JP2899148B2 - Electronic fuel control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic fuel control device for controlling the fuel injection amount of an engine, and more particularly to an electronic fuel control device for suitably controlling the fuel injection amount after starting.

[0002]

2. Description of the Related Art An electronic fuel control apparatus is for calculating and controlling a fuel injection time from signals from detectors for the purpose of improving the power performance of an engine and purifying exhaust gas. The injection time is obtained by a calculation formula (different at the start and after the start) centering on the basic injection time, and the basic injection time is corrected by various correction coefficients to correspond to each state of the engine. .

In particular, since the rotation of the engine is unstable immediately after the engine is started and the engine is liable to stall, a post-starting increase correction coefficient is used to prevent this.

[0004]

FIG. 19 is a timing chart for explaining a problem in the conventional electronic fuel control system, and shows an aged engine characteristic as an example. In the figure, (1) shows the output of the starter signal, (2) shows the engine speed, (3) shows the increase correction coefficient after starting, and (4) shows the time change of the injection time.

When the starter signal rises at time t1, start-up control is started, and as shown in FIG. 19 (2), the engine speed rises while slightly fluctuating.
When the engine speed exceeds the reference rotational speed 11 (for example, 400 rpm), the calculation formula after the start is replaced, and as shown in FIG. 19 (3), the post-start increase correction coefficient decays with time.

Therefore, as shown in FIG. 19 (4), the value of the injection time also attenuates with the passage of time. And at time t3
In FIG. 19 (2), as shown in FIG.
If the engine speed drops below 00 rpm, that is, if the engine falls into an unstable state, the injection time is also attenuated, so in this aged engine, the injection amount required to stabilize engine rotation must be less than become,
After time t3, the engine rotation may not be able to return,
As shown in FIG. 19 (2), when the rotational speed drops to the target rotational speed 11 '(for example, 200 rpm), which is determined to have returned to the start,
The calculation returns to the injection time during start-up, but if the rotation drop is severe, engine stall is caused.

In other words, since the increase correction coefficient after the start is attenuated unilaterally, the control device cannot cope with engine variations. Therefore, an object of the present invention is to provide an electronic fuel control device capable of preventing a decrease in the engine speed even when the engine becomes unstable after the engine is started.

[0008]

In order to achieve the above object, a first aspect of the present invention is a monitoring means for monitoring a cause of a decrease in the engine speed immediately after the start of the engine. When it is determined that there is, a suppression means for suppressing a sudden decrease in the fuel injection time is provided, and the second invention provides the monitoring means with a value of a post-start increase correction coefficient. Monitoring means for detecting that the fuel is being attenuated, wherein the suppression means is provided with at least one of a correction prohibiting means and a lower limit control means when the value of the post-start increase correction coefficient is attenuating; The third invention is characterized in that it is a suppressing means for suppressing a sudden attenuation of the injection time, and the monitoring means is a monitoring means for detecting that the engine water temperature is equal to or lower than a predetermined temperature. When the engine water temperature is equal to or lower than a predetermined temperature, at least one of a damping suppressing unit, a correction prohibiting unit, and a lower limit control unit may be a suppressing unit that suppresses a sudden damping of the fuel injection time. According to a fourth aspect of the present invention, the monitoring means is a monitoring means for detecting that the basic injection time is corrected by the decrease correction coefficient, and the suppressing means is corrected by the decrease correction coefficient. When the determination is made, at least one of the damping suppressing means and the lower limit value controlling means serves as a suppressing means for suppressing the sudden damping of the fuel injection time.

[0009]

In the first aspect of the invention, when the monitoring means detects that the cause of the drop immediately after the start is generated, the suppression means suppresses a sudden decrease in the fuel injection time. In the second invention, when the monitoring means detects that the value of the post-start increase correction coefficient is attenuating, the suppression means determines that there is a cause of a decrease in the rotational speed, and the correction prohibiting means, or the lower limit value control. A sudden decay of the fuel injection time is suppressed by at least one of the means.

In the third invention, when the monitoring means detects that the engine water temperature is lower than a predetermined temperature, the suppressing means determines that there is a cause of a decrease in the engine speed, and the damping suppressing means or the correction inhibiting means comprises: Or lower limit control means,
Abrupt attenuation of the fuel injection time is suppressed by at least one of the means.

[0011] In the fourth aspect of the invention, when the monitoring means detects that the basic injection time is corrected by the decrease correction coefficient, the monitoring means determines that there is a cause of a decrease in the rotational speed, and the damping suppression means or the lower limit. Sudden attenuation of the fuel injection time is suppressed by at least one of the value control means. As described above, it is possible to prevent the engine speed from lowering and dropping as it is.

[0012]

FIG. 1 is an overall configuration diagram showing an electronic fuel control device 1 according to an embodiment of the present invention. Engine 2 has intake pipe 7
Power is generated by an explosion of a mixture of air from the air and fuel injected from the injector 8. 12 is a pressure detector, 13 is a throttle valve, 14 is a valve opening detector, 15 is an intake air temperature detector, 17 is an oxygen concentration detector, 18 is a water temperature detector, and 9 is mounted on the upper part of the cylinder 3. The ignition plug 19 is a power distribution device for detecting the rotation speed of the engine 2.

The control circuit 16 realized by a microcomputer or the like includes an input interface 161 for inputting output signals from each detector, a processing circuit 162, and an output interface 163. The control circuit 16 calculates a fuel injection amount for each process, which is determined by the valve opening time of the injector 8, based on output signals from the detectors 12, 15, 17, 18 and further from the power distributor 19.

Next, the basic operation of the processing circuit 162 of the present invention will be described with reference to FIG. In the present invention, based on this basic operation, it is possible to prevent a drop in engine rotation by various combinations of monitoring means and suppression means. Step S2 is for determining whether or not the engine 2 is in a stable state, that is, whether or not the engine 2 has left the start. For example, in the initialization of the initial routine, 400 is set.
compared with the setting value set in rpm and the engine speed N _EG, determines that the engine speed N _EG does not exit the still start if 400rpm or less, starting below the routine proceeds to step S3~S5 The injection time is determined by the calculation formula at the time.

Starting injection time T _AU = Starting basic injection time T _AU.ST × Intake air temperature correction coefficient FT _AIR. × Various correction coefficients
(1) startup basic injection time T _AU.ST (hereinafter, T _AU.ST) is set according to the temperature T _WAT. Coolant based on water temperature detector 18 (step S3), and the water temperature T _{WAT The} lower the value of. Is, the more difficult it is to atomize the fuel.

The intake air temperature correction coefficient FT _AIR. Based on the intake air temperature detector 15, which changes according to the temperature T _{AI R.} intake air, intake air temperature T _AIR. Is larger as a low, standard temperature (20 In (° C), it is constant at 1.0. Therefore, by correcting T _AU.ST with the correction coefficient FT _AIR. , The engine 2 can respond to the temperature of the intake air. In addition, there are various correction coefficients depending on the control parameters of the engine.

As described above, T _AU.ST is calculated in step S3, and in step S4, the intake air temperature correction coefficient FT _AIR.
AU.ST is integrated, various correction coefficients are calculated in step S5, and the value obtained in step S4 and the various correction coefficients are integrated to obtain T _{AU in} equation (1). It should be noted that the values of the various correction coefficients at the time of starting are determined in advance in a higher-level routine prior to the routine for determining _TAU as shown in FIG.
Numeral 62 indicates that the coefficient value is obtained by various sensors in accordance with the state of the engine and is stored in a memory in the processing circuit 162.

In step S6, the initial set value is set to 400.
The processing proceeds to step S7 while maintaining the
2 calculates K _AFT in the equation (2) based on the output of the water temperature detector 18 and stores the value in a memory. In the next step S18, the processing circuit 162 sends the value of T _AU obtained in steps S3 to S5 to the output interface 163, and the injector 8 injects fuel according to this T _AU .

[0019] Then it is determined that the engine rotational speed N _EG has passed through the starting and exceeds the initial set value 400rpm in step S2, the set value for starting the determination in the next step S8 4
The speed is changed from 00 rpm to, for example, 200 rpm, and the process proceeds to step S9 in order to obtain the injection time T _AU by the following expression after starting. The engine speed will be 200rpm
Until the following, it is determined that the engine 2 has been started.

Injection time T _AU = basic injection time T _P × increase correction coefficient K _AFT after starting × various correction coefficients (2) The basic injection time T _P (hereinafter referred to as T _P ) is a pressure detector. 12
Intake air amount of the engine 2 according to the output of the
Is determined as an injection time that provides a stoichiometric air-fuel ratio based on the engine speed.

After starting, the increase correction coefficient K _AFT (hereinafter, referred to as
K _AFT ) has an initial value determined in advance based on the cooling water temperature T _WAT. Detected by the water temperature detector 18 at the time of engine start, and decreases to 1.0 with time. And to increase the becomes in a state of omission of the start corrected T _P in the K _AFT and injection time T _AU. The various correction coefficients after the start include a deceleration reduction correction coefficient for reducing _TAU when the engine 2 is decelerated, and an air-fuel ratio feedback correction coefficient that changes to a reduction side or an increase side according to the air-fuel ratio. It is.

Now, in step S9, the present invention
A processing step based on a combination of the monitoring means and the suppression means is inserted, and after this processing, the process proceeds to the next step S10. In this step S10, the current K _AFT
On the other hand, it is checked whether or not the timing to attenuate has arrived, and if it has not arrived, no attenuation is performed. If so, in the next step S11, the K _AFT calculated in the previous step S7 is calculated. Then, a constant K smaller than 1 is integrated, the K _AFT is attenuated, and the attenuated value is stored in a memory or the like. The minimum value of K _AFT is
Since it is 1.0, the value of K _AFT is suppressed in the next steps S12 and S13 so as not to become smaller than this minimum value.

Next, at step S14, T_PIs calculated and
K obtained in step 10 in step S15_AFTof
Attenuated value and T_PAnd are integrated. Further to step S16
Multiplying the various correction coefficients in equation (2)
As a result, T in equation (2) _AUIs required. Also,
The values of the various correction coefficients after the start of
Each value obtained in advance by the position routine is stored in the memory.
It is.

In the present invention, a processing step based on a combination of the monitoring means and the suppressing means can be inserted in step S16 instead of step S9, or can be inserted in step S17 executed next. The processing steps inserted in these steps S9 or S16 or S17 will be described later. Then, in step S18, the processing circuit 162 sends the value of T _AU obtained by the processing in steps S14 to S17 to the output interface 163,
The injector 8 injects fuel according to _TAU .

Next, the combination of the monitoring means and the suppression means will be described with reference to FIGS. FIG. 3 is a flowchart in which various suppressing means and monitoring means are combined. As shown by the dotted line, (suppression step P) intended to suppress the attenuation of the K _AFT in suppressing means, or which inhibits the correction to T _P of the decrease correction coefficient (inhibiting step Q), or detected from the distributor 19, etc. Engine speed, or engine water temperature detected by water temperature detector 18, or K _AFT
T _AU than the lower limit for T _AU set based on the value
Of control (suppression step R) so that the value does not fall below 3
There are two embodiments.

As shown in FIG. 3A, when the processing step is configured by combining the suppression step P and the monitoring means, this processing step is inserted into step S9 in FIG.
As described above, the suppression step Q is inserted into step S16 in FIG. 2, and as shown in c, the suppression step R is inserted into step S17 in FIG. Then, as shown in FIG. 3, when each of the suppression steps detects a decrease in the engine speed or a cause of the decrease based on the monitoring means, the process proceeds to YES to perform the suppression control, and if not detected, proceeds to NO to perform the normal control. Like that.

There are three further embodiments of the suppression step P for suppressing K _AFT attenuation. That is, a means (P1) for _keeping the K _AFT constant or increasing, a means (P2) for controlling either the reduction of the K _AFT attenuation rate or the extension of the attenuation cycle (P2), or the attenuation of the K _AFT . Means (P3) for interrupting for a predetermined time.

FIG. 4 shows each embodiment of the monitoring means described above. The monitoring means monitors whether or not the engine speed has exceeded a predetermined speed as indicated by d, that is, monitors a drop in the engine speed (monitoring step 1), and the decay of _KAFT has been completed as indicated by e. G, whether the cause of the drop is monitored (monitoring step 2), whether the engine water temperature has exceeded 20 ° C. as shown by f, ie, the cause of the drop (monitoring step 3), and g As described above, there are four means of monitoring whether or not there is a request for the weight reduction, that is, monitoring the cause of the drop (monitoring step 4).

If a drop in the engine speed or the cause of the drop is detected in each monitoring step, the process proceeds to YES, and the process proceeds to at least one of the three suppressing means described above. As described above, the processing steps configured by combining the monitoring means and the suppression means are performed according to the types of the suppression steps in step S in FIG.
Was inserted into one of 9,16,17, suppression means by detecting the state of the monitoring unit to perform processing for suppressing the attenuation of T _AU.

Hereinafter, each embodiment of the present invention will be described in detail. [First Embodiment] In this embodiment, monitoring means (monitoring step 1) for detecting whether the engine speed exceeds a predetermined value and K
The value of the _AFT and combining the suppression means for either or increased retention (inhibiting step P) constant 5 (denoted by the same reference numerals to the same portions as FIG. 19.) The operation timing chart, FIG. 6 Is the operation flowchart (Engine 2
(Performed by interrupt processing for each process).

As shown in FIG. 5A, at time t1, FIG.
When the starter SW 20 is turned on and the starter signal rises, the control circuit 16 detects this and calculates the injection time T _{AU according} to the starting equation (1). And FIG.
As shown in (2), when the engine speed exceeds the target speed 11 (400 rpm) at time t2, the processing circuit 162 determines that the engine has stopped, and calculates T _AU by changing to the equation (2) after starting. .

After time t2, K _AFT becomes as shown in FIG.
As shown in (4), the value attenuates with the passage of time, and the T _AU also attenuates, but eventually reaches time t3, and as shown in FIG. When a stable state is reached, the processing circuit 16 of the present invention
2 judges that there is a drop in engine speed (2)
Keep K _AFT in the equation constant.

[0033] Thus steep attenuation is prevented T _AU of T _AU as shown in FIG. 5 (4) is longer than the conventional, since the correspondingly fuel is often injected, the engine 2 is stable, 5
As shown in (2), there is no drop in the engine speed. Then, at time t4, when the speed exceeds 400 rpm as shown in FIG. 5 (2), the processing circuit 162 attenuates the K _AFT again as shown in FIG. 5 (3). Accordingly, T _AU is also attenuated as shown in FIG. 5 (4), and the engine speed is stabilized as shown in FIG. 5 (2). After that, the engine speed gradually approaches the idle speed.

As described above, it is possible to prevent the engine speed from dropping as it is even in an unstable state in which the engine speed drops after starting (for example, between times t3 and t4 in FIG. 2). Next, the processing circuit 16
The processing operation 2 will be described with reference to FIG. FIG. 6 shows a form in which a processing step combining the monitoring step 1 and the suppression step P1 is inserted into step S9 of the basic flowchart shown in FIG.

Therefore, the processing other than step S9 is the same as the basic operation shown in FIG. 2, and the description of this basic operation will be omitted. Hereinafter, the process of step S9 will be described. When the engine 2 exits the start, the process proceeds to step S9, and the K _AFT
Start damping control of First, the process proceeds to step P111 (corresponding to monitoring step 1) in step S9, and it is determined whether or not the engine speed exceeds 400 rpm (N _T1 ). If it exceeds, the normal attenuation control of step S10 and thereafter is performed.

On the other hand, when the engine speed _NEG becomes 400 rpm or less, it is determined that the engine 2 is in an unstable state, and the routine proceeds to the next Step P112 (corresponding to the monitoring step 1). This step P112 is for determining whether or not the engine 2 is in an unstable state. The engine speed N _EG is compared with a set speed N _T2 (for example, 300 rpm), and the engine speed N _EG is determined. If it exceeds 300 rpm, T _AU is obtained while keeping the value of K _AFT obtained in the previous routine. (Inhibition corresponding to step P1) further engine speed N _EG is 3 in step P112
When the engine speed becomes equal to or less than 00 rpm, it is determined that the engine 2 is in an even more unstable state, and in the next step P113, the K _AFT obtained in the previous routine is set to a constant K ′ larger than 1.
The correction coefficient K _AFT is increased by integrating
After _{storing the} increased correction coefficient K _AFT in a memory or the like, T _AU
Is required. (Corresponding to the suppression step P1) Therefore, the engine speed N _EG is increased from 300 rpm to 400 rpm.
In the unstable state in the range of T, the sudden decrease of T _AU disappears. In the more unstable state of 300 rpm or less, the K _AFT is increased, and the T _AU is maintained or increased to a substantially constant value. the engine speed N _EG is to return to a stable state is no longer drop after the start of the engine speed.

If NO in step P112, K
1 is greater than constant K to _AFT "by integrating the may be slightly increased K _AFT. Constant K" value of less than a constant K 'in step P113. The combination of the suppression step of only P and the monitoring step 1 has been described above. At least one of the suppression steps (P, Q, R) and the monitoring step 1 are combined to perform the _TAU attenuation suppression processing. It is natural that you can do it.

[Second Embodiment] In this embodiment, a monitoring means (monitoring step 2) for detecting whether or not the attenuation of the K _AFT has ended, and a suppressing means (suppression step Q) for inhibiting the correction of the reduction-side correction coefficient. FIG. 7 is a timing chart thereof. Note that the same components as those in FIG. 5 are denoted by the same reference numerals. Time w1 is the time at which the decay of _KAFT has ended.

That is, in this example, the decay of the K _AFT is determined to be the cause of the decrease in the engine speed, so that the time t2
After the start, the correction of the reduction-side correction coefficient such as the deceleration-reduction correction coefficient is prohibited between the time t2 and w1 during which the K _AFT is attenuating as shown in FIG. 7 (3). . Therefore, a significant reduction of T _AU as shown in FIG. 7 (4) is suppressed, T _AU conventional T shown in this period dotted line l2
_It becomes longer than _AU , and even if the engine speed decreases as shown in FIG.

Then, only after time w1, that is, after the end of the _KAFT decay, the correction of the weight-decrease correction coefficient is performed. That is,
When the engine is unstable during K _AFT attenuation, the correction of the reduction side correction coefficient for reducing the T _AU is prohibited, and the correction of the reduction side correction coefficient is performed after the attenuation, that is, after the engine is stabilized. Next, the processing operation of the processing circuit 162 will be described with reference to FIG. FIG. 8 shows a monitoring step 2 and a suppression step Q in step S16 of the basic flowchart shown in FIG.
And a processing step combining the above is inserted.

Accordingly, the processing other than step S16 is the same as that shown in FIG.
Are the same as the basic operations shown in FIG. 1, and the description of the basic operations will be omitted below, and only the processing in step S16 will be described.
Engine 2 passes through the start, after the T _P is calculated, K _AFT is integrated in this T _P. (Step S14, 1
5). The integrated control of various correction coefficients is initiated for T _P advances to the next step S16. First, step S1
The process proceeds to step Q21 (corresponding to the monitoring step 2) in 6, and it is monitored whether _KAFT is 1, that is, whether the decay of _KAFT is completed. K _AFT is 1, that is, the attenuation of the K _AFT has been completed the correction coefficient reduction side only, such as deceleration decrease correction factor in the next step Q22 is read from the memory for accumulating the coefficients in the T _P. (Normal control) On the other hand, if it is determined in step Q21 that _KAFT is not 1, that is, _KAFT is still attenuated and there is a cause of a decrease in the engine speed, the process proceeds to the next step Q24 (corresponding to the suppression step Q). That is, the reduction correction only on the reduction side, such as the deceleration reduction correction coefficient in step Q22, is prohibited.

In step Q24, various correction coefficients are read from the memory, and it is determined whether a correction coefficient such as a feedback correction coefficient that changes to the decrease side or the increase side depending on the state of the engine is the current decrease side or the increase side. If the value of the correction coefficient is 1 or less, that is, if the value is on the decrease side, the correction in step Q23 for performing the correction for both the decrease and increase is prohibited, and the _TAU is calculated in step S18. On the increase side, this increase correction is performed in step Q2.
Perform in step 3.

That is, when the engine is unstable, that is, during the damping, all the corrections on the decreasing side are prohibited.
If the K _AFT has been attenuated, as described above, step Q
The program proceeds from step 21 to the next step Q22, where the reduction correction is performed, and further proceeds to step Q23 where the correction coefficient is corrected on both the reduction side and the increase side to calculate _TAU . (Normal control) In other words, when the engine becomes stable, that is, when the engine is in a stable state, correction on the decreasing side is performed as before.

[Another embodiment of the second embodiment] In this embodiment, K
Monitoring _{means AFT} attenuation is detected whether or not it is completed to the (monitoring step 2) and T to set the lower limit value for _AU T _AU suppressing suppressing means so as not to fall below the lower limit value (suppression step R) FIG. 9 is a timing chart thereof. Note that the same components as those in FIG. 5 are denoted by the same reference numerals.

That is, in this example, at the time t2 when the K _{AFT is} decaying.
In between ～W1, it may be set to indicate the lower limit guard l4 to T _AU, T _AU controls the T _AU so as not to fall below the lower limit value. The lower limit setting method in the present example is one in which to reduce the extent lower limit N _EG becomes high based on the engine rotational speed as shown in Table 1 below, based on the value of K _AFT is not limited to this, K _The lower limit may be made smaller as the value of _AFT becomes smaller, or the lower limit may be made smaller as the water temperature becomes higher based on the water temperature T _WAT .

[0046]

[Table 1]

Next, the processing operation of the processing circuit 162 will be described with reference to FIG. FIG. 10 shows a form in which a processing step combining the monitoring step 2 and the suppression step R is inserted into step S17 of the basic flowchart shown in FIG. Therefore, the processing other than step S17 is the same as the basic operation shown in FIG. 2, and the description of the basic operation will be omitted below, and only the processing of step S17 will be described.

[0048] After the T _P is calculated by missing a start-up, T _P
KAFT and various correction coefficients are integrated to calculate _TAU . Then, the process proceeds to the next step S17 to start the lower limit value control of _TAU . First, step R21 in step S17
Proceeding to (Monitoring Step 2), as in the first embodiment, K
_It is monitored whether or not the decay of the _AFT has ended. If it is determined that the _KAFT is 1, that is, the decay of the _KAFT has ended, the next step S
Proceeding to 18, the _TAU is calculated as it is. (Normal Control) On the other hand, if the _KAFT is attenuating in step R21, this is regarded as the cause of the drop, and the process proceeds to step R22 (suppression step R). Here, the lower limit value is calculated as shown in Table 1 and the value is stored in the memory.

The next step R23 (suppression step R) is for confirming whether or not the current T _AU is lower than the set lower limit. If not, the T _AU is calculated as it is. but if below, T _AU in step R24 (inhibiting step R) is (sets the lower limit on T _AU) to guard the T _AU so as not to be less than the lower limit value
As a result, as shown in FIG. 9 (4), T _AU becomes longer than before in the decay of K _AFT .

That is, in the present embodiment, in the unstable state of the engine 2, that is, when the K _AFT is being attenuated, the T _AU is guarded so as not to fall below and the T _AU is lengthened to control the engine rotation to be stable. . [Third Embodiment] In this embodiment, has the engine water temperature exceeded 20 ° C. (this 20 ° C. is a standard temperature indicating that the engine 2 is warmed to some extent and the fuel injection can be controlled irrespective of the surrounding outside temperature). The monitoring means (monitoring step 3) for detecting whether or not the detection is performed is combined with the suppression means (suppression step Q) for inhibiting the accumulation of the correction coefficient on the decreasing side, and FIG. 11 is a timing chart thereof. Note that the same components as those in FIG. 5 are denoted by the same reference numerals. At time w2, the engine water temperature is 2
This is the time when the temperature reaches 0 ° C.

That is, in this example, the fact that the engine water temperature is lower than the predetermined temperature (for example, 20 ° C.) after the start is determined to be the cause of the decrease in the engine speed.
As shown in (5), the correction of the weight reduction correction coefficient such as the deceleration weight reduction correction coefficient is prohibited between the time t2 and the time w2 when the engine water temperature is lower than 20 ° C. Accordingly, as shown in FIG. 11 (4), significant weight loss is suppressed T _AU of T _AU is longer than traditional T _AU indicated by the dotted line l2, the engine speed as shown in FIG. 11 (2) Even if the rotation speed decreases, the rotation speed is prevented from dropping.

After time w2, that is, when the engine coolant temperature becomes 2
Only when the temperature reaches 0 ° C. or more, the weight-reduction-side correction coefficient is corrected. Next, the processing operation of the processing circuit 162 will be described with reference to FIG. FIG. 12 shows a form in which a processing step combining the monitoring step 3 and the suppression step Q is inserted into step S16 of the basic flowchart shown in FIG.

Therefore, the processing other than step S16 is the same as that in FIG.
Are the same as the basic operations shown in FIG. 1, and the description of the basic operations will be omitted below, and only the processing in step S16 will be described.
After the T _P is calculated by missing the start, K _AFT is integrated in the T _P. Then, the process proceeds to the next step S16 to start the control of the reduction-side correction. First, the process proceeds to step Q31 (monitoring step 3) in step S16, where the water temperature T _WAT.
C is not reached, NO, that is, T _WAT.
If it is determined that exceeds the C proceeds to the next step Q32, a correction factor of reduction side only, such as deceleration decrease correction factor is read from the memory for accumulating the coefficients in the T _P. (Normal control) On the other hand, when it is determined that T _WAT. Is less than 20 ° C., that is, that there is a cause of a decrease in the engine speed, the next step Q34.
Proceed to (corresponding to suppression step Q). That is, step Q
In other words, the reduction correction only on the reduction side, such as the deceleration reduction correction coefficient at 32, is prohibited.

In step Q34, various correction coefficients are read from the memory, and it is determined whether or not a correction coefficient such as a feedback correction coefficient which can take both the increase side and the decrease side coefficient is smaller than 1, that is, whether the current correction side is present. If YES, that is, if it is on the decreasing side, the correction in step Q33 is prohibited, and T is determined in step S18.
_AU is calculated. If increasing side performs the increasing correction at step Q33, T _AU is calculated in step S18.
(Normal control) That is, when the engine is unstable, that is, when the water temperature is lower than 20 ° C., all the corrections on the weight reduction side are prohibited.
The combination of the suppression step Q and the monitoring step 3 has been described above. Among the suppression steps (P, Q, R),
T _AU by combining at least one and monitoring step 3
Naturally, the process of suppressing the attenuation may be performed.

[Fourth Embodiment] In this embodiment, monitoring means (monitoring step 4) for detecting whether or not there is a request for reduction on the decreasing side and suppressing means for _keeping the value of _KAFT constant or increasing (suppression step P1). FIG. 13 is a timing chart thereof. Note that the same components as those in FIG. 5 are denoted by the same reference numerals. It is to be noted that time w1 is the time at which the decay of the K _AFT has ended, w1 'is the period during which the request for the weight reduction correction has been made, and FIG.

That is, in this example, if there is a correction request on the reduction side in the deceleration reduction correction coefficient or the feedback correction coefficient after the start of the engine 2 as shown in FIG. It is determined that there is
The K _AFT is increased or kept constant during a request, such as during 1 ′. Therefore, as shown in FIGS. 13 (3) and (4), the K _AFT of the present example attenuates more slowly than the conventional K _AFT (13) (time t2 to w1), and T _AU
Is suppressed, and T _AU in the present embodiment is indicated by a dotted line l.
Even if the engine rotation speed becomes longer than the conventional T _AU shown in FIG. 2 and the engine speed decreases as shown in FIG.
Depression as it is is prevented.

Then, after the time w1, that is, only after the decay of the K _AFT is completed, the reduction-side correction coefficient is corrected. Next, the processing operation of the processing circuit 162 will be described with reference to FIG. FIG.
Is a form in which a processing step combining the monitoring step 4 and the suppression step P1 is inserted into step S9 of the basic flowchart shown in FIG.

Therefore, the processing other than step S9 is the same as the basic operation shown in FIG. 2, and the description of the basic operation will be omitted below, and only the processing of step S9 will be described. After the start, the _KAFT attenuation control is started. First, the process proceeds to step P141 (monitoring step 4) in step S9 to read out from the memory whether or not there is a request for the reduction-side correction.
To willing to confirm whether or not it is the timing to decay the current attenuates the K _{AF T} by accumulating the coefficient smaller than 1 K to K _AFT in this case the step S11 if the damping timing if arrived ( K _AFT ; K _AFT × K), and if it has not arrived, the K _AFT is not attenuated. (Normal control) On the other hand, if there is a request for the weight reduction side correction in step P141, the process proceeds to step P142 assuming that the factor is a drop.
The _KAFT is increased by multiplying _KAFT by one or more coefficients K ', for example, 1.2. (Suppression step P1). In the next step S10, if the decay timing (for example, 500 ms interval) has arrived, the signal is attenuated as before (or may not be attenuated).
_AFT is increased, and as a result, T _AU becomes longer than before as shown in FIG. 13 (4).

That is, in the present embodiment, when the engine is in an unstable state, which is a request for a decrease in the amount of the engine, if the engine is in an unstable state, the _KAFT is increased to increase the T _AU to control the engine rotation to be stable. I have. [Another embodiment of the fourth embodiment] In this embodiment, a monitoring means (monitoring step 4) for detecting whether or not there is a request for a correction on the decreasing side at present.
And the attenuation factor of the value of K _AFT control means or to reduce the (K _AFT Do shown decays much time), or controlled by selecting either one or to increase the attenuation period (inhibiting step P2) FIG. 15 is a timing chart thereof. Note that the same components as those in FIG. 13 are denoted by the same reference numerals. The time w1 is the time when the decay of the _KAFT has ended.

That is, in this example, as shown in FIG. 15 (5), when there is a request for the weight reduction correction after the start of the engine 2, it is determined that the cause is a decrease in the engine speed.
K cycle to or attenuating smaller (the ratio of attenuation per unit time) attenuation factor of the _{AF T} is long (e.g. 50
0 ms to 1 sec) or at least one of them is selected, and is continued until the decay of _KAFT ends.

[0061] Thus 15 (3), towards the K _AFT of the present embodiment than K _AFT (l3) of the conventional, as shown in (4) is to attenuate slowly (time t2~w1), T _AU Is suppressed, the T _AU in the present embodiment becomes longer than the conventional T _AU indicated by the dotted line l2, and even if the engine speed decreases as shown in FIG. You will not be depressed. Normal control is performed after time w1, that is, when the decay of _KAFT is completed.

Next, the processing operation of the processing circuit 162 will be described with reference to FIG. FIG. 16 shows a monitoring step 4 and a suppression step P in step S9 of the basic flowchart shown in FIG.
2 is inserted. Therefore, the processing other than step S9 is the same as the basic operation shown in FIG. 2, and the description of the basic operation will be omitted below, and only the processing of step S9 will be described.

After the start, the _KAFT attenuation control is started. First whether or not there is willing weight loss side correction request step in step S9 P241 (monitoring step 4) detecting from the memory, the normal K _AFT attenuation control in step S10,11 Without YES, that request I do. On the other hand, when a request for reduction side corrected in step P241, it is regarded as the fall factor proceeds to step P242 (inhibiting step P2), in order to reduce the attenuation factor of K _AFT, attenuation coefficient used in the step S11 K (< Replace 1) with K1 which is greater and less than 1. In order to lengthen the decay timing instead of this step P242, as shown in step P243 of FIG. 16, the decay timing T used in step S10 is set to a longer T1.
May be substituted. Thereafter, at steps S10 and S11 at this decay rate or decay timing, K
Attenuate _AFT .

As a result, K_AFTDecreases more slowly than before
As shown in FIG. 15 (4), T_AUReduction
Decay is suppressed. That is, in this example, the request for the weight reduction
In the unstable state of the engine 2, K _AFTSlowly
Decay T_AUAnd the engine speed will stabilize.
Control.

[Modification of Another Embodiment] This embodiment is a further modification of the other embodiment of the fourth embodiment. Here, the monitoring means (monitoring step 4) for detecting whether or not there is a request for the weight reduction correction is combined with the suppressing means (suppression step P3) for interrupting the _KAFT attenuation for a predetermined time. It is a timing chart. Note that the same components as those in FIG. 13 are denoted by the same reference numerals. Time w1 is the time at which the decay of _KAFT has ended.

In this example, as shown in FIG. 17 (3), when the engine 2 is started, if there is a request for the reduction side, it is determined that the cause is a decrease in the engine speed, and the _KAFT attenuation is interrupted for a predetermined period. To do it. In this example, it is assumed that a request is made at time t2, attenuation is prohibited during the time T from time t2 to time w3, and attenuation starts after time w3. Therefore, FIG.
7 (3) and (4), the conventional K _AFT (dotted line l)
As a result, the K _AFT of the present example attenuates more slowly than at 3) (time t2 to w1), and the T _{AU of the} present embodiment is longer than the conventional T _AU indicated by the dotted line l2, Even if the engine speed decreases as shown in FIG. 19B, the engine speed does not drop. Normal control is performed after time w1, that is, when the decay of _KAFT is completed.

Next, the processing operation of the processing circuit 162 will be described with reference to FIG. FIG. 18 shows a monitoring step 4 and a suppression step P in step S9 of the basic flowchart shown in FIG.
3 is inserted. Therefore, the processing other than step S9 is the same as the basic operation shown in FIG. 2, and the description of the basic operation will be omitted below, and only the processing of step S9 will be described.

After the start, the _KAFT attenuation control is started. First, the process proceeds to step P341 (monitoring step 4) in step S9 to read out from the memory whether or not there is a request for the reduction-side correction. If NO, that is, if there is no request, the process proceeds to steps S10 and S11 and the normal K _AFT Performs damping control. On the other hand, if there is a request for the weight-reduction correction in step P341, it is regarded as the cause of the drop and the process proceeds to step P342.
Then, it is confirmed whether or not the interruption flag indicating whether or not interruption of the damping control has been performed once before is "1".
That is, if the interruption control is performed, the normal attenuation control is performed as described above.

On the other hand, if the flag is "0" in this step, that is, if there has been no interruption of the attenuation control before, step P34
Proceed to 3 starts interruption control of damping, but to prevent would set the interrupt time (e.g. 3sec) per the T _AU routine turns, once upright "1" to set the flag Only to set. That is, in this step P343, it is confirmed whether or not the interruption time setting flag indicating whether or not the interruption time has been set once is "1". Proceed to Step P346 without performing.

If the flag is "0", that is, if the setting is not performed, the setting process is performed. That is, after the interruption time is set to 3 sec in step P344 (in this example, counting is started by an interruption routine at this time), the next step P
In 345, the interruption time setting flag is set to "1", and the flow proceeds to Step P346. In step S346, it is determined whether or not the count value has passed 3 seconds, that is, whether or not the interruption is in progress or the interruption has ended. Therefore, the count value is 3se
If it is within c, it means that the operation is suspended, so steps S10 and S11
And the interruption control is maintained by skipping the attenuation process of. When the count value exceeds 3 seconds, the process proceeds to the next step P347 to perform the damping control, the interrupt flag is set to "1" to indicate that the interrupt control has been performed, and the next step S10,
At 11, normal damping control is performed again.

Therefore, when there is a request for a weight reduction correction, the K _AFT is generally increased as compared with the conventional case, and
As shown in FIG. 17 (4), T _AU becomes longer than before. (Note that, in this example, steps P342 to 347 correspond to the suppression step.) That is, in this example, if the engine 2 is in an unstable state, ie, a request for the reduction-side correction is required, K _AFT
The _TAU is lengthened by suspending the damping of the engine and the control is performed so that the rotation of the engine becomes stable.

As described above, the third embodiment has been described with respect to the three embodiments. However, the _TAU attenuation control may be performed by combining at least one of the suppression steps (P, R) with the monitoring step 4. Of course.

[0073]

As described above, according to the present invention, when it is determined that there is a cause of a decrease in the engine speed, a sudden decrease in the fuel injection amount is suppressed, so that the engine becomes unstable especially after the engine is started. However, it is possible to prevent the engine speed from dropping. In addition, since the cause of the drop is monitored instead of the drop in the engine speed itself, the unstable state of the engine can be detected quickly, and the engine stall can be more reliably prevented.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an electronic fuel control device 1 which is an example of the present invention.

FIG. 2 is a flowchart showing a basic operation of the processing circuit 162.

FIG. 3 is a flowchart in which various suppression means and monitoring means are combined.

FIG. 4 is a flowchart illustrating an example of a monitoring unit.

FIG. 5 is a timing chart showing the first embodiment.

FIG. 6 is a flowchart illustrating an operation of the processing circuit 162 according to the first embodiment.

FIG. 7 is a timing chart showing a second embodiment.

FIG. 8 is a flowchart showing the operation of the second embodiment.

FIG. 9 is a timing chart showing another embodiment of the second embodiment.

FIG. 10 is a flowchart showing the operation of another embodiment of the second embodiment.

FIG. 11 is a timing chart showing a third embodiment.

FIG. 12 is a flowchart showing the operation of the third embodiment.

FIG. 13 is a timing chart showing a fourth embodiment.

FIG. 14 is a flowchart showing the operation of the fourth embodiment.

FIG. 15 is a timing chart showing another embodiment of the fourth embodiment.

FIG. 16 is a flowchart showing the operation of another example of the fourth example.

FIG. 17 is a timing chart showing a modification of the other embodiment of the fourth embodiment.

FIG. 18 is a flowchart showing an operation of a modification of the other example of the fourth example.

FIG. 19 is a timing chart of a conventional electronic fuel control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic fuel control device 8 Injector 162 Processing circuit 20 Starter SW

Claims (4)

(57) [Claims] 1. A detecting means for detecting each state of an engine, and based on the detecting means, when the engine is changed from a starting state to a non-starting state, a basic injection time and a post-start increase correction coefficient which attenuates as time elapses. And various correction coefficients including a reduction correction coefficient for reducing the fuel injection time,
An electronic fuel control device comprising: fuel injection time setting means for setting the fuel injection time by correcting the basic injection time with the various correction coefficients; a monitoring means for monitoring a cause of a decrease in engine speed immediately after starting; An electronic fuel control device, further comprising a suppression unit that suppresses a sudden decrease in the fuel injection time when the monitoring unit determines that there is a cause of a decrease in the engine speed. 2. The monitoring means for detecting that the value of the post-start increase correction coefficient is attenuating, wherein the suppressing means determines that the value of the post-start increase correction coefficient is attenuating. When it is determined, the setting is made based on the value of the correction amount prohibition means for prohibiting the correction of the decrease correction coefficient with respect to the basic injection time, or the engine speed detected by the detection means, or the engine water temperature, or the post-start increase correction coefficient. 2. A steep decay of the fuel injection time is suppressed by at least one of lower limit control means for controlling the fuel injection time so as not to fall below the lower limit value of the fuel injection time. An electronic fuel control device as described in the above. 3. The monitoring means is means for detecting that the engine water temperature is equal to or lower than a predetermined temperature based on the detection means. Attenuation suppression means for suppressing the attenuation of the post-increase correction coefficient, or correction inhibition means for inhibiting the correction of the decrease correction coefficient with respect to the basic injection time, or the engine speed detected from the detection means, or the engine water temperature, or Lower limit value control means for controlling the fuel injection time so as not to fall below the lower limit value of the fuel injection time set based on the value of the post-start increase correction coefficient,
2. The electronic fuel control device according to claim 1, wherein the sudden decrease in the fuel injection time is suppressed by at least one of the following. 4. The monitoring means detects that the basic injection time is corrected by the decrease correction coefficient, and the suppressing means determines that the basic injection time is corrected by the decrease correction coefficient. Then, the fuel injection set based on the value of the post-start increase correction coefficient or the engine speed or the engine water temperature detected by the attenuation suppression unit that suppresses the attenuation of the post-start increase correction coefficient, or the engine speed detected by the detection unit. 2. The electronic fuel according to claim 1, wherein a steep decay of the fuel injection time is suppressed by at least one of lower limit value control means for controlling the fuel injection time not to fall below a lower limit value of time. Control device.