FR2527691A1 - METHOD FOR CONTROLLING CONTROL DEVICES OF INTERNAL COMBUSTION ENGINES IMMEDIATELY AFTER THE END OF A FUEL CUT - Google Patents

Abstract

The invention relates to a method for controlling an internal combustion engine control device using, among the control parameters, values of the pressure prevailing in the intake manifold. ENGINE 1 HAS AN INTAKE PORT 2 IN WHICH A PRESSURE SENSOR 8 MEASURES THE PRESSURE. TO CORRECT THE INADEQUATE VALUE OF THIS PARAMETER IMMEDIATELY AFTER THE END OF A FUEL CUT, THE VALUE OF THE PRESSURE PARAMETER IS MODIFIED, BETWEEN THE END OF THE CUT AND A PREDETERMINED LATER INSTANT, BY A PREDETERMINED QUANTITY.

Description

The present invention relates to a method of

  apparatus for controlling the control devices of internal combustion engines, especially a control method of this type which is designed to nominally change the pressure in the intake manifold which is used as the control parameter of a device engine control system, immediately after the end of a fuel cut-off operation, in order to obtain a control value of the engine control device which is appropriate to the actual state of engine running, so as to improve the characteristics of the engine emission, fuel consumption, etc.

of the motor.

  The prior art, as shown, for example, by the provisional publication of Japanese Patent (KOKAI) No. 57-191426, teaches to interrupt the supply of fuel to an internal combustion engine when the engine is operating in a field.

  operation, for example in a region of death.

  leration, in order to improve the emission characteristic and the engine fuel consumption, as well as to prevent overheating of the exhaust purification means, such as a three-component catalyst, placed in the exhaust pipe

of the motor.

  It is also known that the actual amount of intake air delivered to an internal combustion engine is greater during the normal combustion of the engine than during the run without combustion (this operation will be called simply below vacuum drive, it is that is to say without combustion in the engine), namely that the efficiency-suction of the engine is

  higher during normal combustion than during training.

  This means that, as long as the intake air quantity remains the same, the absolute pressure in the intake manifold is higher during the empty drive.

  of the engine than during normal normal combustion

  when determining various control values

  putting to control the operation of a combustion engine

  internally, for example the amount of fuel to be supplied, the synchrotron

  ignition, the amount of recirculation of the exhaust gas

  and the amount of additional air used to control the idle speed, by means of the absolute pressure in the intake manifold, these control values are determined

  depending on the absolute pressure in the intake manifold

  if we. However, the absolute pressure of the intake manifold that exists immediately after the end of a fuel cut-off operation proves to have a greater value than during the normal combustion operation of the engine Si -ette

  higher absolute pressure of the intake manifold is di-

  applied as a control parameter, for example

  the quantity of fuel to be supplied, it may be the engine an excessive amount of fuel, which deteriorates the emission characteristics, fuel consumption, etc.,

of the motor.

  It is an object of the invention to provide a method for controlling a device for controlling the operation of an internal combustion engine, which method is designed to

  nominally change the measured value of the pressure in the tubu-

  the intake lane serving as a control parameter, a predetermined amount, immediately after completion of a fuel cutoff operation, to obtain a control value of the control device that is appropriate to the actual state of the fuel; motor operation in this case, which improves the emission characteristics and fuel consumption of the engine, as well as its ease

driving.

  The invention proposes a method for controlling

  a control device for an internal combustion engine, in function

  at least one control parameter having values of the pressure in the intake passage measured by a pressure sensor placed in an intake passage of the engine The method according to the invention is distinguished in that it comprises the following operations: (1) detecting whether or not it occurs under the conditions

  engine operation, a transition from a functioning state to

  requiring an interruption of the fuel supply of the engine to an operating state requiring the fuel supply of the engine; (2) altering the value of the pressure in the intake passage that is measured by the pressure sensor by a predetermined amount from the moment immediately following the detection of the transition to the instant when the engine has finished running a predetermined number of races; and (3) applying the thus modified value of the intake passage pressure to control the control device. The above-mentioned pressure sensor may comprise an absolute pressure sensor designed to measure the absolute pressure prevailing in the intake passage, in which case operation (2) above consists in reducing by a predetermined amount the value the absolute pressure measured by this pressure sensor

  absolute in the intake passage.

  Preferably, the predetermined predetermined number of engine strokes is set to one of the following values: (1) the number of engine strokes required for the absolute pressure of the intake passage to fall from a level to producing for the transition quoted above at a level corresponding to the normal engine running after the transition; and (2) the number of engine strokes required for the absolute pressure of the intake passage to begin to fall from a level occurring for the above-mentioned transition to a corresponding level.

  to the market in normal combustion of the engine, after the transition.

  In addition, preferably, the predetermined amount

  referred to above, of which is reduced during the operation (2)

  mentioned above, the measured value of the absolute pressure in the

  admission is fixed at a value corresponding to the difference

  between the value of the absolute pressure of the intake passage occurring for the uncontrolled running of the engine and the value of the absolute pressure of the intake passage occurring for normal engine running, provided that the speed

  motor rotation is the same in these two modes of operation.

  The higher the speed of the motor, the higher the predetermined amount of reduction of the absolute pressure in the intake passage will be set at a high value. According to another aspect of the invention, the operation (2) mentioned above consists in reducing the value of the absolute pressure of the intake passage measured by the pressure sensor.

  absolute, of a predetermined quantity, of the moment immediately

  following the detection of the transition at the moment when all the cylinders of the engine were fueled after

the transition.

  The engine control devices to which the method of the invention can be applied may comprise a fuel injection device which is designed to control the amount of fuel to be supplied to the engine, at least as a function of the absolute pressure. prevailing in the intake passage Preferably, the fuel injection device is adapted to inject fuel successively into the cylinders of the engine

  in synchronism with the production of pulses of an indi-

  a predetermined value of the crankshaft angle of the engine, and the predetermined number of strokes is set to a value at least equal to the number of strokes corresponding to the time required for the fuel injection device to perform a number of strokes.

  injections equal to the number of engine cylinders after a

  in the operating state requiring the power supply

engine fuel.

  The following description, designed as an illustration

  invention aims to provide a better understanding of its features and advantages; it is based on the accompanying drawings, in which: Figure 1 is a block diagram illustrating an example of the set of a fuel supply control device to which the method of the invention can be applied; Fig. 2 is a circuit diagram showing an electric circuit lying within an electronic control unit (ECU) shown in Fig. 1; Figure 3 is a flowchart explaining a way

  to nominally change the value of the pressure prevailing in the tubu-

  lure of admission, immediately after the end of the operation of shutting down the engine fuel; FIG. 4 is a timing diagram showing, by way of example, modifications of the absolute pressure prevailing in the intake manifold as a function of the passage of time, at the moment of a fuel cut-off operation of the engine, and immediately after completion thereof, as well as a way to produce control signals to fuel injection valves for injecting fuel into the engine cylinders; FIG. 5 is a graph showing the relationship between the absolute pressure prevailing in the intake manifold during the engine vacuum drive and during normal combustion operation, and the engine suction efficiency; and FIG. 6 is a view showing a table of the

  relationship between predetermined APBA values, corresponding to

  nominal changes in the absolute pressure prevailing

  in the intake manifold, and the rotational speed of the engine Ne.

  We will now describe the invention so

  detailed with reference to the drawings.

  Referring first to FIG. 1, there is illustrated an example of an assembly of a fuel supply control device for internal combustion engines, to which the invention is to be applied. an internal combustion engine, which may for example be of the four-cylinder type, and to which is connected an inlet passage 2 containing an air shutter 3 An air shutter opening sensor 4 is mounted

  on the air shutter 3 to measure its opening, and it is electric

  connected to an electronic control unit (ECU) 5,

  to provide the latter with an electrical signal indicating the opening

measured shutter.

  A fuel injection valve 6 is placed

  in the inlet passage 2 slightly upstream of an intake valve

  one of the corresponding cylinders of the engine, not shown,

  and between the engine 1 and the air shutter 3, in order to deliver the fuel

  Each of these fuel injection valves 6 is connected to a fuel pump, not shown, and is electrically connected to the ECU 5, so that the opening times of the valves or quantities of fuel injected are controlled by signals produced

by VUCE 5.

  On the other hand, a sensor 8 of absolute pressure

  communicating via a pipe 7 with the interior of the intake passage 2, slightly downstream of the air shutter 3 The absolute pressure sensor 8 is intended to measure the absolute pressure prevailing in the passage of input 2 and applies to the ECU 5 an electrical signal indicating the measured absolute pressure A

  intake air temperature sensor 9 is placed in the pas-

  2, downstream of the absolute pressure sensor 8, and is also connected to the ECU 5 to provide a signal

  electrical indicating the measured temperature for the intake air.

  A temperature sensor 10 of the cooling water

  The motor, which may consist of a thermistor or the like, is mounted on the main body of the motor 1 so as to be recessed in the peripheral wall of a cylinder of the engine internally filled with cooling water. , a signal

  electrical output of the sensor 10 being delivered to VUCE 5.

  An engine speed sensor 11 (hereinafter

  after called "Ne sensor") and a cylinder determination sensor 12 are placed on a camshaft> not shown, of the engine 1 or on its crankshaft, not shown The sensor It is

  intended to produce a pulse for a particular crankshaft angle

  motor crankshaft every time the engine crankshaft has turned 180, that is to say the production of each pulse of a deadhead signal (TDC), while the sensor 12 is intended to produce a impulse for a particular crankshaft angle

  of a particular cylinder of the engine The impulses above indicate

  produced by the sensors 11 and 12 are delivered to the ECU 5.

  A three-component catalyst 14 is placed in the exhaust pipe 13 from the main body of the engine 1 to

  to eliminate the compounds HC, CO and N Ox contained in the exhaust gases.

  An oxygen sensor (called a sensor of 2) is inserted into the exhaust pipe 13 upstream of the three-component catalyst 14 in order to measure the oxygen concentration of the gases.

  exhaust and deliver to VUCE 5 an indi-

  as the measured concentration value.

  Also connected to VUCE 5 is a sensor 16 for measuring atmospheric pressure and a starter switch 17

  used to actuate the starter motor 10, which are respectively

  intended to deliver to VUUCE an electrical signal indicative of the measured atmospheric pressure and an electrical signal indicative of

  the position, use or non-use of the starter.

  The ECU 5 uses the various motor parameter signals delivered to it to determine the operating conditions of the engine, including the conditions giving rise to the engine.

  a fuel cut, as well as to calculate the duration of the

  Valve valve ALL of the fuel injection valves 6 according to the determined operating conditions of the engine using the following equation: TOUT = Ti x K 1 + K 2 (1)

  o Ti represents the basic value of the fuel injection duration

  Injection and fuel injection valves 6 are calculated according to the absolute pressure PBA of the intake passage and the rotation speed Ne of the engine, while K and K represent

1 K 2

  correction coefficients whose values depend on the values of the signals coming from the various sensors mentioned above, namely the air shutter opening sensor 4, the absolute pressure sensor 8 of the intake passage, the sensor 9 temperature of

  the intake air, the temperature sensor 10 of the cooling water

  11, the Ne sensor, the determination sensor 12

  of cylinder, the sensor 15 of 02 the sensor 16 of atmospheric pressure

  and the starter switch 17, these coefficients being calculated by means of predetermined equations, so as to optimize

  start-up facility, emission characteristics, fuel consumption

  fuel consumption, ease of acceleration, etc., of the engine.

  The ECU 5 delivers control signals to the fuel injection valves 6 so as to open the latter with a utilization coefficient corresponding to the duration of opening of the fuel injection valve 6.

  saves ANY calculated as above.

  FIG. 2 represents an electrical circuit belonging to

  1 to the ECU 5 of FIG. 1 L 2 motor feedback signal from the Ne sensor h1 of FIG. 1 is applied to a waveform 501, where its pulse waveform is

  consistent, and is issued to a central processing unit (hereinafter

  after called UCT) 503 as a PIH signal, as well as a counter 502 of value Me The counter 502 of value Me counts the lapse of time between a previous pulse of the rotational speed signal of the engine produced for a predetermined crankshaft angle of the engine and a pulse present of the same signal produced for the predetermined crankshaft angle, these signals being delivered to it by the sensor 11 of Ne, so that the value of Me counted by the counter corresponds to the inverse of the actual rotational speed Motor No. The Me value counter 502 delivers the Me value counted to the CPU 503 via a bus line

510 of data.

  The respective output signals of the sensor 4 of

  air shutter opening, absolute passage pressure sensor 8

  PBA, the temperature sensor 10 of the cooling water

  motor, all these sensors appearing in FIG. 1, and other sensors if they exist, see their voltage levels offset by a predetermined level of tension by a unit 504 of FIG.

  level shift and are successively applied to a converter

  analog-to-digital system 506 via a multiplexer 505

  The analog-to-digital weaver 506 successively converts the above signals into digital signals and delivers them to the CPU 503.

via the bus line 510.

  The CPU 503 is also connected to a read-only memory (hereinafter referred to as "MEI") 507, to a random access memory (hereinafter called

  "MEV") 508 and to a control circuit 509, via the bus line 510.

  MEV 508 temporarily stores the resulting values of various calculations from VUCT 503, while the MEM 507 stores a control program that executes within CPU 503, a basic duration card Ti of fuel injection for the fuel injection valves 6, etc. The CPU 503 executes the control program stored in the MEM 507 in order to calculate the valve opening time TOUT of the fuel injection valves 6 as a function of the various signals of the above motor parameters, and outputs the calculated ALL value to the control circuit 509 via the data bus line 510. The control circuit 509 outputs control signals corresponding to the above TOUT value at the valves. 6 fuel injection so

to open them.

  FIG. 3 is a flowchart showing a way of correcting the value of a signal PB An of absolute pressure in the intake manifold which is produced immediately after the end of a fuel cut-off operation, according to the invention, this

  correction being executed by UCT 503 of FIG.

  Firstly, it is determined during step I of FIG. 3 that the engine operates in a region where a fuel cutoff is performed, based on the values of the engine operating parameter signals coming from the engines. various sensors mentioned above If the response is positive, the value of an NMPB control variable defined below, is set to a predetermined value, for example 4, which corresponds to the number of cylinders of the engine, during a step 2 of FIG. 3, while, at the same time, during a step 3, the duration TOUT of fuel injection by the fuel injection valves 6 is set to zero FIG. 4 shows how the control signals of the fuel injection valves 6 are produced during fuel cut-off operation and immediately after the end of the fuel cut, and it also shows how the absolute pressure of the intake manifold PBA varies inIn FIG. 4, the suction, compression, explosion and exhaust strokes of each cylinder are respectively designated by the numbers 1, 2, 3 and 4. It should be noted that in FIG. lines in broken lines a indicate that

  the control signals are not delivered to the injection valves

  respective fuel consumption of the cylinders during the

fuel cut.

  We refer again to Figure 3 If the

  answer to the question in step 1 is negative, it is then determined

  If the value of the NMPB control variable is zero or not, in step 4 it is necessary to determine whether or not the engine cylinders have been fueled a predetermined number of times, correspondingly the time required for the influence of a difference t PB Aj, between the absolute pressure of the intake manifold PBA for operation in fuel cutoff, or free drive, and the absolute pressure of the intake manifold for normal combustion operation, decreased by a significant degree after the cessation of fuel cut-off In other words, this NMPB control variable is introduced for the following reason.

  shows experimental results showing the differences between

  values between the absolute pressure of the intake passage

  appearing when the engine is running in a cut-off state

  This is indicated by the experimental results of FIG. 5, insofar as the absolute pressure of the inlet passage remains constant, the suction efficiency of the engine for the combustion engine. walking in normal combustion (inda

  line in Figure 5) is greater than that corresponding to

  free-running dummy (represented by the dashed lines in Figure 5), i.e., the actual amount of intake air that is delivered to the engine in the running state of combustion normal is greater than that corresponding to the free drive, as has already been noted Conversely, the absolute pressure of the intake passage for the free drive of the engine is greater than that corresponding to the normal running in combustion, in the measure o the same amount of air

  intake is delivered to the engine. Thus, if, during the training

  motor, the quantity of fuel delivered is determined

  measured on the basis of the measured value of the absolute pressure of the intake manifold in the same way as in the case of

  the amount of fuel delivered during the fuel

  engine, the air-fuel ratio of the mixture delivered to the engine becomes too rich during free training, if the absolute pressure of the intake manifold is the same during

  free training and during normal burning.

  To avoid this inconvenience, the amount of car-

  to deliver to the engine after a fuel cut-off has ended and before the engine has completely left the free drive state to reach a normal burned operating condition In practice, the first value of the quantity fuel to be injected into each of the cylinders after the end of a fuel cut-off operation must be reduced before four pulses of the PMH signal have been produced from the end of the fuel cut-off operation, when the sensor absolute pressure can already detect that a normal value of the absolute pressure of the PBA intake manifold is

  that prevailing during normal engine running.

  In order to effect this reduction in the quantity of fuel to be delivered, according to the invention, an intentional modification is carried out

  the nominal value of the absolute pressure of the intake manifold

  PBA, as will be described in detail below. To determine the instant of the nominal variation of the absolute pressure of the intake manifold PBA, the value of the NMPB control variable indicated above is set to 4 since the difference between the absolute pressure of the intake manifold for the free drive and that corresponding to the normal combustion run increases with the speed of rotation of the engine, as illustrated by the experimental results of FIG. it is also necessary that the pressure difference at PB whose absolute pressure of the intake manifold must be nominally modified is set so as to increase with the speed of rotation of the engine. Returning again to FIG. 3 The predetermined number of times that has been set in step 3 is determined on the basis of the engine specifications or operating characteristics and, for example, in the present embodiment, it is set to a value equal to the number of cylinders of the engine However, if necessary, it is possible to set this number to a larger value, such as, as indicated below, for example: i) the number of races performed by the engine after the end of a fuel cut-off operation and before the absolute pressure of the intake manifold has fallen to a value that can be assumed for normal engine running; (ii) the number of races performed by the engine after the end of a fuel cut-off operation and before the absolute pressure of the intake manifold has begun to decrease, by a level corresponding to the free training in the direction of a level corresponding to normal engine running; (iii) the number of races performed by the engine after the end of a fuel cut-off operation and before the absolute pressure of the intake manifold has fallen to a predetermined value between the level corresponding to the drive free and the level corresponding to the normal burning step, for example the average value of these two levels. In case i), the variation of the absolute pressure of the intake manifold is applied continuously up to

  the influence of the fuel cut-off operation has

  The end of the nominal change is indicated by the dashed line (i) in Figure 4. In case (ii), the nominal change in the absolute pressure of the intake manifold is maintained until that the cylinder of the engine which has received the earlier of the fuel from among all the cylinders after the end of the fuel cut-off operation (the cylinder NO 2 in FIG. 4) begins to cause a variation of the pressure

  the intake manifold, and point o terminates the change in

  The nominal displacement is indicated by the line (ii) in broken lines in Figure 4. In case (iii), the nominal variation of the absolute pressure is interrupted during a transition of the operating conditions of the motor of the free drive. normal burning direction, and point o ends

  nominal variation is indicated by the line (iii)

  In case iii), the influence of the nominal variation of the absolute pressure of the intake manifold can be minimized in comparison with the other cases i) and ii), since the variation of the absolute pressure of the intake manifold the intake manifold that is applied to the fuel supply control is smaller in case (iii), which is due to the fact that

  the actual absolute pressure in the intake manifold the difference

  In addition, according to the present embodiment, as previously established, the number Nh PB is set to a value equal to the number of cylinders of the engine. This is due to the fact that after was fueled during

  the first consecutive exhaust and suction races, -

  the first fueled cylinder (the cylinder N O 2 in Figure 4) can produce an exhaust pressure that can

  actually change the absolute pressure of the intake manifold.

  during its second suction stroke, when all four cylinders have already been fed with the first fuel values, so that the nominal variation of the absolute pressure of the intake manifold ends on this occasion that is, immediately before the exhaust pressure of the first fueled cylinder can actually change the absolute pressure of the intake manifold, the point then being indicated by the dashed line (iv) of FIG. 4 Whereas, in the example of FIG. 4, the absolute pressure of the intake manifold decreases from a level corresponding to the free drive to a level corresponding to the normal combustion step during the third suction stroke of the cylinder n '2, fed the first fuel, it will be noted that the time course of pressure decreases varies depending on the structure of the emission and exhaust systems of the mo In addition, according to a method in which the fuel supply of each cylinder of the engine is not performed in synchronism with the production of each pulse of the PMI signal,

  but o the fuel supply of several cylinders is

  kills at once for example, it is possible to set the predetermined number NMPB to a value equal to the quotient obtained by dividing the total number of cylinders by the number of those

  are fueled simultaneously.

  Referring back to FIG. 3 If the answer to the question in step 4 is negative, the program proceeds to step 5, where the value of the NMPB control variable is decreased by one, and the new value is stored Then the value of the quantity k PB Aj used for the nominal change of the absolute pressure of the intake manifold PBA is determined as a function of the rotation speed Ne of the engine, during step 6 FIG. 6 shows a map of values of this quantity at PB Aj of nominal variation set in relation to the rotation speed Ne of the motor. According to this map, the geometric relation is based on the experimental results of FIG. values of the quantity h PB Aj of nominal variation are read when the rotational speed Ne of the motor increases However, the possible relationships are not limited to the relationship shown by the map of Figure 6, and it is po It is possible to conceive in another way the functional relations between the amount of nominal displacement of the motor and the motor rotation speed, according to the specific characteristics or operating characteristics of the motor to which the process

of the invention is applied.

  During step 7 of FIG. 3, the value of the absolute pressure of the intake manifold PB An measured for a given pulse of the signal DM is reduced by the value of the quantity h PB Aj of nominal variation which has been determined at

  during step 6, and the value of the fuel injection duration

  ALL is calculated from the new absolute pressure of the inlet manifold PBA (= PB An h PB Aj), using equation (1) above, in step 8 Steps 5 to 7 are repeated until it is determined in step 4 that the value of the control variable NIMPB is equal to zero, i.e. until a new fuel value is injected into each of the cylinders as shown in the example of Fig. 4 (this being indicated by the control signals b in Fig. 4) when the question

  of step 4 leads to a positive response, no other variations

  The nominal pressure is applied to the value PB An of the absolute pressure of the intake manifold which is measured by the absolute pressure sensor 8, and the measured value PB An is directly applied to the calculation of the injection time of fuel ALL using equation (1) to produce control signals

  c, indicated in FIG. 4, for injection valves 6

fuel.

  While the embodiment which has just been described applies to an internal combustion engine which is not equipped with an undercombustion chamber, the method of the invention can naturally be applied to combustion engines.

  internal combustion chambers. In addition,

  of the invention may not only be applied to a

  control system of the fuel supply such as that illustrated

  described above, but also to any other type of

  engine control systems, eg control devices

  ignition timing, recirculation control devices

  exhaust gases, and idle speed control device, to the extent that they use a signal indicating the (absolute) pressure in the intake manifold as the operating parameter of the engine used to set the operating control value

of the motor.

  Of course, those skilled in the art will be able to

  giner, from the process whose description has just been given

  merely illustrative and in no way limitative, various

  variants and modifications that are not outside the scope of the invention.

R E V E N D I C A T IO N S

  1 Control method of a control device

  for an internal combustion engine (1) having an intake passage

  sion (2) and a pressure sensor (8) which measures the pressure in said intake passage in response to at least one control parameter having values of said inlet passage pressure measured by said pressure sensor, immediately after the end of the interruption of the supply of fuel to said engine, the method being characterized in that it consists in: (1) detecting whether or not a transition occurs in the operating state of said engine an operating state requiring the interruption of the fuel supply of said engine to an operating state requiring fuel supply of said engine

  engine; (2) modify the value of the said pressure of the admission passage

  measured by said pressure sensor, by a predetermined amount

  a moment immediately following the detection of the transition at a time when said engine has finished performing a predetermined number of races; and (3) applying the value of said thus modified pressure of the intake passage to control said

control device.

  2 Control method of a control device

  for an internal combustion engine (1) having an intake passage

  sion (2) and a pressure sensor (8) which measures the absolute pressure in said intake passage in response to at least one control parameter having values of said intake passage absolute pressure measured by said sensor of absolute pressure, immediately after the end of the interruption of the fuel supply of said engine, the method being characterized in that it consists in: (1) detecting whether or not it occurs in the state of operation of said engine a transition of a

  operating state requiring an interruption of the

  fueling said engine to an operating state required

  siting the fuel supply of said engine; (2) reducing the value of said absolute pressure of the intake passage measured by said absolute pressure sensor by a predetermined amount,

252? 691

  a moment immediately following the detection of said transition at a time when said engine has completed a predetermined number of races; and (3) applying the value of said thus reduced absolute pressure of the intake passage to control said controller. Method according to claim 2, characterized in that said predetermined number of strokes is set equal to

  number of races of said engine necessary for said pressure

  absolute flow of the intake passage falls from a corresponding level

  said transition to a level corresponding to the walking in com-

  normal bombardment of said engine, after said transistion.

  4 Process according to claim 2, characterized in that said predetermined number of strokes is set equal to a number of strokes of said engine necessary for said pressure

  of the intake passage begins to fall from a corresponding level.

  laying down said transition to a corresponding level

  the normal combustion of the said engine, after the said

  sition. A method according to claim 2, characterized in that said predetermined amount of which said measured value of said absolute pressure of the intake passage is reduced during said step (2) is set to a value corresponding to the difference between the value of the absolute pressure of the intake passage occurring for the uncontrolled running of said engine

  and the value of the absolute pressure of the intake passage occurs

  for the normal combustion of said engine, provided that the rotational speed of said engine is the same between

two operating states of said engine.

  Process according to claim 5, characterized in that said predetermined quantity is set equal to values

  higher when the rotational speed of said motor increases.

  Process according to any one of the claims

  1, 5 or 6, characterized in that said control device comprises

  takes a fuel injection device (6) for controlling the amount of fuel delivered to said engine, at least

  function of said absolute pressure prevailing in the passage of atl; I.

  if we. 8 Process according to claim 7, characterized in that said engine has several cylinders, said fuel injection device being designed to inject fuel into said cylinders successively in synchronism with the production (11) of pulses of a signal indicating a predetermined crankshaft angle of said engine, said predetermined number of races being set at least equal to the number of races corresponding to the duration

  necessary for the said fuel injection device to

  kills a number of injections equal to the number of cylinders dudi.

engine after said transition.

  9 A method of controlling a com Lande system for an internal combustion engine (1) having a plurality of cylinders, an intake passage (2) and a pressure sensor (8) which measures the absolute pressure prevailing in said passage of admission, in response to at least one control parameter having values of said absolute pressure of the intake passage measured by: said absolute pressure sensor, immediately after the end of the interruption of the fuel supply of said engine, the method characterized in that it comprises the following operations: (1) detecting whether or not the operating state of said engine occurs in a transition state of an operating state requiring an interruption

  from the fuel supply of said engine to a state of operation

  requiring the fuel supply of said engine; (2) reducing the value of said absolute pressure of the intake passage measured by said absolute pressure sensor, by a predetermined amount, by an instant immediately following the detection of said transition at a time when all the cylinders of said engine were fueled after said transition; and (3) apply the

  value of said absolute pressure thus reduced by the admission passage

  sion for controlling said control device.

  A method according to claim 9, characterized in that said predetermined amount of which said measured value of said absolute pressure of the intake passage is reduced during step (2) is set equal to a value corresponding to the

  difference between the value of the absolute pressure of the

  occurring for the uncontrolled running of the engine and the value of the absolute pressure of the intake passage occurring for normal combustion performance of the engine, provided that the rotational speed of the engine is the same between the two engines.

operating states of the engine.

  The method of claim 10, characterized in that said predetermined amount is set equal to higher values as the rotational speed of said motor increases.

  Process according to any one of the claims

  9 to 11, characterized in that said control device comprises a fuel injection device (6) which controls the quantity of fuel delivered to said engine, at least according to said

  absolute pressure prevailing in the intake passage.

  The method according to claim 12, characterized in that said engine has a plurality of cylinders, said fuel injection device being adapted to inject fuel into said cylinders successively in synchronism with the production (11) of pulses of a signal indicating a predetermined crankshaft angle of said engine, said predetermined number of races being set at least equal to the number of races corresponding to the time required for said fuel injection device to perform a number of injections equal to the number of said cylinders;

  said engine after said transition.