FR2728023A1 - METHOD AND DEVICE FOR CONTROLLING AN INTERNAL COMBUSTION ENGINE AND FOR OPTIMIZING ITS IDLE OPERATION - Google Patents

Abstract

a) Method and device for controlling an internal combustion engine and for optimizing its operation at idling b) method and device characterized in that the pre-control and / or the raising of the setpoint can be weighted by means of a factor of F-weighting and in that the weighting coefficient can be predefined as a function of the control deviation.

Description

I

  "Method and device for controlling a combustion engine

  internally and to optimize its functioning at the

  The state of the art The invention relates to a method and a device

  tif to control an internal combustion engine, in part

  In particular, the idling of the internal combustion engine, in which, starting from a comparison between a setpoint and an actual value of the speed of rotation, it is possible to predefine an adjustment deviation and a regulator,

  starting from the predefined adjustment deviation a factor of

  control which is used to actuate a specific adjusting member

  the power, a pre-order and / or an increase of

  the setpoint being provided.

  Such a process and such a device are known

  to control an internal combustion engine by the docu-

  DE-OS 31 30 080 (US-A 4 425 888). In this document it

  is described a method and a device for adjusting the speed

  rotational tess in particular of an internal combustion engine with spontaneous ignition. Depending on the difference between a setpoint and an actual speed value

  of rotation, a regulator determines a regulating factor

  tion which is used to solicit an electromagnetic organ of

  setting, which determines the amount of fuel to inject.

  To prevent the speed of rotation from falling below

  of the speed setpoint, we pre-

  sees the value of con-

  sign for the idle speed when we have

  dyes a determined rotation speed. The amount whose setpoint is increased then decreases as a function of time. In addition, document DE OS 41 12 848 (US-A 5 251 598) discloses a system for regulating the speed of rotation of an internal combustion engine.

  in slow motion. In this case, provision is also made for a regulation

  form, starting from the difference between a value of

  setpoint and an actual value, a signal which is used to

  cite a regulator. In addition, it is planned what

  calls for a pre-order, which influences depending on the

  general rotation speed the output signal from the

  additive adjustment gane. This pre-order is

  connected or disconnected when a certain threshold is reached

born from the speed of rotation.

  The disadvantage in the case of these systems is that the value, for which one activates the pre-order or the

  setpoint increase, is predefined

  fixed lesson. In the case of a variable load of the internal combustion engine, there is a variable behavior of the gas discharge. This means, regardless of which consumer devices

  electricity, such as heating the

  rear net or the air conditioning system, which are plugged in, that the rotation speed drops to a speed

  different or differently far below its value

  their threshold. Consequently, a compromise value must be chosen for the value at which the

  pre-order or raising the threshold value.

Subject of the invention

  The subject of the invention is, in the case of a pro-

  transferred and a device used to control an internal combustion engine of the type mentioned at the start of improving

  the behavior of the internal combustion engine, in particular

  link to optimize its idling and is

  characterized in that the pre-order and / or raising of

  the setpoint can be weighted using a fac-

  weighting of F. Advantages of the invention Thanks to the mode of operation of the invention, it is possible that a behavior will always be established

  favorable when changing to rotational speed

  slow even in the case of different operating conditions

  operation of the internal combustion engine.

  Other advantages of the invention are characteristic

  in that: - the weighting coefficient can be predefined as a function of the adjustment deviation,

  - pre-order and / or increase of the set value

  gne takes place as a function of the speed of rotation, - in the case of the pre-order, the weighting factor F takes in the case of a small adjustment deviation a large value and in the case of large adjustment deviations a small value , - when the setpoint is raised the weighting factor takes in the case of a small adjustment deviation

  a small value and in the case of a large difference in re-

glage a great value.

  Drawings The present invention will be described below in more detail using the embodiments shown in the accompanying drawings in which: - Figure 1 shows a block diagram

  of a control device for an internal combustion engine

dull,

  - Figure 2 shows a detailed representation of the regu-

reader with pre-order,

  - Figure 4 shows a detailed representation of the regulation

  tor with an increase in the set value and, - Figures 3 and 5 show the dependence of a factor of

  F weighting according to the DN deviation of the setting.

  Description of the exemplary embodiments

  The method according to the invention and the device according to the invention will be described below by taking

  for example their application to an internal combustion engine

  dull spontaneous ignition. The invention may, however,

  fold without problems also in the case of other types of internal combustion engines. In this case, the corresponding elements must be changed. Thus, for example, in the case of an internal combustion engine with ignition by external equipment, the throttle valve comes in place of the regulating member which serves to influence the quantity of fuel to be injected. In the case of a

  internal combustion of this type the output signal of the

  lator influences the regulating member 100 which determines the power whereas it is in this case a valve

  strangulation. In addition, we can save some

  some elements or add other elements.

  Figure 1 shows a functional diagram

  block by device of the invention. A regu-

  idle speed generator 14 delivers an output signal UPI, via an addition point 13 and a minimum selection il, to an adjustment member 100 which determines the

  power. Depending on the input signal, this re-

  glage drives the corresponding amount of fuel into the combustion chambers of an internal combustion engine

  spontaneous ignition, not shown. In the case of a mo-

  internal combustion ignition with ignition controlled by an appliance

  external reillage the adjusting member 100 influences the position of the throttle valve or of an adjusting member

  which is used to influence the idle speed.

  A 110 speed detector detects

  detects the effective speed N of the motor

  internal bustion. This rotational speed N comes to a

  limiting characteristic field 12, to a character field

  running behavior 16, at a comparison point 17 as well as at a pre-order 70. At another input of the comparison point 17 is the output signal SN

  a preset 7 of the set value. This pre-

  definition of setpoint 7 predefines a setpoint SN for the idling speed. The

  output signal DN of the comparison point 17 which corresponds to

  spends at the adjustment deviation, arrives at the idle regulator 14. The pre-order 70 produces an output signal

  UD, which arrives with a negative sign at a point of summa-

  tion 15. At the second entry of the summation point 15

  finds the output signal of the characteristic field of com-

  walking behavior 16. At the entrances to the character

  that of walking behavior 16, is the signal of the

  speed 17 as well as the output signal from the

  accelerator pedal position finder 5.

  The output signal of the summation point 15 arrives at the addition point 13. The output signal UPID of the addition point 13 is compared in a minimal selection

  11 to the output signal of the limiting characteristic field

  tion 12. The smaller of the two signals is used to control

  the regulating member 100 which determines the power.

  The device according to the figure then operates as follows. Depending on the difference DN between the output signal SN of the preset value setpoint 7 and the effective speed N, the idle speed regulator calculates an adjustment signal UPI for the adjustment member 100. We subtract of this adjustment signal in the addition point the output signal of the pre-order 70 UD, at the input of which is the effective rotation speed N. This pre-order preferably has a

differentiation behavior.

  If the accelerator pedal is not in action-

  born, this signal predominantly determines the quantity of fuel to be injected. If the accelerator pedal is actuated, the characteristic field of walking behavior 16 produces a signal as a function of the effective speed of rotation N and the position of the accelerator pedal.

  Release. In minimum selection 11 this signal is li-

  set to the highest authorized value, which depends at least on the effective speed of rotation N. Usually, it is expected that the fraction D 70 will only be active when the speed of rotation falls below a value threshold, which is larger

  than the usual idling speed.

  Instead of an organ D, it is also possible to choose a block with a similar mode of transmission. The transmission mode is essentially constituted in such a way that a signal occurs, when the speed of rotation drops sharply, which acts in the opposite direction to the fall of the speed of rotation. When the speed of rotation presents variations of small amounts, a small correction quantity is used and in the case of variations

  large amount involves a large correction.

  The correction variable is only connected when the

  rotation rotation drop. In this way, we manage to prevent the rotation speed from falling below the value

threshold SN.

  It then appeared that in the case of such a system, a different transient mode occurred as a function of the load of the internal combustion engine. This means that the actual value of the speed of rotation N approaches at a speed different from the value of the desired speed of rotation SN. In order to improve this transient mode, we plan to modify the device, such as

represented it in figure 2.

  In Figure 2 we have provided the elements that

  have already been described in FIG. 1, numerical references

  ques corresponding. The DN signal, which corresponds to

  the difference between the setpoint SN and the actual value

  tive N of the speed of rotation, also arrives at a characteristic field 200. The output signal F of this characteristic field 200 arrives at a combination point 210. At the combination point 210 the input signals are preferably combined by multiplying them. The second input variable of this combination point uses the output signal of the pre-order 70. The output signal

  from combination point 210 arrives at addition point 15.

  The mode of transmission of the characteristic field

  that is shown in figure 3. It is not mandatory

  that the block 200 is produced in the form of a cam field

  characteristic. A cor- rect transmitter can also be provided.

  responding with a corresponding mode of transmission. In the case of a small deviation from the DN setting, a factor is obtained which is almost equal to 1. In the case of large deviations from

  setting the factor approaches zero. Befor-

  reference we choose a function F according to the following formula

boasts: IDM F = exp

  Alternatively, you can also choose a function

  transmission according to the following formula: const F = const + IDNI

  The first function is usually desi-

  generated as an exponential function and the second function

  tion as a hyperbolic function. In the case of large-

  const dors these are constants. In the case of the va-

  their DN is the adjustment deviation which corresponds to the difference between the setpoint value SN and the actual value N of the speed of rotation. This transmitter 200 ensures that the output signal of the pre-order 70 is weighted in the case of large deviations from the setting DN with respect to the value 0. This

  has the consequence that the pre-order 70 is not operational

  tional in the case of large adjustment deviations. In the case of small deviations from the DN setting, however, the weighting factor almost takes the value 1. This has the effect that the pre-order is fully operational in the

  case of small adjustment deviations. The transition from a pre-

  order which is not operational and a pre-order which is fully operational is done little by little. Thanks to the fact that the pre-order is weighted using a

  function F, which weights the output quantity of the precom-

  demands all the more strongly as the adjustment deviation DN is

  smaller, we can have a weak start of the precom-

  order. Thanks to this operating mode we have almost

  days the same transient mode regardless of the charge

of the internal combustion engine.

  Instead of the pre-order 70, it is also possible to provide that, as in the case of document DE-OS 31 30 080, the setpoint value SN is raised accordingly. Correspondingly to the weighting of the pre-order can

  also take place a weighting of this increase in the

  their speed of rotation SN, the operating mode

  ment of the transmitter 200 being inverted, that is to say that it is a large weighting factor which acts in the case

  a large adjustment deviation and a small weighting factor

  tion which acts in the event of a small adjustment deviation.

  An embodiment corresponding to FIG. 4 has been shown. The corresponding elements have again been provided with the same reference numbers. In the case of

  this embodiment the pre-order 70 is lacking.

  The preset value 7 is completed

  by blocks 220 and 200. In block 7 the deposit was made

  their usual set point SN of the rotation speed of

  slowed down in a way that corresponds to that of the document DE-

OS 31 30 080.

  Block 220 forms the value AN, whose speed

  setpoint rotation must be noted. The difference in re-

  glage DN is sent to a transmitter 200, which presents the

  transmission mode which corresponds to that of FIG. 5.

  The transmitter 200 acts on a combination point 215 which corresponds to the combination point 210 in FIG. 2 with its output signal. On the second input of the combination point 215 is the output signal of the block 220. The output signal of the combination point 215 is

  routed to addition point 225, at the second entry from the

  what is the output signal of the preset value setpoint 7. When the point output signal

  225 combination point 17 is requested

  you. The predefined setpoint 7 predefines the setpoint SN as in FIG. 1 as a function of different operating parameters, such as for example the engine temperature. This value is added to the output value of raising the setpoint value 220 modified by the weighting coefficient F. In the case of large adjustment deviations, the value whose setpoint value SN is raised is almost equal to AN. In the case of a small value this value tends to zero.

R E V E N D I CATIONS

  1) Method for controlling a combustion engine

  internal operation, in particular the idling of the combustion engine

  internal tion, in which, starting from a comparison between a setpoint and an actual value of the speed of rotation, it is possible to preset a control deviation and a regulator, starting from the set deviation predefines a factor of regulation which is used to actuate a regulating member determining the power, a pre-order and / or an increase in the set value being provided, a process characterized in that the pre-order and / or the increase in

  the setpoint can be weighted using a fac-

weighting F.

  2) Method according to claim 1, character-

  se in that the weighting coefficient can be predefined

  finished according to the adjustment deviation.

  3) Method according to claim 1 or 2, ca-

  characterized in that the pre-order and / or raising of the set value takes place as a function of the speed of

rotation.

  4) Method according to one of the pre- claims

  cédentes, characterized in that in the case of the precom-

  the weighting factor (F) takes a large value in the case of a small adjustment deviation and in the case of

  large adjustment deviations a small value.

  ) Method according to one of claims 1 to

  3, characterized in that when the setpoint is raised the weighting factor takes a small value in the case of a small adjustment deviation and in the case

  a large adjustment deviation a large value.

  6) Method according to one of claims pre-

  cédentes, characterized in that we have for the weighting factor (F) the relation: IDNI F = exp on Il in which it is for const of a constant quantity

  and in the case of DN of the adjustment deviation.

  7) Method according to one of claims pre-

  cédentes, characterized in that we have for the weighting factor (F) the relation: const F = const + DI in which for const it is a constant quantity

  and in the case of DN of the adjustment deviation.

  - 8) Device for controlling a motor with

  internal bustion, in particular the idling of the

  internal bustion, with means which, starting from a comparison between a set value and a real value of the speed of rotation, predefined a control deviation, a regulator which, starting from the adjustment deviation, predefined a regulating factor which served to actuate a regulating member which determines the power, by providing

  a pre-order and / or an increase in the set value

  gene, device characterized in that the pre-order and / or the increase in the set value are weighted at

  using a weighting factor (F).