JPH0416623B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an engine intake air amount control device.

(Prior art) When the throttle valve of an engine is suddenly closed to put the engine into deceleration mode, the air-fuel ratio may become overbalanced due to a sudden decrease in the amount of intake air.
It is generally known that deceleration shocks are more likely to occur due to sudden changes in torque.

On the other hand, some devices have a spring or dash pot inserted in the middle of the connecting member that connects the accelerator pedal and the throttle valve to transmit the operation of the accelerator pedal to the throttle valve with a delay.
(See Publication No. 59-152152). In other words, even if the accelerator pedal is suddenly released, the throttle valve does not immediately become fully closed in order to alleviate the deceleration shock.

On the other hand, in order to prevent the above-mentioned overburden, a technique is also known in which air is supplied as deceleration (dash pot) air when the engine is decelerated. That is, the amount of deceleration air at the beginning of deceleration is determined based on the operating state of the engine immediately before deceleration, and the amount of deceleration air is gradually reduced as deceleration progresses, thereby attempting to prevent overbite or deceleration shock.

(Problem to be Solved by the Invention) However, even if the amount of deceleration air at the initial stage of deceleration is determined according to the operating state of the engine, the degree of decrease is constant, so for example, when the engine speed is high, If the deceleration air is reduced even by a large degree of reduction from 2000 to 2000, the deceleration driving state that the driver expects, that is, the feeling of deceleration, will be obtained at first, but this will tend to cause deceleration shock (torque shock), and conversely, the degree of deceleration will decrease. If it is made small, there is a problem that the above-mentioned feeling of deceleration cannot be obtained.

(Means for Solving the Problems) FIG. 1 shows the basic concept of the present invention.

That is, a throttle valve 11 is provided in an intake passage 6 that introduces intake air into the engine body 1.
In the intake passage 6 downstream of the throttle valve 11,
A deceleration air passage 12 having a valve 13 is connected to supply air as deceleration air when the engine is decelerated and to gradually reduce the amount of deceleration air.

Thus, the present invention provides the deceleration air amount control means 25 that controls the deceleration air amount so that the amount of deceleration air decreases per unit time as the time elapses from the start of deceleration of the engine increases; The present invention is characterized in that it includes a reduction amount changing means 26 that changes the reduction amount of deceleration air per unit time in accordance with the operating state of the engine.

(Function) In the case of the present invention, the amount of deceleration air is controlled so that the amount of deceleration air decreases per unit time as the time elapses from the start of engine deceleration. It is possible to suppress the deceleration shock (torque shock) by increasing the amount of decrease in the early stage to obtain a feeling of deceleration, and decreasing the amount of decrease in the later stages of deceleration. In addition, since a means is provided to change the amount of reduction according to the operating condition of the engine, for example, when the engine speed is high at the beginning of deceleration, the amount of reduction described above is increased to enhance the feeling of deceleration, while at the end of deceleration, when the engine speed is high, the amount of reduction is increased. As the number decreases, the amount of decrease can be reduced to prevent deceleration shock.

(Effects of the Invention) Therefore, according to the present invention, the amount of deceleration air is controlled such that the amount of deceleration air decreased per unit time as the time elapsed from the start of deceleration of the engine becomes longer. Since the control means and the reduction amount changing means change the reduction amount of the deceleration air per unit time according to the operating condition of the engine, it is possible to prevent a deceleration shock while giving a feeling of deceleration, especially at the beginning of deceleration. Even when the engine speed is high, the system is quickly brought to a close to fully closed state (with a reduced amount of deceleration air), allowing the driver to obtain the deceleration feeling he or she expects while also preventing torque shock during deceleration. .

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

In the engine intake air amount control device whose overall configuration is shown in FIG.
The exhaust gas is supplied to the combustion chamber 9 above the piston 8 of the cylinder block 7 through an intake passage 6 which is interposed in this order, and exhaust gas is discharged through an exhaust passage 10.

The throttle chamber 4 has a throttle valve 1.
A bypass passage 12 is provided for bypassing 1 from upstream to downstream thereof, and this bypass passage 12 is opened and closed by a bypass air control valve 13 formed by a duty solenoid valve. A throttle switch 14 is attached to the throttle chamber 4 and is turned on when the throttle valve 11 reaches an opening below the idling opening. Further, a water temperature sensor 15 is attached to the cylinder block 7 to detect the temperature of the engine cooling water, a rotation detection sensor 17 is attached to the crankcase 16 to detect the engine rotation speed from the rotation of the crank pulley, A load detection sensor 18 is attached to the downstream intake passage 6 to detect the engine load. Then, in response to the outputs of the throttle switch 14, water temperature sensor 15, rotation detection sensor 17, and load detection sensor 18, the controller 19 outputs an activation signal to the bypass air control valve 13 to decelerate the air downstream of the throttle valve 11. It is designed to be supplied as air or idle speed control air.

As shown in FIG. 3, the controller 19 includes a deceleration determining section 21, a bypass air amount setting section 22 that bypasses the throttle valve 11, and a target control amount generating section 23. In other words, deceleration determination section 2
1 determines whether the engine is in a deceleration state based on on/off of the throttle switch 14, and determines whether the engine is in an idling state based on the engine rotation speed N _E detected by the rotation detection sensor 17. judge.

Then, the bypass air amount setting unit 22 determines the deceleration air amount Q _DPT at the initial stage of deceleration based on the engine speed N _E , the engine water temperature THW measured by the water temperature sensor 15, and the engine load CE measured by the load detection sensor 18.
Set the deceleration air amount Q _DPK during subsequent deceleration operation and the rotation speed control air amount Q _FB during idling operation. In other words, the amount of deceleration air Q _DPT at the beginning of deceleration is the engine speed
The higher the N _E , the larger the engine load CE, and the lower the engine water temperature THW, the larger the amount. In addition, Q _DPK during deceleration operation is based on the engine speed N _E and the elapsed time t from the start of deceleration, and is calculated as T _DP −ΔQ _DPK shown in the following equations (1) and (2) and in Figure 4.
Set by characteristic table.

Q _DPK (i) = Q _DPK (i-1) - ΔQ _DPK ... (1) T _DP = t + a × 1000 / N _E ... (2) In this case, at the beginning of deceleration, Q _DPK (0) = Q _DPT . can be,
As shown in equation (1), a value obtained by sequentially subtracting a predetermined reduction amount ΔQ _DPK at regular intervals is set as the deceleration air amount Q _DPK . This reduction amount ΔQ _DPK is T _DP obtained from equation (2)
This is indexed from FIG. 4, and the longer the elapsed time t from the start of deceleration, the larger T _DP becomes, and therefore the smaller ΔQ _DPK becomes. Also, the engine speed N _E
The higher the value, the smaller the T _DP , and therefore the larger the ΔQ _DPK .
In other words, the amount of decrease in deceleration air per unit time decreases as the elapsed time t from the start of deceleration increases, and the amount of deceleration air changes from the initial rapid decrease state to a gradual decrease state. As the engine speed increases, the amount of deceleration air increases and the amount of deceleration air decreases rapidly, and as the engine speed decreases, the amount of reduction decreases and the amount of deceleration air gradually decreases. Note that a in equation (2) is a constant depending on the type of engine.

Also, the rotation speed control air amount Q _FB during idling operation
is the target rotation speed No. according to the engine coolant temperature THW
Based on the difference ΔN(i) between (i) and the actual engine rotating fluid _NE , it is determined to reduce this difference ΔN(i).

Further, the target control amount generating section 23 determines the duty of the bypass control valve 13 corresponding to the amount of bypass air set by the bypass air amount setting section 22, and outputs a pulse signal of this duty to the bypass air control valve 13. .

The specific control flow is shown in Fig. 5. After initial set (step 1), 25 m
Proceed to the following flow with a sampling period of sec.
First, after reading the engine speed N _E , it is determined whether or not the throttle switch 14 is OFF (steps 2 and 3). When it is OFF (during normal driving when the throttle valve 11 is opened to the idle opening or more), the engine load CE is read and this value is calculated from map 1 shown in Fig. 6 according to the engine speed N _E and the engine load CE. N Index the air amount Q _DPN for initial deceleration corresponding to _E and CE, read the engine water temperature THW, and from Table 2 shown in Figure 7, calculate the air amount Q _DPW for initial deceleration corresponding to THW.
(Steps 4 to 7). And above
Find the initial deceleration air amount Q _DPT by adding Q _DPN and Q _DPW , set the flag F _A , and change Q _DPT to Q _DP.
(Steps 8-12).

Therefore, by adding other air amount Q _ELSE determined by the flow rate after startup and the flow rate of external load (cooler, etc.) to the above Q _DP , we can calculate the duty D(i) according to the air amount Q _B.
is indexed from the QB- _D characteristic table 3 shown in FIG. 8, and a pulse signal of the duty D(i) is output to the bypass air control valve 13 (steps 13 to 15).
That is, in steps 3 to 12 above, even during normal driving when the throttle valve 11 is open, the bypass air control valve 13 is opened at an opening degree that corresponds to the operating state of the engine, with the intention that the engine will enter deceleration operation. , is a process of waiting so that an appropriate initial deceleration air amount can be obtained, and therefore, the above-mentioned Q _B is successively changed and controlled according to the operating state of the engine.

Then, when it is determined that the throttle valve 11 has reached the idle opening position by turning on the throttle switch 14 in step 3, the engine is stopped depending on whether Q _DP is zero or not in step 16. It is determined whether the vehicle is in idle operation or deceleration operation. At the moment when the throttle valve 11 reaches the idle opening position, Q _DP ≠ 0 and the engine is in deceleration operation, so the judgment in step 16 is NO and the process proceeds to step 17.

N in step 17 above is counted up from the start of deceleration (N = 0 in the initial set), and the elapsed time t = 25 × N from the start of deceleration, which is determined by this N, and the engine rotation speed _{N DP} (i) is required (step 18). and,
The decrease amount ΔQ _DPK (i) corresponding to the above T _DP (i) is indexed from the ΔQ _DPK - T _DP characteristic table 4 shown in FIG.
If flag F _A is set, calculate Q _{DPK (i) by subtracting ΔQ DPK (} i) from the initial deceleration air amount Q _DPT and lower flag F _A (zero ₎ . If not, Q _DPK (i) is obtained by subtracting ΔQ _DPK (i) from the previous deceleration air amount Q _DPK (i-1) (steps 18 to 23). In other words, the flag F _A is used to determine whether or not the deceleration air reduction control is being performed for the first time. If Q _DPK (i) obtained by the above subtraction is greater than zero, proceed to the flow from step 13 as Q _DP , and if it is not greater than zero, proceed to this step.
Set Q _DPK (i) to zero, therefore Q _DP =0, and proceed to step 13 (steps 24 to 26).

That is, when the deceleration operation described above continues, it passes through step 21 the first time, and continues through step 21 from the second time onwards.
23, the deceleration air amount Q _DP gradually decreases. When the engine speed N _E at the beginning of deceleration is high, T _DP is small and therefore ΔQ _DPK is large, that is, the amount of reduction in deceleration air per unit time is large. As shown by H in , the engine speed N _E rapidly decreases, but as the engine speed N _E decreases, T _DP becomes large and ΔQ _DPK becomes small (the amount of decrease per unit time is small). breath,
The engine speed N _E will be relaxed.
On the other hand, if the engine speed N _E at the beginning of deceleration is low, the engine speed is as shown by L in Figure 9.
N _E will decrease relatively gradually from the beginning.

In any case, as the elapsed time t from the start of deceleration increases, the amount of reduction in deceleration air per unit time decreases, but if deceleration operation is continued,
A state where Q _DPK (i)≦0 occurs, and the processing at step 25 results in Q _DP = 0, and the decision at step 16 is
If YES, the engine will be in an idling state, and the flow will proceed to step 27 and subsequent steps, where feedback control will be performed to set the engine speed N _E to a predetermined idle speed.

In other words, the engine rotation speed N _FB (i) at which feedback control should be started according to the engine coolant temperature THW
is indexed from the characteristic table 5 shown in FIG.
It is determined whether the current engine speed N _E is smaller than the above N _FB (i), and whether the clutch is OFF or not, and whether the gear is OFF or not.
While setting Q _FB to zero, if N _E reaches the rotational speed at which feedback control is required, and the clutch etc. determines that the engine is essentially in an idling state, it will proceed to feedback control ( Steps 28-31).

In this feedback control, first, the TW-
No(i) Target engine speed No. from characteristic table 6
(i) and the difference ΔN from the current engine speed N _E
Find (i) (steps 32 and 33). And ΔN(i)
According to ΔN(i)−ΔQ _FB (i) characteristic table 7 shown in FIG. 12, the feedback air amount ΔQ _FB (i) is indexed, and if ΔN(i)>0, ΔQ _FB (i Subtract ΔN(i)
If ≦0, calculate Q _FB (i) by adding ΔQ _FB (i), use this as the feedback control air amount Q _FB , proceed to the flow from step 13 onwards, and output the duty D(i) (step 34-38).

Therefore, in the case of the engine intake air amount control device described above, the amount of deceleration air decreases over time, so the amount of deceleration air is rapidly decreased in the early stage of deceleration to provide a feeling of deceleration, while in the late stage of deceleration, the amount of deceleration air is decreased rapidly. can suppress torque shock during deceleration by reducing the amount of reduction in the amount of deceleration air, and the amount of reduction described above changes depending on the engine speed, and the amount of deceleration air decreases rapidly at high engine speeds, so the amount of deceleration air can be reduced quickly. The feeling of deceleration improves as the engine becomes close to closed, and the amount of deceleration air gradually decreases as the rotation speed decreases, thereby preventing torque shock during deceleration. In addition, since the amount of deceleration air at the beginning of deceleration changes depending on the operating state of the engine before starting deceleration operation, the sudden and gradual reduction in the amount of deceleration air described above can be performed smoothly without interfering with engine operation. By determining the presence or absence of the amount of deceleration air (step 16), it is possible to smoothly shift from control of deceleration air to control of idle speed.

In the above embodiment, the reduction amount of deceleration air is controlled based on the engine rotation speed and the elapsed time from the start of deceleration, but if the engine water temperature is high, the reduction amount of deceleration air is increased, etc. The amount of decrease may be corrected using operating state parameters.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, FIG. 1 is a block diagram of the present invention (diagram corresponding to claims), FIG. 2 is an overall block diagram of an engine intake air amount control device, FIG. 3 is a block diagram of the control system, and FIG. Figure 4 is an index table of deceleration air reduction amount, Figure 5 is a control flow diagram, Figure 6 is an index map of initial deceleration air amount determined by engine speed and engine load, and Figure 7 is determined by engine water temperature. Figure 8 is an index table for the initial air amount during deceleration, Figure 8 is an index table for duty, Figure 9 is a characteristic diagram showing changes over time in engine speed during deceleration, and Figure 10 is an index table for engine speed at the start of feedback control. 11 is an index table for the target engine speed, and FIG. 12 is an index table for the amount of feedback air. 1...Engine body, 6...Intake passage, 11...
...Throttle valve, 12...Bypass passage, 13...
...Bypass air control valve, 17...Rotation detection sensor, 19...Controller, 25...Deceleration air amount control means, 26...Decrease amount changing means.

Claims (1)

[Scope of Claims] 1. An intake air amount control device for an engine that supplies air as deceleration air to an intake passage downstream of a throttle valve when the engine is decelerated, and the amount of deceleration air gradually decreases, deceleration air amount control means for controlling the amount of deceleration air such that the amount of deceleration air decreased per unit time as the time elapsed from the start of deceleration of the engine becomes longer; and the amount of deceleration air decreased per unit time. An intake air amount control device for an engine, comprising: a reduction amount changing means that changes the amount of air intake according to the operating state of the engine. 2. The reduction amount changing means is configured to increase the reduction amount per unit time of the deceleration air as the engine speed increases, based on the engine rotation speed representing the operating state of the engine. Engine intake air amount control device.