JPH02115543A - Fuel feed control device for engine - Google Patents

Abstract

PURPOSE:To control the speed lower quickly to the target speed by starting the reduction control of the fuel feed quantity when the lowering of the sped is requested, and thereafter, returning to the fuel feed when the speed reaches the target speed requested by a driver. CONSTITUTION:When a driver lowers the speed a little, an acceleration pedal is backed to the release side by the predetermined quantity, and the throttle valve open degree is changed to be reduced by the amount of it. Therefore, a fuel feed means 9 is controlled by a reduction control start means 25 so that the reduction control of the fuel feed quantity to an engine is performed. When the reduction change of the throttle valve open degree is concluded and the open degree is fixed at the predetermined open degree value, the target speed corresponding to it is computed by a target speed computing means 26. At the point of time when the speed is lowered to the target speed, since a reduction control concluding means 27 works so as to conclude the reduction control of the fuel feed quantity by the means 25, the fuel feed quantity to the engine is returned to the normal value and a vehicle maintains the real speed (the target speed).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in an engine fuel supply control device that controls the fuel supply amount to be reduced during deceleration operation of the engine.

(Prior Art) Conventionally, as disclosed in Japanese Patent Laid-Open No. 56-18036, for example, a fuel supply control device for this type of engine has been used to control the supply of fuel to the engine during deceleration operation in which the engine is reversely driven from the wheel side. It is known that the fuel supply is cut (stopped) controlled to improve fuel efficiency. Furthermore, in the method disclosed in Japanese Patent Application Laid-Open No. 63-80031, when coasting operation and slow acceleration operation are performed alternately in constant speed driving control of a vehicle, in the former coasting operation, the engine is While cutting the fuel supply to idle operation state,
The power connection/disconnection clutch is disengaged, and the vehicle is temporarily driven by inertia.

(Problems to be Solved by the Invention) By the way, during normal driving in response to the driver's operation of the accelerator pedal, the driver may partially release the accelerator pedal to slightly reduce the vehicle speed.
It is desirable to quickly reduce the vehicle speed to the target vehicle speed.

However, in the above conventional system, in the former case, the timing to perform fuel cut control is limited to the time when reverse drive is performed from the wheel side, so in the situation where the vehicle speed is slightly reduced, the fuel cut is not performed because it is not during reverse drive. Not done. In addition, in the latter case, fuel cut control is limited to constant speed driving control, so
Similar to the former, fuel cut is not performed. Therefore, in both of the conventional systems described above, in a situation where the vehicle speed is slightly reduced, the reduction in vehicle speed is slow due to the continued fuel supply.

Moreover, there is a drawback that fuel efficiency decreases by the amount of fuel supplied.

The present invention has been made in view of the above, and its purpose is to appropriately perform fuel amount reduction control (including cut control) even when the vehicle speed slightly decreases in response to the driver's operation. , to control the vehicle speed to quickly decrease to the target vehicle speed.

(Means for Solving the Problem) In order to achieve the above object, in the present invention, if there is a request to reduce the vehicle speed, control to reduce the fuel supply amount is started, and then the target vehicle speed requested by the driver is started. If so, the fuel supply will be restored.

That is, the specific configuration of the present invention is based on an engine fuel supply control device that controls the fuel supply amount to decrease during deceleration operation of the engine. As shown in FIG. 1, there is a fuel supply means 9 for supplying fuel to the engine, an opening detection means 15 for detecting the opening of the throttle valve, and an opening detection means 15 for detecting the opening of the throttle valve. A reduction control starting means 25 is provided for starting control of the fuel supply means 9 to reduce the amount of fuel supplied to the engine when the amount of fuel is decreased. Furthermore, vehicle speed detection means 17 for detecting vehicle speed;
A target vehicle speed calculating means 26 receives the output of the opening detecting means 15 and calculates a target vehicle speed corresponding to the throttle valve opening at the end of the decreasing change in the throttle valve opening; and a vehicle speed detected by the vehicle speed detecting means 17. A reduction control terminating means 27 is provided for terminating the reduction control of the fuel supply amount by the reduction control starting means 25 when the vehicle speed matches the target vehicle speed calculated by the target vehicle speed calculation means 26.

(Function) With the above configuration, in the present invention, when the driver attempts to reduce the vehicle speed slightly, the accelerator pedal is returned to the open side by a predetermined amount, and the throttle valve opening is decreased by that amount. . As a result, the fuel supply means 9 is controlled by the reduction control start means 25 to perform reduction control (including cut control) of the amount of fuel supplied to the engine. As a result, the driving torque of the engine is reduced by the amount of fuel that is reduced, and the vehicle speed decreases more quickly.Fuel consumption is also reduced by the amount of fuel that is reduced, resulting in better fuel efficiency. and,
When the throttle valve opening degree has finished decreasing and is fixed at a predetermined opening value, the target vehicle speed calculation means 26 calculates a target vehicle speed corresponding to this predetermined opening value. In this case, the vehicle speed is still decreasing.

Then, when the vehicle speed has decreased to the calculated target vehicle speed, the reduction control termination means 27 operates and the reduction control of the fuel supply amount by the reduction control initiation means 25 is terminated.
The amount of fuel supplied to the engine returns to its normal value, and the vehicle maintains its actual vehicle speed (target vehicle speed). that time,
The point in time when the fuel supply to the engine is restored is the point in time when the throttle valve opening and the actual vehicle speed correspond well to each other, so that the torque shock caused by the restoration of the fuel supply can be suppressed to a small extent.

(Effects of the Invention) As explained above, according to the engine fuel supply control device according to the present invention, when it is desired to slightly reduce the vehicle speed, etc.
When the throttle valve opening is returned to half, the amount of fuel supplied to the engine is controlled to decrease, and the fuel supply is restored when the vehicle speed drops to the target vehicle speed corresponding to the throttle valve opening that has finished decreasing. Therefore, it is possible to reduce the vehicle speed to the target vehicle speed earlier and improve fuel efficiency by the amount of the decrease in the fuel supply amount. Furthermore, torque shock associated with restoration of fuel supply can be suppressed to a minimum.

(Example) Hereinafter, an example of the present invention will be described based on the drawings from FIG. 2 onwards.

FIG. 2 shows an overall schematic configuration of an engine fuel supply control device according to an embodiment of the present invention. In the figure, 1 is an engine, and 2 is a piston 4 inserted into a cylinder 3 of the engine 1.
5 is an intake passage whose one end communicates with the combustion chamber 2 and whose other end opens to the atmosphere via an air cleaner 6;
7 is an exhaust passage whose one end communicates with the combustion chamber 2 and the other end is open to the atmosphere. A throttle valve 8 for controlling the amount of intake air, and a fuel injection valve (fuel supply means) 9 for injecting fuel into the engine 1 downstream of the throttle valve 8 are arranged in the intake passage 5. The combustion chamber 2 is provided with an intake valve 10 at the opening of the intake passage 5, an exhaust valve 11 at the opening of the exhaust passage, and a spark plug 12 at the top.

Further, 15 is an opening sensor (opening detection means) that detects the opening of the throttle valve 8, 16 is a water temperature sensor that detects the engine cooling water temperature, and 17 is a vehicle speed sensor (opening detection means) that detects the vehicle speed.
18 is a shift lever position sensor that detects the gear position of the transmission based on the shift lever position; 19 is an engine rotation speed sensor that detects the rotation speed of the crankshaft 1a of the engine 1; and 20 is the rotation of the crankshaft 1a. This is a crank angle sensor that detects angles. Therefore, each of the above sensors 1
The 5 to 20 detection signals are each input to a controller 22 having an internal CPU or the like.

Next, the control of the amount of fuel injected from the fuel injection valve 9 by the controller 22 will be explained based on the control flow shown in FIG. 3.

After starting, in step S1, engine speed N1, shift lever position (gear position) P1, throttle valve opening T1, and vehicle speed V are monitored based on detection signals from each sensor. After that, in step S2, it is determined whether or not the fuel cut area is reached. This determination is based on engine rotation speed N > 10
00r, p, m and the shift lever position is other than N (neutral position). If it is not in the fuel cut region, in step S3, the throttle valve opening T1, vehicle speed V, and shift lever position P are set to the previous value T-.
wT1, v-vl, P-Pl and return to step S1.

On the other hand, if it is in the fuel cut region, the rate of change of the throttle valve opening T is dT/dt(-(T-T+
)/sampling period), and in step S5, it is determined whether or not deceleration operation is being performed based on dT/dt <-α (-α is a value corresponding to deceleration operation).

Then, if the vehicle is not in deceleration operation, the hood returns to step S1, while if it is in deceleration operation where dT/dt<-α, the process proceeds to step S6 and subsequent steps in order to cut the amount of fuel injected from the fuel injection valve 9.

That is, during deceleration operation, first, in step S6, the previous target basic vehicle speed is determined based on the throttle valve opening-target basic vehicle speed characteristic shown in FIG. 4 according to the previous throttle valve opening T1 and the current shift lever position P. Calculate v□. Here,
The target basic vehicle speed characteristics shown in Figure 4 are based on the target basic vehicle speed, which is the maximum vehicle speed that can be maintained at each throttle valve opening for each shift lever position (1st to 5th forward speed). This is a correspondingly stored vehicle speed map. Then, based on the difference between the previous target basic vehicle speed VO and the previous actual vehicle speed v1 calculated above in step S7, the vehicle speed correction coefficient K is set to v.
When (, > Vl, it is determined that the vehicle is running on an uphill slope, etc., and the value is set to K<1, and when v (, -V, it is determined that the vehicle is traveling on a flat road, etc., and the value is set to -1, V.

When <Vl, it is determined that the vehicle is traveling downhill, etc., and the respective values are set to K>1.

Then, in step S8, the current target basic vehicle speed VOT is calculated based on the target basic vehicle speed characteristics shown in FIG. 4 in accordance with the current throttle valve opening T and shift lever position P. Thereafter, in step S9, the current target basic vehicle speed voT is corrected by multiplying it by the vehicle speed correction coefficient of the value calculated above, and until the actual vehicle speed V decreases to the corrected target basic vehicle speed (VOTXK), Fuel injection from the fuel injection valve 9 is stopped to perform a fuel cut.

Thereafter, from step SIO onward, as shown in FIG. 5(c), the fuel injection amount is gradually increased from the predetermined vehicle speed 2, and the fuel injection is completely restored at the target basic vehicle speed (VoT XK). In other words, during fuel cut, there is no fuel adhering to the wall of the intake passage 5, and if the fuel is suddenly restored, the air-fuel ratio of the mixture will become leaner by the amount of fuel adhering to the wall at the beginning of the restoration.
Fuel is attached to the wall surface of the intake passage 5 in advance.

That is, in step SIO, first the vehicle speed decrease rate Δ■/Δt
After calculating, in step Sll, the fuel injection starting vehicle speed V
2 based on the following equation, the vehicle speed reduction rate ΔV/Δt is set to the high vehicle speed side (earlier) at the turn-on.

V2-VOTXI (10B・(8V/△t) (B is a constant) Then, in step S+2, the vehicle speed V is monitored, and when the vehicle speed reaches V-V2 in step S13, the target basic vehicle speed (VOTXK) is set in step SI4. ) Intended fuel injection ff1A at
After calculating o, in order to increase the fuel amount step by step toward this desired injection ff1Ao, the number of fuel injections i (initial value - 1) is added by "1" in step S15, and step S
+6, the transient injection amount A at the time of the i-th fuel injection is A=
AoX (i/F) (F is vehicle speed v2 ~ (VoT XK)
In step 517, the crank angle θ is monitored. In step 518, the crank angle θ is waited until the injection timing is reached. In step SI9, the fuel injection amount is set to the transient injection amount A. The fuel injection valve 9 is driven and controlled so as to do so. Then, in step 320, the transient injection amount A
-Ao or i-F is determined, and if A<AO and i-F, after adding the number of injections i to i-i+1 in step S2+,
Repeat the above operation to increase the amount of A step by step for each injection, and when it reaches A-AQ or i-F, step S
Return to 1.

Although not shown in the above control flow, during the cut control of fuel injection from the fuel injection valve 9, as shown in FIG. 5(d), the ignition timing of the air-fuel mixture is simultaneously retarded, and then,
The ignition timing of the ignition plug 12 is controlled so that the ignition timing is advanced back to the normal ignition timing at the start of transient injection and ftA injection (vehicle speed V-V2).

In other words, at the start of fuel cut control, the fuel adhering to the wall of the intake passage 5 is sucked into the combustion chamber 2 and burned, causing torque fluctuations at the beginning of deceleration, so the torque fluctuations are suppressed to a small level by retard control of the ignition timing. while ensuring that the fuel is combusted. Furthermore, the reason why the ignition timing is reset in advance before the target vehicle speed reaches the target vehicle speed (at the vehicle speed V2 when the transient injection ff1A starts) is to suppress torque fluctuations when the fuel is restored.

Therefore, in the control flow of FIG. 3 above, step S
a, S5. The reduction control starting means starts controlling the fuel injection valve 9 to stop (cut) the amount of fuel supplied to the engine 1 when the throttle valve opening T detected by the opening sensor 15 decreases by S9. 25. Further, in steps 86 to S8, the opening sensor 1
5, when the throttle valve opening T decreases, the target vehicle speed (VOT) corresponding to the current throttle valve opening T is sequentially set.
The target vehicle speed calculation means 26 is configured to repeat the calculation of VoT XK) and finally calculate the target vehicle speed (VoT XK) corresponding to the throttle valve opening T at the end of the decreasing change. Further, in step S9, the fuel cut is continued until the vehicle speed V detected by the vehicle speed sensor 17 decreases to match the target vehicle speed (VOTXK) calculated by the target vehicle speed calculation means 27, and this vehicle speed matches. At the time point (V-V2), a reduction control termination means 27 is configured to terminate the fuel supply stop control by the reduction control initiation means 25.

Therefore, in the above embodiment, when the throttle valve opening degree T is returned halfway as shown in FIG. 5(b) based on the driver's operation of the opening side of the accelerator pedal, the fuel injection to the engine 1 is stopped as shown in FIG. As shown in (c), since the cut control is immediately performed, the vehicle speed decreases quickly (see (a) in the same figure). Furthermore, fuel efficiency improves by the amount that fuel supply is stopped.

While the throttle valve opening degree T is decreasing, the target vehicle speed (VOTXK) corresponding to the throttle valve opening degree T at that time is sequentially changed.
) is calculated, and the vehicle speed V2 (V2 > V
o7 xK), the transient injection amount A from the fuel injection valve 9
fuel injection is started, and this transient injection amount A is increased stepwise at each injection timing until the actual vehicle speed V reaches the target vehicle speed (Vo T
When the target vehicle speed (VoT XK) is reached, the desired injection jlAo is reached, and the fuel reduction control ends at the target vehicle speed (VoT XK). Therefore, the throttle valve opening degree T and the actual vehicle speed V
Since the fuel supply is completely restored at the time when the two correspond well to each other, the torque shock that accompanies the restoration of the fuel supply is effectively suppressed.

Therefore, even when there is a request to slightly reduce the vehicle speed by partially returning the throttle valve opening, the vehicle speed can be quickly reduced to the target vehicle speed by controlling the reduction in the amount of fuel injection, and driving performance can be improved. , fuel efficiency can be improved by reducing the fuel injection amount. Furthermore, torque shock associated with restoration of fuel supply can be effectively suppressed.

In the above embodiment, the target vehicle speed corresponding to the throttle valve opening degree (T2 in FIG. 5 (b)) at which the decreasing change has been completed is calculated, but the present invention is not limited to this. This also includes a case where the engine speed corresponding to the vehicle speed is calculated and this engine speed is used as the target vehicle speed. Similarly, the throttle valve opening may be indirectly detected based on the amount of depression of the accelerator pedal.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention. Figures 2 to 5 show embodiments of the present invention, with Figure 2 being a general schematic diagram, Figure 3 being a control flowchart showing fuel injection control, and Figure 4 being the target basic vehicle speed relative to the throttle valve opening. A diagram showing the characteristics, and FIG. 5 is an explanatory diagram of the operation. DESCRIPTION OF SYMBOLS 1... Engine, 8... Throttle valve, 9... Fuel injection valve (fuel supply means), 15... Opening degree sensor (opening degree detection means), 17... Vehicle speed sensor (vehicle speed detection means) )
, 22...Controller, 25...Reduction control starting means, 26...Target vehicle speed calculation means, 27...Reduction control terminating means. Figure 1 Figure 2 Figure 2

Claims (1)

[Claims] (1) An engine fuel supply control device configured to reduce the amount of fuel supplied during deceleration operation of the engine, which includes a fuel supply means for supplying fuel to the engine, and an opening detection that detects the opening of a throttle valve. and reduction control starting means for starting control of the fuel supply means to reduce the amount of fuel supplied to the engine when the throttle valve opening detected by the opening detection means decreases, and the vehicle speed is reduced. a vehicle speed detecting means for detecting; a target vehicle speed calculating means for receiving the output of the opening detecting means and calculating a target vehicle speed corresponding to the throttle valve opening at the end of the decreasing change in the throttle valve opening; and the vehicle speed detecting means. and a reduction control terminating means for terminating the fuel supply amount reduction control by the reduction control starting means when the vehicle speed detected by the engine matches the target vehicle speed calculated by the target vehicle speed calculation means. Fuel supply control device.