in step 306 a first calibration is selected for use of the curative amenity module 14. This first calibration comprises a first set of phase shifts, 9, and amplitudes, G, established as a function of powertrain operating parameters and intended for the determination of a correction torque Ccor representative of the first type acceleration. This first calibration may be in the form of a map, establishing a correspondence between the phase shift cp and the amplitude G and a data pair composed of the engine speed N and the speed gear ratio Rv engaged. This mapping can be integrated into the module 13 for detecting the type of acceleration. When an acceleration without passage of games is detected (branch NO from step 305), a second calibration is used in step 308 for the use of the healing approval module 14. This second calibration comprises a second set of phase shifts, 9, and of amplitude, G, as a function of operating parameters of the powertrain and intended for the determination of a correction torque Ccor of oscillations of regime representative of the second type of 'acceleration. This second calibration may be in the form of a mapping, establishing a correspondence between the phase shift, 9, and the amplitude, G, to be applied as a function of the engaged gear ratio, Rv and the engine speed N. and a torque of data composed of the engine speed N and the speed gear ratio Rv engaged. This mapping can be integrated into the module 13 for detecting the type of acceleration.

The phase shifts, 9, and amplitudes, G, of the two calibrations are advantageously established beforehand from engine tests.

In the case of an acceleration with passage of games, it is useful to apply the first calibration only during the tilting of the engine, because once the engine games passed, the engine is placed in support on its holds and one finds oneself in the same conditions as for an acceleration without passage of games, that is to say with oscillations related to the chain of transmission. It is then possible to envisage in step 307 an application duration, Db, of the first calibration. This duration of application must cover the shock related to the tilting of the engine on its holds, so the first speed bump as shown in Figure 4. This duration of application is a function of the load, deduced in fact from the position, Pa, the accelerator pedal and the gear ratio, Rv, engaged, because the more energy is applied, the faster the changeover takes place.

At the end of this duration of application, it returns (passage from step 307 to step 308) to the second calibration, specific to accelerations without passage of games. The module 14 of curative approval monitors the evolution of the engine speed N. The module 14 aims to attenuate the oscillation of the regime following the torque request by generating in a step 104, a correction torque, Ccor, using the first or second calibration depending on the type of acceleration in effect. Thus, following a torque request, the procedure for determining the correction torque, Ccor, comprises the steps consisting in: - examining the evolution of the engine speed, - identifying from the evolution of the engine speed the type of engine acceleration, A, directly following the torque request, - select the calibration adapted to the type of acceleration identified, the calibration in question establishing a phase shift, 9, and an amplitude, G, according to the operating parameters of the powertrain , preferably gear ratio engaged Rv, and the engine speed N. It is thus expected to have a calibration type of acceleration and thus select the right calibration from a separate set of calibration to each type of acceleration (A) identified. The phase shift, 9, is between -1 and 0, -1 corresponding to a phase opposition with respect to the engine speed oscillation. The amplitude, G, is between 0 and 1. -soler the regime oscillations by filtering the evolution of the engine speed by the application of the phase shift, 9, resulting from the selected calibration, - build the correction torque, Ccor applying the amplitude, G, from the selected calibration to the engine speed oscillation. In the case of an acceleration of the first type, that is to say with a clearance crossing, the phase shift, 9, of the correction torque preferably corresponds exactly to a phase opposition with the engine speed oscillation. In the case of an acceleration of the second type, with no clearance crossing, the phase shift, 9, is preferably comprised around the phase opposition with the engine speed oscillation at +/- 2 PMH. The torque resulting from the correction torque, Ccor, and from the indicated torque, Ci, is the final torque, Cf, (ie Cf = Ci + Ccor) sent to the motor in a step 105 and then converted into a control of different organs, such as for example a quantity of fuel to be injected into the cylinders of the engine. The method of the invention has the advantages of substantially limiting the violent jolts or rebounds felt during acceleration and deceleration, which reduces customer complaints on this item.

This method does not require a structural modification of the computer that embeds the instructions required for its implementation. The improvement of the performance on the vehicles equipped with a heat engine is obtained without material overcost.

Finally, the development is simplified because there is no more problem of compromise because of the distinction of the type of acceleration. This results in a saving of time, brilliance and driving pleasure.

Claims (10)

REVENDICATIONS1. A method for determining a correction torque (Ccor) of the engine speed oscillation of a power train comprising a heat engine (1) and a transmission (2), in which, following a torque request: - we scan the evolution of the engine speed, -selects a calibration establishing a phase shift (9) and an amplitude (G) as a function of powertrain operating parameters, - the oscillation of the engine speed is isolated from the evolution of the engine speed (N) by filtering the evolution of the engine speed by the application of the phase shift (9), the correction torque (Ccor) is determined by applying the amplitude (G) to the engine speed oscillation (N), the method being characterized in that a type of acceleration (A) is identified following the torque request, in that the calibration establishing the phase shift (9) and the amplitude (G) is selected from a set separate calibration for each type of acceleration (Identified. 2. Method according to claim 1, wherein the heat engine being placed on wedges, the type of acceleration (A) is identified between a first type of acceleration during which the tilting of the engine (1) on its holds has and a second type of acceleration during which the tilting of the engine (1) on its holds does not take place. The method of claim 2, wherein the type of acceleration (A) is determined from the engine speed gradient (AN). 4. The method of claim 3, wherein the engine speed gradient (AN) is compared to a threshold (Sg) of engine speed gradient. 5. The method of claim 4, wherein the threshold (Sg) of engine speed gradient is of the order of 100tr / min / s. The method according to any one of claims 2 to 5, wherein when the second type of acceleration is identified, a tilting time (Db) of the heat engine (1) on its shims is determined and the correction torque ( Ccor) is determined from the calibration selected for the first type of acceleration only during the determined switching time (Db). 7. The method of claim 6, wherein when the tilting time (Db) of the engine on its shims is exceeded, the correction torque (Ccor) is determined from the calibration selected for the second type of acceleration. 8. A method according to claim 6 or claim 7, wherein, the transmission (2) comprising a gearbox, the switching time is determined from a mapping establishing a correspondence between the switching time (Db) and a data pair composed of the engine speed (N) and a gear ratio (Rv) engaged. 9. The method of claim 8, wherein, the transmission (2) comprising a gearbox, the phase shift (9) and the amplitude (G) are determined from a mapping establishing a correspondence between the phase shift (9). ) and the amplitude (G) and a data pair composed of the engine speed (N) and the speed gear ratio (Rv) engaged. 10. Vehicle equipped with a powertrain comprising a heat engine (1) and a transmission (2), characterized in that it comprises means for determining a correction torque (Ccor) of engine speed oscillations comprising the instructions required to implement the method according to any one of the preceding claims.