FR2658245A1 - METHOD AND DEVICE FOR CONTROLLING THE ELECTROMAGNETIC VALVE OF A FUEL PUMP. - Google Patents

Abstract

a) Method for controlling the electromagnetic valve of a fuel pump, b) characterized in that when calculating the control instant and the end of control instant, the switching times (TA , TE) of the electromagnetically actuated valve (20) and device for controlling the electromagnetic valve in which means are provided which, when calculating the control instants and the end of control, take into account the switching times (TA, TE) of the electromagnetically actuated valve (20). c) The invention relates to methods and devices for controlling the electromagnetic valves of fuel pumps.

Description

"Method and device for controlling the electric valve

  tromagnetic fuel pump "

  The invention relates to a method for controlling

  der the electromagnetic valve of a fuel pump

  with an electronic control device, which

  depending on the characteristic quantities of the function-

  ment, determines the desired start of repression and the desired duration of repression, and from

  these data, calculates the moment of control and the in-

  end of command for the electromagnetically actuated valve The invention also relates to

  a device for implementing the method.

  Such a device is known from SAE Paper 85 05 42. In this document, a control device for a fuel pump is described.

  in which an electronic control unit,

  through a terminal stage of

  power, an electrically actuated valve

  at the pump The control unit determines, in

  function of the operating state of the engine with

  internal combustion, the desired instants for the start of the discharge and the end of the discharge of the fuel pump From these desired times, the control unit calculates the control time for the stage

  power terminal, so that the electric valve

  the magnetic pump takes a position such that the fuel pump discharges the fuel, or puts an end to the discharge In this case, the control pulse takes place a certain time before the desired instant at which the electromagnetic valve is to be actuated.

  way the fuel is repressed.

  For various reasons, such as, for example, manufacturing tolerances or hydraulic effects, temperature effects, changes in the electromagnetic valve or the control circuit, switching times of the

  electromagnetic valve are subject to

  The actual start of refoulement and the duration of

  actual practice of repression or the end of repression.

  differ more or less strongly from the values

  The result is that the differences are not

  of the beginning of the injection and the quantity

  injected in relation to the desired values.

  The object of the invention is to compensate in a process and in a device of the type initially mentioned, the dispersions to which the

  switching time of the electromagnetic valve.

  In this way, the actual start of the refusal

  and the actual duration of the discharge, or the actual end of the discharge, no longer deviate from the predefined values For this purpose, the method according to the invention is characterized in that when calculating the control time and the end of the order, the switching times are taken into account

  of the electromagnetically operated valve.

  The process according to the invention and the

  corresponding positive effect, have the advantage that the switching times of the electromagnetic valve are taken into account, and that simultaneously the influence of these switching times and their dispersion on the start of the discharge and the end of the discharge are As a result, there is no longer an undesirable difference in the actual values of the start of the injection and the amount injected relative to the desired values. Other features of the invention make it possible to envisage advantageous forms of

realization of it.

  Thus, according to a characteristic of

  the invention the desired end of the repression is calculated

  according to the actual start of repression, and

  the desired duration of the refoulement.

  According to another characteristic of the invention

  tion, the actual start-up time is calculated

  starting from the actual beginning of the repression.

  According to another characteristic of the invention

  the actual switch-off time is cal-

  from the effective end of repression.

  According to another characteristic of the invention

  respectively calculated switching times

  again the electromagnetic actuated valve-

  are stored and are used for other assays.

  According to another characteristic of the invention

  the switching times of the

  born electromagnetically, are stored in characteristic fields according to size

  characteristics of operation.

  According to another characteristic of the invention

  a weighted value of the switching times

measured is stored.

  According to another characteristic of the invention

  measured switching times are checked for their plausibility with the aid of the

memorized switching times.

  Finally, according to another characteristic of the invention, only the recognized switching times

as plausible are memorized.

  The invention also relates to a device for implementing the method described above, characterized in that means are provided which, when

  computation of the moments of control and end of com-

  request, take into account the switching times of the

  electromagnetically operated valve.

  The invention will be explained in more detail

  hereinafter with the aid of the embodiments

attached drawings.

  Figure 1 schematically shows a dis-

  positive control for a Diesel injection pump controlled by electromagnetic valve, Figure 2 shows the correlation between

  the command times E, A and the desired values

  values and actual values for the beginning of the

  the end of repression and the duration of

  Figures 3 and 4 are sequential diagrams of the operating mode of the controller. Figure 1 shows the control device

  for the fuel pump controlled by electric valve

  tromagnetic energy for diesel engines

  of a fuel pump 10 having a piston

  pump tone 15, fuel is brought to different

  cylinders of internal combustion engines, not shown

  A fuel pump 10 may be associated with each cylinder, or a fuel pump (distributor pump) successively dose the fuel of the different cylinders.

  communication with an electromagnetic valve 20.

  The valve 20 receives switching pulses via a power terminal stage 40 of an electronic control unit 30 which comprises a fixed value memory. A transmitter 70 which is disposed on the electromagnetic valve 20 or on a injection nozzle, not shown, delivers

  signals to the electronic control unit 30

  positive measurement 50 detects the rotational movement of the camshaft 60 of the pump or the crankshaft shaft and delivers a signal corresponding to

  the electronic control unit 30 Other detections

  80, information on additional quantities

  such as the speed of rotation n, the temperature T or the load L (position of the

  accelerator pedal) reach the electronics unit

order number 30.

  The control unit 30 determines, in function

  detection of the quantities detected by the detectors 80 and rotational displacements of the camshaft 60 of the pump or of the crankshaft detected via the measuring device 50, the desired start of the "FBS" discharge. and the duration of

  "FDS" discharge of the fuel pump 10 In par-

  of these set values for the start of the discharge "FBS" and the discharge time "FDS", it then calculates the control instants E and A for the power terminal stage 40 The calculation is carried out so that the valve At the moment "FBI" takes a first position.

  which starts the repression of the pump and the in-

  stant "FEI" a second position 52 in which the

  the fuel pump comes to a stop again

  As a characteristic of the function

  tion, it may be introduced, inter alia,

  or more of the speed of rotation, temperature

  air temperature, lambda value, fuel

  other temperature values, or a

  signal which characterizes the position of the pedal of ac-

  celerator, or the desired speed of travel

  The measuring device 50 essentially picks up a signal which indicates the position of the cam shaft of

  the pump or the crankshaft shaft

  positive measurement 50, it is possible to use, inter alia, an additive indicator, an eddy current indicator, or another indicator of the position of the camshaft of the pump or of the crankshaft.

  The camshaft of the internal combustion engine

  ne, or a tree coupled with it (tree of town-

  brequin) acts as a camshaft of the pump.

  The camshaft of the pump drives the pump piston so that the fuel is pressurized

  in the fuel pump 10 The electromagnetic valve

  20 then orders the establishment of the

  The electromagnetic valve is arranged so that when this valve is open, no significant pressure is established. Only when the

  electromagnetic valve 20 is closed that it

  blows a pressure in the fuel pump

  however, can also be used when the electromagnetic valve is arranged so that a significant pressure build-up does not occur.

  place only when the valve is open.

  For an appropriate pressure in the fuel pump, a valve, not shown, opens and the

  fuel arrives, via the fuel nozzle

  jection, not shown, in the combustion chamber.

  In order to check when the solenoid valve opens or closes, transmitter 70 is used.

  70 can also be attached to the injection nozzle

  and then generates a signal which characterizes the actual start or effective end of the fuel injection into the combustion chamber. Instead of the output signal of the transmitter 70, a signal can also be used which indicates in which position is the electromagnetic valve Such a signal is obtained by exploiting the currents flowing in the

  electromagnetic valve or the voltages

  to this electromagnetic valve.

  Figure 2 shows the time course of the different periods. Figure 2a shows the desired start of the "FBS" discharge and the desired end of the "FES" discharge. The desired duration of the "FDS" discharge is then the time

  between the desired beginning of repression and the end

hated from repression.

  In Figure 2b is indicated the evolution of the

  control signal for the electromagnetic valve.

  From the control instant E until the control end time A, the electromagnetic valve is supplied with current It is assumed that between the control on opening and closing of the electromagnetic valve, the period The control moment at the opening E is consequently at a time interval TE before the

  desired start of the "FBS" discharge.

  it elapses a certain time after the moment

  end of command A until the elec-

  As a consequence, the command end instant A is at a time of

  switch off the TA before the desired end of

"FES".

  In Figure 2c is indicated the position of the

  needle of the electromagnetic valve

  pe takes, during the actual switch-on time "TEI" after the control instant at opening E, the

  If from this position Si, the

  pressure starts in the fuel pump.

  The effective start time "TEI" does not coincide, as a general rule, with the switch-on time TE. Consequently, the instants of the actual start of the "FBI" discharge do not coincide with the desired start of the backflow. "FBS" The same is true for the end of the repression The end time of command A is at the effective time of disconnection "TAI" before the actual end of the repression

  In the normal case, the desired end of the refusal

  and the actual end of the repression also did not

not at the same time.

  Dispersions of switching times

  "TAI", "TEI" staff depend on different parameters

  These are, for example, the manufacturing tolerances, the hydraulic effects, the effects of

  temperature, changes in the electrical valve

  tromagnetic or in the terminal stage of

  In addition, in different operating states,

  the dispersions may be different.

  To compensate for these dispersions, it is pro-

  As shown in Figure 3, it is first provided in step 100 values for

  the switching times TE, TA of the valve

  born electromagnetically These values are deposited

  in a fixed value memory 35 of the electronic unit

  order 30 in the form of constant values

  It is particularly advantageous that the times

  in a characteristic field.

  according to the characteristic quantities of the

  the most important functioning influencing them.

  In the second step 110 the desired instants for the start of the "FBS" discharge and for the duration of the "FDS" discharge are determined in a known manner,

  that is, using characteristic fields.

  The opening control instants E for the electromagnetic valve are located at the time TE of activation of the electromagnetic valve before the desired start of the discharge "FBS".

  actual "FBI" refoulement is detected through

  a transmitter 70 not described in more detail.

  As a transmitter 70, it is possible, for example, to use a known contact indicator or a travel indicator. However, the effective closing of the electromagnetic valve can also be detected. Thanks to a time indicator inside the control unit 30 , the calculation of the effective time of activation "TEI" of the electromagnetic valve is

performed at step 130.

  At step 135 can be connected an interrogation

  This plausibility query

  bility checks whether the effective start time "TEI" has a plausible value The desired instant for the end of the discharge "FES" is then determined at 140 starting from the discharge time "FDS" and the actual start of the discharge "FBI" The desired end of the "FES" discharge is then calculated, for example

according to the formula FES = FBI + FDS.

  Thanks to this way of proceeding, a defect

  in the actual duration of refoulement can be

  Such a defect may arise from an effective start of "FBI" discharge different from the desired start of the "FBS" discharge. If the calculation is performed starting from the desired start of the "FBS" discharge, the discharge time is shortened or decreased. extends when the desired value and the actual value of start of

  refoulement differ from each other.

  In step 145 is then carried out the calculation of the control end time A for the electromagnetically actuated valve This control end time A is at the switch-off time TA of the electromagnetically operated valve before the desired duration. of the "FES" discharge In step 150 the old characteristic field value for the

  switch-on time TE of the electromagnetic valve

  gnetic is replaced by the new value "TEI".

  This only happens when the interrogation

  plausibility acknowledges that the new value is plausible Different strategies can then

  On the one hand, the old value can always be

  days be replaced by the newly calculated value

  If it is replaced by a weighted value

  on several new values.

  Since the transmitter 70 detects the effective end of the "FEI" discharge next to the actual start of the "FBI" discharge, the actual switching time "TAI" can also be measured and used for the following injections. indeed, the method in FIG. 3 must be modified correspondingly to FIG. 4. The steps 110 and of FIG. 3 correspond to FIG. 4 to step 160. At this step 160, step 170 is then connected, in which the effective end of the "FEI" discharge is detected, and in which the effective shut-off time "TAI" of the electromagnetically actuated valve is calculated at step 175 a

  plausibility query can then have equal

  as in Step 135 The non-plausible values

  are rejected and are not memorized or

  they are used for the following dosages

  te, the characteristic field values for the switching times TE, TA are modified at step

180.

he

  These new values find their use

  for the following injections Using the times

  measured switching of the electrically actuated valve

  tromagnetically, the values stored in the characteristic field for the switching times TE, TA of the electromagnetically actuated valve,

  are corrected in a particularly advantageous way

  The old characteristic field values TE, TA are replaced, particularly

  simple, by the new measured times of setting

  cooked or switched off "TEI", "TAI" The former

  ns characteristic field values for switching times, can also be replaced by

  average values established in any form

than.

  A particular advantage of this device is that, in the event of a transmitter failure or in cases of operation where there is no measurement value, the values for

  TE, TA switching of the electro-

  genetically, are taken from the characteristic field.

  teristic. A particularly advantageous embodiment of the invention results from the fact that the measured values for the switching on and off times "TEI", "TAI" of the actuated valve

  electromagnetically, are verified with regard to

  their plausibility by means of the characteristic field values If the measured switching times for the electromagnetically operated valve, and which strongly serves values TE, TA stored in the characteristic fields, they are identified as

  not plausible, and the measured values are rejected.

  Thanks to the plausibility interrogation, faults can be easily recognized and there may be switching on the operation in emergency operation or a fault indication.

can be ordered.

  If several electromagnetic actuated valves

  gnetically are provided for an internal combustion engine, the arrangements described above may be applied individually for each valve

  electromagnetically actuated, or to be applied

  in common for a group of valves or for

  all valves electromagnetically operated.

  It is particularly advantageous when these arrangements

  are applied for each actuated valve

  electromagnetically, because thus dispersions

  different electromagnetic actuated valves

  can be compensated.

Claims (10)

  1. Method for controlling the electric valve   tromagnet (20) of a fuel pump (10), with an electronic control device (30), which, depending on the characteristic quantities of the operation, determines the desired start of the discharge (FBS)   and the desired duration of refoulement (SDS), and in particular   so much of this data, calculates the control time and the end command time (E, A) for the valve   electromagnetically actuated (20), characterized   in that when calculating the command time and the command end time, the switching times (TA, TE) of the valve are taken into account   electromagnetically actuated (20).   The process according to claim 1, wherein   in that the desired end of repression (FES)   calculated on the basis of the actual start of the   (FBI) and the desired duration of refoulement (SDS).   3 Process according to any one of   1 or 2, characterized in that the weather   The activation factor (TEI) is calculated in   both from the actual start of repression (FBI).   4. Process according to any one of   Claims 1 to 3, characterized in that the time   effective switching off (TAI) is calculated in   starting from the effective end of the repression (FEI).   5. Process according to any one of   Claims 1 to 4, characterized in that the times   switching respectively calculated again from the   electromagnetically actuated valve, are stored   and are used for other dosages.   6. Process according to any one of   4 or 5, characterized in that the times   TE, TA switching of the electrically actuated valve   magnetically, are stored in fields that are   characteristics (35) according to characteristic quantities ticks of operation.   7. The method of claim 6, wherein   characterized in that a weighted value of the com- measured mutation is stored.   8. Process according to any one of   Claims 1 to 7, characterized in that the times   measured switching are controlled in   their plausibility by using switching times. memorized.   9. Process according to any one of   claims 1 to 8, characterized in that only the   switching times recognized as plausible, are stored.   A device for controlling the electromagnetic valve (20) of a fuel pump (10), with an electronic control device (30), which determines, according to the characteristic quantities of the operation, the desired start of the discharge (FBS) and the desired duration of discharge (SDS), and calculates from these data, the control instant and the control end time (E, A) for the electromagnetically actuated valve (20), characterized in that means are provided which,   the calculation of the moments of control and the end of com-   specify the switching times (TA, TE) of the electromagnetically actuated valve (20).