JP3985779B2 - Engine fuel supply control device - Google Patents

Description

  The present invention relates to an engine control device, and more particularly to an engine fuel supply control device that stops fuel supply (performs fuel cut) after a predetermined delay time elapses after a predetermined fuel cut condition is satisfied.

As a fuel cut method, it is known that the fuel supply is stopped after a predetermined delay time has elapsed since the fuel cut condition such as the throttle valve being fully closed is satisfied, and the transmission range is the neutral range. The delay time is changed between when the vehicle is in the vehicle and when the vehicle is in the travel range (see Patent Document 1).
When the transmission is in the neutral range, the delay time is set to be short so that the air-fuel ratio does not transition to a rich state to prevent the emission from deteriorating. By setting and reducing torque (engine speed) smoothly, deceleration shocks and noise caused by drive system gears are prevented.
Japanese Patent No. 260755

However, when the conventional fuel cut method (delay time setting) is applied to a vehicle equipped with a manual mission, there are the following problems.
That is, in a vehicle equipped with a manual mission, the shift position enters the neutral range when a quick shift-up operation is performed such as depressing the accelerator pedal and simultaneously depressing the clutch pedal (releasing the clutch). Until this time, a long delay time is maintained, and during that period, the fuel cut is not performed, so the decrease in the engine speed becomes dull. Moreover, since the load (on the driving side) is eliminated by releasing the clutch, it is also conceivable that the engine speed increases. For this reason, it is not possible to realize a quick and shock-free shift up.

  On the other hand, when the fuel cut condition is satisfied and the clutch is disengaged, the delay time is shortened (set to 0) to prevent the engine speed from being blown up, and the shift is quick and shock-free. On the other hand, it is possible to change the fuel cut delay time according to the clutch engagement and release, such as preventing the deceleration shock by setting a longer delay time when the clutch is engaged. It is done.

However, the measures described above still have problems when a so-called double clutch operation is performed during downshifting.
In other words, in double clutch operation, first, the clutch is released and the shift position is set to the neutral range, the clutch is engaged, and then the accelerator pedal is depressed to reduce the engine speed to the engine speed corresponding to the gear position after the downshift. After the engine speed has been adjusted, the clutch is released again and the gear is put into the desired position for smooth shifting (shifting down). When the fuel cut condition is satisfied, a long delay time is set because the clutch is engaged.

  For this reason, if the accelerator pedal is depressed in the neutral range to adjust the engine speed, but the engine speed has increased too much, the delay time that is set (long) even if the fuel cut condition is satisfied Until this time elapses, the fuel cut is not performed, and the engine speed does not decrease rapidly, and eventually the problem remains that it takes time to adjust the engine speed.

  The present invention has been made paying attention to such a problem, and an object of the present invention is to realize a quick shift while preventing a deceleration shock due to a fuel cut in an engine provided with a manual transmission.

Therefore, the first engine fuel supply control device according to the present invention is disposed between the engine and the transmission when the fuel supply is stopped after a predetermined delay time has elapsed since the fuel cut condition is satisfied. When the clutch is engaged, at the time of downshifting, the fuel cut condition is determined depending on whether or not the fuel cut condition is satisfied after the engine speed adjustment operation for adjusting the engine speed to the speed after the downshift is performed. Change the delay time. That is, when the fuel cut condition after the engine speed adjustment operation is performed, the first value is set as the delay time, and in other cases ( that is, the fuel cut condition without performing the engine speed adjustment operation). There is in) when satisfied was decided to set the longer second value than the first value as the delay time.

In the second engine fuel supply control device according to the present invention, at the time of downshifting, a clutch disposed between the engine and the transmission is engaged, and the accelerator operation is performed when the transmission is in the neutral state. In such a case, the fuel supply is stopped when the accelerator operation is stopped.

According to the first engine fuel supply control device of the present invention, when the clutch is engaged, in principle, a relatively long delay time (second value) has elapsed since the fuel cut condition was satisfied. By stopping the fuel supply later, the deceleration shock accompanying the fuel cut will be prevented, but when the fuel cut condition is satisfied after the engine speed adjustment operation is performed, even if the clutch is engaged, A short delay time (first value) is set. For this reason, at the time of downshifting, the engine speed adjustment operation was performed to match the speed after the downshift, but as a result, the engine speed exceeded the speed after the downshift (too high) In this case, it is possible to quickly reduce the rotational speed, so that it is possible to realize a speed change without a shock at the time of downshifting while preventing a deceleration shock accompanying a fuel cut .
Further, according to the second engine fuel supply control apparatus of the present invention, when an accelerator operation is performed when the clutch is engaged and the transmission is in the neutral state at the time of shift down , the accelerator operation is lost. If the engine speed is excessively increased by adjusting the engine speed by operating the accelerator during downshifting, the fuel supply is stopped without confirming whether or not the fuel cut condition is met. Even in such a case, the engine speed can be quickly reduced, and a smooth downshift without a shock can be realized.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing a configuration of a manual transmission vehicle (hereinafter simply referred to as a vehicle) according to an embodiment of the present invention. As shown in this figure, an engine 1 and a manual transmission (manual transmission, hereinafter referred to as MT) 3 connected to the engine 1 via a clutch 2 are mounted on the vehicle.

The crankshaft 101 that is the output shaft of the engine 1 is coupled to the input side (clutch disc) 201 of the clutch 2, and the input shaft 301 of the MT 3 is coupled to the output side (clutch plate) 202 of the clutch 2. . The output shaft of the MT 3 is coupled to the wheel drive shaft 6 and the drive wheel 7 via the propeller shaft 4 and the differential gear 5.
The clutch 2 is released or engaged according to the position (depressed position) of the clutch pedal 8 that is depressed by the driver. When the driver depresses the clutch pedal 8 to release the clutch 2, the mechanical coupling between the crankshaft 101 and the input shaft 301 of the MT3 is released, and the transmission of power from the engine 1 to the drive wheels 7 is interrupted. When the driver finishes depressing the clutch pedal 8 and the clutch pedal 8 returns to its original position and the clutch is engaged, the crankshaft 101 and the input shaft 301 of the MT3 are mechanically coupled, and the engine 1 Then, power is transmitted to the drive wheel 8 via MT3.

  MT3 is shifted by a driver operating a shift lever (not shown). This MT3 is provided with a synchromesh mechanism, and gears having different rotational speeds are quickly synchronized with each other at the time of gear shifting so that the gear shifting operation is smoothly performed. The synchromesh mechanism is well known and will not be described in detail, but may be a key type inertia lock, a pin type inertia lock, or a servo type inertia lock.

  The operation of the engine 1 is controlled by a control unit (hereinafter referred to as C / U) 10. The C / U 10 includes an accelerator sensor 21 that detects the accelerator opening APO (the amount of operation of the accelerator pedal 9), a crank sensor 22 that detects the rotational speed (engine speed Ne) of the crankshaft 101, and the engine coolant temperature Tw. Detection signals of various sensors such as a water temperature sensor 23 for detecting the vehicle speed and a vehicle speed sensor 24 for detecting the vehicle speed Vs are input. Further, the clutch pedal switch 25 for detecting that the clutch pedal 8 is depressed and the clutch 2 is completely released, and the idle pedal that operates in a state where the accelerator pedal 9 is completely returned (a throttle valve is fully closed, not shown). Operation signals such as a neutral switch (inhibitor switch) 27 that operates when the switches 26 and MT3 are in the neutral state are also input.

  In the present embodiment, a so-called clutch start system is employed in which the starter motor (cell motor) is not energized even if the ignition key (not shown) is turned to the engine start position without depressing the clutch pedal 8. In the clutch start system, a clutch switch for detecting the release of the clutch 2 is used as the clutch pedal switch 25 (also used as a clutch pedal).

  The C / U 10 executes engine control such as fuel supply control (fuel injection control) on the basis of various input signals. In particular, regarding the fuel injection control, the fuel of the engine 1 according to the operating state at normal times. While controlling the drive of the injection valve (not shown) to supply the optimum amount of fuel to the engine 1, when the predetermined fuel cut condition is satisfied, the drive of the fuel injection valve is stopped and the fuel to the engine 1 is stopped. The supply is stopped.

Next, processing executed by the C / U 10 will be described using a flowchart.
FIG. 2 is a flowchart showing a fuel injection control routine according to the present embodiment, which is executed every predetermined time.
In S101, the engine operating state such as the accelerator opening APO, the engine speed Ne, the coolant temperature Tw, the vehicle speed Vs, etc. is read.

  In S102, the fuel injection amount Qf is calculated based on the read operating state. The fuel injection amount Qf is based on, for example, a basic fuel injection amount map assigned according to the accelerator opening APO and the engine speed Ne based on the read accelerator opening APO and the engine speed Ne. The fuel injection amount Qfbase is calculated, and is calculated by performing correction according to the coolant temperature Tw and the like.

In S103, it is determined whether or not the fuel cut flag Fcut is zero. If Fact = 0, the process proceeds to S109. If Fcut = 1, the process proceeds to S104. The fuel cut flag Fcut is normally set to 0 (when the predetermined fuel cut condition is not satisfied) and set to 1 when the predetermined fuel cut condition is satisfied (see FIG. 3).
In S104, a predetermined value CNT1 for determining the fuel cut delay time is set. This predetermined value CNT1 is set in a delay time setting routine (FIG. 4) described later.

In S105, the count value CNT is incremented by one. The count value CNT indicates an elapsed time after the fuel cut condition is satisfied (after the fuel cut flag Fcut is set to 1).
In S106, it is determined whether or not the counted up count value CNT has reached a predetermined value CNT1. If the predetermined value CNT1 has been reached, the process proceeds to S107, and if not, the process proceeds to S109.

In S107, the fuel injection amount Qf is set to 0 on the assumption that the time (delay time) determined by the predetermined value CNT1 has elapsed since the fuel cut condition was satisfied. As a result, the supply of fuel to the engine 1 is stopped after a predetermined delay time has elapsed since the fuel cut condition was established.
In S108, the count value CNT is cleared (CNT = 0).

  In S109, the fuel injection amount Qf is set as the output injection amount Qfset, and the drive pulse Ti corresponding to the output injection amount Qfset is output to the fuel injection valve. As a result, the fuel injection valve is driven by this drive pulse Ti to supply the fuel of the output injection amount Qfset to the engine 1. On the other hand, when the fuel cut condition is satisfied, the engine 1 Stop supplying fuel to

FIG. 3 is a flowchart showing a routine for setting the fuel cut flag Fcut, which is executed every predetermined time.
In S201, the idle switch signal SWid and the engine speed Ne are read.
In S202, it is determined whether or not the value of the read idle switch signal SWid is 1. If SWid = 1, the process proceeds to S203, and if SWid = 0, the process proceeds to S207. The idle switch signal SWid is set to 1 when the accelerator pedal 9 is fully returned, and is set to 0 otherwise.

In S203, it is determined whether or not the fuel cut flag Fcut is zero. If Fcut = 0, the process proceeds to S204. If Fcut = 1 (that is, the fuel cut is being executed), the process proceeds to S207.
In S204, it is determined whether or not the read engine speed Ne is equal to or higher than a predetermined fuel cut permission speed Ne1. If Ne ≧ Ne1, the process proceeds to S205, and if Ne <Ne1, the process proceeds to S207.

In S205, the fuel cut flag Fcut is set to 1 assuming that the fuel cut is possible.
In S206, it is determined whether or not the engine speed Ne has become equal to or lower than a predetermined fuel resupply speed Ne2 (<Ne1) after the fuel cut. If Ne ≦ Ne2, the process proceeds to S207, and if Ne> Ne2, the process proceeds to S205.

In S207, the fuel cut flag Fcut is set to 0 in order to stop the fuel cut (restart the fuel supply).
FIG. 4 is a flowchart showing a routine for setting a fuel cut delay time, which is executed every predetermined time. The value set as the predetermined value CNT1 is determined by this flow.

In S301, an idle switch signal SWid, a clutch switch signal (clutch pedal switch signal) SWcl, a neutral switch signal SWneu, and the like are read.
In S302, it is determined whether the fuel cut flag Fcut is 1 or not. If Fcut = 1, the process proceeds to S308, and if Fact = 0, the process proceeds to S303.
In S303, it is determined whether or not the clutch switch signal SWcl is zero. If SWcl = 0, the process proceeds to S304, and if SWcl = 1, the process proceeds to S307.

In S304, it is determined whether or not the neutral switch SWneu is 1. If SWneu = 1, the process proceeds to S305, and if SWneu = 0, the process proceeds to S307.
In S305, it is determined whether or not the idle switch SWid = 0. If SWid = 0, the process proceeds to S306, and if SWid = 1, the process proceeds to S307.
In S306, the engine speed adjustment operation flag Fadj is set to 1. This rotation speed adjustment operation flag Fadj is normally set to 0, and is set to 1 when the driver performs an operation for adjusting the engine rotation speed to the engine rotation speed after the shift down when the driver shifts down. Is done.

In S307, the engine speed adjustment operation flag Fadj is set to 0.
That is, when the clutch 2 is engaged (SWcl = 0) and the MT3 is in the neutral state (SWneu = 1), the accelerator pedal 9 is depressed (SWid = 0). Estimated that engine rotation adjustment operation (so-called double clutch operation) is performed quickly by changing the rotation speed to the rotation speed after downshifting and matching the synchromesh mechanism with the rotation speed of the gear after downshifting. it can. In S302 to S305, it is determined (estimated) whether or not the engine speed adjustment operation has been performed by the driver. As a result, when the engine speed adjustment operation is performed, Fadj is set to 1 in S306. If it is set and the engine rotation adjustment operation is not performed, Fadj is set to 0 in S307.

When Fcut = 1 in S302, the process proceeds to S308. In S308, it is determined whether the clutch switch signal SWcl = 0. If SWcl = 0, the process proceeds to S309, and if SWcl = 1, the process proceeds to S312.
In S309, it is determined whether or not the engine speed adjustment operation flag Fadj is 1. If Fadj = 1, the process proceeds to S310, and if Fadj = 0, the process proceeds to S311.

In S310, since the fuel cut condition after the engine speed adjusting operation (that is, the double clutch operation) is established (immediately after), the predetermined value CNT1 for determining the delay time of the fuel cut is set to the first value. Set to a value a1 of 1.
In S311, the predetermined value CNT1 for determining the delay time is set to the second value a2 (>) assuming that the fuel cut is in a normal state where the clutch 2 is engaged (the engine speed adjustment operation is not performed). Set to a1).

In S312, the predetermined value CNT1 that determines the delay time is set to the third value a3 (<a2), assuming that the fuel cut is in a state where the clutch 2 is disengaged.
In the above description, the presence or absence of the accelerator operation is determined (detected) by the idle switch signal SWid, but the accelerator opening APO may be used instead.

  In S310 to S312, different delay times are set as the first value a1, the second value a2, and the third value a3. However, a1 and a3 are shorter than a2. If there is, it may be set appropriately according to each engine, for example, a1 = a3. Further, in this case, a1 = a3 = 0 may be performed to perform fuel cut without delay (fuel supply is stopped immediately after the fuel cut condition is established).

FIG. 5 is a time chart showing changes during the fuel cut of the present embodiment described above.
When the accelerator pedal 9 is completely returned, the idle switch 27 is turned on (SWid = 1). At this time, if the engine speed Ne is equal to or higher than the fuel cut permission speed Ne1, the fuel cut flag Fcut is set to 1, and the count value CNT starts counting up (time t1).

  Here, when the clutch pedal 8 is not depressed and the clutch switch (clutch pedal switch) 25 is OFF, in principle, the fuel cut delay time CNT1 is set to the relatively long second value a2, and the count is performed. Until the value CNT reaches the second value a2 (time t5), the fuel supply is continued (A1). For this reason, the engine speed Ne gradually decreases (B1).

  However, when the clutch switch 25 is OFF and the neutral switch 27 is ON and the idle switch 25 is switched from ON to OFF (the accelerator pedal 9 is depressed) (time t3 to t4), It is determined that the engine speed adjustment operation (double clutch operation) has been performed (in this case, the fuel cut flag Fcut is also set to 0), and thereafter, the accelerator pedal 9 is completely returned to the fuel cut flag Fcut. Is set to 1, the fuel cut delay time CNT1 is set to the first value a1 (which is shorter than the second value a2 and 0 here) (time t4), Immediately, the fuel supply is stopped (A2). For this reason, even if the engine speed Ne is excessively increased by the engine speed adjusting operation, the target engine speed (that is, the engine after the downshift is compared with the case where the fuel supply is not immediately stopped (B4)). The number of rotations) decreases rapidly toward TNe (B2).

  On the other hand, when the fuel cut flag Fcut is set to 1 and the clutch pedal 8 is depressed and the clutch switch 25 is turned on (time t2), the fuel cut delay time is the third value a3 (the second value a2). (Time t2) and the supply of fuel is immediately stopped (A3). For this reason, compared with the case where the fuel supply is not immediately stopped (B5), the engine speed Ne is rapidly reduced (B3) while preventing the engine from blowing up.

When the accelerator pedal 9 is depressed or the engine speed Ne becomes equal to or lower than the predetermined fuel resupply speed Ne2, the fuel cut flag Fcut is set to 0 and the fuel supply is resumed.
According to the above-described embodiment, when the fuel supply is stopped after a predetermined delay time has elapsed after the fuel cut condition is satisfied, the engine speed adjustment operation (double clutch operation) is performed when the clutch switch 25 is OFF. When the fuel cut condition is satisfied after the above, the first value a1 (= 0) is set as the delay time, and in other cases, the second value a2 (> a1) is set as the delay time. Is set. For this reason, when the clutch 2 is engaged, in principle, a deceleration shock caused by a fuel cut is prevented, and even if the engine speed increases excessively due to a double clutch operation during a downshift, the downshift is performed. Since the target engine speed TNe is quickly reduced to the subsequent target engine speed TNe, it is possible to easily adjust the engine speed at the time of downshifting.

Whether or not the engine speed adjustment operation has been performed can be easily determined by confirming the operation of the clutch switch 25, the neutral switch 27, and the idle switch 26 (S303 to S305).
Further, when the fuel cut is performed, when the clutch 2 is in the released state, the third value a3 (= 0) is set as the delay time, so that the engine speed increases due to the clutch 2 being released. This makes it possible to quickly reduce the engine speed while preventing the shift, and in particular, it is possible to realize a speed change that is quick and shock-free when shifting up.

  In the above-described embodiment, the fuel cut condition is that (1) the idle switch SWid = 1 and (2) the engine speed Ne is equal to or higher than the fuel cut permission speed Ne1 (see FIG. 3), when the engine speed adjustment operation (double clutch operation) is performed, the engine speed Ne increases. In this case, the fuel cut condition is satisfied only by determining (1) above. It can be determined whether or not. Therefore, in the fuel cut determination after the engine speed adjustment operation (double clutch operation), it is determined whether or not the fuel cut condition is satisfied only by the above (1) instead of the normal fuel cut determination (FIG. 3). You may comprise so that it may do.

  Further, in the above embodiment, the description is mainly focused on the fuel cut performed for the purpose of reducing the fuel consumption. However, if attention is paid only to the engine speed adjustment operation (double clutch operation), the engine speed adjustment is performed. The fact that the accelerator operation has been lost after the operation (accelerator pedal 9 has returned) can be presumed that the engine speed has increased excessively. In order to decrease the fuel supply, it is conceivable to immediately stop the fuel supply.

That is, when the engine speed adjustment operation is performed (when the clutch switch SWcl = 0, the neutral switch SWneu = 1, and the idle switch SWid = 0).
Then, when the driver stops the depression of the accelerator pedal 9 (that is, when the idle switch SWid is switched from 0 to 1), the fuel injection amount Qf is set to 0 and is left as it is for a predetermined period. For example, it is very easy to adjust the engine speed during downshifting. This is because the demand for accelerator operation when adjusting the engine speed can be alleviated (the accelerator pedal may be depressed slightly more).

  In this case, the fuel cut condition is basically satisfied, but it is not necessary to make a positive fuel cut determination. Further, the period during which the fuel supply is stopped (the predetermined period) may be set according to, for example, the engine speed and the accelerator operation amount at that time.

1 is a configuration diagram of a vehicle according to an embodiment of the present invention. It is a flowchart which shows a fuel-injection control routine. It is a flowchart which shows a fuel cut flag setting routine. It is a flowchart which shows the delay time setting routine of a fuel cut. It is a time chart which shows the change at the time of a fuel cut.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Clutch, 3 ... Manual transmission (MT), 6 ... Wheel drive shaft, 7 ... Drive wheel, 8 ... Clutch pedal, 9 ... Accelerator pedal, 10 ... Control unit (Fuel supply stop means, fuel cut judgment) Means), 21 ... accelerator sensor, 22 ... crank sensor (engine rotation detecting means), 23 ... water temperature sensor, 24 ... vehicle speed sensor, 25 ... clutch pedal switch (engaged / released state detecting means), 26 ... idle switch (accelerator operation) Detection means), 27 ... Neutral switch (neutral state detection means)

Claims (5)

A fuel supply control device for an engine connected to a transmission through a clutch that is fastened or released by a driver's operation,
An engagement / disengagement state detecting means for detecting that the clutch is engaged or disengaged;
An engine speed adjusting operation determining means for determining whether or not an engine speed adjusting operation for adjusting the engine speed to the speed after shifting is performed;
Fuel cut determination means for determining whether or not a predetermined fuel cut condition is satisfied;
Fuel supply stop means for stopping the supply of fuel after a predetermined delay time has elapsed since the fuel cut condition is satisfied,
When the fuel cut condition is satisfied after the engine speed adjustment operation is performed while the clutch is engaged, the fuel supply stop means sets the first value to the engine speed adjustment operation. When the fuel cut condition is satisfied without being performed, a second value that is longer than the first value is set as the delay time. Neutral state detecting means for detecting that the transmission is in a neutral state;
An accelerator operation detecting means for detecting presence or absence of an accelerator operation by the driver,
The engine speed adjusting operation determining means determines that the engine speed adjusting operation is performed when an accelerator operation is performed when the clutch is engaged and the transmission is in a neutral state. Item 2. A fuel supply control device for an engine according to Item 1.   3. The engine according to claim 1, wherein the fuel supply stop unit sets a third value shorter than the second value as the delay time when the clutch is disengaged. Fuel supply control device.   The engine fuel supply control device according to any one of claims 1 to 4, wherein at least one of the first value and the third value is set to 0. A fuel supply control device for an engine connected to a transmission via a clutch that is fastened or released by a driver's operation,
Engagement / release state detecting means for detecting that the clutch is engaged or disengaged;
Neutral state detecting means for detecting that the transmission is in a neutral state;
An accelerator operation detecting means for detecting presence or absence of an accelerator operation by the driver;
During downshifting, the clutch is engaged, and when the transmission there is an accelerator operation during the neutral state, the fuel supply stop means for stopping the supply of fuel when the accelerator operation is exhausted,
An engine fuel supply control device comprising: