JPS61118541A - Engine idle rotation controller - Google Patents

Abstract

PURPOSE:To prevent hunting by increasing the intake air supply or fuel supply with correspondence to the varying condition and the magnitude of the load of torque converter upon shifting from N-range to travel-range under idling. CONSTITUTION:In order to maintain the idle rotation constant, control means E will regulate fuel supply or intake air supply to engine A through rotation control means D. Upon operation of shift lever C' from N-range to travel-range, load correction means F will feed a correction signal to rotation regulating means D thus to increment the fuel supply or intake air supply by specific amount. Here, correction modifying means G will detect variation of the slip rate of torque converter C' or the variation factor of transmitting force such as the internal fluid temperature thus to increment the correction amount to be set through load correction means F with correspondence to the increment of slip rate or load. Consequently, excessive increase of engine rotation or hunting can be prevented.

Description

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

(Prior art) In automobile engines, the amount of intake air or fuel supply is adjusted in order to improve fuel efficiency when idling, to prevent engine stalling, or to promote warm-up when starting the engine. The idle rotation speed is controlled to the optimum rotation speed. However, in the past, this idle rotation speed was controlled only according to the warm-up state of the engine detected by the cold instant water function and the state of external loads such as coolers and lamps. When an automatic transmission having a hydraulic torque converter is provided in the power transmission path of a vehicle, the following problems have occurred. That is, when the shift lever of an automatic transmission is operated from N range to a driving range such as D range or R range with the engine running at idle (hereinafter referred to as N-D operation), the internal As the friction element is fastened, the turbine of the torque converter is restrained from a freely rotating state to a state at a certain rotational speed, so a load is applied to the engine due to the viscous resistance of the fluid in the torque converter, which causes the engine to The idle speed drops from the optimum speed corresponding to the cooling water temperature and external load conditions.

To solve this problem, for example, according to Japanese Patent Application Laid-open No. 54-98413, the amount of intake air is adjusted to a predetermined amount not only when an external load such as a cooler or a lamp is applied, but also when operating the automatic transmission from N to D. It is proposed to increase the According to this, the problem that the idle speed of the engine decreases due to the load acting from the torque converter side during the -1N-D operation can be prevented. However, if the amount of intake air is simply increased by a predetermined amount during the N-+D operation, the engine speed will hunt or an error with respect to the target engine speed will occur due to the following reasons.

In other words, the load acting on the engine due to the N-+D operation of the automatic transmission is a decrease in the turbine rotation speed of the torque converter due to the engagement of the friction element, in other words, an increase in the slip ratio between the pump and the turbine in the torque converter. However, due to the slow engagement of the friction elements, the turbine rotation speed gradually decreases over a certain period of time after the N-D operation, as shown in FIG. 7(a). Therefore, the slip rate or load of the torque converter gradually increases. On the other hand, if the intake air amount is increased by a predetermined m at the same time as the N→D operation, as shown in the same figure (b),
In the engine, when the load from the torque converter side is small, the amount of intake air increases rapidly, and the rotational speed temporarily increases significantly as shown in the same figure (C), resulting in hunting. Become.

In addition, the above load is due to the viscous resistance of the fluid in the torque converter, so this load is small when the fluid temperature is high, where the viscous resistance is small, and becomes thick when the fluid temperature is low, where the viscous resistance is large. , N-+
If the amount of increase in intake air during D operation is constant, Fig. 7 (
As shown by the broken line (A) in C1, when the fluid temperature is high, the idle speed becomes higher than the target rotation, and the broken line (B)
As shown in , when the fluid temperature is low, the idle rotation speed becomes lower than the target rotation speed.

(Object of the Invention) The present invention is provided with an automatic transmission having a hydraulic torque converter in a power transmission path for transmitting engine output to wheels, and in which the shift lever of the automatic transmission is moved during idle rotation of the engine. In an engine that increases intake air m or fuel supply amount when operating from N to D,
By increasing the amount of intake air, etc. in accordance with the state of the load acting from the torque converter side, it is possible to prevent fluctuations in engine speed during N→0 operation and occurrence of errors with respect to the target idle speed. With the goal.

(Structure of the Invention) In order to achieve the above object, the engine idle speed control device according to the present invention is characterized by having the following structure.

That is, as shown in FIG.
In the configuration provided with an automatic speed change mc having an automatic transmission mc, a rotation speed adjusting means for adjusting the fuel supply device or the intake air m to change the idle speed when the engine is idling; a control means E for controlling the rotation speed adjusting means so as to match the target rotation speed, and a shift lever CI of the automatic transmission IIC;
Load correction means F for correcting the rotational speed adjustment means so as to increase the fuel supply amount or the intake air amount by a predetermined amount when F is operated from the N range to the travel range, and in addition to these, the above-mentioned A correction amount changing means G is provided for changing the correction layer by the load correction means F according to the state of the torque converter C'. This correction amount changing means G is N
→ Changes in the slip ratio of torque converter C' during the D operation and factors that change the transmission force of torque converter C', such as fluid temperature within torque converter C', are detected, and the increase in the slip ratio, that is, torque converter C' Load correction means F according to the increase in the load acting on the engine A from
Increase the correction amount set in . Further, when the fluid temperature is low, that is, when the load on the torque converter C' is large, the correction amount is increased, and when the fluid temperature is high, that is, when the load is small, the correction amount is reduced.

(Effects of the Invention) According to the above configuration, when the shift lever of the automatic transmission is shifted from the N range to the driving range while the engine is idling, the amount of intake air or fuel supplied to the engine is reduced. With the above operation, the amount is increased depending on the change in the load acting on the engine from the torque converter and the magnitude of the load. This prevents a significant increase in engine speed and accompanying hunting caused by a sudden increase in the amount of intake air or fuel supply when the load is small, and also prevents the engine from being affected by the fluid temperature in the torque converter. Even if the load changes, the engine speed will always match the target speed with high accuracy.

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

As shown in FIG. 2, an automatic transmission 41I2 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 output shaft 3. ing. The automatic transmission 2 includes a hydraulic torque converter 4 and a gear transmission mechanism 5 in which the gear ratio is changed by selectively engaging friction elements, and the torque converter 4
The pump 4a is directly connected to the engine speed 1a, and the turbine 4 is driven by the pump 4a via hydraulic oil.
b-, and a stator 4G that is interposed between the pump 4a and the turbine 4b to increase torque, and the rotation of the turbine 4b is input to the gear transmission mechanism 5 via the turbine shaft 4d. It looks like this. 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 the gear transmission mechanism 5 also 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. When operated to a running range such as lunge or R range, a predetermined friction element is engaged and the turbine shaft 4d and output shaft 3 are connected.
In addition, in the D range, 2 range, etc., the gear ratio between the turbine shaft 4d and the output shaft 3 is changed depending on the vehicle speed when the vehicle is running.

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 engine 1
an electromagnetic control valve 10 that adjusts the amount of intake air supplied to the
is installed, and the opening degree or opening/closing time ratio (
duty ratio) is controlled by a control signal a from the controller 11. The controller 11 receives a rotation signal from an engine rotation sensor 12 that detects the rotation speed of the engine 1, and a throttle opening signal C from a 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 in the automatic transmission 2.
A shift position signal f from a shift position sensor (inhibitor switch) 16 that detects the position of the transmission 2, and a turbine rotation signal q 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. and an oil temperature signal from an oil temperature sensor 18 that detects the temperature of the hydraulic oil in the transmission 2.

Here, the configuration of the controller 11 will be explained with reference to FIG. 3. The controller 11 includes an idle control region determination circuit as a circuit for basic mi control, into which the engine rotation signal and the throttle opening signal C are input. 21, a target rotation speed setting circuit 22 into which the water temperature signal d is input;
a feedback control circuit 23 to which the output signal I of the circuit 22 and the engine rotation signal S are input;
a target control valve opening setting circuit 24 that inputs the output signal j of the target control valve opening setting circuit 24; a load correction amount setting circuit 25 that inputs the load signal e and outputs a correction signal k to the target III Ill u opening setting circuit 24; Output signal l of the idle control region setting circuit 21 and output signal m of the target control valve opening setting circuit 24
and a drive circuit 26 which outputs a control signal a to the control valve 10 by inputting a signal a to the control valve 10, and each of these circuits 21 to 26 controls the idle speed when the engine 1 is idling according to the engine water temperature and the external load. It is designed for feedback control. In addition to the above configuration, this controller 11 includes a torque converter slip ratio calculation circuit 27 to which an engine rotation signal and a turbine rotation signal g are input, and a viscous resistance calculation circuit 2 to which an oil temperature signal is input.
8, a torque converter load calculation circuit 29 to which the output signals n and Q of these calculation circuits 27 and 28 and the shift position signal f are input, and the output signal p of the calculation circuit 29 is used for the load correction. The signal is input to the m calculation circuit 25.

However, the controller 11 is a micro combination.
It is configured by the user 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.

As shown in FIG. 4, the controller 11 first inputs the engine rotation signal and the throttle opening signal C in steps 81 to S3, and determines the operating range based on the engine rotation speed N and the opening of the throttle valve 8. is within a predetermined idle control region. If the engine speed N is below a predetermined speed and the throttle valve 8 is engaged, it is determined that the engine is in the idle control region, and then in step 84.8s, the engine water temperature is determined based on the water temperature signal d. At the same time, the idle target rotation speed NO is set according to the water temperature, that is, the warm-up state of the engine 1. Next, the controller 11 compares the target rotation speed No. with the actual engine rotation speed N in step S6, and compares the target rotation speed No. with the actual engine rotation speed N.
When is smaller than the target rotational speed NO, in step S7, an advantage ΔNXK1 (K1: constant) corresponding to the deviation 4N is added to the previous control IDo for the control valve 10. If the actual rotational speed N is higher than the target rotational speed No plus the dead zone of the constant rotational speed α, steps $8 to S9 are executed, and the previous control tlliD is executed.

From I! Subtract 1NXK2 (K2: constant).

Then, the value obtained in this way is set as the current basic control ff1Do in step S10.

Next, the controller 11 outputs the load signal e in step S11.
Input the state of the external load from step S1.
In step 2, the first load correction mD+ is set in accordance with this external load. Also, step S13. In S14, the turbine rotation speed N [and oil IT
At the same time, input the turbine rotation speed N in step S+s.
Slip ratio β between pump 4a and turbine 4b in torque converter 4 from t and engine speed N=
(N-Nt)/N is calculated, and the second load correction amount D2 corresponding to this slip ratio β is = βXK3 (K3: constant)
Set. Here, the slip ratio β means that when the shift lever 6 of the automatic transmission 2 is shifted to the N range while the vehicle is stopped, the turbine 4b is restrained by the gear transmission mechanism 5 of the transmission 2. However, the shift lever 6 rotates at approximately the same rotation speed as the engine output shaft (pump 4a of the torque converter 4).
When the gear shift mechanism 5 is shifted to a driving range such as the D range, the turbine rotational speed Nt decreases to zero in accordance with the engagement operation of the friction elements in the gear transmission mechanism 5, so that the slip ratio β becomes 1. In that case, the turbine rotational speed Nt gradually decreases over a certain period of time after the N-D operation as shown in FIG. 5 (81), so the slip ratio β also gradually increases. As becomes larger, the torque converter load acting on the engine 1 from the torque converter 4 side increases, and the second load correction ID2 is increased in accordance with this increase in load. The load changes depending on the viscosity of the hydraulic oil in the torque converter 4, and this viscosity corresponds to the oil temperature T of the hydraulic oil, so the lower the oil temperature T (the higher the viscosity), the greater the load becomes. The higher the value (the lower the viscosity), the smaller the viscosity becomes.

Therefore, in step 316, the controller 11
The second load correction IDz obtained in step S+s is corrected using a correction coefficient of 4, which decreases as the oil temperature T increases with the characteristics shown in FIG. Find load correction ff1D2=DzXK4. Then, in step S11, the load correction amount D2 corresponding to the torque converter load obtained as described above and the first load correction mD1 corresponding to the external load are set in step S1o.
is added to the basic control amount Do set in , and the final control amount D
(-Do +DI +D2) is determined, and in step S1a, the opening degree of the control valve 10 corresponding to this IIIIIMD is set, and a control signal a is output to the control valve 10 so as to achieve this opening degree.

As a result, when the engine 1 is idling, the control valve 10
The amount of air depending on the opening degree of the bypass passage 9 shown in FIG.
The opening degree of the control valve 10, that is, the intake air gap is determined by correcting mm corresponding to the engine water temperature according to the external load and the torque converter load. Therefore, the idle speed of the engine 1 is controlled to the optimum target speed corresponding to the warm-up state and the load state. Particularly during N-40 operation of the automatic transmission 2 where the l/lux converter load acts, as shown in FIG. Since the slip ratio is increased in response to an increase in the slip ratio or an increase in the load, the engine rotation speed is controlled to the target rotation speed without fluctuation, as shown in FIG. 4(C). In addition, as shown by the broken line (c) in Figure 5 (bl), when the oil temperature of the hydraulic oil is low, which causes the torque converter load to increase, the amount of intake air is large, and when the oil temperature is high, which causes the load to decrease, the broken line (c) ), the intake air is reduced, so that the idle speed of the engine 1 always matches the target speed with high precision, regardless of changes in the torque converter load due to oil temperature.

Note that when the operating range of the engine 1 is not in the idle control range, the controller 11 executes steps S3 to S'9 in FIG. 4, and sets the standby amount of the control valve 10. During this standby, when the operating range suddenly shifts from outside the idle control range to within the range, if the opening degree of the control valve 10 is zero, the engine speed will drop and there is a risk of engine stalling. This is to keep the control valve 10 at an appropriate distance when exiting from the idle control area.

In this embodiment, the idle speed is controlled by increasing or decreasing the intake air amount, but in the case of an engine with a constant intake air amount such as a diesel engine, it may be controlled by increasing or decreasing the fuel supply amount. It turns out. Further, in this embodiment, the basic control IDo for the control valve 10 is set according to the deviation AN between the target rotation speed No. and the actual rotation speed N, and the actual rotation speed N is feedback-controlled. Set the control ff1Do to the target rotation I in advance.
The actual rotation speed N may be controlled in an open manner by setting it in correspondence with aNo.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing the basic concept of the present invention. 2 to 6 show embodiments of the present invention, 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 land roller. FIG. 5 is a time chart showing the action and effect, and FIG. 6 is a characteristic diagram showing the characteristics of oil temperature correction. FIG. 7 is a time chart showing the problems of the conventional technology. 1... Engine, 2... Automatic transmission, 4... Torque converter, 6... Shift lever-19, 10...
Rotation speed adjusting means (9... bypass passage, 10... control valve), 11... control means, load correction means, correction amount changing means (controller).

Claims (1)

[Claims] (1) A rotation speed adjusting means that includes an automatic transmission having a fluid torque converter in a power transmission path that transmits the engine output to the wheels, and changes the engine rotation speed by adjusting the amount of fuel supply or the amount of intake air; a control means for controlling the rotation speed adjusting means so that the engine rotation speed matches a predetermined idle target rotation speed; and a fuel supply amount when the shift lever of the automatic transmission is operated from the N range to the driving range. or a load correction means for correcting the rotation speed adjustment means so as to increase the amount of intake air by a predetermined amount, the engine idle speed control device comprising: An engine idle speed control device comprising correction amount changing means for changing the correction amount by the load correction means.