JP3849682B2 - Engine control device - Google Patents

Description

  The present invention relates to an engine control device, and more particularly to an engine control device that stops fuel supply (performs fuel cut) after a predetermined delay time has elapsed 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 short to prevent the air-fuel ratio from transiently becoming rich, thereby preventing emission deterioration, while when the transmission is in the traveling range, the delay time is lengthened. 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.

  In order to improve the upshift feeling, especially in vehicles equipped with manual missions, it is necessary to reduce the engine speed to the optimum at the time of upshifting. In recent years, however, higher engine output and higher efficiency have been achieved. As a result, the intake collector tends to increase and the fuel cut delay time has become longer. With the above-mentioned conventional technology, the decrease in the engine speed during the shift-up operation is further slowed down, resulting in a quick shift. There was a problem in terms of realizing ups and preventing shocks when shifting up.

  The present invention has been made paying attention to such problems, and an object of the present invention is to realize a speed change without a shock while preventing a deceleration shock due to a fuel cut in an engine provided with a manual transmission.

  For this reason, the engine control apparatus according to the present invention is provided in an engine connected to a drive wheel via a clutch that is fastened or released by a driver's operation (for example, depression of a clutch pedal), and a predetermined fuel cut condition Is established, the fuel supply is stopped after a lapse of a predetermined delay time, and when it is detected that the clutch has changed from the engaged state to the semi-engaged state before the delay time has elapsed, The engine output is controlled so as to maintain the engine speed when the clutch is engaged.

  According to the engine control apparatus of the present invention, even when the clutch is opened by the driver before the fuel cut delay time elapses, it is the initial stage of the opening operation (completely released). When the previous half-engaged state is detected, and the engine output control is performed so as to maintain the engine speed in the immediately previous half-engaged state, if the clutch operation by the driver is slow or Even when the fastening state is maintained (when the load on the drive side is substantially eliminated), the engine speed can be reliably prevented from being blown up. Thereby, especially at the time of upshifting, it is possible to accelerate the decrease in the engine speed due to the subsequent fuel cut (after the delay time has elapsed), and it is possible to realize a speed change without a shock.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic 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 (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 transmission of power from the engine 1 to the drive wheels 7 (that is, the engine 1). And the connection with the driving wheel 7 are cut off. 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 Power is transmitted from to the drive wheels 8 (the engine 1 and the drive wheels 7 are connected).

  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. Also, the first clutch pedal switch 25 that operates when the depression amount of the clutch pedal 8 is deep and detects that the clutch 2 is completely released, and the second clutch that operates when the depression amount of the clutch pedal 8 is shallow. Operation signals such as an idle switch 27 that operates in a state where the pedal switch 26 and the accelerator pedal 9 are completely returned (a throttle valve is fully closed (not shown)) 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 first clutch pedal switch 25 (also serves as a combination).

  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.
2 to 4 are flowcharts showing a fuel injection control routine according to the present embodiment, which are executed at predetermined time intervals.
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. This 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 S104. If Fcut = 1, the process proceeds to S111 (FIG. 3). 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. 5).
In S104, the calculated fuel injection amount Qf is set as the output injection amount Qfset, and a drive pulse Ti corresponding to the output injection amount Qfset is output to the fuel injection valve of each cylinder. Thereby, the fuel of the output injection amount Qfset is supplied from the fuel injection valve to each cylinder of the engine 1.

  In S111 (FIG. 3), a clutch switch signal (first clutch pedal switch signal) SWcl1 is read, and it is determined whether or not the read clutch switch signal SWcl1 is “1”. If SWcl1 = 1, the process proceeds to S124, and if SWcl1 = 0, the process proceeds to S112. The setting of the clutch switch signal SWcl1 will be described later (see the description of S122).

In S112, the gear ratio R (= engine speed Ne / vehicle speed Vs) at the current shift position, that is, the shift position before (immediately before) the depression of the clutch pedal 8 is calculated.
In S113, the second clutch pedal switch signal SWcl2 is read, and it is determined whether or not the value of the read second clutch pedal switch signal SWcl2 is zero. If SWcl2 = 0, the process proceeds to S114, and if SWcl2 = 1, the process proceeds to S117. The second clutch pedal switch 26 is always turned on when the clutch pedal 8 is not depressed, and is turned off when the clutch pedal 8 is depressed. The second clutch pedal switch signal SWcl2 is a second clutch pedal sensor. It is set to 0 when 26 is ON, and to 1 when it is OFF (immediately after the start of depression of the clutch pedal 8). Therefore, when the second clutch pedal switch signal SWcl2 is switched from 0 to 1, it means that the driver has depressed the clutch pedal 8, and in the present embodiment, this signal SWcl2 is 1 When the clutch switch signal SWcl1 is 0, the clutch 2 is half-engaged.

In S114, a first value CNT1 that sets the length of the delay time of fuel cut for all cylinders (# 1 to #n) when the clutch 2 is in the engaged state is set.
In S115, the count value CNT is incremented by one. The count value CNT indicates an elapsed time after the fuel cut condition is established.
In S116, it is determined whether or not the counted up first count value CNT1 has reached the first value CNT1. If it has reached, the process proceeds to S126, and if not, this flow is terminated.

In S117, the target rotational speed TNe (= transmission ratio R × vehicle speed Vs) is calculated. The target engine speed TNe is to be maintained if the clutch 2 is engaged at the shift position before the depression of the clutch pedal 8 (that is, the engine speed immediately before the clutch is engaged). Corresponds to Ne1.
In S118, the current engine speed Ne is detected, and a difference ΔNe (= Ne−TNe) between the detected engine speed Ne and the target engine speed TNe is calculated.

In S119, it is determined whether ΔNe is greater than zero. If ΔNe> 0, the process proceeds to S120, and if ΔNe ≦ 0, the process proceeds to S122. When ΔNe> 0, the calculated ΔNe corresponds to the amount of the engine 1 that has blown up due to the clutch 2 being in a semi-engaged state.
In S120, the number of cylinders to perform fuel cut (number of fuel cut cylinders) m (= ΔNe / α) is calculated in order to reduce the amount of blow-up (ΔNe) and set the engine speed to the target engine speed Te. To do. Here, α is set according to the number of cylinders for each engine. For example, when the engine speed that decreases by performing fuel cut for one cylinder is 50 (100) rpm. Is α = 50 (100).

In S121, the fuel injection amount Qf for the calculated number m of cylinders is set to 0, and partial fuel cut is executed. For example, when it is m = 1, while select one cylinder among all the cylinders (# 1~ # n) (#a ), the fuel injection quantity Qf _a of the selected cylinder to zero, it The fuel injection amounts of the cylinders other than the cylinder are left as Qf, and these are set as the output injection amounts Qfset _i (i = 1 to n), and the drive pulse Ti _i corresponding to each output injection amount Qfset _{i is applied} to the fuel injection valve of each cylinder. Output. As a result, even when the engine 1 is blown up at the initial stage of the depression operation of the clutch 2, the engine speed can be quickly converged to the target engine speed TNe.

  That is, immediately after the start of depression of the clutch pedal 8 after the fuel cut condition is satisfied, the engine output suppression control is performed so as to maintain the engine speed (target engine speed) according to the driving state before the clutch pedal operation. Will be done. It should be noted that the engine control may be performed so as to maintain the target engine speed. In addition to the case where the partial fuel cut is performed as described above, the fuel injection amount Qf (that is, the fuel injection amount of all cylinders) is uniformly set. It may be corrected to decrease or the ignition timing may be changed.

  In S122, the clutch switch signal (first clutch pedal switch signal) SWcl1 is read, and it is determined whether or not the value of the read clutch switch signal SWcl1 is 1. If SWcl1 = 1, the process proceeds to S123, and if SWcl1 = 0, this flow ends. This clutch switch signal SWcl is set to 1 when the clutch pedal 8 is depressed and the clutch 2 is completely released, and is set to 0 otherwise.

In S123, a second value CNT2 (<CNT1) that sets the length of the delay time of fuel cut for all cylinders (# 1 to #n) when the clutch 2 is in the (complete) disengaged state is set. To do. Note that the second value CNT2 may be set to 0 to perform fuel cut without a delay time.
In S124, the count value CNT is incremented by one.

In S125, it is determined whether the counted up count value CNT has reached the second value CNT2. If it has reached, the process proceeds to S126, and if not, this flow is terminated.
In S126 (FIG. 4), the fuel injection amount Qf is set to 0, assuming that a predetermined delay time (CNT1 or CNT2) has elapsed after the fuel cut condition is satisfied.

  In S127, the set fuel injection amount Qf is set as the output injection amount Qfset, and a drive pulse Ti corresponding to the output injection amount Qfset is output to the fuel injection valve of each cylinder. Thus, when the clutch 2 is engaged after the fuel cut condition is satisfied, the fuel cut is executed for all the cylinders after the first value CNT1 has elapsed, and the fuel cut condition is satisfied. When the clutch 2 is completely disengaged, fuel cut is executed for all cylinders after the second value CNT2 (<CNT1) has elapsed.

When the fuel cut for all cylinders is executed, the count value CNT is cleared (CNT = 0) in S128 and the process is terminated.
FIG. 5 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.ltoreq.Ne2, the fuel cut is stopped (fuel supply is resumed), so the routine proceeds to S207, where the fuel cut flag Fcut is set to zero. If Ne> Ne2, the process proceeds to S205.
FIG. 6 is a time chart showing changes at the time of fuel cut in 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, the fuel cut delay time is set to the first value CNT1 that is relatively long, and the fuel value is kept until the count value CNT reaches the first value CNT1 (time t4). Is continued (A1). For this reason, the engine speed Ne gradually decreases (B1).

  On the other hand, when the clutch pedal 8 is depressed and the second clutch pedal switch 26 is turned OFF (SWcl2 = 1), if the clutch 2 is engaged, the engine speed to be held is set as the target engine speed TNe and the current engine speed is set. When the number Ne exceeds the target engine speed TNe, engine output suppression control (partial fuel cut) is started so as to decrease the amount (the amount of blow-up) (time t2). Therefore, the engine speed Ne is maintained at the speed immediately before the clutch pedal 8 is depressed (target engine speed TNe) (B2).

When the clutch pedal 8 is further depressed and the clutch switch (first clutch pedal switch) 25 is turned on (SWcl1 = 1), the clutch 2 is completely released, and the delay time of the fuel cut is the second value CNT2 (the first CNT2). 1 is set to a value shorter than the value CNT1, which is 0 here (time t3), and the supply of fuel is immediately stopped (A3). For this reason, the engine speed Ne is rapidly reduced (B3).
Thereafter, when the shift operation (upshift) is completed and 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 resumed.

  According to the embodiment described above, when the fuel supply is stopped after a predetermined delay time has elapsed after the fuel cut condition has been established, if the clutch 2 is in a semi-engaged state before the delay time has elapsed, Since the output (suppression) control of the engine 1 is performed so as to maintain the engine speed (target engine speed TNe) in the clutch engaged state (S113 to S121, B2 in FIG. 6), before the clutch 2 is completely released. Thus, it is possible to reliably prevent the engine speed from rising when the load on the drive side is substantially eliminated. Thereby, especially at the time of upshifting, it is possible to accelerate the decrease in the engine speed due to the subsequent fuel cut (after the delay time has elapsed), and it is possible to realize a speed change without a shock.

  In addition, when performing the fuel cut, the delay time is shortened when the clutch 2 is in the open state compared to other times (when the clutch 2 is in the engaged state). By setting (CNT1) (S114), while preventing a deceleration shock (A1 in FIG. 6), a short (or zero) delay time (CNT2) is set at the time of shifting (shifting up) when the clutch 2 is released. By setting (S123), the engine speed can be quickly reduced (B3 in FIG. 6). As described above, when the clutch 2 is in the half-engaged state, output control of the engine 1 is performed so as to maintain the engine speed, so that the engine speed in the half-engaged state is increased (B4 in FIG. 6). ) Can also be prevented, so that a quick and shock-free shift can be realized more effectively, especially when shifting up.

  Further, in the present embodiment, as the output control of the engine 1, the difference ΔNe between the engine speed when the clutch 2 is in the half-engaged state and the engine speed (target engine speed TNe) in the clutch-engaged state immediately before the clutch 2 is set. Is greater than 0, the fuel supply amount is reduced according to the difference ΔNe (fuel supply to some cylinders is stopped) (S113 to S121), and the engine is used only when necessary. Output control (suppression control) is performed, and only by controlling the fuel supply amount, it is possible to prevent deceleration shock at the time of fuel cut and improve shift feeling.

  In the embodiment described above, the engine output control (suppression control) is performed after the fuel cut condition is satisfied. However, the engine output control (suppression) is performed when the clutch 2 before the fuel cut condition determination is in a semi-engaged state. As a result, the engine output control (suppression control) may be performed from the fuel cut determination to the release of the clutch 2 (in other words, before the delay time elapses).

Configuration diagram of a vehicle according to an embodiment of the present invention Flow chart showing fuel injection control routine (1) Flow chart showing fuel injection control routine (2) Flow chart showing fuel injection control routine (3) Flowchart showing fuel cut flag setting routine Time chart showing changes during 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, output control means), 21 ... accelerator sensor, 22 ... crank sensor (engine rotation detection means), 23 ... water temperature sensor, 24 ... vehicle speed sensor, 25 ... first clutch pedal switch (open state detection means), 26 ... first 2 clutch pedal switch (semi-engaged state detecting means), 27 ... idle switch

Claims (6)

An engine control device connected to drive wheels via a clutch that is fastened or released by a driver's operation,
Engine rotation detecting means for detecting the engine speed;
A semi-engagement state detecting means for detecting that the clutch has changed from an engagement state to a semi-engagement state;
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;
Output control means for controlling the output of the engine so as to maintain the engine speed in the immediately preceding clutch engaged state before the delay time has elapsed and the clutch is in a semi-engaged state;
An engine control device comprising: An open state detecting means for detecting that the clutch is in an open state;
2. The engine control apparatus according to claim 1, wherein the fuel supply stop means sets a delay time shorter when the clutch is in an open state than when the clutch is in an open state.   3. The engine control apparatus according to claim 2, wherein the fuel supply stop means immediately stops the supply of fuel when it is detected that the clutch is released.   The output control means controls the output of the engine when an engine speed when the clutch is in a half-engaged state is larger than an engine speed when the clutch is in an immediately preceding clutch-engaged state. The engine control apparatus as described in any one of 1-3.   The output control means reduces the fuel supply amount according to a difference between an engine speed and an engine speed in the immediately preceding clutch engaged state when the clutch is in a semi-engaged state. The engine control device according to any one of 4.   6. The engine control apparatus according to claim 5, wherein the output control means stops the supply of fuel to some cylinders of the engine.