DE10206199C1 - Automobile engine control reduces rev variation between opposite ends of drive train upon load direction transition - Google Patents

Abstract

The engine control allows an increase in the engine revs upon a transition from a push to pull loading direction of the automobile drive train for a defined waiting time in the free-running phase, before a delay or reduction during an engagement time as in DE 10104372. The waiting time and the engagement time are determined from the play and/or elastic deformation within the drive train, the angular velocity at the primary side at he end of the push operation, the angular velocity at the secondary side at the engagement point, the acceleration characteristics of the engine, the braking characteristics of the engine and/or the operating rate of the power control.

Description

The invention relates to the control of an engine on a Game and / or elasticity drivetrain after the Claim 2 of the main patent.

In view of great comfort are in motor vehicles between engine and drive wheels in the transmission considerable elasticity is provided. This is especially true if there is a so-called dual mass flywheel, its The primary side and its secondary side are torsionally elastic with one another are drive-coupled, the primary side on the motor side and the secondary side are arranged on the drive train side. in addition comes a more or less big game, which one hand practically inevitable between gear elements of the Drive train, especially within a manual transmission and the main drive joints of the wheel drive, available and if necessary, also specified in the design of the two-mass flywheel can be.

By interposing the elasticities and / or the The game can be largely vibrational Achieve decoupling between engine and drive train. However, comparative without any special measures strong load change reactions occur.

From DE 34 04 154 C2 and DE 195 38 369 A1 it is known, load changes by appropriate control of the Dampen motors.  

DE 44 31 640 A1 shows the possibility of Load change impacts by controlling the turbine torque to reduce transducers arranged in the drive train.

The object of the invention is to provide an advantageous possibility to create the comfort with load changes low design effort to increase even further.

This object is solved by the features of claim 1. The automatic control reduces during a load Alternating speed differences between the engine and Powertrain and / or between converter end and far end of the drive train before consuming the Game or the elasticity.

The invention is based on the general idea of load changes, in particular push-pull load changes, to record and through an automatic intervention in the control of the engine or converter temporarily during the load change achievable speed and angular momentum differences between Motor and input of the drive train or between primary and secondary mass of the two-mass flywheel or between playful elements of the drive train before termination limit or minimize the load change, so that in Result no significant load can occur or ideally, the same speed is reached at the docking point, the maximum rotation angle specified by the design between engine and drive train or between primary and Secondary mass of the two-mass flywheel or between playful elements of the drive train is defined.

The invention takes advantage of the fact that modern Motor vehicles with a so-called electronic accelerator pedal are equipped, in which the one caused by the driver Pedal position only the setpoints of operating parameters, in particular the motor or converter, to which the Actual values through an electronic converter or motor control  can be adjusted according to the specified characteristics by for example in an internal combustion engine from the electronic engine control on the one hand a throttle valve to control the supply of combustion air and on the other hand Injection quantities and injection times of one Fuel injection and / or ignition timing of one Ignition system are controlled accordingly. With such a The system only needs the engine control to "know" how the motor can be controlled to avoid a load should if the driver does not have one previously while driving Accelerator pedal suddenly pressed hard, d. H. if the Driver from overrun to pronounced train operation of the Wants to pass over the vehicle. Basically the same applies to the electronic converter control, in particular that Turbine torque of the converter controls.

The invention can therefore be achieved by appropriate Configuration of the control of the motor or converter, d. H. by configuring appropriate control programs, realize without any other design changes.

According to the invention, a distinction is essentially made between two phases: a waiting time t ₁ , in which the engine torque is transferred to the drive train without further measures, and an intervention time t ₂ , during which the intervention in the engine torque takes place. The intervention consists in a reduction in the engine torque output, in a deceleration of the drive train or a reduction in the acceleration of the drive train. The times t ₁ and t ₂ can be fixed a priori or learned or optimized during several load control. Factors influencing the determination of times t ₁ and t ₂ are the total angle ϕ _GES (total angle resulting from play and / or elastic deformations), the angular velocity of the primary side when shear operation ends ω ₀ , and the angular velocity of the secondary side at the docking time ω _ν , the acceleration capacity of the motor _B and / or the braking capacity of the motor _D. The acceleration capacity can depend on the inertia of the drive train elements involved, on the performance of the drive unit and / or on the performance request specified by the driver. The braking capacity depends in particular on a maximum drag torque of the drive unit, a change in the output torque of the drive unit as a result of the intervention and / or the deceleration effect of additional units such as, for example, switchable auxiliary units or brake units on the drive unit side. In a first approximation (neglecting the deceleration of the secondary side assuming short times for walking through the game and / or the elasticities), the angular velocity ω _{ν of} the secondary side at the time of docking can be equated with the angular velocity ω _{0 of} the primary side at the end of overrun operation, because for the passage of the game to the secondary side, no or only slight acceleration moments are transmitted from the primary side and for the short times, delays on the primary side, for example due to driving resistance, are negligible.

According to a particularly simple embodiment of the invention the waiting time and the intervention time are determined about the formulas given in claim 2. This represent at least a good approximation of the physical Conditions and can be particularly simple and efficient way in an effective working control to implement.

According to a further proposal of the invention a reduction in engine torque during the intervention period via an ignition intervention and / or a change in the Throttle position. This type of intervention is equally easy to implement, for example as a result  using the conditions of a motor control, such as effective.

In a further control according to the invention, as Trigger event for the beginning of the waiting time of a push operation and a limit value of a change of a Power actuator used. These signals are there anyway in a motor controller and are used to generate the Easy to check trigger pulse. Give at the same time these signals at least approximately exactly replacing the Primary side from the secondary side again.

According to a further proposal of the invention, additional at the waiting time one of the rate of change of the Power control element dependent additional waiting time determined. Around the additional waiting time becomes the intervention after the expiry of the Waiting time further delayed. Hereby the wish of the Driver after a high agility of the vehicle particularly well be met. The delay in the intervention can here with the acceptance of a load, however in reduced scope compared to known load control systems, or with an increased intensity Intervention to completely avoid load impact.

The acceleration capacity of the motor _B and / or the braking capacity of the motor _D is preferably determined using a map. The aforementioned angular accelerations can be determined in a particularly simple manner from the map. The map can be stored a priori or can be adapted while driving. Dependencies of the aforementioned angular accelerations, for example on environmental parameters such as delays due to driving resistance, air resistance, road inclination, vehicle mass with or without consideration of a loading condition, outside temperatures for the drag torque or the output power of the drive unit can be taken into account in a simple manner.

According to a further proposal of the invention, the Waiting and operating time and / or when docking point the drive torque is ramped or with a linear, Curved or stair-shaped rise enlarged. This can the increase function of vehicle or environmental parameters be dependent. This can be a particularly convenient Train crossing can be achieved. For example, this is Design of particular advantage in terms of dynamic load of the downstream Drive train. Using this design can inflate Vibration rashes of the subframe, especially one Strikes the same on stops of the bearing elements of the Subframe against the body, avoided.

Otherwise, the preferred features of the Invention on the claims and the following explanation referred to the drawing, based on which particularly preferred Embodiments of the invention are described in more detail.

It shows

Fig. 1 is a schematic representation of a drive train of a motor vehicle,

Fig. 2 is a diagram showing the angular velocities ω of the primary and the secondary mass of a two-mass flywheel in a push-pull load change in the drive train as a function of the angle of rotation ϕ.

Referring to FIG. 1 a not-shown motor vehicle has driven wheels 1 which are drivingly connected by drive shafts 2, a differential gear 3, and a propeller shaft 4 to the output of the transmission 5, the input through a coupling 6 and a two-mass flywheel 7 is drivingly connected to an internal combustion engine 8 . The cardan shafts 2 and the cardan shaft 4 typically have a plurality of joints 9 , each of which has a certain amount of play, to which the play in the gears 3 and 5 is added, ie the drive train is more or less markedly free of play.

In addition, the drive train has a pronounced elasticity because the cardan shafts 2 and the cardan shaft 4 have a greater or lesser degree of torsional elasticity and, moreover, the primary and secondary masses of the two-mass flywheel 7 are distinctly torsionally elastic connected to one another and generally also the Coupling 6 is provided with torsionally elastic transmission elements.

The engine 8 or its engine torque is controlled by the driver by means of an accelerator pedal 10 , which in turn is connected to an input of an electronic engine control 11 , which on the input side has a sensor system 100 ( not shown in more detail) for further operating parameters, such as, for. B. engine speed, wheel speeds or the like. Is connected and on the output side a throttle valve 12 for controlling the supply of combustion air to the engine 8 , an injection system 13 for injecting fuel into the combustion chambers of the engine 8 and / or an ignition system 14 through which the fuel controls -Air mixture in the combustion chambers in the case of Otto engines can be ignited at controllable ignition times. On the basis of appropriate programming or on the basis of stored characteristic maps, the engine control 11 can "decide" which measures are optimal when the accelerator pedal 10 is actuated, and carry out these measures so that the power or the torque of the motor 8 corresponds to the driver's request in accordance with the actuation of the accelerator pedal 10 be adjusted.

In the example in FIG. 2 it is now assumed that the vehicle is initially in an operating phase with overrun operation, ie the vehicle is moving against a braking moment of the engine 8 , for example on a downhill section.

In such an operating phase, the entire drive train is resiliently biased against the engine 8 , the secondary mass of the two-mass flywheel being in contact with the primary mass in the thrust direction under elastic prestressing. In such a coasting operation, the primary mass according to curve K _p and the secondary mass according to curve K _{s have} practically the same angular velocities ω before reaching an angle of rotation ϕ ₀ . In the example in FIG. 2, these angular velocities ω are constant up to the angle of rotation ϕ ₀ during overrun operation. However, it is also conceivable that the angular velocities ω decrease or increase, depending on whether the braking torque of the motor 8 is greater or less than the thrust torque of the drive train.

When the angle of rotation ϕ ₀ is reached, the driver should now actuate the accelerator pedal 10 , which is not actuated during overrun operation, comparatively strongly, ie the driver wants to switch to pronounced train operation, for example to accelerate the vehicle.

On the one hand, this leads to the angular velocity of the primary mass of the two-mass flywheel 7 increasing in accordance with the curve K _p . This is equivalent to the fact that the angular momentum of the crank mechanism of the engine 8 and the primary mass of the flywheel 7 associated therewith increases more or less continuously.

On the other hand, now the drive train, the push-side abutment withdrawn at the primary mass of the flywheel 7, the increasingly faster rotating primary mass of the flywheel means 7 outputs the drive train in the thrust direction increasingly free. As a result, the elasticities in the drive train that are prestressed in the thrust direction increasingly relax, with the result that the secondary mass of the flywheel 7 is accelerated in its previous direction of rotation. When the angle of rotation ϕ ₁ is reached, the tensioning of the drive train in the thrust direction is ended. The secondary mass of the flywheel 7 now rotates due to the inertia effects the φ before reaching the rotational angle of ₁ reached angular velocity further, that the secondary mass of the flywheel 7 rotating in a freewheeling phase with in comparison to the rotational speed of the wheels 1 more or less increased speed further wherein the game in the drive train in the direction of pull is increasingly consumed. If the secondary masses exceed the angle of rotation ϕ ₂ , the drive train becomes free of play in the direction of pull. Now the angular velocity of the secondary mass is more or less decelerated until the secondary mass of the flywheel 7 at an angle of rotation ϕ _{3 reaches} an angular velocity which is mathematically assigned to the speed of the drive wheels 1 , taking into account the gear ratio 5 .

After exceeding the angle of rotation ϕ ₀ , the speed of the primary mass of the flywheel 7 increases continuously. This is possible because the two masses of the two-mass flywheel 7 are coupled to one another via a large-stroke elasticity.

With increasing rotational movement of the primary mass after exceeding the angle of rotation ϕ ₀ , the elasticities within half of the two-mass flywheel 7 are increasingly consumed or stretched in the direction of pull.

Without special measures according to the invention, which are explained below, significant speed differences between the primary and secondary mass of the two-mass flywheel 7 remain, so that a more or less pronounced angular momentum difference between the engine and the drive train would have to occur if the primary mass relative to the secondary mass the maximum possible relative rotation. In the example in FIG. 2, this angular momentum _{difference would} reach the value W _prim -W _sec .

Before the primary mass reaches the angle of rotation ϕ ₄ , ie the desired docking position, the invention provides for automatically delaying the further increase in the speeds of the engine 8 and primary mass of the flywheel 7 , or even temporarily reducing this speed somewhat, for example by the fact that the engine control 11 the ignition times of the ignition system 14 are adjusted in the "late" direction and / or the injection system 13 is switched to reduced or vanishing injection quantities for the fuel.

The curve K _p1 shows an example of the course of the speed of the engine 8 and the primary mass of the flywheel 7 when the ignition of the engine 8 is reversed to "late" at an angle of rotation ϕ _{p of} the primary mass. Subsequently, the speed of the engine and thus the speed of the primary mass of the flywheel 7 remains largely constant, so that the speed differences between the primary and secondary mass of the flywheel 7 can no longer increase or even decrease because the speed of the secondary mass due to the increasing tension of the two-mass flywheel 7 increases in the direction of pull.

If, at the angle of rotation der _{q of} the primary mass, the fuel injection into the engine 8 is temporarily interrupted, the speed of the engine 8 and thus the primary mass of the flywheel 7 even decreases according to a curve K _p2 , so that the speeds of the two flywheels are particularly close of the flywheel 7 can be reached when the two masses dock onto one another in the direction of pull.

When the speed differences at the docking point have largely compensated for one another, the power or the torque of the motor 8 is increased again by the motor controller 11 in accordance with the position of the accelerator pedal 10 . A largely synchronous increase in the speed of the primary and secondary masses of the flywheel 7 now takes place.

The result can be as far as possible load-free push-pull transition.

The method of operation of the engine control 11 according to the invention, ie the temporary reduction in engine power during the transition phase between push and pull, can be easily implemented.

On the one hand, the engine control 11 “knows” the respective engine torque and “knows” whether an accelerator pedal 10 , the position of which the engine control 11 constantly registers, is in overrun mode when the accelerator pedal 10 is not actuated. If the driver now strongly depresses the accelerator pedal 10 , the engine control 11 "knows" that a transition from overrun to train operation will subsequently take place.

Due to the design of the drive train and the engine, the time course of the speeds of the primary mass and the secondary mass of the flywheel 7 between the angles of rotation ϕ ₀ and ϕ _{4 of} the primary mass is determined in a largely reproducible manner, so that the times at which the engine control 11 detects the increase in engine speed 8 initially delayed, can be specified. Such measures alone can achieve a significant reduction in the rotational impact when changing from pushing to pulling operation.

If necessary, the engine control 11 can also take into account the rotational speeds of the wheels 1 and the gear ratio or the shift stage of the transmission 5 and the engine speeds. Depending on the design of the drive train, these parameters largely determine the rotational speeds of the secondary mass of the flywheel 7 after an increase in the rotational speed of the primary mass. In this way, the motor controller 11 can, if necessary in the sense of a regulation, largely adapt the speeds of the motor 8 to a desired value in order to reach the docking point.

In principle, the invention can also be used for a pull-push Transition. Here is before reaching the Docking point in the direction of thrust automatically the motor power increased briefly to reduce a train-push load impact or to avoid.

If a hydrodynamic converter is arranged between the engine and the drive train, the engine speed is not an essential variable for the speed of the side of the converter remote from the engine; rather, the torque transmitted by the converter or the turbine torque of the converter are important parameters in this case. In order to avoid or reduce a load shock during a load change in the presence of a converter, it is provided according to the invention to control the transmitted torque of the converter or its turbine torque in a manner analogous to the control of the engine speeds shown above, the engine speed possibly corresponding to the desired one transmitted torque or changed according to the desired turbine torque of the converter. By controlling the aforementioned moments, the difference in the speeds of the converter-side end and the converter-distant end of the drive train having elasticity and play can be influenced in the same way as it is shown above with reference to FIG. 2 for the speeds of primary and secondary masses of a two- Mass flywheel was explained.

If necessary, the drive train can have several branches exhibit. In a four-wheel drive vehicle are in the Usually two branches, one for the front axle or axles and one for the rear axle or axles. In case in the respective constructive training of  Drive train does not achieve all elasticities and games in the branches can be consumed simultaneously, the Control of the engine speed or the Transformer torque occur accordingly several times.

Additionally or alternatively, there is the possibility of Reaching a docking point for a branch of the Drive train the moment of the engine and / or the converter shaped in such a way that trucks are avoided.

Through a shaped increase in engine torque and / or Torque can also cause vibrations in the drive train be dampened or prevented.

With a transition from pushing to pulling the Motor speed increase in the freewheeling phase initially approved and then delayed and / or reduced. The Engine speed will start at a point in time within the Freewheeling phase kept constant for a while. The Engine speed will be within or after a point in time the freewheeling phase temporarily lowered. An engine control represents the ignition timing of an ignition system of the engine temporarily to "late". An engine control controls temporarily reduced an injection system of the engine or vanishing injection quantities of the motor driving Fuel around. During a transition from push to pull operation the increase in turbine torque becomes one in the powertrain arranged converter initially allowed in the freewheeling phase and then delayed and / or reduced. The turbine moment is starting with a point in time in the freewheeling phase temporarily held constant. The turbine torque of the Transducer will be within or after a time Freewheeling phase temporarily reduced. With a transition from Pull or push operation is the engine power or that Turbine torque of a converter arranged in the drive train increased briefly. The increase in engine torque and / or Turbine torque of the converter is after the end of  Free-running phase or when reaching a docking point with predefined or predefinable form. At a Powertrain with multiple branches become multiple occurrences Speed differences between the engine and the branches of the Drive train or between the converter end of the Drive train and the distal ends of the branches of the Drive train reduced.

Claims (8)

1.Control of an engine on a drive train with play or elasticity and / or a hydrodynamic converter between an engine and a drive train with play and / or elasticity, which in the event of a load change with reversal of direction of an engine torque between a phase of decreasing elastic preload in the original Direction of load and a phase with increasing elastic tension in the new load direction undergoes a free-running phase consuming the play in the new load direction, in particular in a motor vehicle and in particular when arranging a two-mass flywheel whose primary mass on the engine side and secondary mass on the drive side with one another with limited rotatability are rotationally elastic connected to one another in relation to one another, wherein
the automatic control limits speed differences occurring during a load change between the engine and the drive train or between the converter-side end and the converter-far end of the drive train before consuming the play or the elasticity and
in the case of a transition from an overrun mode to a train mode, the speed increase of the engine in the freewheeling phase is initially permitted for a waiting time and is then delayed or reduced during an intervention time,
according to claim 2 of the main patent 101 04 372
characterized by
that the waiting time t ₁ and the intervention time t ₂ are dependent
from an overall angle ϕ _GES = S + E resulting from play S and / or elastic deformation E,
the angular velocity of the primary side at the end of overrun operation ω ₀ ,
the angular velocity of the secondary side in the docking time ω _ν ,
the acceleration capacity of engine _B ,
the braking capacity of the engine _D and / or
the speed of actuation of a power actuator
be determined. 2. Control according to claim 1, characterized in that the waiting time over
and the intervention time over
be determined. 3. Control according to claim 1 or 2, characterized, that during the intervention period a reduction in the Engine torque via an ignition intervention and / or a The throttle valve position is changed. 4. Control according to one of claims 1 to 3, characterized, that as the trigger event for the start of the waiting time, the Existence of a push operation and a limit value of one Modification of a power control element is used.   5. Control according to one of claims 1 to 4, characterized, that the intervention only takes place if the change of the Power control element and / or the rate of change of the power control element is above a limit value. 6. Control according to one of claims 1 to 5, characterized, that in addition to the waiting time, one of the change areas speed of the power control-dependent additive waiting time is determined by which after the waiting time the intervention is delayed. 7. Control according to one of claims 1 to 6, characterized in that the acceleration capacity of the motor _B and / or the braking capacity of the motor _{D are determined} via a map. 8. Control according to one of claims 1 to 7, characterized, that after the waiting and deployment time and / or when reached of the docking point the drive torque is ramped or with linear, curved or stair-shaped rise enlarged becomes.