JP4560997B2 - Engine control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine control device.
[0002]
[Prior art]
A conventional engine control device is described in JP-A-5-2222997.
In the engine control device described in the publication, the intake air amount during idle operation is feedback-controlled, and the engine speed is kept at the target speed.
[0003]
[Problems to be solved by the invention]
However, when the fuel is different, that is, when heavy fuel is used, the engine speed cannot reach the target speed by intake air amount feedback.
[0004]
That is, when heavy fuel is used, a large amount of fuel adheres to the intake port during cold start of the engine, the fuel vaporization ratio decreases, and the combustion state deteriorates. When the combustion state deteriorates, if feedback control for increasing the intake air amount is performed, the negative pressure in the intake pipe decreases, so that the fuel vaporization amount further decreases and the combustion state further deteriorates.
Therefore, when such control is performed, the engine speed does not reach the target speed.
[0005]
This invention is made | formed in view of such a subject, and it aims at providing the engine control apparatus which can hold | maintain a combustion state favorably.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problems, the engine control apparatus according to the present invention includes an “intake asynchronous injection” that ends fuel injection before the intake period of the engine and an “intake synchronous injection” that ends fuel injection within the intake period of the engine. The present invention is directed to a control device that controls the injector so that the air is taken in the intake port.
[0007]
  This controller is(A) ActualEngine speed isMore than a given value than the target engine speedWhen it falls, perform intake synchronous injection,(B)afterwards, RealAsynchronous intake injection is performed when the engine speed increases to the target value.(C)Along with this intake asynchronous injectionFruitEngine speed isThan the target engine speedSwitch to intake synchronous injection if it drops below a predetermined value, and continue asynchronous intake injection if it doesn't drop above a predetermined value.When the actual engine speed in the operation (B) increases to a target value, it is determined whether the advance margin of the ignition timing of the engine is a predetermined value or more. Asynchronous intake injection in operation (B) is performed and the ignition timing is advanced, and if it is less than the predetermined value, intake asynchronous injection is not performed.It is characterized by controlling the injector.

[0008]
When heavy fuel is used, the amount of fuel adhering during intake asynchronous injection is large, and the combustion state is likely to deteriorate. Therefore, intake synchronous injection is preferable when starting the engine.
On the other hand, if it is not a heavy fuel, the amount of fuel adhering is relatively small, and therefore, intake air asynchronous injection in which air and fuel are sufficiently mixed is preferable. Even with the same fuel, depending on the temperature difference between the regions where the engine is applied, each can be handled as a separate fuel.
[0009]
In order to discriminate between these fuels, the control device of the present invention (1) performs intake synchronous injection when the engine speed decreases, and attempts to improve the combustion state. (2) After that, when the engine speed increases to the target value as a result of the trial, the intake air asynchronous injection is performed, and the mixing of air and fuel is promoted to further improve the combustion state. However, this process serves not only to improve the combustion state but also to determine the fuel characteristics. That is, the cause of the decrease in the engine speed in the above (1) can be considered when the idle speed control (ISC) is functioning separately or when the friction amount of the piston is increased. If a phenomenon of a decrease in the number, that is, a phenomenon in which the engine speed decreases in the step (2) is observed, it can be estimated that the cause is that the fuel is heavy.
[0010]
Therefore, in the step (3), when the engine speed again decreases by a predetermined value or more due to the asynchronous intake injection in the step (2), the fuel is handled as a heavy fuel, that is, a heavy fuel. Switch to intake synchronous injection. When the engine speed does not decrease by a predetermined value or more, the fuel can be handled as not being heavy fuel, so the intake asynchronous injection in step (2) is continued.
[0011]
  In addition,Of the intake asynchronous injection in the operation (C)The duration of the continuation is several seconds or more. When the time of several seconds or more has elapsed, the warming up of the intake port of the engine is almost completed, and another control may be started.
[0012]
In addition, since fuel adhesion is likely to occur when the water temperature is equal to or lower than a predetermined value, it is preferable that the control of the injector is performed when the water temperature at the time of starting the engine is equal to or lower than a predetermined value.
[0013]
In addition, if the engine speed is controlled by adjusting the ignition timing after detecting engine combustion deterioration, the engine speed can be controlled regardless of the fuel characteristics. It can be close to the target value.
[0014]
In particular, if there is a history of switching after detecting combustion deterioration of the engine, it can be estimated that the fuel is heavy, so if the engine speed is controlled by adjusting the ignition timing, even if it is heavy fuel Since the engine speed can be controlled, the engine speed can be brought closer to the target value than the control based on the supply air amount.
[0015]
In addition, if there is no history of switching after detecting the combustion deterioration of the engine, it can be estimated that the fuel is not heavy fuel, so the advance amount of the current ignition timing is determined, and the subsequent determination based on the determination result What is necessary is just to determine a control method.
[0016]
At this time, since it is estimated that the fuel is not heavy fuel, when the advance amount of the ignition timing is less than a predetermined value, it is not necessary to perform control by the ignition timing. By adjusting the amount of air supplied to the intake port, the engine speed can be controlled, and the burden on the engine can be reduced.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an engine control apparatus according to an embodiment will be described.
[0018]
FIG. 1 is a block diagram of an engine system including an engine control apparatus according to an embodiment.
[0019]
The engine E includes an intake port PA that guides air and fuel to the combustion chamber, and an exhaust port PE that discharges exhaust gas generated in response to combustion in the combustion chamber. The crankshaft of the engine E is rotated by the combustion, The rotational speed is detected by the rotational speed sensor R as the engine rotational speed.
[0020]
An intake pipe TB is connected to the intake port PA, and a throttle valve V is interposed in the middle of the intake pipe TB. An injector I is attached to the intake port PA. Fuel is supplied to the injector I from the fuel tank FT via the fuel pump FP. The opening degree of the throttle valve V and the timing of fuel injection from the injector I are controlled by control signals Si and Sv from the electronic control unit ECU, respectively. Note that a bypass passage may be provided in the intake pipe TB, and the flow rate of the bypass passage may be controlled in addition to the throttle valve V as a method for controlling the amount of air supplied to the intake port.
[0021]
An exhaust pipe TB ′ through which exhaust gas passes is attached to the exhaust port PE, and an oxygen sensor OX is disposed in the exhaust pipe TB ′. The engine temperature is detected by a water temperature sensor W attached to the water jacket of the engine E.
[0022]
Output signals from the rotation speed sensor R, the water temperature sensor W, and the oxygen sensor OX are input to the electronic control unit ECU, and the electronic control unit ECU determines the opening degree of the throttle valve V and the injector based on these input signals. It functions as an engine control device that controls the fuel ejection timing from I. The details will be described below.
[0023]
  FIG. 2 is a timing chart for explaining the control according to the embodiment. The electronic control unit ECU performs “intake asynchronous injection” that terminates fuel injection before the intake period of the engine E and “intake synchronized injection” that terminates fuel injection within the intake period of the engine E in the intake port PA. To control the injector I.
[0024]
The electronic control unit ECU performs intake synchronous injection when the engine speed input from the rotational speed sensor R decreases, and performs intake asynchronous injection when the engine speed increases to a target value thereafter. When the engine speed again decreases by a predetermined value or more with the injection, the control is switched to the intake synchronous injection. When the engine speed does not decrease by the predetermined value or more, the injector I is controlled to continue the intake asynchronous injection.
[0025]
FIG. 3 is a graph showing the time dependency of the engine speed when heavy fuel is used. In the graph, the fuel injection method performed at each time is described. The high level indicates the intake asynchronous injection, and the low level indicates the intake synchronous injection.
[0026]
When heavy fuel is used, if the water temperature (the temperature of the intake port) is low, the amount of fuel adhering during intake asynchronous injection is large and the combustion state is likely to deteriorate. preferable. On the other hand, if the fuel is not heavy (light fuel), and the water temperature (intake port temperature) is high, the amount of fuel adhering is relatively small, so intake asynchronous injection in which air and fuel are sufficiently mixed is preferable. . Even with the same fuel, depending on the temperature difference between the regions where the engine is applied, each can be handled as a separate fuel.
[0027]
The electronic control unit ECU performs intake synchronous injection immediately after turning on the ignition switch, but thereafter performs intake asynchronous injection when the (actual) engine speed exceeds the target engine speed. In the description, the actual engine speed is simply referred to as engine speed.
[0028]
After switching to intake asynchronous injection, (1) If the engine speed decreases (a given value or more than the target engine speed), intake synchronous injection is performed again (time T1), and the combustion state is improved. Try.
[0029]
(2) After that, when the engine speed has increased to the target value as a result of the improvement trial, intake asynchronous injection is performed (T2), and further improvement of the combustion state is attempted by promoting the mixing of air and fuel. . However, this process serves not only to improve the combustion state but also to determine the fuel characteristics. That is, the cause of the engine speed reduction in the above (1) can be considered when the idle speed control (ISC) is functioning separately or when the friction amount of engine internal parts such as pistons is increased. If a second engine speed reduction phenomenon at time T2, that is, a phenomenon in which the engine speed decreases in step (2) is observed, it can be estimated that the fuel is heavy.
[0030]
Therefore, in the step (3), when the engine speed again decreases by a predetermined value or more due to the asynchronous intake injection in the step (2), the fuel is handled as a heavy fuel, that is, a heavy fuel. Therefore, switching to intake synchronous injection is performed (time T3).
[0031]
FIG. 4 is a graph showing the time dependency of the engine speed when light fuel is used. In the graph, the fuel injection method performed at each time is described. The high level indicates the intake asynchronous injection, and the low level indicates the intake synchronous injection.
The control up to immediately before the step (3) is the same as the method described with reference to FIG. 3, but here, the engine speed does not decrease by a predetermined value or more in the step (3). In this case, since the fuel can be handled as not being heavy fuel, the intake asynchronous injection in the step (2) performed after the time T2 is continued.
[0032]
The duration of the continuation is several seconds or more. When the time of several seconds or more elapses, warming of the intake port of the engine is completed, so air-fuel ratio (A / F) feedback (FB) control, etc. based on the outputs of the sensors R, W, OX described above Another control may be started. Note that this example does not prevent the intake air asynchronous injection from being performed in the air-fuel ratio feedback control.
[0033]
FIG. 5 is a flowchart for executing the above control. When the ignition switch is turned ON, the engine E starts and the idle fuel injection timing control routine starts.
[0034]
First, it is determined whether or not deterioration of combustion is detected, for example, when the engine speed is lower than the target engine speed (S1). Until the combustion deterioration is detected, intake asynchronous injection is performed (S10).
[0035]
When the combustion deterioration is detected, it is determined whether or not the air-fuel ratio feedback control is started (S2). If the conditions for starting the air-fuel ratio feedback control are satisfied, the air-fuel ratio feedback control is started. In this example, air-fuel ratio feedback control is performed by intake asynchronous injection (S10).
[0036]
If the conditions for starting the air-fuel ratio feedback control are not satisfied, it is next determined whether or not the flag E is OFF (S3). If it is OFF, whether or not the engine speed has recovered to the target engine speed. (S4). That is, assuming that the deviation of the current engine speed from the target engine speed is ΔR and the first threshold value is NE1 (for example, NE1 = −20 rpm), when ΔR is larger than NE1, for example, when ΔR = −10 rpm, It is determined that the engine speed has recovered to the target engine speed.
[0037]
When the engine speed has recovered, it is determined that the ignition timing advance angle margin is greater than or equal to a predetermined value (S5). If the advance angle has a margin, intake asynchronous injection is performed and the flag E is turned on (S6). If there is no room, intake synchronous injection is performed.
[0038]
In other words, when the ignition timing has a margin over a predetermined value (for example, crank angle: 5 degrees) with respect to the advance side guard value (near MBT), the control returns to intake asynchronous injection, but is less than this predetermined value. In this case, it does not return to intake asynchronous injection. This is because, in the case of heavy fuel, when the intake-synchronous injection is switched to the intake-asynchronous injection, the rotational speed decreases, but the ignition timing is advanced if there is a margin for the advance side guard value. This is because it is possible to suppress a decrease in the engine speed, and when there is no allowance, when the fuel injection method is switched to the intake synchronous injection without advancing the ignition timing, the intake asynchronous injection is switched. This is because an uncomfortable feeling due to a change in the number of rotations can be suppressed. Further, when such a guard value is used, the threshold value NE2 of the decrease range of the engine speed can be set small.
[0039]
Since the flag E is turned on in step S6, in the next flow, it is determined in step S3 that the flag E is not OFF, and further, the engine speed has decreased due to the change to intake asynchronous injection in step S6. Is determined (S7). That is, assuming that the deviation of the current engine speed from the target engine speed is ΔR and the second threshold value is NE2 (for example, NE2 = −100 rpm), when ΔR is smaller than NE1, for example, when ΔR = −150 rpm, It is determined that the engine speed has decreased by a predetermined value or more than the target engine speed.
[0040]
When the engine speed has decreased (S7), the intake asynchronous injection is switched to the intake synchronous injection, and the flag X is turned ON (S8).
[0041]
If the engine speed does not decrease (S7), it is determined whether or not the flag X is ON (S9). If the flag X is not ON, that is, if the engine speed does not decrease due to intake asynchronous injection, this is a light fuel. Thus, the intake asynchronous injection is continued (S10). Further, when the flag X is turned ON even once, that is, when the engine speed is reduced by the intake asynchronous injection, it is determined in the flag X determination step (S9), which is a heavy fuel. And intake synchronous injection is performed (S8).
[0042]
In addition, since fuel adhesion is likely to occur when the water temperature is equal to or lower than a predetermined value, the above-described control is preferably performed when the water temperature at the time of starting the engine is equal to or lower than the predetermined value.
[0043]
FIG. 6 is a graph showing the time dependence of the amount of hydrocarbon (HC) discharged from the engine per unit time. In the figure, the speed of the vehicle on which the engine is mounted is also shown. (1) is a graph when the asynchronous intake control is performed from the start of the engine to the air-fuel ratio feedback control, (2) is a graph when the control according to the above embodiment is performed, and (3) is a combustion It is a graph at the time of performing intake synchronous control after performing deterioration until air-fuel ratio feedback control is performed. From the graph, it can be seen that when the control (2) is used, the amount of HC is small compared to (3).
[0044]
FIG. 7 is a flowchart for feedback control of the engine speed when the engine is idling.
[0045]
When the ignition switch is turned ON, the engine E is started and the engine speed feedback control routine at the time of idling is started.
[0046]
First, it is determined whether or not deterioration of combustion is detected, for example, when the engine speed is lower than the target engine speed (S21). Until the deterioration of combustion is detected, the amount of air supplied to the intake port is controlled to maintain the engine speed at the engine speed during idling and to perform speed feedback control (S28). When the combustion deterioration is detected, it is determined whether or not the air-fuel ratio feedback control is started (S22). If the conditions for starting the air-fuel ratio feedback control are satisfied, the air-fuel ratio feedback control is started. In this example, the air-fuel ratio feedback control performs feedback control of the engine speed by adjusting the air amount (S28).
[0047]
If the conditions for starting the air-fuel ratio feedback control are not satisfied, it is determined whether or not the flag E is OFF (S23). If it is OFF, that is, before the intake asynchronous injection is set after the recovery of the engine speed. If there is, the engine speed is feedback controlled by controlling the ignition timing (S24).
[0048]
On the other hand, if the flag E is ON, that is, after the intake asynchronous injection is set after the recovery of the engine speed, it is determined whether or not the engine speed has further decreased as in step S7 in FIG. If the engine speed is lowered, the engine speed is feedback controlled by controlling the ignition timing (S24). When the engine speed does not decrease, it is determined whether or not the advance amount of the ignition timing is less than a predetermined value (eg, crank angle 3 degrees) (S26). Attenuation is made zero, and the control is switched to feedback control of the engine speed by controlling the air amount (S27).
[0049]
If the advance amount of the ignition timing is greater than or equal to a predetermined value, feedback control by adjusting the air amount is impossible, and therefore feedback control of the engine speed by adjusting the ignition timing is continued (S24).
[0050]
By the above control, the engine speed feedback control based on the ignition timing can be terminated early, so that the advance amount is attenuated to zero, and the deterioration of the catalyst warm-up property can be suppressed.
[0051]
In addition, in this control, the engine speed is controlled by adjusting the ignition timing after detecting the deterioration of combustion of the engine, so that the engine speed can be controlled regardless of the characteristics of the fuel, rather than the control based on the supply air amount. The engine speed can be brought close to the target value.
[0052]
The control of this example can be used in combination with the above-described control. That is, in the control of this example, if there is a history of switching the injection method after detecting the deterioration of combustion of the engine (S8, S25), it can be estimated that the fuel is heavy, so the engine speed can be adjusted by adjusting the ignition timing. The engine speed can be controlled even with heavy fuel, and the engine speed can be brought closer to the target value than the control based on the supply air amount.
[0053]
Further, in the control of this example, after detecting the deterioration of combustion of the engine, if there is no history of switching, it can be estimated that the fuel is not heavy fuel, so the advance amount of the current ignition timing is determined (S26). ), And the subsequent control method is determined based on the determination result. At this time, since it is estimated that the fuel is not heavy fuel, when the advance amount of the ignition timing is less than a predetermined value, it is not necessary to perform control based on the ignition timing. Therefore, since the engine speed is controlled by reducing the advance amount and adjusting the amount of air supplied to the intake port, the burden on the engine can be reduced (S27).
[0054]
Next, control for suppressing hunting immediately after engine startup will be described. This control can also be combined with the above-described control. If the engine speed is detected and hunting is likely to occur, the feedback gain in the feedback control of the engine speed may be lowered, or the engine speed region (dead zone) where the feedback control is not performed may be enlarged. The details will be described below.
[0055]
FIG. 8 is a flowchart for feedback control of the engine speed when the engine is idling. By turning on the ignition switch, the engine speed feedback control routine when the engine E is idling is started. First, a water temperature at the time of engine start (engine temperature: intake port temperature) is detected, and it is determined whether the water temperature is equal to or lower than a predetermined value (the engine is in a cold state or a semi-warm state) (S31). When the water temperature is higher than the predetermined value, the amount of air supplied to the intake port is controlled so that the ISC feedback gain or the dead zone is set to a normal value and the engine speed during idling is substantially constant (S36).
[0056]
When the water temperature is lower than the predetermined value, it is detected whether the engine speed after the start is lower than the predetermined value (S32), and the control of step S36 is performed until the engine speed is decreased. It is detected whether the number has increased or decreased by a predetermined value or more than the target engine speed, that is, whether the engine speed has caused an overshoot (S33).
[0057]
If the engine speed has not caused an overshoot, control in step S36 is performed. If it has occurred, it is determined whether the start condition for air-fuel ratio feedback control is satisfied (S34), and the condition is satisfied. Thus, when the air-fuel ratio feedback control is started, the control of step 36 is performed.
[0058]
When it is determined whether the start condition of the air-fuel ratio feedback control is satisfied (S34), if the air-fuel ratio feedback control is not started because the condition is not satisfied, the ISC feedback gain is set to the normal value. The dead zone is further reduced, or the dead zone is increased from the normal value, and feedback control of the engine speed during idling is suppressed or prohibited (S35). Here, instead of the feedback control, feedback control may be performed in which the engine speed during idling is made constant by controlling the ignition timing.
[0059]
FIG. 9 is a graph showing the time dependency of the engine speed when the feedback gain is reduced. Immediately after starting the engine, if the engine speed falls below the rotation drop detection threshold, it is determined that the engine speed has dropped, and then the deviation of the engine speed from the target engine speed is detected as a lower limit or upper limit overshoot. When the threshold value is exceeded, it is determined that the engine speed has caused hunting and feedback controllability has deteriorated, and ISC (control for adjusting the amount of air supplied to the intake port so that the engine speed becomes the idle speed) The feedback gain in the engine speed feedback control is reduced, and hunting of the engine speed is suppressed. The dotted line indicates the engine speed when such gain reduction is not performed.
[0060]
In the figure, the time dependence of the rotational speed feedback air amount (correction amount) by ISC is also shown. As the feedback gain decreases, the amount of time change of the air amount decreases. The dotted line indicates the amount of air when gain reduction is not performed.
[0061]
In this control, a dead zone in which feedback control of the engine speed is not performed is set within a predetermined range from the target engine speed.
[0062]
FIG. 10 is a graph showing the time dependency of the engine speed when the dead zone is expanded. Immediately after starting the engine, if the engine speed falls below the rotation drop detection threshold, it is determined that the engine speed has dropped, and then the deviation of the engine speed from the target engine speed is detected as a lower limit or upper limit overshoot. When the threshold value is exceeded, it is determined that the engine speed has caused hunting and the feedback controllability has deteriorated, the dead zone where the engine speed feedback control by ISC is not applied is expanded, and the engine speed hunting is suppressed. The dotted line indicates the engine speed when the dead zone is not expanded.
[0063]
In the figure, the time dependence of the rotational speed feedback air amount (correction amount) by ISC is also shown. As the dead zone expands, the amount of time change of the air amount decreases. The dotted line indicates the amount of air when the dead zone is not expanded.
[0064]
In the above-described control, hunting suppression control such as feedback gain reduction was started using the detection of feedback control performance deterioration as a trigger, but without such trigger, hunting suppression was automatically performed before the start of air-fuel ratio feedback control. It is good also as performing control.
[0065]
FIG. 11 is a flowchart for feedback control of the engine speed during idling based on such a method. By turning on the ignition switch, the engine speed feedback control routine when the engine E is idling is started. First, the water temperature at the time of engine start is detected, and it is determined whether the water temperature is equal to or lower than a predetermined value (S41). When the water temperature is higher than a predetermined value, the ISC feedback gain is set to a normal value, and the amount of air supplied to the intake port is controlled so that the engine speed during idling is substantially constant (S47).
[0066]
When the water temperature is lower than the predetermined value, it is detected whether the engine speed after the start is lower than the predetermined value (S42), and the control of step S47 is performed until the engine speed is decreased. It is determined whether a predetermined time has passed later (S43).
[0067]
If the predetermined time has not elapsed after the engine is started, the above-described hunting suppression control such as reducing the ISC feedback gain is performed (S44). When a predetermined time has elapsed after the engine is started, it is determined whether or not the start condition of the air-fuel ratio feedback control is satisfied (S45), and if the air-fuel ratio feedback control is started by satisfying the condition, Then, it is determined whether or not the rise of the water temperature from the start is less than a predetermined value, and if it is greater than or equal to the predetermined value, control in step S47 is performed, and if it is less than the predetermined value, control in step S44 is performed. Note that, as a result of determining whether or not the start condition of the air-fuel ratio feedback control is satisfied, the control of step S44 is also performed when the air-fuel ratio feedback control is not started because the condition is not satisfied.
[0068]
In addition, you may transfer to step S44 or S47 after the determination conditions of step S42 by making said step S43, S44, S45 into an independent determination condition, respectively.
[0069]
As described above, in this embodiment, after the temperature of the intake port rises, the amount of fuel adhering to the port decreases, and after the response of the rotational speed to the change in the ISC air amount is recovered, the feedback gain By setting as usual, hunting can be suppressed.
[0070]
As described above, according to the engine control apparatus described with reference to FIGS. 1 to 6, when the engine speed increases to the target value after the engine speed decreases, the fuel supply timing to the intake port of the engine is set before the intake operation. If the engine speed again decreases by a predetermined value or more due to this intake asynchronous injection, the fuel supply timing is switched to the intake operation, and if it does not decrease by the predetermined value, it is not switched. Accordingly, the combustion state can be favorably maintained.
[0071]
In addition, according to the engine control device described in (2), the engine speed feedback control based on the ignition timing can be terminated early.
[0072]
Further, according to the engine control apparatus described in FIG. 8 and subsequent figures, hunting can be suppressed by detecting an overshoot of the engine speed.
[0073]
【The invention's effect】
According to the engine control device of the present invention, the combustion state can be maintained satisfactorily.
[Brief description of the drawings]
FIG. 1 is a block diagram of an engine system including an engine control apparatus according to an embodiment.
FIG. 2 is a timing chart for explaining control according to the embodiment.
FIG. 3 is a graph showing the time dependence of the engine speed when heavy fuel is used.
FIG. 4 is a graph showing the time dependency of the engine speed when light fuel is used.
FIG. 5 is a flowchart by a control device.
FIG. 6 is a graph showing the time dependency of the amount of hydrocarbon (HC) discharged from the engine per unit time.
FIG. 7 is a flowchart for feedback control of the engine speed when the engine is idle.
FIG. 8 is a flowchart for feedback control of the engine speed when the engine is idle.
FIG. 9 is a graph showing the time dependency of the engine speed when the feedback gain is reduced.
FIG. 10 is a graph showing the time dependency of the engine speed when the dead zone is expanded.
FIG. 11 is a flowchart for feedback control of the engine speed during idling.
[Explanation of symbols]
E ... Engine, ECU ... Electronic control unit, FP ... Fuel pump, FT ... Fuel tank, I ... Injector, OX ... Oxygen sensor, PA ... Intake port, PE ... Exhaust port, R ... Speed sensor, TB ... Intake pipe, TB '... exhaust pipe, V ... throttle valve, W ... water temperature sensor.

Claims (3)

In the control device for controlling the injector so that the intake asynchronous injection that ends the fuel injection before the intake period of the engine and the intake synchronous injection that ends the fuel injection within the intake period of the engine are performed in the intake port,
(A) The intake-synchronized injection is performed when the actual engine speed decreases by a given value or more than the target engine speed . (B) After that , when the actual engine speed increases to the target value, the intake air Asynchronous injection is performed. (C) When the actual engine speed decreases by a predetermined value or more than the target engine speed due to the intake asynchronous injection, switching to the intake synchronous injection is performed. Continue the intake asynchronous injection ,
When the actual engine speed in the operation (B) has increased to a target value, it is determined whether the advance margin of the ignition timing of the engine is greater than or equal to a predetermined value. An engine control device that performs the intake asynchronous injection in the operation (B), advances the ignition timing, and controls the injector not to perform the intake asynchronous injection when the ignition timing is less than a predetermined value . The engine control device according to claim 1, wherein the duration of the intake asynchronous injection in the operation (C) is several seconds or more. The engine control device according to claim 1 or 2 , wherein the control of the injector is performed when a water temperature at the time of starting the engine is equal to or lower than a predetermined value.

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