FR2693765A1 - Control system for the metering of fuel of an internal combustion engine. - Google Patents

Abstract

a) Control system for metering the fuel of an internal combustion engine, b) system characterized in that the means for triggering the acceleration enrichment are capable of being influenced in a complementary manner by the speed (v) the vehicle. c) The invention relates to control systems for metering the fuel of internal combustion engines.

Description

"Control system for the metering of fuel of a combustion engine

  The invention is based on a control system for the metering of the fuel of an internal combustion engine according to operating characteristics such as the speed of rotation, the load and the temperature, as well as a desire for acceleration, with means for determining a fuel metering signal from the signals of the characteristic quantities of the operation, with means for perceiving the demand

  acceleration, means for triggering acceleration enrichment, and means for controlling an additional amount of fuel to be metered.

  It is known that for the metering of fuel in an internal combustion engine, a quantity

  A fuel injection called acceleration enrichment is injected. When the throttle valve, for a constant speed of rotation, opens suddenly according to the desired acceleration, the

  Air-fuel mixture is depleted for a short time. Higher fuel enrichment is therefore necessary to obtain a good transition behavior. The control unit recognizes

  is born from the modification of the load signal,

  so for example from the modification of the year

  throttle valve, if there is a process

  acceleration and it triggers, in this case, an enir-

speed of acceleration.

  As during the warm-up phase during

  that the engine is cold, further enrichment of acceleration is necessary only when the engine

  is hot, in a known injection system with

  acceleration richness, the engine temperature is detected using a temperature detector and

  this is taken into account for accelerating enrichment.

  In this way, a temperature-dependent enrichment factor is formed, so that in the case of a cold engine, more enrichment is obtained.

  important for a hot engine, which is necessary

  because for a cold engine, the gas-air mixture

is less well prepared.

  Such enhancement of acceleration is for example described on page 29 in the document "Bosch,

  Technische Unterrichtung, Kombiniertes Zind und Ben-

zineinspritzsystem Motronic ".

  The acceleration enrichment known is, according to the invention, furthermore improved in that during the acceleration enrichment, it is in

  supplement taken into account the speed of the vehicle

  dragged by the internal combustion engine.

  As the signal indicating the speed of the vehicle is usually present in the control unit anyway, an exploitation of this speed signal in correlation with the enrichment

  acceleration, is possible without problems and without

  thought. It is particularly advantageous that

  different enhancements of acceleration are pos-

  for the case of stopping the vehicle and for the case of a speed of the vehicle which is above a

  threshold that can be predefined.

  acceleration richnesses can be achieved in that, when a running state is recognized, due to the exceeding of a determined threshold, depending for example on the speed of change of the angle of the

  throttle valve, an accelerator enrichment

  when a stopping of the vehicle is

  it is detected, it is only above a threshold of

  speed of modification of the angle of the check valve

  higher than an accelerator enrichment

tion is performed.

  Thanks to these provisions, we are certain that when we pass a high speed, there is no impoverishment of the mixture, even if we give the gases

  At the same time, if there is a desire to accelerate

  ration, when the load is zero, the mixture is not too enriched and it is thus guaranteed that even in the latter case, there are no values unnecessarily

high exhaust gas.

  The invention is shown in the accompanying drawings and will be explained in more detail in the

description below.

  Figure 1 shows schematically the

  essential parts of the communication system

  For the determination of fuel, Figure 2 is a block diagram

  specifies conditions for triggering the

  acceleration richness according to the invention.

  In Figure 1 is indicated a diagram by

  blocks of a control system for the determination of

  of an internal combustion engine, which

  a vehicle, not shown In this diagram, the

  control wheel is indicated by 10, the cylinder head of the internal combustion engine by 11 and the tubing

  suction and exhaust pipe by 12 and 13.

  The control apparatus 10 is connected to a plurality of detectors which measure the quantities necessary for the control of the internal combustion engine. Let us mention, by way of example: 14: throttle valve detector for the measurement of the angle of the throttle valve,: air quantity measurement, 16: rotation speed sensor, 17: lambda sensor 18: speed measurement (tachometer) to measure the speed v of the vehicle 19: temperature sensor 'air,

  20: Engine temperature sensor.

  The detectors mentioned which may,

  other detectors, provide the control unit with the necessary data for the control. In addition, the

  start-up designated by 21 is also brought to the

control order.

  The detectors mentioned must not all be present, for example, the measurement of the quantity of air can be suppressed when the quantity of air is determined empirically from the angle a of the flap. strangulation and

the speed of rotation n.

  Injection or ignition signals prepared

  res by the control unit are represented by 22

  and 23 The control apparatus comprises beside the

  usual positive calculation, also memory means 24 in which are deposited different characteristic quantities or different characteristic fields and in which the measured data

  or calculated may be listed.

  From the detector signals used

  the control unit 10 recognizes the current state of operation of the internal combustion engine and produces appropriate injection and ignition signals.

  the control apparatus 10, if there is a desire to accelerate

  ration for a constant speed of rotation

  and if, eventually, an accelerating enrichment

  tion and therefore, if a more

high, is necessary.

  If an enrichment of acceleration is born

  necessary, we finally detect, as in the systems

  my current checks, if the speed of change

  angle of the throttle valve exceeds one

  threshold value This threshold value must be suf-

  low for example, when you go from a high speed, it does not happen

  too much impoverishment of the fuel mixture-

  air, even if the gases are given slowly.

  In the case of a request for acceleration, while the vehicle is stationary, an enrichment

  acceleration can quickly lead to an enrichment

  important effect of the mixture which results in a clear alteration of the exhaust gases.

  advantage of not proceeding with an ener-

  acceleration every time the opening of the throttle valve increases slightly, and at this

  effect, the threshold value for the speed of change

  angle of the throttle valve when

  exceedance, must perform the accelerated enrichment

  ration, and be high enough not to

  all too often, an accelerated enrichment

  In order to optimally satisfy these requirements,

  these contraries, the method according to the invention is

indicated in Figure 2.

  In FIG. 2, the process according to the invention

  tion for acceleration enrichment is

  in the form of a block diagram in

  which is only indicated the part of the enrichment

  The acceleration differential which differs from the known methods After the introduction of the acceleration enrichment at the end of the process according to FIG. 2, the higher dosage of the fuel used in the case

  of a necessary enrichment of acceleration, is de-

completed.

  In the case of the process represented on the

  In FIG. 2, the acceleration enrichment is set as a function of the speed of a vehicle driven by an internal combustion engine. In this case, it is verified, in a first step S 1 in the control apparatus, in which there are present the necessary data delivered by different detectors, if the engine temperature, which is determined using a detector

  engine temperature, has exceeded a threshold

  predefined, for example 500 C. If it is found in step 51 that this temperature threshold is exceeded, it is checked in step 52 if the speed v of the vehicle determined by the speed detector, for example, a tachometer has or has not exceeded a predefined limit value v G This predefined limit value v G may, for example, be the speed 0, but it may also be used as a limit value, a speed from 4 km / h At step 52, it is finally checked

  if the vehicle is stationary or is running, for reasons

  then produce accelerations of different acceleration

  ent. If we see in step 52 that the speed

  is equal to 0, or that the speed is

  below the limit value of for example 4 km / h, the

  triggering characteristic field of the enrichment

  stored acceleration in the communication device

  command, is activated at a step 53 for v = 0.

  If it is found in step If the temperature threshold of the engine TG is not exceeded, or if it is found in step 52 that the speed is

  above the predefined limit value, the field

  feature of triggering enrichment

  acceleration is activated in step 54 for v + 0.

  Immediate activation of the characteristic field

  trigger for accelerating enrichment

  for v $ O is done without checking the speed

  of the vehicle, because when the engine is cold, an engine

  acceleration is good already for low acceleration leaps, and therefore for an engine

  cold, a low trigger for enrichment

  acceleration is necessary.

  According to whether the triggering characteristic field of the acceleration enrichment is activated, therefore, depending on whether the step 53 or 54 is carried out, it is checked in step 55 or in step 56

  if the trigger value da / dt which allows the enri-

  acceleration value, is exceeded The trigger threshold value exceeded in step 55 and the trip threshold value

  exceedance of which is verified in step 56, differs

  corresponding requirements,

  they are for example contained in the fields

  characteristics concerning accelerated enrichment

  for v = 0 or v $ 0, or they are

according to these fields.

  The trip threshold value, which is used in the case of a stationary vehicle, or a very low speed (v = 0 or v <4 km / h)

  is higher than the trigger threshold value

  The overrun is checked at step 56 for a speed other than 0. The control unit switches, depending on the operating state, from an acceleration enrichment threshold for the vehicle to the vehicle. stopping at a threshold of enrichment of access

leration for the origin of walking.

  If it is noted in steps 55 or 56, that the trip threshold value for the modification of the angle of the throttle valve is

  not exceeded, it is recognized at step 57 that an en-

  acceleration is not necessary, and, consequently, the acceleration enrichment signal

is not put.

  If it is found in step 55 or 56 that the respective threshold value for the speed of change of the angle of the throttle valve da / dt

  exceeded, it is recognized at step 58 that an enir-

  Acceleration decrease is necessary, and therefore, the acceleration enhancement signal is put Then, is implemented the increase in the amount of fuel achieving acceleration enrichment, and that there is no place to explain here in more detail. Instead of the speed of modification of the throttle valve, one can call on another

  characteristic size to recognize whether an

  acceleration is required, for example changing a TL / dt load signal or

  the modification of the air mass dm Luft / dt.

Claims (7)

R E V E N D I C A T IO N S   1. Control system for dosing the fuel of an internal combustion engine according to   of characteristic quantities of the operation, such   the speed of rotation, the load and the temperature   as a function of a desire to accelerate   tion, with means for the determination of a   a fuel metering system based on the signals of the characteristic quantities of the operation, with means for perceiving the demand for the acceleration, means for triggering an enrichment   acceleration, and means for controlling a quantity   additional fuel quantity to be metered,   characterized in that the means for triggering the acceleration enrichment are likely   to be influenced in a complementary way by the speed (v) of the vehicle.   2. Control system according to the claim   1, characterized in that when the speed of the vehicle increases, the triggering of the enrichment   acceleration becomes more sensitive.   3. Control system according to the claim   2, characterized in that the influence of   of the vehicle on triggering the enrichment   acceleration, is such as during the stopping of the vehicle, or at a speed of the vehicle   is below a speed limit, preferably   below 4 km / h, a first trip threshold is provided and for a higher vehicle speed   high, a second trigger point for the de-   clipping of acceleration enrichment.   4. Control system according to the claim   3, characterized in that the first threshold of   Trigger is higher than the second threshold.   5 Control system according to any one   claims 3 or 4, characterized in that   the trigger point or the thresholds   time, are selected according to the time   engine temperatures and are lower for   lower temperatures than for higher temperatures.   6. Control system according to the claim   5, characterized in that for lower temperatures, the second triggering threshold is   1-0 selected regardless of vehicle speed.   7. Control system according to the claim   6, characterized in that for lower temperatures, the second triggering threshold is   identical to the trigger threshold for v $ 0.   -15 8 Control system according to any one   Claims 1 to 7, characterized in that the   triggering depends at least on the rotation speed   tion and / or rate of change of the posi- the throttle valve.   9 Control system according to any one   claims 1 to 8, characterized in that   at least one characteristic field is provided from which, depending on the speed of rotation and / or   the modification of the throttle valve, are   values that determine which changes in the throttle valve are triggered, and these values are corrected   depending on the speed of travel, or are likely to   tible to be extracted according to the speed of market.   10. Control system according to any one   one of claims 1 to 7, characterized in that   the triggering of the acceleration enrichment takes place according to a modification of the signal of load d TL / dt or dm-Luft / dt.