FR2790037A1 - METHOD AND DEVICE FOR CONTROLLING A MOTOR VEHICLE - Google Patents

Abstract

A method and device for controlling a vehicle, comprising a first system for controlling the amount of fuel metered into an internal combustion engine for driving the vehicle, a second system for controlling the amount of air, which is supplied to the combustion engine internal, a torque magnitude being increased when connecting an auxiliary drive mechanism. Means are provided which increase the quantity of fuel in a delayed manner relative to the quantity of air.

Description

STATE OF THE ART The invention relates to a method and a device

  to order a motor vehicle.

  A method and a device for controlling a vehicle

  hicule are known. Usually these have a first system, used to control the amount of metered fuel for the internal combustion engine, and a second system used to control the amount of air that is supplied to the internal combustion engine. When an auxiliary drive mechanism, such as that of an air conditioning system, is connected, an intervention is produced which increases the torque of the internal combustion engine. This intervention

  can for example increase the amount of fuel to be injected

ter, or increase the desired torque.

  In the case of such a system, when the desire has been detected for the compressor of the air conditioning installation to start, an additional quantity is superimposed on the quantity desired by the driver. This increase in

  fuel only takes place when this is above

  torized taking into account the highest authorized quantities of fuel, in particular taking into account

  consider exhaust emissions. Liberation

  the ensuing electrical compressor from the installation

  air conditioning takes place with a slight delay, so that

  the internal combustion engine can supply the additional torque

  required. As the flow of additional torque, made available by the engine, and the flow of torque

  actually received by the compressor do not coincide exactly

  Over time, there is a fluctuation in the propulsion torque. In this way we can detect during the

  compressor connection suddenly in the vehicle running

cule. Subject of the invention

  The subject of the invention is a method and an arrangement

  to order a vehicle, to minimize fluctuations

  undesirable reactions in the propulsion torque. This problem is solved in that the amount of fuel is increased

  delayed compared to the amount of air.

Advantages of the invention

  As the amount of fuel increases

  delay with respect to the amount of air, you can

  Minimize, in the case of the operating mode according to the invention, fluctuations in the propulsion torque

  when connecting auxiliary drive mechanisms.

  It is particularly advantageous when connecting

  an auxiliary drive mechanism, increase the amount of air and increase the amount of fuel to

  inject after the expiration of a waiting time after the increase

  the amount of air. We get a realization

  simple using to control the amount of air a pre-

  first quantity (MDRO) which is formed by starting from a desired torque and an output signal from an idle regulator and / or by using to control the quantity of fuel a second quantity (MDA) which is formed by starting a desired torque of the idle governor output signal, and a first limitation value (smoke characteristic field).

  There is a significant reduction in fluctua-

  the propulsion torque by being able to predefine the

  waiting time in such a way that it takes into consideration

  ration the dead time of the second system used to control

the amount of air.

  To implement the method, the invention pre-

  sees a device for controlling a vehicle, comprising a first system for controlling the quantity of fuel which is dosed in an internal combustion engine to drive the vehicle, a second system for controlling the quantity of air, which is supplied to the engine with internal combustion, a magnitude of torque being increased when an auxiliary drive mechanism is connected, characterized in that means are provided which increase the quantity of fuel of

  delayed way compared to the amount of air.

  Drawings The present invention will be described below in more detail on the basis of several exemplary embodiments, represented in the appended drawings, in which: - Figure 1 shows a block diagram of the device according to the invention, - Figures 2 and 3 show different signals carried as a function of time, and FIG. 4 shows a schematic diagram of the method

lon the invention.

  Description of the exemplary embodiments

  In Figure 1 there is shown the device se-

  lon the invention used to control a vehicle, from a block diagram. The operating mode according to the invention is described in the following, taking as an example an internal combustion engine of the Diesel type, which

  includes as auxiliary drive mechanism a

  air conditioning installation presser. However, the operating mode according to the invention can also be used in the case of other internal combustion engines, in particular

  in the case of internal combustion engines with spark ignition

  tan and direct injection. In addition we can also use it

  be in the case of other auxiliary drive mechanisms or when increasing the torque desired by

  following other comings. Such driving mechanisms

  n additionally are for example a generator which can be ordered or the desire, as regards a quantity, of another control unit such as for example an order

gearbox.

  In Figure 1 is designated by 100 a first system for controlling the amount of fuel, which is dosed for an internal combustion engine not shown. A second system has been designated by 110 which is used to control the

  quantity of air, which is dosed for the internal combustion engine

  dull. The two systems form control signals for different adjustment members, not shown. The first system used to control the injection of fuel 100

  controls for example a solenoid valve or a piezo element

  electric adjustment, which controls the injection. In particular

  linking the first system controls the start of the injection, the duration of the injection and / or the course of the injection by

  a corresponding preset of a correct control signal

  corresponding for the adjustment element. The second system used to control the quantity of air controls in particular a throttle valve, a gas recycling valve

  exhaust and / or a compressor.

  Both the first control system 100 and the second control system 110 are requested by

  signals from a conversion. The 120 conversion requested

  quotes the first control system 100 and the second system

  control tem 110 by an MEA signal, which corresponds to the

  current amount of fuel to inject. Furthermore the con-

  version 120 uses the first control system 100 with a setpoint quantity MES for the quantity of fuel to be injected, and it also controls the second system 110

  for a gross MERO quantity of fuel to be injected.

  We bring to the conversion 120 signals relating to

  the torque, which includes a target torque quantity MDS, a current torque signal MDA and a signal

  MDRO, which corresponds to the gross torque. These signals are prepa-

res by different components.

  A predefinition of the FP 130 torque delivers a

  general MDW for the desired propulsion torque at first

  entry of a first combination point 140. On this combination point 140 there is also the output signal MDL which corresponds to the desired torque of an idle speed regulator 131. In addition the output signal MDK of a control 132 of an auxiliary drive mechanism is about to

  connection 140. The output signal of connection point 140 ar-

  shore on the one hand to a first minimum selector 150 and on the other hand to a second combination point 142. On the second

  Combination point 142 is additionally the exit signal

  tie MDKV of the auxiliary drive mechanism control

  132. The output signal 142 which corresponds to the signal

  MDRO with regard to the gross torque, arrives at the conver-

sion 120.

  On the second entry of the first selection

  minimum 150 is the MDR output signal of a field

  smoke characteristic 133. The output signal MDR of the smoke characteristic field also arrives at a third combination point 164, on the second input of which there is an output signal from a block 160. The output signal from the

  combination point 164 arrives at a second selection mid

nimal 155.

  The output signal of the first selection mid-

  150 which is designated by MDA, and which corresponds to the

  current ple, arrives at conversion 120. In addition, the MDA signal arrives at a second combination point 144, at the input of which is applied the output signal MDAR of a walking stability regulator 134. The output signal of the second

  combination point 144 also arrives at the second selection

  minimum level 155. At the second minimum selector 155 there also arrives the output signal MDG of a motor protection 135,

  which can also be designated as terminal regulation.

  Block 160 only prepares an applicable quantity

  corn. The technical background lies in the fact that the li-

  smoke mite is raised by means of combination point 146, to allow the stability regulator 134 to have a positive adjustment zone above the limit

MDR smoke.

  This system works as follows: the

  desired MDW propulsion torque is predefined by the preset

  nition of torque 130. This predefinition of torque 130 pre-

  defines the desired drive torque according to the driver's wish. The driver's wish is preferably predefined by an FP accelerator pedal or by a part

  operating a speed regulator.

  For the desired propulsion torque MDW we move

  in combination point 140 the MDL pair, which predefi-

  nit idle regulator 131. In this case it is the

  MDL torque which is necessary to adjust the rotational speed

  idling. In addition we add to the point of combination

  a MDK correction torque which is necessary to provide

  define the torque drawn by the additional auxiliary actuation mechanisms. In the case of such additional auxiliary drive mechanisms it is for example an air conditioning installation. In addition, an MDV correction torque can be added to the combination point 140 which is necessary to compensate for the losses of the internal combustion engine. These are in particular losses

  which are caused by friction. This correction value

  tion MDV is supplied by a block 136.

  The couple thus formed arrives at the first selection

  minimum tion 150, in which it is combined with the if-

  general output smoke characteristic field MDR 133.

  In this case, the smaller of the two signals is selected.

  This means that the torque, which is applied at the output of the combination point 140, is limited to the authorized MDR torque

  to the maximum which is provided by the characteristic field of fu-

  133. The output signal from the combination point 140 cor-

  corresponds to the gross torque MDRO which corresponds to the desired propulsion torque MDW, the propulsion torque MDW being corrected with the output signal from the idle speed regulator 131 and the

  input mechanism control 132 output MDK

auxiliary drive.

  The output signal of the first selection mid-

  nimal 150 is brought as current MDA couple to conversion 120. In the case of this current MDA couple it is a

  greatness that is necessary, to realize the wish of the con-

  conductor and idling speed, auxiliary drive mechanisms being taken into account and the torque being limited to a first limiting value. The first limitation value corresponds in the embodiment shown to the MDR torque authorized at the maximum of

  smoke characteristic field 133.

  Starting from this current MDA couple the conversion

  calculates the current amount of MEA fuel to be injected.

  This current torque MDA is not modified by the idle regulator 134 and by the engine protection 135. This value is used to calculate the start of injection, because the

  regulation of the start of the injection cannot follow the

  rapid changes in the setpoint by the regulator

134 of walking stability.

  The output signal of the combination point 140, where only the desired drive torque MDW is combined

  and the idle speed regulator output signal MDL 131, ar-

  further shore at a combination point 142, where it is combined

  born with the propulsion torque MDKV. This signal thus formed MDRO, which is located at the output of the combination point 142, is substantially obtained by the addition of the inputs coming from the desired propulsion torque MDW, which is used for the propulsion of the internal combustion engine, and from the torque MDL, which is necessary to maintain the idle speed. Starting from this value which is not affected by any limit value or by any rapid adjustment device, the conversion 120 calculates a gross quantity MERO. This gross quantity and in this way the gross torque MDRO are used to control the components in the system 110 which is used to control the quantity of air. The components of the system not shown used to control the amount of air

  are the regulation of the supply pressure and / or the

exhaust gas cycling.

  According to the invention, the MDKV bypass torque is added to this gross torque MDRO. This correction of the MDRO gross torque does not introduce any modification of the quantity of fuel injected, and in this way of the torque delivered by the internal combustion engine. Only the

  system regulators which is used to control the quanti-

  air tees are controlled more strongly. By this measure, the system is directly before the occurrence of a jump in the current torque due to the MDK value when connecting an auxiliary drive mechanism, taken from the optimal operating point of emission of so that the required jump can be performed quickly and optimally

  with the excess oxygen already prevailing.

  The output signal of the combination point 144

  is supplied at the same time as the output signal of the protection

  135 of the motor and the output signal from the character field

  smoke probability 133 to a second minimum selection 155, which provides the set value for the set torque

  MDS. This setpoint is converted in the conversion

  120 in the MES set quantity, which indicates the quantity

tity of fuel to be injected.

  In FIG. 2, various signals have been plotted as a function of time t. In partial figure 2a, the output torque of the AMD motor has been plotted in a solid line and the propulsion torque MD in a dashed line. In the partial figure 2b we have carried the torque that the

  compressor of the air conditioning system, which corresponds

  responds to the MDK signal. In the partial figure 2c, the signal K has been carried, the high level of which indicates that the compressor

  the air conditioning system is connected.

  At the instant tl the signal K rises to its great value

  their, that is to say that the compressor of the air conditioning system is connected. During the usual increases

  of the desired torque when adding the connection of an installation

  air conditioning lation the AMD output torque of the engine

  slowly increases from time tl. At the same time the signal MDK increases in the form of a jump and falls to an increased value compared to the time interval before the instant t1. This has the consequence that at an instant which is clearly after the instant t1, the output torque of the motor AMD has increased and the propulsion torque MD is at its

old value.

  Upon detection of the desire to switch on the compressor of the air conditioning system at time tl, after a successful test, a superimposition is issued

  possible quantity desired by the driver, which corresponds

  ponders the desired MDW propulsion torque, the desire for

  additional quantity corresponding to the MDK signal. Of the-

  rolling over time of this additional torque MDK is oriented towards the reception by the compressor of a measurable torque. Preferably this signal is a function of the pressure prevailing in the compressor. Absolute contributions

  in this case, quantities are determined empirically.

  The electrical release of the compressor from the

  air conditioning takes place slightly delayed

  designed so that the engine can supply the required additional torque. As the torque which is supplied by the engine by the passage of the quantity and since the actual reception of the compressor does not coincide exactly in time, it

  produced from the resulting torque, already under conditions

  static, a fluctuation in the propulsion torque MD. In this way a jerk is detectable in the

  vehicle when the compressor is connected.

  According to the invention, it has been observed that during the sudden increase in the quantity injected, a corresponding increase in the quantity of oxygen also forms part of the

  combustion process. In static operation the mo-

  modern sources are predominantly at an operating point which is optimal for emissions, so that when there is an excess of oxygen, exhaust gases are recycled to maintain the value

  resulting lambda in an area of optimal value.

  The constituent mechanical parts for regulating

  the amount of air supports inertia, which does not

  do not make sudden changes in the amount of oxygen or fresh air. According to the invention it is consequently planned to add with the gross value MDRO of the couple a derived value MDKV. Thanks to this correction, there is no variation in the torque MD delivered by the motor. Only

  the neutral air system adjusters are controlled

more strongly.

  This is shown in Figure 3. In Figure 3 the corresponding signals are plotted as in Figure 2 with corresponding lines. In addition, the partial torque MDKV has been drawn in the partial figure 2b under the

  form of a line in dots and dashes. The command 132 of me-

  auxiliary drive mechanism determines when activating

  The compressor in the air conditioning system develops the torque that should be expected based on the current operating conditions, in particular the pressure in the compressor. In this case, we can determine

  by measuring the correct reproduction over time of the

  torque rotation during application. Electrical release of the compressor and connection of the desired torque

  MDK are delayed by a TS time by command 132 of the mechanism

  auxiliary training, TS time required by the

  air system to adjust the new optimal conditions.

  Directly with the occurrence of signal K the drift torque

  vation MDKV is added to the gross value MDRO, so that the motor control can prepare the

air system.

  FIG. 4 shows a corresponding diagram.

  laying of the method according to the invention. We check by a pre-

  first interrogation 400 if the signal K exists, signal which indicates an actuation of the compressor of the installation of

  air conditioner. If this is not the case, a step 400 is carried out.

  rolls again. If there is a corresponding signal, this is the case at time tl, the preset value MDKV is then delivered in step 410. This value corresponds to the value

  maximum MDK torque required by the compressor of the

air conditioning system.

  In the next step 420, a time counter is set to zero. Then the time counter is increased in step 430. By the interrogation 440 it is checked whether the content of the time counter is greater than a value TS. If this is not the case, the MDK signal is then delivered in step 450. The threshold value TS corresponds to the waiting time, the magnitude MDK of which is delayed with respect to the appearance of the signal K.

  This means that if the compressor in the installation

  air conditioning or another auxiliary drive mechanism must be connected, the amount of air is first increased and after a TS waiting time the amount of fuel to be injected is increased. The waiting time, until

  the torque or the quantity of fuel to be injected is increased

  tee, is predefined so that the waiting time takes into account the dead time of the system used to

control the amount of air.

1l

Claims (4)

CLAIMS S) A method for controlling a motor vehicle, comprising a first system for controlling the quantity of fuel metered in an internal combustion engine to drive the vehicle, a second system for controlling the quantity of air, which is supplied to the engine at internal combustion, a quantity of torque being increased when an auxiliary drive mechanism is connected, characterized in that the quantity of fuel is increased in a delayed manner relative to the quantity of air.   2) Method according to claim 1, characterized in that when connecting an auxiliary drive mechanism, the amount of air is increased and the amount of fuel to be injected is increased after a waiting time has elapsed   after increasing the amount of air.   3) Method according to claim 1 or 2, characterized in that to control the amount of air using a first quantity (MDRO) which is formed from a desired torque   and an output signal from an idle speed regulator.   4) Method according to one of the preceding claims,   characterized in that to control the quantity of fuel a second quantity (MDA) is used which is formed starting from a desired torque, from the output signal of the idle regulator and from a   first limitation value (characteristic field of fu- mée).    ) Method according to one of the preceding claims,   characterized in that the waiting time can be preset so that it takes into account the dead time of the second system   used to control the amount of air.   6) Device for controlling a vehicle, comprising a pre-   mier system to control the quantity of fuel dosed   in an internal combustion engine to drive the vehicle   cule, a second system for controlling the quantity of air, which is supplied to the internal combustion engine, a magnitude of torque being increased when connecting an auxiliary drive mechanism, characterized in that means are provided which increase the amount of fuel   0 delayed compared to the amount of air.