WO2017134369A1 - Methods and systems for controlling air torque when switching from the freewheeling operative mode - Google Patents

Abstract

The invention relates to a computing device for controlling the air torque in the admission distributor of a spark-ignition engine, when switching from the freewheeling operative mode of said motor vehicle, said motor vehicle being provided with an acceleration body and a braking body, the switching from the freewheeling operative mode of the motor vehicle being triggerable by pressing applied to the acceleration body or by actuating the braking body, said computing device being designed to control, following the triggering of the switching from the freewheeling operative mode of the motor vehicle and during the closing phase (33) of the traction chain for switching from said operative mode, the maintenance of a level of air torque associated with the pressure applied to the acceleration body.

Description

 AIR TORQUE CONTROL METHODS AND SYSTEMS WHEN EXCEEDING FREEWHEEL OPERATING MODE

The invention relates generally to methods and systems for controlling the freewheel mode of operation of a motor vehicle equipped with a spark ignition internal combustion engine.

 The invention is more particularly the methods and systems for controlling the air torque during the closing of the drive train, to exit the freewheel operating mode.

 The freewheel mode of operation, also known as "operating mode in declutched mode" (or "coasting" in English terminology), is to open the vehicle traction system, when the requested torque by the driver becomes weak or no. In this case, the engine is disconnected from the vehicle wheels and can idle or stop.

 In real-world use of a vehicle, the coasting mode of operation is generally activated when the kinetic energy accumulated by the vehicle is sufficient to advance the vehicle at the speed desired by the driver. Because of its inertia, the vehicle can, in fact, continue to run on flat or slightly sloping roads, without the engine needs to provide engine torque to the wheels. Similarly, on a downhill road, the vehicle can maintain its speed or accelerate, without the need for engine power. It is also possible to activate this operating mode with the "stop and start" function, if the vehicle is equipped with it.

Thus, in freewheel mode, the engine can idle or be stopped, while the vehicle continues its course. For example, when the driver anticipates his arrival on obstacles requiring a decrease in speed, the driver releases the accelerator earlier, and takes advantage of the kinetic energy of the vehicle to travel in free-wheeling mode the distance separating it from the obstacle.

The graph of Figure 1 illustrates the torque behavior CM (effective average torque available on the crankshaft) of the engine of the vehicle, as a function of time t, from the input to the output of the freewheel mode of this vehicle.

 [0007] In the graph of FIG. 1, different phases are distinguished, corresponding respectively to

 activation of the freewheel operating mode of the motor vehicle when the driver releases the accelerator and does not actuate the brake (that is to say at the exit of an acceleration phase);

 at the input 12 in this mode of operation, carried out by the opening of the traction chain by controlling the disengagement of the motor whose motor torque CM is immediately reduced;

 maintaining the idling speed of the engine (or even the cancellation of this engine speed) to which corresponds a zero engine torque CM;

 at the revival 14 of the engine speed by controlling the engine torque CM to reach a target engine speed, allowing the closing of the power train and therefore the output, triggered by the support of the driver on the accelerator pedal or on the vehicle brake pedal, coasting mode;

 at the closing 16 of the traction chain, while the engine speed is kept constant which corresponds to a zero motor torque CM.

The engine torque CM required by the driver is then controlled during phase 17. Indeed, if the output 14 of the coasting mode of operation is triggered by pressing the accelerator pedal, an increase of RM engine speed (which is the case of phase 17 of Figure 1) is required, once the drive chain is closed, to gradually reach the speed of the input shaft of the gearbox. On the other hand, if the output 14 of the coasting mode of operation is triggered by the pressing on the brake pedal, a reduction of the engine torque CM (not shown) is required to progressively reach the driver's will. In other words, once the drive chain closed (so after revival 14 speed), the torque achieved by the motor is respectively, depending on whether the accelerator pedal or the brake pedal is actuated, positive or negative. In particular, for a spark ignition internal combustion engine more commonly known as a gasoline engine, the closing phase 16 of the power train is not immediate and comprises, in fact, a regulation of the air torque. The regulation of the air torque is so named because it is converted into control of the valve which controls the air load admitted to the engine. The higher the "air" torque set point, the more the throttle will open and therefore more air will be admitted into the engine.

 The freewheel mode of operation has proved its worth, especially as an interesting opportunity to reduce fuel consumption and polluting emissions, when using a motor vehicle.

 However, this mode of operation is not without imperfections, particularly with regard to the regulation of the air torque, during the closing phase 16 of the traction chain, to exit the freewheel operating mode.

[0012] The current regulation of the air torque when the traction chain closes to exit the freewheel mode of operation is not optimal.

Indeed, controlling an air torque whose level tends to zero Nm (thick line interrupted in Figure 1), regardless of the engine torque CM required by the driver at the output of the freewheel operating mode, brings penalties , in terms of performance and driving ergonomics. In particular, the higher the level of engine torque required by the driver, the longer the duration 18 of provision of this torque is high. Starting from an almost zero air torque, the provision of a large engine torque required by the driver requires a significant duration, altering the response time to the will of the driver.

An objective is to provide a fine control of the air torque during the output of the freewheel mode of operation, in a motor vehicle equipped with a petrol engine.

Another objective is to provide methods and systems for optimum control of the air torque, when closing the power train to exit a freewheel mode of operation, so as to ensure ergonomic and comfortable driving to the driver of a motor vehicle equipped with a petrol engine. For these purposes, it is proposed, in a first aspect, a computer for controlling the air torque in the intake manifold of a spark ignition internal combustion engine in a motor vehicle at the exit of the mode of coasting operation of this motor vehicle, this motor vehicle being provided with an acceleration member and a braking member, the output of the freewheel operating mode of the motor vehicle can be triggered by the depression of the vehicle; acceleration member or by the actuation of the braking member, the computer being configured to control, following the triggering of the output of the freewheel operating mode of the motor vehicle, the maintenance, during the closing phase of the traction chain to leave this mode of operation, an air torque level associated with the degree of depression of the acceleration member.

Improved with the invention the control of the engine torque according to different parameters (including the will of the driver) to achieve the speed setpoint while minimizing the fuel consumption of the vehicle (output of the mode "freewheeling" ") And guaranteeing a good driving pleasure for the driver. The invention therefore relates in particular to the management of the outputs of the "freewheel" mode with a differentiation of the engine control according to the will of the driver (acceleration or deceleration).

The calculator has, according to various embodiments, the following characteristics, if any combined:

 - Following the triggering of the output of the freewheel operating mode by depression of the acceleration member, the controlled air torque level is greater than or equal to a predefined air torque threshold level; the threshold level of air torque is associated with a range of degrees of depression of the accelerator member;

 following the triggering of the output of the coasting operating mode by the actuation of the braking member, the controlled air torque level is lower than a predefined air torque threshold level, the degree of depression of the organ acceleration being considered zero;

the controlled air torque level is zero. It is proposed, in a second aspect, a method for controlling the air torque in the intake manifold of a spark ignition internal combustion engine in a motor vehicle during the output of the freewheel operating mode. of this motor vehicle, this motor vehicle being provided with an acceleration member and a braking member, the output of the freewheel operating mode of the motor vehicle can be triggered by the depression of the body of acceleration or by the actuation of the braking member, this method comprising, following the triggering of the output of the freewheel operating mode of the motor vehicle, the following steps

 identification by the computer, in a database or in a map, of a predefined threshold level of air torque associated with a degree of depression of the acceleration member; and

 control of maintaining, during the closing phase of the power train to exit this operating mode, an air torque at least equal to the identified threshold level.

The invention relates, in a third aspect, to a motor vehicle comprising the calculator presented above.

 This motor vehicle has, according to various embodiments, the following characteristics, if any combined:

 this vehicle comprises an air actuator configured to maintain in the intake manifold, during the closing phase of the traction chain, the controlled air torque level;

 this vehicle comprises a motorized butterfly whose opening section is controlled by the computer;

 this vehicle comprises a database which, at a degree of depression of the accelerator pedal, associates a threshold level of air torque.

Other characteristics and advantages of the invention will appear more clearly and concretely on reading the following description of embodiments, given below with reference to the accompanying drawings, in which: Figure 1 schematically illustrates the behavior in engine torque and air torque of a motor vehicle, following the activation of the freewheel mode; 2 schematically illustrates a motor vehicle comprising means for controlling, in various embodiments, the air torque, when closing the traction chain to exit the freewheel operating mode;

 FIG. 3 schematically illustrates the behavior over time of the engine torque and the air torque, according to various embodiments, during the output - triggered by the depressing of the accelerator pedal - of the freewheel operating mode of a motor vehicle;

 FIG. 4 schematically illustrates the behavior in time of the engine torque and the air torque, according to various embodiments, during the output - triggered by the actuation of the brake pedal - of the freewheel operating mode of a motor vehicle.

Referring to FIG. 2, there is shown an automobile vehicle comprising an acceleration member 1, hereinafter referred to as "accelerator pedal 1". This accelerator pedal 1 is capable of being actuated by a driver of the automobile vehicle, for the control of a motor torque CM. A position sensor 2 makes it possible to measure the degree of depression of the accelerator pedal 1. This position sensor 2 communicates the degree of depression of the accelerator pedal 1 to a computer 5, also referred to as engine control.

The vehicle 10 comprises, also, a braking member 3, hereinafter called "brake pedal 3". This brake pedal 3 may be actuated by a driver of the motor vehicle to apply a brake torque (i.e. a negative motor torque CM) to the drive wheels of the motor vehicle.

A second sensor 4, distinct or not from the first position sensor 2, is configured to sense the pressed state or the relaxed state of the brake pedal 3 and to communicate this state to the computer 5.

The automotive vehicle 10 comprises a spark ignition internal combustion engine 6 (designation referring to to the combustion that characterizes it), more commonly known as gasoline engine. This automobile vehicle can be hybrid or not.

The internal combustion engine 6 spark ignition, comprises a predetermined number of cylinders, each forming a combustion chamber, adapted to allow the combustion of an air / fuel mixture. This combustion is supervised by the computer 5.

According to various information, including those communicated to it by the sensors 2 and 4 positioned, respectively, on the accelerator pedal 1 and the brake pedal 3, the computer 5 is programmed to control the operation of the internal combustion engine with spark ignition.

The computer 5 is, in fact, configured to adjust via appropriate actuators different operating parameters of the engine 6 influencing the combustion of the air / fuel mixture (such as the amount of air admitted into the cylinders). , the mass of fuel injected, or ignition to trigger combustion).

 At the exit of an acceleration phase, for example when approaching an obstacle where the driver releases the accelerator pedal 1 without operating the brake pedal 3, the freewheel operating mode s active, by opening the drive chain of the automobile vehicle.

 [0031] As long as neither the accelerator pedal 1 nor the brake pedal 3 is actuated, no engine or braking torque is controlled by the computer 5, and the vehicle 10 continues to run in freewheel mode. .

 The pressing of the accelerator pedal 1 triggers (step 31 in Figure 3) the output of the freewheel operating mode.

 Accordingly, the computer 5 controls, during the recovery phase 32 of the engine speed, a motor torque CM to reach a target engine speed, allowing the closing of the power train to exit the operating mode coasting .

Once the target engine speed reached, the latter is kept constant the time of the closing phase 33 of the drive chain. During this phase, the motor torque level CM is reduced to zero Newton-meter (Nm). During the closing phase 33 of the traction chain for an output of the freewheel operating mode triggered by the actuation of the accelerator pedal 1, instead of decreasing the air torque to a value almost zero (thick line interrupted 36), the computer 5 controls the maintenance in the engine intake manifold 6 of an air torque level greater than or equal to a predetermined threshold level 34 (dashed thick line superimposed on FIG. motor shown in solid thick line). Threshold level 34 is non-zero.

For this, the computer 5 controls, via an air actuator, a threshold level 34 of air torque (by adjusting the air pressure in the intake manifold measured by a sensor placed in this member) during the closing phase 33 of the traction chain.

In one embodiment, the air actuator is an air regulating valve, such as a motorized butterfly, whose opening section controlled by the computer 5 can regulate the air flow rate. through the intake distributor. It follows that during the closing phase 33 of the drive train, the computer 5 controls the value of the opening section of the air control valve, so as to maintain the air torque at one (or above a pre-defined non-zero threshold level 34.

 Advantageously, the maintenance, during the closing phase 33 of the drive train, of the air torque above a predetermined non-zero threshold level allows the spark ignition internal combustion engine 6 to have a enough air to achieve a motor torque required by the driver. The threshold level 34 of air torque makes it possible to supply air to the internal combustion engine 6 with spark ignition, so as to respond quickly to its demand for air and to reach a target engine torque more quickly.

In other words, the maintenance of the engine torque at a level at least greater than the threshold level 34 is a reserve of air torque, to have faster air needed to obtain a significant engine torque (A reserve of air torque capable of guaranteeing the achievement of a high engine torque by the success of a plurality of combustion in all the cylinders of the engine as soon as the traction chain is closed). So we temporarily put engine layout 6 more air than necessary, in order to prepare a charge on it.

 Compared to the state of the art, where the level 36 (thick line interrupted) of air torque at the end of the closing phase 33 of the power train is almost zero, the revival of the engine torque is, here, faster, because there is no need to wait for the arrival of the amount of air needed for this stimulus. The upstream maintenance of the air torque above the threshold level 34, during the closing phase of the traction chain makes it possible to quickly serve in air the revival of the engine torque CM, at the traction chain closure.

 This results in a dynamic reserve of air, allowing a saving of time (duration 35 in Figure 3) in the provision of engine torque. Thus, the engine torque required by the driver is reached faster.

The threshold level 34 above which the air torque is maintained during the closing of the traction chain 33 is, in one embodiment, defined as a function of the degree of depression of the accelerator pedal 1. In other words, according to the degree of depression of the accelerator pedal 1, a threshold level 34 (or a minimum level 34) corresponding air torque is controlled by the computer 5. The degree of depression reaches the computer 5 since the accelerator pedal 1 position sensor 2.

 In one embodiment, the computer 5 is provided with a database of threshold levels 34 of engine torque CM, associated with degrees of depression of the pedal 1 of acceleration. This database associates a degree of depression of the accelerator pedal 1 with a threshold level of air torque. As a variant, the minimum level of air torque is, by way of example, determined from a cartography, making it possible to make the correspondence between different degrees of depression of the accelerator pedal 1 and different predetermined threshold air torque levels. .

 In one embodiment, a threshold level 34 of air torque is associated with a range of degrees of depression of the accelerator pedal 1. For example,

a first threshold level 34 is associated with the degrees of depression strictly below 50% of the maximum degree of depression possible; a second threshold level 34 is associated with degrees of depression between 50% and 75% of the maximum degree of depression possible;

 a third threshold level 34 is associated with degrees of depression strictly greater than 75% of the maximum degree of depression possible.

In one embodiment, the air torque is maintained, during the closing phase of the drive train to exit the freewheel operating mode, to a level dependent content (and not thresholds) of the degree depressing the accelerator pedal 1 (and therefore the driver torque).

The variation of the threshold level 34 of air torque, depending on the degree of depression of the accelerator pedal 1, has the effect of responding best to the will of the driver, translated by the degree of depression of the accelerator pedal 1. By way of example, this makes it possible to reach a target engine torque more quickly, in response to an extreme driver will, via a significant degree of depression of the accelerator pedal 1.

 In an implementation, following the tripping 31 of the output of the freewheel operating mode by the actuation of the brake pedal 1, the computer 5

 receives, from the position sensor 2, the degree of depression of the accelerator pedal 1;

 identifies, in a database or in a cartography, a predefined threshold level of air torque associated with this degree of depression; and

 control, therefore, maintaining, during the closing phase of the power train to exit the freewheel operating mode, an air torque in the intake distributor at least equal to the threshold level 34 associated with the degree of depression of the accelerator pedal 1.

The computer 5 controls, thus, the maintenance during the closing phase 33 of the drive train, to exit the freewheel mode, a level of air torque associated with the degree of depression of the pedal 1 of acceleration.

Maintaining the air torque above the threshold level 34 remains active until the end of the closing phase 33 of the chain. traction. As a result, from the beginning of the closing phase of the drive train, the computer 2 maintains an active air reserve, in order to anticipate a sufficient air torque making it possible to reach more quickly the engine torque required by the driver. . Advantageously, this has the effect of anticipating a possible lack of air in the engine, so as to quickly achieve a significant engine torque required by the driver. More generally, this method makes it possible to mitigate a lack of air, during acceleration, starting from a zero effective engine torque CM (which is the case during the closing phase 33 of the power train) , preceded by a restart phase 32 of engine speed where the engine torque is strictly positive.

 Figure 4 illustrates the control of the air torque during closing of the drive chain following the actuation of the brake pedal 3 (step 41) to exit the freewheel operating mode.

 When the brake pedal 3 is actuated to exit the coasting mode, the degree of depression of the accelerator pedal 1 is considered to be zero.

In this case, the computer 5 controls, through the air actuator, an air torque level below a threshold level 44 of air torque. In one embodiment, the computer 5 is configured to control a zero level or slightly greater than 0 Nm of the air torque.

 The computer 5 generates control signals controlling the air actuator (such as by controlling the opening section of a motorized throttle), so as to reduce the air torque in the intake manifold to a level below the predefined threshold level 44 which is lower than the level 45 of interrupted thick air torque of the state of the art. This results, advantageously, a gain 46 in energy consumption.

 [0054] It is, indeed, assumed that

by pressing the brake pedal 3 to exit the freewheel operating mode, the driver of the motor vehicle 10 does not need a significant air torque temporarily. The level of air torque is thus reduced to a zero level, in order to minimize the consumption in fuel and polluting emissions of the vehicle; on the other hand

 by pressing the accelerator pedal 1 to exit the freewheel operating mode, the driver needs to have positive torque quickly to the wheel

(proportional to the degree of depression of the accelerator pedal 1). As a result, the air torque level is maintained at a high level, to arrive more quickly at the desired engine torque by the driver once the power train is closed. The revival is thus dynamic with a better driving pleasure.

More generally, the computer 5 adapts the air setpoint during the closing of the drive chain, depending on the degree of depression of the accelerator pedal 1, the actuation of the brake pedal 3 being equivalent to a degree of depression of the accelerator pedal 1. As a result, the air torque is defined during the closing phase of the drive train, depending on the will of the driver of the vehicle.

 Of course, parallel to the control of the air torque via the air actuator, the computer 2 controls various operating parameters of the engine 6, such as the value of the ignition advance and the injection parameters (fuel mass injected, injection time). These parameters are in particular regulated by the computer 5, as a function of the air torque in the intake distributor (or in the combustion chambers), as well as the speed of the engine 6.

 Advantageously, the methods and systems described above allow an output of the fast freewheel operating mode (in particular, when the interruption is triggered by pressing the accelerator pedal), so that it preserves a good driving pleasure; and

 no energy (especially when the interruption is triggered by pressing the brake pedal), so as not to penalize the consumption gain of this mode of operation).

Advantageously, the methods and systems described above allow the motor torque CM to approach as quickly as possible. dynamic setpoint, in response to the driver demand, when the freewheel mode is exited

Claims

A computer (5) for controlling the air torque in the intake manifold of a spark ignition internal combustion engine (6) in an automobile vehicle (10) upon exiting the freewheel operating mode of that engine vehicle (10) automobile, this vehicle (10) automobile being provided with a member (1) of acceleration and a member (3) for braking, the output of the operating mode coasting of the vehicle (10) automobile which can be triggered by the depression of the accelerating member (1) or by the actuation of the braking member (3), this calculator (5) being characterized in that it is configured to control, further when the output of the freewheel operating mode of the vehicle (10) of the car is triggered, the maintenance, during the closing phase (33, 43) of the traction chain to leave this mode of operation, of a level of air torque associated with the degree of depression of the member (1) acceleration.  2. The calculator (5) of claim 1, wherein following the triggering of the output of the freewheel operating mode by depression of the member (1) acceleration, the controlled air torque level is higher or equal to a threshold level (34) of predefined air torque.  3. The computer (5) of the preceding claim, wherein the threshold level (34) of air torque is associated with a range of degrees of depression of the member (1) acceleration.  4. The computer (5) of claim 1, wherein following the triggering of the output of the coasting operating mode by the actuation of the member (3) braking, the controlled air torque level is less than a threshold level (46) of predefined air torque, the degree of depression of the accelerating member (1) being considered zero. 5. The computer (5) of the preceding claim wherein the controlled air torque level is zero. 6. Method for controlling the air torque in the intake manifold of a spark ignition internal combustion engine (6) in an automotive vehicle (10) upon the release of the coasting operation mode of that vehicle (10) ) automobile, this vehicle (10) automobile being provided with an organ (1) acceleration and a braking member (3), the output of the freewheel operating mode of the vehicle (10) automobile being triggered by the depression of the member (1) acceleration or by the actuation of the member (3) for braking, this method being characterized in that it comprises, following the triggering of the output of the freewheel operating mode of the vehicle (10) automobile, the following steps  identification by the computer (5), in a database or in a map, of a predefined threshold level of air torque associated with a degree of depression of the accelerating member (1); and  control of maintaining, during the closing phase (33, 43) of the power train to exit this operating mode, an air torque at least equal to the threshold level (34) identified.  7. Vehicle (10) automobile comprising the computer (5) of any one of claims 1 to 4.  8. Vehicle (10) automobile according to the preceding claim, comprising an air actuator configured to maintain in the intake manifold, during the closing phase (33, 43) of the traction chain, the controlled air torque level. .  9. Vehicle according to the preceding claim, wherein the air actuator is a motorized butterfly whose opening section is controlled by the computer (5). 10. Vehicle according to any one of claims 7 to 9 further comprising a database which, at a degree of depression of the accelerator pedal (1), associates a threshold level of air torque.