JPH0574700B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an idle speed control device for an automobile engine, and particularly to a transmission equipped with a hydraulic torque converter in a power transmission path that transmits engine output to wheels. The present invention relates to an idle speed control device for an engine.

(Prior art) In automobile engines, in order to improve fuel efficiency and prevent engine stalling during idling,
Alternatively, for the purpose of promoting warm-up at the time of starting, etc., the amount of intake air or the amount of fuel supply is adjusted to perform feedback control of the idle rotation speed to the optimum rotation speed. This idle rotation speed control involves controlling a rotation speed adjustment means that adjusts the intake air amount or fuel supply amount so that the actual rotation speed matches a preset target rotation speed according to the operating state of the engine. Therefore, when the operating range of the engine shifts from the predetermined idle range to the normal running range, the engine speed adjusting means operates to reduce the amount of intake air in an attempt to prevent the engine speed from increasing. Therefore, the rotational speed adjusting means is in a state in which the amount of intake air, etc. is zero or extremely small in the driving region. Then, when the vehicle is stopped, it shifts from the driving range to the idle range in this state and the idle speed is controlled again, but in that case, the initial state of the speed adjusting means is set to the engine Since the engine speed is in a state where the engine speed is decreased, the engine speed will temporarily drop immediately after the start of the control. Therefore, especially when the degree of this drop is sudden, or when the control to restore the rotational speed is delayed in response to this drop, a so-called engine stall may occur.

In order to avoid such problems, the intake amount for the rotation speed adjusting means should be set so that the required intake air amount or fuel supply amount can be obtained by the rotation speed adjusting means when the engine operating range is in the running range. death,
Control of the idle rotation speed may be started from this state. However, if this amount of standby is too large, the effectiveness of the engine brake will deteriorate when the car is running, especially when decelerating, and this will cause problems such as poor fuel efficiency, while if the amount of standby is too small, engine stalling will be reliably prevented. The problem is how to set this standby amount.

In particular, in a car equipped with an automatic transmission having a hydraulic torque converter in the power transmission path from the engine to the wheels, if the transmission is in a driving range such as D range, the car will run inertia during deceleration. As a result, a driving force in the opposite direction is applied to the engine from the transmission side via the torque converter, but it depends on whether or not this reverse driving force is acting when the operating range enters the idle range. As a result, the likelihood of engine stalling differs significantly.

For example, as disclosed in Japanese Patent Application Laid-Open No. 55-156230, when the shift position of the automatic transmission is in the travel range where reverse driving force acts, that is, when there is little risk of engine stalling, when decelerating By reducing the standby amount of the rotation speed adjusting means in It is conceivable to increase the above-mentioned standby amount to reliably prevent engine stalling. However, the reverse driving force that acts on the engine via the torque converter always fluctuates even when the transmission is shifted to a driving range such as D range, and therefore, as stated in the above publication, the reverse driving force that acts on the engine changes constantly. Simply changing the standby amount depending on whether it is in the N range or not, is not enough to achieve precise control such as setting the intake air amount to the minimum amount necessary to prevent engine stalling, and minimizing engine braking and deterioration of fuel efficiency as much as possible. will not be performed. Further, the above-mentioned publication suggests that the above-mentioned standby amount is variably controlled in accordance with the vehicle speed while the transmission is in the driving range, but the above-mentioned reverse driving force is The larger the reduction ratio of the transmission, the larger the reduction ratio, and it does not correspond only to the vehicle speed, so this method also allows for accurate control of the amount of intake air, etc. to the minimum amount necessary to prevent engine stalling. I can't.

(Object of the Invention) The present invention provides an automatic transmission that is equipped with an automatic transmission having a hydraulic torque converter in a power transmission path that transmits engine output to wheels, and that adjusts the amount of intake air or fuel supply during idle to control engine rotation. This is to deal with the above-mentioned actual situation in an engine equipped with an idle control means that feedback-controls the engine speed to the target rotation speed, and the amount of intake air or fuel supply at the start of idle control when transitioning from the driving range to the idle range. By setting the amount of standby, that is, the standby amount of the rotation speed adjusting means, in advance to an optimal amount outside the idle control area, engine braking performance and fuel efficiency during deceleration will not be deteriorated due to the standby amount being too large. , the purpose is to prevent engine stalling immediately after the start of the idle control.

(Structure of the Invention) The engine idle speed control device according to the present invention is characterized in that it is configured as follows to achieve the above object.

That is, in a configuration in which an automatic transmission D having a hydraulic torque converter C is provided in a power transmission path that transmits the output of an engine A to wheels B as shown in FIG. 1, the intake air amount of the engine A or The idle speed of the engine A is controlled by the engine speed adjusting means E that adjusts the fuel supply amount to change the engine speed, and the idle control means F that controls the engine speed adjusting means E in a predetermined address control area. The configuration is such that feedback control is performed so that the rotation speed matches the target rotation speed corresponding to the load, warm-up state, etc. In addition to this configuration, load correction means G corrects the adjustment amount by the rotation speed adjustment means E according to the load on the engine.
and a region determining means H for determining whether or not the engine operating region belongs to the idle control region, and further comprising a turbine rotational speed detecting means I for detecting the rotational speed of the turbine C' in the torque converter C. , an idle state in which the load correction means G corrects the correction amount in response to an output signal from the turbine rotation speed detection means I in a state in which the engine operating range is determined to be outside the idle control range by the region determination means H; An out-of-area correction means J is provided.

According to such a configuration, the load correction means G adjusts the rotation speed adjustment means depending on the load on the engine, in other words, depending on whether the range of the automatic transmission D is the traveling range or the N range. The adjustment amount of the intake air amount, etc., that is, the standby amount is corrected by E, and this correction amount is further applied to the turbine rotation speed detected by the turbine rotation speed detection means I by the idle area correction means J during deceleration. It will be corrected accordingly. In that case, since the turbine rotation speed corresponds to the reverse driving force acting on engine A from torque converter C during deceleration, the above standby amount, that is, the intake when the operating range of engine A enters the idle control range during deceleration. The amount of air or the amount of fuel supplied will be set according to the reverse driving force acting on engine A.

(Effects of the Invention) According to the above configuration, the amount of intake air at the start of idle control is set according to the speed change via the torque converter and the reverse driving force acting on the engine from the machine side. The amount of air and the like are adjusted with high precision in accordance with the likelihood of engine stalling immediately after the engine operating range shifts from outside the idle control range to within the idle control range. Therefore, engine stalling when the amount of intake air is too small is reliably prevented, and deterioration of engine braking performance and fuel efficiency during deceleration when the amount of intake air is too large is also prevented. .

(Example) Examples of the present invention will be described below.

As shown in FIG. 2, an automatic transmission 2 is provided on the output side of the engine 1, and the engine output is transmitted to wheels (not shown) via the automatic transmission 2 and an output shaft 3.
It is now being transmitted to The automatic transmission 2 has a hydraulic torque converter 4 and a gear transmission mechanism 5, and the torque converter 4 has a pump 4a directly connected to the engine output shaft 1a, and It has a driven turbine 4b and a stator 4c that is interposed between the pump 4a and the turbine 4b to increase torque, and the rotation of the turbine 4b is transmitted to the gear transmission mechanism 5 via the turbine shaft 4d. It is now being entered. Further, this gear transmission mechanism 5 cuts off the connection between the turbine shaft 4d and the output shaft 3 when the shift lever 6 is shifted to the N range, and also cuts off the connection between the turbine shaft 4d and the output shaft 3 when the shift lever 6 is shifted to the D, 2, 1 range or the R range. When the vehicle is operated to a driving range such as a range, the turbine shaft 4d and the output shaft are connected to each other, and in the D range or 2 range, the turbine shaft 4d and the output shaft 3 are connected in accordance with the vehicle speed when the vehicle is traveling. The reduction ratio between the two can be switched.

On the other hand, the intake passage 7 of the engine 1 is provided with a bypass passage 9 that bypasses the throttle valve 8, and the amount of intake air supplied to the engine 1 through the passage 9 is adjusted on the bypass passage 9. An electromagnetic control valve 10 is arranged, and the opening degree or opening/closing time ratio (duty ratio) of the control valve 10 is controlled by a control signal a from a controller 11. The controller 11 receives a rotation signal b from an engine rotation sensor 12 that detects the rotation speed of the engine 1;
Throttle opening signal c from the throttle opening sensor 13 that detects the opening of the throttle valve 8.
, a water temperature signal d from a water temperature sensor 14 that detects the cooling water temperature of the engine 1 , a load signal e from an external load 15 acting on the engine 1 such as a cooler or a lamp, and a shift lever 6 in the automatic transmission 2 . A shift position signal f from a shift position sensor (inhibitor switch) 16 that detects the position, and a turbine circuit signal g from a turbine rotation sensor 17 that detects the rotation speed of the turbine shaft 4d in the torque converter 4 of the transmission 2. It is now being entered.

Here, the configuration of the controller 11 will be explained based on FIG. 3. First, the controller 11 includes, as an idle control circuit, a target rotation speed setting circuit 18 to which the water temperature signal d is inputted, and the circuit 1.
The control valve target opening setting circuit 20 is provided with a feedback control circuit 19 to which the output signal h of 8 and the engine rotation signal b are input, and a control valve target opening degree setting circuit 20 to which the output signal i of the circuit 19 is input. In addition, the controller 1
1 is a circuit for controlling the standby amount of the control valve 10, and includes a turbine rotation speed detection circuit 21 to which the turbine rotation signal g is input, and an output signal j of the circuit 21 and the water temperature signal d are input. The control valve standby amount setting circuit 22 is further provided as a circuit for switching between the idle control and the control valve standby amount control according to the operating state, and is configured to control the engine rotation signal b, the shift position signal f, and the throttle opening degree. The control valve drive mode setting circuit 24 includes an operating range determination circuit 23 to which the signal c is input, and a control valve drive mode setting circuit 24 to which the output signal k of the circuit 23 is input. and,
Output signal l of the control valve drive mode setting circuit 24
is directly inputted to the first AND circuit 25 to which the output signal m of the control valve target opening degree setting circuit 20 is inputted, and to the second AND circuit 26 to which the output signal n of the control valve standby amount setting circuit 22 is inputted. As a result, when the shift position of the automatic transmission 2 is in a driving range such as the D range, and the operating range of the engine 1 is in a predetermined idle control range, the control valve target opening setting circuit 20 The output signal m is outputted from the first AND circuit 25 as a signal m', and when the idle control region is not in the above-mentioned idle control region, the output signal n of the control valve standby amount setting circuit 22 is outputted as a signal n' from the second AND circuit 26. It's summery. Furthermore, in addition to the above configuration, the controller 11 includes the first and second AND circuits 25,
26 output signals m', n' (either one of these signals m', n') and the load signal e are input, and an output signal o of the circuit 27 is input. The control valve 10 is driven by a control signal a outputted from the drive circuit 28.

This controller 11 is constituted by a microcomputer and operates according to the flowchart shown in FIG. Next, the operation of this controller 11 will be explained according to the flowchart shown in FIG. The operation shown in this flowchart is performed when the automatic transmission 2 is shifted to the travel range.

As shown in FIG. 4, the controller 11 first inputs the load signal e, water temperature signal d, engine rotation signal b, and throttle opening signal c in steps _S1 to _S4 , and then inputs the engine rotation signal b in step _S5 . It is determined whether the operating range is in a predetermined idle control range based on the engine rotational speed N indicated by the throttle opening signal c and the opening of the throttle valve 8.
If the engine speed N is below a predetermined speed and the throttle valve 8 is closed, it is determined that the engine is in the idle control region, and then in step _S6 , the input in step _S2 above is determined. The idle target rotation speed N ₀ is set according to the engine water temperature indicated by the water temperature signal d, that is, the warm-up state of the engine 1.
This target rotational speed N ₀ is set so as to decrease as the engine water temperature increases, as shown by the symbol A in FIG. Next, in step _S7 , the controller 11 compares the target engine speed _N0 set as described above with the actual engine speed N, and compares the actual engine speed N0.
is smaller than the target rotational speed _N0 , in step _S8 , the amount ΔN×K ₁ corresponding to the deviation ΔN (K ₁ : constant)
is added to the previous control amount D ₀ for the control valve 10. If the actual rotation speed N is higher than the target rotation speed N ₀ plus the dead band of constant rotation speed α, steps S ₉ to S ₁₀ are executed to determine the deviation ΔN′ from the previous control amount D ₀ . (=N- _N0 ) by the amount ΔN'× _K2 ( _K2 : constant). Then, in step _S11 , the value obtained in this way is applied to the control valve.
The basic control amount D for ₁₀ is set as ₀ . next,
In step _S12 , the controller 11 adds the load correction amount D1, which corresponds to the state of the external load indicated by the load signal e inputted in step _S1 , to _the basic control amount _D0 to obtain the final control amount (=D ₀ +D ₁ ), and further, in step _S13 , the control valve 1 corresponding to this control amount D is determined.
The opening degree is set to 0, and the control signal a of the control valve 10 is outputted so that this opening degree is achieved. Then, by repeating steps _S1 to _S13 , the control valve 10
The opening degree is variably controlled, and an amount of air corresponding to the opening degree is sucked into the engine 1 through the bypass passage 9 shown in FIG. 2, thereby increasing the engine rotation speed N.
is feedback-controlled to the target rotational speed _N0 .

On the other hand, the engine rotation speed N indicated by the engine rotation signal b input in step S ₃ is equal to or higher than the predetermined rotation speed, or the throttle valve 8 is opened as indicated by the throttle opening signal c input in step S ₄ . If the degree is equal to or higher than the predetermined value, the controller 11 determines in step _S5 that the operating region is not in the idle control region, and controls the standby amount of the control valve 10. That is, step S ₅ to step S ₁₄
After executing and inputting the turbine rotation signal g, a standby amount _D0 is set in step _S15 based on the rotation speed of the turbine 4b or turbine shaft 4d of the torque converter 4 indicated by the turbine rotation signal g. This standby amount D ₀ is set to decrease as the turbine rotation speed increases, as shown by the symbol B in Fig. 6, but when the engine water temperature is low, which tends to cause engine stalling, as shown by the symbol C. The overall amount will be increased. Then, the controller 11 performs step control as in the case of idle control.
In step _S12 , the load correction amount _D1 is added to the standby amount _D0 to obtain the final control amount D (= _D0 + _D1 ), and in step _S13 , the opening degree of the control valve 10 corresponding to this control amount D is determined. is set, and a control signal a is output to the control valve 10 so as to achieve this opening degree. As a result, even when the operating region is not in the idle control region, that is, in the normal driving region, by repeating the above processing, the opening degree of the control valve 10 is variably controlled according to the control amount D. The amount of intake air passing through the bypass passage 9 shown in FIG. 2 is controlled according to this opening degree.

In this case, when the throttle valve 8 in the intake passage 7 is fully closed while the automobile is running, resulting in a deceleration state, the only air that is taken into the engine 1 is the air that passes through the bypass passage 9. In this state, the engine enters the idle area from the running area, and the amount of intake air at that time corresponds to the opening degree of the control valve 10, that is, the standby amount that changes depending on the turbine rotation speed as shown in FIG. When the turbine rotation speed is high, the intake air amount is small, and when the turbine rotation speed is low, the intake air amount is large. Therefore, if the turbine rotation speed is high and therefore the reverse driving force acting from the transmission 2 side to the engine 1 via the torque converter 4 during deceleration is large, in other words, even if the intake air amount is reduced, it will not reach the idle control region. The amount of intake air is reduced when there is little risk of engine stalling during deceleration, thereby preventing deterioration of engine braking performance and fuel efficiency caused by increasing the amount of intake air more than necessary during deceleration.

On the other hand, if the turbine rotational speed is low and the above-mentioned reverse driving force is small, then when the engine rotational speed drops to the idle control region, step _S6 in Fig. 4 is performed.
Engine stall is likely to occur due to a delay in feedback control of the idle rotation speed by _S13 , etc. In this case, the standby amount of the control valve 10 is set to a large value, and the opening degree or the control valve 10 is changed. Idle control is started from a state where the amount of intake air is large. Therefore, even in such a case, stalling of the engine immediately after the transition from the driving range to the idle control range is prevented.

In this way, the amount of intake air during deceleration is accurately controlled according to the magnitude of the reverse driving force corresponding to the turbine rotation speed of the torque converter 4 in the automatic transmission 2, in other words, according to the ease with which engine stall occurs. As a result, engine stalling can be reliably prevented without deteriorating engine braking performance or fuel efficiency during deceleration due to an unnecessarily large amount of intake air.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing the basic concept of the present invention. 2 to 6 show embodiments of the present invention, in which FIG. 2 is a control system diagram, FIG. 3 is a block diagram showing the configuration of the controller, and FIG. 4 is a flowchart showing the operation of the controller. 5th and 6th
The figure is a graph showing the control characteristics of the target idle rotation speed and the standby amount, respectively. DESCRIPTION OF SYMBOLS 1... Engine, 2... Automatic transmission, 4... Torque converter, 9, 10... Rotation speed adjustment means (9... Bypass passage, 10... Control valve), 11...
...Idle control means, load correction means, idle area outside correction means (controller), 12, 13...
Area determination means (engine rotation sensor, throttle opening sensor), 17...Turbine rotation speed detection means (turbine rotation speed sensor).

Claims (1)

[Claims] 1 Equipped with an automatic transmission having a hydraulic torque converter in a power transmission path that transmits engine output to the wheels, and a rotation speed adjusting means that changes the engine speed by adjusting the fuel supply amount or intake air amount, and a predetermined Idle control means that operates the rotation speed adjustment means in an idle control region to perform feedback control so that the engine rotation speed matches the target rotation speed, and corrects the adjustment amount by the rotation speed adjustment means according to the load on the engine. An engine idle speed control device comprising a load correction means and a region determining means for determining whether or not an operating region of the engine is in the idle control region, the engine idle speed control device controlling the rotation speed of a turbine in the torque converter. Correction by the load correction means upon receiving an output signal from the turbine rotation speed detection means in a state where the engine operating range is determined to be outside the idle control range by the turbine rotation speed detection means and the region determination means. 1. An engine idle speed control device, comprising: an idle range out-of-range correction means for correcting the amount.