JPH08246921A - Method and equipment for detecting fuel injection quantity at time of operation restart of cylinder under state of operation interruption - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the comfortableness of a running operation and exhaust gas discharge characteristic by deciding an increased fuel injection amount following to the residual gas in a cylinder, when the fuel injection amount at the operation restart time of the cylinder in the operation interception state is increasingly corrected, in an internal combustion engine. SOLUTION: A real residual gas amount dtirg is calculated through the multiple amount calculation 101 depending on an engine temperature, under the consideration of a real temperature and peripheral pressure at the engine brake operation mode. When the first combustion cycle at the operation restart time of the cylinder under the operation interception state is elapsed and finished, it is transmitted to the adding point 103 through the switch 102 controlled by an operation interception signal B. The correction value is added and piled to a load value t1 at this adding point 103. By division 106 of the obtained amount tlsum by a prescribed air number λ soll, the fuel injection amount tes required in the combustion cycle after the operation restart of the cylinder under the operation interception state of the internal combustion engine is found out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection amount detection method and device when restarting the operation of a cylinder in an internal combustion engine under a cutoff condition, in which a basic fuel injection amount is combined (superposed) with an increased fuel injection amount. ) The method and the device.

[0002]

BACKGROUND OF THE INVENTION Individual cylinders are sometimes deactivated during drive slip control (ASR) or engine braking operating modes or due to speed limitations. At the time of resuming the operation of the cylinder that has been put into the operation cut-off state (shut-off), the initial (initial) fuel amount adjustment state is regular with respect to driving comfort and exhaust emission characteristics. In the case of the cylinder-selective fuel injection system known from DE 43 28 835 A1, the increased fuel injection quantity at the resumption of operation of the cylinder in the deactuated state (disengaged) is equal to the deactuated fuel injection cycle. It depends on the number.

[0003]

SUMMARY OF THE INVENTION An object or object of the present invention is to provide an initial (initial) fuel quantity adjustment state when an operation of a cylinder (actuated to be cut off) under an operation cutoff state is restarted. The object of the present invention is to provide an improved technical means with respect to driving comfort and exhaust emission characteristics as compared with the prior art.

[0004]

According to the present invention, excellent characteristic values relating to driving comfort and exhaust gas emission characteristics are solved as follows according to claim 1, that is,
The increased fuel injection amount with respect to the first (first) injection after the restart of the operation of the cylinder in the operation cut-off state (the operation cut-off state) is determined depending on the residual gas in the cylinder. Claims 2 to 7 show the development of the present invention. The object of claim 8 is a fuel injection amount detection device at the time of resuming the operation of a cylinder (which has been in a non-operation state) under an operation cutoff state in an internal combustion engine.

[0005]

EXAMPLE First, when the cylinder which has been put into the operation shut-off state (shut-off) is restarted, a considerable amount of residual gas exists in the cylinder. In particular, in the case of a relatively long shut-off of the cylinder, the residual gas consists almost exclusively of fresh air. In order to achieve the specified number of air (λ = 1) in the cylinder, the wall film (membrane) action and effect are once applied to the cylinders that are in the respective operation interruption states (blocked) at the time of the restart. In order to compensate for this, an increased fuel quantity is injected, which quantity of fuel is advantageously stoichiometric with the residual gas.

In FIG. 1 a block schematic diagram of the following device is shown, namely, a device for determining the amount of increased (excess) fuel required for wall film compensation and residual gas burnout. Has been done. In the present embodiment, from the map (characteristic region) in block 100 (this depends on the camshaft crossover angle wnwe and the engine speed), in the engine brake operating mode under a predetermined temperature and a predetermined ambient pressure. The amount of residual gas is calculated. The actual residual gas amount dtlrg is calculated via the multiplied amounts fdkh and tab, taking into account the actual temperature and the actual ambient pressure in the engine brake operating mode, where the amount fdkh
Represents the ratio of the actual ambient pressure to a given ambient pressure, the quantity tab being a function of the engine temperature and the intake air temperature. In the illustrated embodiment, for simplicity, the multiplication amount tab depending on the exhaust gas temperature is calculated in block 101 depending on the engine temperature tmot. When the camshaft crossover angle wnwe depends only on the engine speed n, the residual gas amount dtlrgo can also be calculated through a speed-dependent map (characteristic curve).
Correction value dtlrgs corresponding to residual gas amount dtlrgs
Is transmitted through the switch 102 to the addition point 103 only in the following cases (cases), that is, when the operation of the cylinder in the operation cutoff state (non-operation state) of the internal combustion engine is restarted: Only when the (first) combustion cycle has elapsed has passed the transmission to the relevant summing point 103. Switch 1
02 is controlled by the operation cutoff signal B. The operation cutoff signal has a value of 1 when the cylinder is cut off, and
When attempting to restart the operation of a cylinder that has been in the operation cutoff state (non-operation state) in the internal combustion engine, the value shifts to 0. The delay circuit 104 and the differential point 105 form the original control signal for the switch 102. Thereby, the switch is closed on the transition of the deactivation signal from 1 to 0. The first time after resumption (for all other cycles except the first combustion cycle, switch 102 is placed in the 0 state.

The correction value (dtlrgs) is additively superimposed on the load value t1 at the addition point 105. Thereby, the amount t1
Sum is obtained. By dividing this amount t1sum by the predetermined air number λsoll in block 106, the fuel injection amount tes required in the combustion cycle after the restart of the operation of the cylinder in the operation cutoff state (non-operation state) in the internal combustion engine Is detected.

The previously calculated injection quantity tes does not reach the cylinder due to the wall film effect.
Therefore, an additional point 10 is added to the calculated injection amount tes.
An increased air quantity dtewf must be added via 7. As a result, the actual injection amount ti is formed, which is in addition to the basic injection amount and the injection amount that depends on the residual gas in the cylinder, and additionally the increased air amount for compensating the wall film effect. including.

The state of detection of the increased air injection amount dtewf (which is necessary for compensating the wall film effect) is as follows.
Similarly, shown in FIG. From the map (characteristic region, characteristic curve) in block 108 and the map (characteristic region, characteristic curve) in block 109, the steady wall film (film) amount wfo (target value under λ = 1) Value t
It is calculated depending on 1, the engine speed n, and the engine temperature tmot. The target value of the wall film (film) amount wfo is the coefficient fw.
It is multiplied by frg and this factor is obtained by dividing the correction value (dtlrgs) corresponding to the residual gas by the load value t1 and subsequently adding with the value 1. In order to obtain the actual target value wflam of the wall film quantity, in block 111 the product of both quantities wfo and fwfrg is divided by a predetermined air number λ soll.

Target value wfo for the amount of wall film (film)
Is transmitted (transmitted) through the switch 112 only in the following cases due to the subsequent processing of the increased air injection amount dtewf, that is, the switching passage (transmission) is performed only when the operation cutoff signal B indicates the restart of the cylinder. ) Will be done. Otherwise, switch 12 is set to the value 0. A time-dependent wall film (film) wflamt is simulated through the memory (PTI element) 113. The time constant zfw of the memory 113 is the block 1
14 and 115 are set by two maps (characteristic region, characteristic curve) depending on the load value t1 and the engine temperature tmot. The switch 116 controlled by the operation cutoff signal B load is
Switching through (transmission) the time constant zfw from the map of the block 114 (characteristic region, characteristic curve) for the normal operation mode or the time constant from the map of the block 115 (characteristic region, characteristic curve) for the interruption during engine braking. To do. A time-dependent wall film amount wflamt is calculated for each cylinder with a time lag. Increased air injection amount dtew required for wall film compensation
f is the calculated cycle film wall delay element 117 and summing point 118 of the actual cycle form the difference. The increased air injection amount dtewf obtained as described above is additively superimposed on the injection amount tes at the addition point 117. Thus, the fuel quantity ti introduced into the cylinder is obtained.
The switch 119 is controlled by the shutoff signal B and is set to the value 0 in the following cases, that is, the value 0 is set when the cylinder is to be cut off. The switch is closed when the cylinder is restarted.

FIG. 2 shows another modified embodiment (embodiment) for the calculation of the fuel injection amount ti when the cylinder whose operation has been interrupted is restarted. Correction value calculated by Fig. 1 (dtl
rgs) is divided by a predetermined air numerical value (set air number) (λsoll) in block 200, and the correction value (dtlrgs) thus generated is added point 201.
The injection amount tes corrected in is added to the basic injection amount te corresponding to the load. The corrected injection amount tes thus formed is, as described above, the increased air injection amount dt.
It is superposed on (added to) ewf and then converted into a value ti.

The injection operation of one cylinder is shut off once or
It can be based that, if carried out more than twice in succession, the residual gas in the cylinder consists mostly of fresh air and not of exhaust gas.

In this case, the correction value dtlrgs for detecting the injection amount tes is set to the calculated residual gas amount dt.
Can be set equal to lrg. However, when the cylinder is shut off only once or twice, the exhaust gas in the residual gas is not completely replaced by fresh air. Especially in the case of vibration (reciprocal) switching operation of the cylinder,
In other words, when the cylinder is cyclically operated or cut off, for example, when the ASR-EZ (driving slip control or traction control) is performed, the above-mentioned correction value dt is set.
lrgs, which are based on residual gas consisting essentially of fresh air, cannot be used. Therefore, in the circuit block 119 of FIG. 1, the correction value dfgas, which is changed with respect to the correction value dtrlgs, is determined according to the following process procedure: The exhaust gas component of the residual gas in the cylinder is
It decreases as the number of cylinder cutoffs increases. The exhaust gas amount ΔAbgas after the i-th operation interruption is obtained as follows.

[0014]

[Equation 1]

Here, t1 (i) is the load in the i-th cycle, and dtrlg (i) represents the amount of residual gas remaining in the cylinder after the i-th cycle.
Fresh air df in residual gas after i-th shut-off
gas is obtained as follows.

[0016]

[Equation 2]

In the case of an oscillating (reciprocating) switching operation of the cylinder, the fresh air dfgas in the residual gas is calculated by the equation (1).
And from equation (2),

[0018]

(Equation 3)

Under the assumption that the residual gas amount changes little from cycle to cycle, equation (3) is simplified as follows.

[0020]

[Equation 4]

The value dtlrg or dfgas can be switched through depending on whether a relatively long shut-off of the cylinder has occurred or an oscillating (reciprocal) switching action of the cylinder of the cylinder has occurred. The control signal for the switch is derived from the operation cutoff signal B as shown in FIG. Block 121 detects the number of cylinder deactivations before resumption. In the case where the number of cylinder cut-offs is 1, and the cut-off signal B simultaneously signals the restart, the AND gate 122 sends the control signal for the switching passage (transmission) to the switch 120. As a result, the switch has the value dfga.
Switch to s. In all other cases, the value dtlrg is switched (transmitted) as a correction value (dtlrgs).

In the above-described embodiment (embodiment), the increased air injection amount dtewf is determined depending on the amount of residual gas in the cylinder whose operation has been cut off. However, other criteria can also be used for the detection of the increased air injection quantity dteuf, for example the amount of residual gas, the density, or
Compositions can also be used.

[0023]

According to the present invention, at the time of restarting the operation of a cylinder that has been in the operation cut-off state (shut-off), the initial (initial) fuel amount adjustment state is the driving comfort and exhaust gas emission. As a result, it is possible to realize the technical means which is improved as compared with the conventional technology in terms of characteristics.

[Brief description of drawings]

FIG. 1 is an operation cutoff state (non-operation state) in an internal combustion engine.
It is a block connection diagram of the fuel injection amount detection device at the time of resuming the operation of the placed cylinder.

FIG. 2 is a partial modification example of the configuration of the block connection diagram of the fuel injection amount detection device at the time of restarting the operation of the cylinder placed in the operation cutoff state (non-operation state) in the internal combustion engine shown in FIG. It is a schematic diagram of (embodiment).

[Explanation of symbols]

100 Map (Characteristic region) 101 Map including engine temperature dependence (Characteristic region, characteristic curve) 102 Switch 103 Summing point 104 Delay element 105 Differential point 106 Block including division 107 Summing point

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hong Zhan Germany Schwieberdingen Richard-Warkner-Strasse 14

Claims (8)

[Claims] 1. A method for detecting a fuel injection amount when resuming the operation of a cylinder in an operation cutoff state (non-operation state) of an internal combustion engine, wherein a basic fuel injection amount is combined with an increased fuel injection amount. In this method, the increased fuel injection amount for the first (first) injection after resuming the operation of the cylinder under the operation cutoff state is determined depending on the residual gas in the cylinder. Fuel injection amount detection method when resuming cylinder operation. 2. A correction value (dtlrg) which depends on the residual gas.
s) is added to the load value (t1) of the internal combustion engine to form a corrected load value (tlsum), and the load value is divided by a predetermined set air number (λsoll),
2. The method according to claim 1, characterized in that a fuel injection amount (tes) required for adjusting and setting the predetermined set air number ([lambda] soll) is obtained. 3. The fuel injection amount (tes) required for adjusting and setting the predetermined set air number (λsoll) is set to a correction amount (dt).
ewf) combined (superimposed) with the correction amount (dteuf)
The method of claim 2, wherein is suitable for compensation of wall film (wflam). 4. A method according to claim 3, characterized in that the correction amount (dtewf) is detected from the difference in the amount of wall film determined for two successive injection cycles. 5. The correction amount (dtwef) is combined with a predetermined fuel injection amount (tes), and the predetermined fuel injection amount is a correction value (d) depending on the basic fuel injection amount and the residual gas.
tlrgs), and the correction value (dtlrgs) is a predetermined air number (λso).
The method according to any one of claims 1 to 4, characterized in that it is obtained by dividing by (11). 6. A correction value (d when connecting the cylinder for additional operation).
fgas), the correction value being dependent on the load, the residual gas, and the number of fuel injection cycles in the shut-off state. 7. Each time between two fuel injection cycles
A correction value (dfgas) is formed at the time of cyclic operation interruption and additional operation injection of a cylinder in which one operation interruption is performed, and the correction value is dependent on load and residual gas.
2 Method described. 8. A fuel injection amount detection device at the time of restarting the operation of a cylinder under an operation cutoff state in an internal combustion engine, wherein the basic fuel injection amount is combined (superposed) with the increased fuel injection amount depending on the device. In the apparatus configured as described above, there is provided means for determining the fuel injection amount depending on the residual gas existing in the cylinder before restarting the operation of the cylinder under the operation cutoff state. Is
A cylinder in an internal combustion engine in an operation cutoff state, characterized in that the fuel injection amount is generated only for the first (first) injection after the operation of the cylinder in the operation cutoff state is restarted. Fuel injection amount detection device when the operation of the fuel cell is restarted.