JPS60224949A - Auxiliary air controller for internal-combustion engine - Google Patents

Abstract

PURPOSE:To increase the engine brake effect by placing an auxiliary air control valve in a bypath detouring a throttle valve and controlling said valve to supply auxiliary air inversely proportional to the square of engine rotation while proportional to the falling speed under deceleration. CONSTITUTION:An auxiliary air control valve 13 is placed in a bypath 12 detouring a throttle valve 11 in an intake path and controlled through valve control means 18. While means 14 for detecting the decelerating state of engine and means 15 for detecting the engine rotation are provided to operate the falling speed of rotation and the square of rotation respectively through falling speed operating means 16 and square operating means 17 on the basis of detected engine rotation. Upon detection of engine falling speed condition through deceleration detecting means 14, the auxiliary air control valve 13 is controlled through valve control means 18 to supply such auxiliary air as inversely proportional to the square of engine rotation while proportional to the falling speed in order to reduce the auxiliary air at the initial stage of deceleration.

Description

TECHNICAL FIELD The present invention relates to an auxiliary air control device for an internal combustion engine, and more particularly to an improvement in an auxiliary air control device for an internal combustion engine that controls the amount of auxiliary air that bypasses a throttle valve.

(Prior Art) As a conventional auxiliary air control device for an internal combustion engine, there is, for example, one shown in FIG.
Duke? 4ri. In the figure, ■ indicates an intake pipe, and 2 indicates a throttle valve installed upstream of the collecting portion IA of the intake pipe 1. The intake pipe 1 is provided with a bypass passage 3 that bypasses the throttle valve 2, and an auxiliary air control valve 4 is interposed in the bypass passage 3 to make the opening area of the passage 3 variable. Also,
The throttle valve 2 is equipped with an opening sensor (idle switch) 5 for detecting its opening, and an output signal from the opening sensor 5 is input to a control unit 6. Other detection signals such as engine speed, engine water temperature, intake air amount, etc. are input to the control unit 6, and the operation of the auxiliary air control valve 4 is controlled based on these input signals. That is, as shown in FIG. 2, when the throttle valve 2 becomes approximately fully closed (to in the figure), the engine speed (ttl
In response to a decrease in A y ) (deceleration state), the control valve 4
gradually decreases the opening area and increases the amount of auxiliary air (curve X)
The engine speed is reduced to the idle control value.

However, in such a conventional auxiliary air control device, when the engine decelerates (after the idle switch 5 is turned OFF), the opening degree of the auxiliary air control valve 4 is adjusted to a predetermined value as the engine speed decreases. Since the control method was such that the amount of auxiliary air is gradually decreased to the specified value or is decreased according to a preset rate of change, a large amount of auxiliary air is still supplied at the beginning of deceleration, and the rotation speed does not decrease sufficiently. There is a problem in that the effectiveness is insufficient, and when fuel is cut during deceleration (cutoff of fuel supply to the engine), the recovery shock is large when resupplying the fuel.

Furthermore, in this conventional device, the idle switch 5 is
If the output setting value of the control unit 6 (i.e., the opening degree of the control valve 4) is made smaller when switching from F to ON, the response delay of the intake system will be delayed, especially in the deceleration state at neutral or clutch disengagement. Engine stalling is likely to occur due to insufficient intake air volume (due to the large volume of the intake system, there is a delay in the response of the pressure in the intake pipe, which causes the pressure in the intake pipe to drop at low engine speeds, reducing the intake air volume). There were also problems.

(Object of the Invention) Therefore, in order to compensate for the insufficient amount of air during deceleration and increase the pressure inside the intake pipe, and to reduce the amount of auxiliary air at the beginning of deceleration, the present invention provides a The purpose is to solve the above problem by supplying an amount of auxiliary air proportional to the rate of decline.

(Structure of the Invention) The auxiliary air control device for an internal combustion engine according to the present invention, as shown in its overall structure in FIG. a deceleration detection means 14 for detecting the deceleration state of the engine; a rotation speed detection means 15 for detecting the rotation speed of the engine; a reduction speed calculation means 16 for calculating the speed at which the rotation speed is reduced; and a calculation means for calculating the square of the rotation speed. and a valve control means 18 that controls the opening degree of the auxiliary air control valve 13 based on the calculation results of the reduction speed calculation means 16 and the square calculation means 17.
The configuration includes the following.

(Example) Embodiments of the present invention will be described below based on the drawings.

4 to 7 show an embodiment of the present invention.

First, the configuration will be explained. Note that the same parts as in the conventional example (FIG. 1) will be described using the same reference numerals. In FIG. 4, 1 is an intake pipe, which includes an upstream collecting section IA and a downstream branching section IB.
It has . Throttle valve 2 provided upstream of collecting part IA
A bypass passage VII 3 is provided in this intake pipe l, and in the middle of this bypass passage 3 there is an auxiliary air control valve 4 (hereinafter referred to as A) which is a solenoid valve whose opening area is variable.
AC valve) is installed. Further, an idle switch 5 is attached to the throttle valve 2, and an ON signal is input to the control unit 6 when the opening degree of the throttle valve 2 is less than a predetermined value (for example, 6 degrees). That is, the idle switch 5 constitutes deceleration detection means.

Further, in the figure, 7 is a crank angle sensor (rotation speed detection means) for detecting the engine speed, and its output signal is input to the control unit 6.

FIG. 5 shows the contents of this control unit 6.

This control unit 6 mainly consists of a microprocessor, memory, and interface.

The rotation speed signal from the crank angle sensor 7 is sent to the rotation speed calculation section 2.
1 to calculate the engine rotation speed, and this engine rotation speed N is input to the memory 22.1/N-1 calculation section 23 (square calculation means) and rotation drop rate calculation section 24 (decrease speed calculation means), respectively. be done. The memory 22 stores the engine speed, and the 1/N1 calculation unit calculates the reciprocal of the square of the engine speed, 1/N. The rotation rate calculation means calculates the rate of decrease in the engine rotation speed from the difference between Δ stored in the memory 22, the rotation speed No. 1d seconds ago, and the current rotation speed N (Nold-N). The calculation results of the 1/N calculation unit edict and rotational descent rate calculation unit sae are input to the deceleration additional duty calculation unit δ,
This additional duty calculation unit δ calculates an additional duty value during deceleration by multiplying these calculation results and a constant, and adds the value to the addition unit 26.
Enter. The addition section adds this additional duty to the basic duty value input from the idle control duty calculation section.
The values are added and output to the auxiliary air control valve drive output generator a. This drive output generating section generates an output signal for driving the AAC valve 4 according to this added duty value.

The above-mentioned duty calculating sections 5, 27, the adding section, and the output generating section n collectively constitute a valve control means.

Next, the effect will be explained.

In the auxiliary air control device according to the present invention, when the throttle valve 2 becomes substantially fully closed, an ON signal is inputted to the control unit 6 by the idle switch 5. As a result, the basic D determined based on the engine speed signal N when decelerating is determined.
The additional duty value determined based on the rotational speed reduction rate and the reciprocal of the square of the rotational speed is added to the duty value, and the AAC valve 4 is operated and controlled according to the output signal to supply an appropriate amount of auxiliary air to the engine. supply

FIG. 7 is a flowchart showing the control program. Note that this program is executed every fixed time ΔT. First, the engine speed N+ is read at Pl, and this engine speed N+ is compared with a predetermined value (900r, p, va) at P2. If it is larger than the predetermined value (Nl>900), it is checked at PB whether the idle switch 5 is ON (deceleration determination). If it is ON, store Ni in P4 and calculate the rotational speed inverse proportion bone in PB (Nz -1/N+ -')
. Next, at P6, the number of rotations (Ni
-1) is read. Then, Pl calculates the rotation reduction rate NR (NR-(Nl-Ni-+)/ΔT), and PB calculates the additional duty value during deceleration (Dad = -N
・NR). Then, in P9, the basic duty at idle
Value (DI (1) is read out from memory and these Duty values are added in PIO (DT = DadXDz (1)
, Furthermore, this drive DuLy value DT is set to A in Pll.
Output to AC valve 4. Note that the above steps P2 and P
At B, the rotation speed does not exceed the specified value (N l ≦90Or,
p, m), and if the idle switch 5 is OFF, the additional duty value is set to 0 in step PI2 (D
ad=0), proceed to P9. In other words, in these cases, it is determined that the engine is not in a deceleration state, and the preset basic Du
The amount of auxiliary air is controlled based on the ty value.

Here, in order to eliminate the response delay of the pressure in the intake manifold when the engine decelerates, as mentioned above, the additional auxiliary air amount is determined by the reciprocal of the square of the rotation speed l/N0 and the rotation speed reduction rate dN.
The reason for making it proportional to /dt is as follows.

That is, assuming that the engine is a continuous suction pump, during deceleration, the difference between ge and gi, expressed by the following equation, becomes a change in the manifold negative pressure.

ge-ηv/120 ・(PB ・Ve)/RT・N
---(ll gt=const --(21) Also, from the thermodynamic equation of state, PV-GRT ---131.

And the change in manifold pressure per unit time is the above (
11 (from formula 21+31, dDEs/dt=RT/Vc=dGe/dt=RT/V
c-g I -7v/120 ・V e/V c-P
B −N --(41).

Here, when Vc=O, ge=gi, so FB =L20 RT/ (ηV ・Ve) ・gi
-1/N ・-1-+51.

Also, when Vc≠0, if we calculate gi from equations (4) and (5) to establish the same relationship for the manifold internal pressure pB as equation (5), then, assuming the additional air amount as Δg+, dPB /d t =RT/Vc H(g i +Δgi
)77V/120 ・Ve/Vc-N-PB--(61)

From equations (5) and (6), Δg+= 120/? v-Vc/Ve-gi・1/N1
・d N / d t (It becomes 71.

Therefore, the additional air amount Δgl is the reciprocal of the square of the rotation speed 1/N
1 and the rate of decrease in rotational speed dN/dt.

In addition, in the equation (7) to (1) above, ■C: Volume of the manifold, P8: Pressure inside the manifold, T: Temperature inside the manifold (assumed constant), Gc: Weight of air inside the manifold, ge: The amount of intake air in the engine per unit time, gi: constant (because it exceeds the critical pressure), R: gas constant, e: engine displacement, N: engine rotational speed, ηV: volumetric efficiency, respectively. it's shown.

In addition, Figure 6 shows the amount of auxiliary air (output duty value from the control unit to the AAC valve)
, the pressure Z in the intake pipe shows a change over time to after the throttle valve 2 is closed (the idle switch 5 is turned on from OFF).

In the figure, x and y indicate the conventional auxiliary air amount and engine speed, respectively. In this way, in this embodiment, by controlling the opening degree of the AAC valve 4 during deceleration and compensating for the lack of air amount, an appropriate amount of air is always supplied to the engine (inside the combustion chamber). As a result, it is possible to prevent engine stalling and reduce fuel cover sink during fuel cut. Furthermore, since the amount of air can be reduced at the start of deceleration, the reduction in rotational speed can be accelerated.

FIGS. 8 and 9 show other embodiments. In this embodiment, the reciprocal of the square of the engine speed in the previous embodiment is 1/
The calculation is simplified by replacing N:'' with an appropriate value (constant).

The other configurations are similar to those of the previous embodiment.

That is, as shown in FIG.
ld-N)≠I/Δt) is multiplied by a constant (preset) different from the constant in the above embodiment. Further, FIG. 9 shows changes in the amount of auxiliary air xO1, the engine speed YO1, and the intake pipe pressure Zo during deceleration according to this embodiment. Further, its operation is roughly the same as that of the above-mentioned embodiment.

(Effects) As explained above, according to the present invention, an appropriate amount of auxiliary air can be supplied to the engine at all times during deceleration, and as a result, the decrease in rotational speed during deceleration can be accelerated, and the effectiveness of engine braking is increased. Also, it is possible to eliminate the problem of glue cover shock during fuel canting.

It also prevents engine stalling caused by a delay in the intake system pressure response and improves drivability.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing a conventional auxiliary air control device, Fig. 2 is a graph showing changes over time in the auxiliary air amount and engine speed during deceleration by the conventional device, and Fig. 3 is a graph showing the change over time of the auxiliary air amount and engine speed during deceleration by the conventional device. FIG. 4 is a schematic overall configuration diagram of the auxiliary air control device, FIG. 4 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 5 is a block diagram showing its control, and FIG. 6 is a diagram showing the configuration during deceleration according to this embodiment. FIG. 7 is a flowchart showing an example of the control program, FIG. 8 is a block diagram showing another embodiment of the present invention, and FIG. The figure is also a graph similar to FIG. 6. If - throttle valve, 12 bypass passage, 13 auxiliary air control valve, 14 deceleration detection means, 15 rotational speed detection means, 16 - reduction speed calculation means, +7 - first power calculation means, l8 valve control means. Agent Patent Attorney Agagun Part 14 Figure 3

Claims (1)

[Claims] an auxiliary air control valve interposed in a bypass passage that bypasses a throttle valve; a deceleration detection means for detecting a deceleration state of an engine; a rotation speed detection means for detecting a rotation speed of the engine; A reduction speed calculation means for calculating, a square calculation means for calculating the square of the rotational speed, and a valve for controlling the opening degree of the auxiliary air control valve based on the calculation results of these reduction speed calculation means and the square calculation means. An auxiliary air control device for an internal combustion engine, comprising a control means.