JP2000220500A - Engine idle control device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To correct the engine output in consideration of a difference in responsiveness of an automatic transmission according to a change in viscosity due to oil temperature, and to eliminate driver discomfort. An automatic transmission having a torque converter disposed in a power transmission path of an engine, an inhibitor switch for detecting an operation position of a selector lever, and an oil temperature for detecting an oil temperature of the automatic transmission. When the sensor 29, the turbine speed sensor 28 for detecting the turbine speed Nt, the ISC valve 9 for adjusting the output of the engine, and the selector lever 26 are switched between the neutral range and the traveling range, the oil temperature Ot is reduced. If the correlated state quantity is equal to or more than a predetermined value, the shift range switching is detected.If the correlated state quantity is less than the predetermined value, it is detected that the turbine speed has changed. A control unit 6 for performing a corresponding engine output correction is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle control device mounted on an engine to which an automatic transmission having a torque converter is connected, and more particularly to a method of changing the engine speed in response to a load change during shifting of a shift range. The present invention relates to an idle control device for an engine that can be operated.

[0002]

2. Description of the Related Art Generally, the idling speed of an engine is set low within a range where engine stall does not occur, so as to improve fuel efficiency, and furthermore, the idling speed drops when the engine load fluctuates. When a rotation fluctuation such as a blow-up or the like is detected, the engine output is increased or decreased to prevent the rotation fluctuation. However, even if the output is adjusted by detecting a rotation fluctuation such as a drop in idle speed, the added adjustment amount generates torque that effectively acts on the drop in engine speed and rotation fluctuation. After the elapse of a predetermined time after the decrease in the response, the response differs depending on the engine type and the characteristics specific to the control means, and there has been a problem that the controllability is reduced due to the variation in the response.

In idle speed control of a vehicle equipped with an automatic transmission equipped with a torque converter in a power transmission system of the vehicle, switching positions of a shift lever when the vehicle is stopped, for example, P, R, N, D, Generally, control is performed to increase or decrease the output value at the time of idling according to each range such as 3, 2, L, and the like. That is, the driving ranges D, R, 3, 2, L, etc. and the stopping ranges P, N
In such a case, the load applied to the engine from the automatic transmission side increases and decreases. For this reason, engine output control is performed so as to generate an output balanced with the load corresponding to the shift range,
Excessive fluctuation of the idling speed is prevented.

For example, when a switch from the stop range to the drive range is detected using an inhibitor switch signal which is a position signal of a shift range, the load on the automatic transmission increases with the shift. An idle speed control) valve is used to increase the amount of intake air to increase output and prevent a decrease in target idle speed. Alternatively, when switching from the travel range to the stop range, the load on the automatic transmission side decreases with the shift, but the intake air amount is reduced by the ISC valve, the output is reduced, and the target idle speed rapidly increases. Is suppressed.

[0005] In such an automatic transmission with a torque converter, there is a time lag until the load actually applied to the engine fluctuates with respect to the shift operation of the shift lever. For example, when shifting up from the N range (stop range) to the D range (running range), the idle speed adjusting means responds to the detection of the shift operation of the shift lever before the load on the automatic transmission is applied to the engine. Is activated, the engine speed is increased, and so-called air blowing is likely to occur. Also, at the time of downshifting from the D range to the N range, the rotation speed adjusting means operates in response to the detection of the shift operation before the load received by the engine in the D range is not released, and the engine rotation speed decreases, An engine stall may occur.

Therefore, after a shift operation from the N range to the D range, a predetermined engine output is increased after a predetermined delay time has elapsed, or the engine output is increased.
As disclosed in Japanese Unexamined Patent Publication, the load fluctuation on the automatic transmission side is detected by a change in the turbine speed of the torque converter,
After that, there is one that corrects the idle speed of the engine.

[0007]

In the idle control for changing the engine output by the difference between the load on the automatic transmission in the stop range and the load in the traveling range, especially at extremely low temperatures, the oil (ATF) in the automatic transmission is changed. Due to the increase in the viscosity of ()), there is a situation in which the sense of discomfort given to the driver increases. That is, since the load on the automatic transmission is proportional to the oil viscosity,
At extremely low temperatures, the output difference to be reinforced by the engine output increases, and a larger correction is required. Furthermore, at extremely low temperatures, the resistance of the pipeline communicating with a frictional engagement element such as a clutch inside the automatic transmission increases, and the operation of the clutch or the like has a large response delay, and the switching timing tends to be shifted. As described above, at extremely low temperatures, a relatively large engine output correction is required, and the response delay of the operation of the clutch and the like is large. These influences together cause the engine to be blown up, giving the driver an uncomfortable feeling. Therefore, as disclosed in Japanese Patent Publication No. 6-65555, a load change is detected by a change in the turbine speed of the torque converter, and then the idle speed of the engine is corrected to prevent blow-up and engine stall. There is one that reduces the sense of discomfort.

However, when the idle control is started in response to the change in the turbine speed as described above, although the effect is effective in the region where the oil temperature of the automatic transmission is low, the viscosity of the oil is low in the region where the oil temperature is relatively high. However, if the engine output change control is started after the turbine speed has changed due to higher responsiveness, the engine output correction will be delayed due to the load fluctuation on the automatic transmission side, causing engine stall. However, there is a problem that the driver feels strange.

SUMMARY OF THE INVENTION It is an object of the present invention to correct an engine output at an appropriate timing in consideration of a difference in responsiveness of an automatic transmission according to a viscosity change due to an oil temperature, thereby eliminating an uncomfortable feeling of an engine. It is to provide a control device.

[0010]

In order to achieve the above object, according to the first aspect of the present invention, there is provided an automatic transmission arranged in a power transmission path for transmitting an engine output to wheels. It has a fluid torque converter, detects the operating position of the selector lever for switching the shift range of the automatic transmission by lever position detecting means, and detects the state quantity correlated to the oil temperature of the automatic transmission by oil temperature detecting means. Or estimating, detecting the turbine speed of the torque converter by turbine speed detecting means, adjusting the output of the engine by engine output adjusting means, comprising control means,
The control means, when switching between the neutral range and the traveling range of the selector lever is performed, when the state quantity correlated with the oil temperature is equal to or more than a predetermined value, detects the switching of the range, If it is less than a predetermined value, it is detected that a change has occurred in the turbine speed, and then the operation of the engine output adjusting means is controlled so as to perform engine output correction corresponding to a load change due to switching of the range. ing.

Here, when the state quantity correlated with the oil temperature is equal to or more than a predetermined value, the switching of the range is detected, and then the output of the engine corresponding to the load change due to the switching of the range is corrected. In the high oil temperature range, the output correction of the engine can be accelerated, and when the state quantity correlated with the oil temperature is less than a predetermined value, it is detected that a change has occurred in the turbine speed, and then the range is switched. The output correction of the engine corresponding to the load fluctuation can be delayed. As a result, the timing of engine output correction can be appropriately set in accordance with the difference in responsiveness of the automatic transmission caused by the difference in viscosity due to the oil temperature of the automatic transmission.

[0012]

1 and 2 show an engine idle control apparatus 1 to which the present invention is applied. This idle control device 1 is mounted on an in-line four-cylinder engine E. The output of the engine E is connected to the drive wheels 21 via a power transmission path PT. The power transmission path PT is the engine E
, An automatic transmission 18 having an automatic transmission mechanism (not shown), a propeller shaft 19, a differential 20, and a drive wheel W, and torque is transmitted in this order. You.

The engine E has a throttle valve 3 in an intake passage 2, and a rotary shaft 301 of the throttle valve 3 is connected to a throttle lever 4 outside the intake passage 2. The throttle lever 4 is driven to open and close by a step motor 5,
The step motor 5 is controlled by a control unit 6 described later. A throttle opening sensor 7 that outputs opening information of the throttle valve 3 as intake air amount information is attached to the other end of the rotating shaft 301, and a detection signal thereof is output to the control unit 6. An intake bypass passage 8 is formed bypassing the throttle valve 2 in the intake passage 2,
Is controlled by the ISC valve 9 to open and close. The ISC valve 9 is urged to close by a spring 901 and can be opened by a fixed amount by a step motor 11 as an actuator. The motor is connected to a control unit 6 described later. Reference numeral 12 denotes a first idle air valve, which is configured to automatically perform warm-up correction during idling in accordance with the cooling water temperature.

Here, the step motor 5 for operating the opening θs of the throttle valve 3 and the step motor 11 for operating the position (opening position) of the ISC valve 9 constitute an engine output adjusting means for adjusting the output of the engine. I do.
The ISC valve 9 is equipped with an ISC position sensor 13 that emits opening position information corresponding to the position (opening position) of the valve 9. The intake gas flows into the intake manifold 16 from the throttle body 14 through the surge tank 15 through the surge tank 15, and is mixed with fuel in a combustion chamber (not shown) in the engine E to become exhaust gas after combustion, and the exhaust gas passes through the exhaust manifold 17 through the intake manifold 2. Not passed through the exhaust system and released into the atmosphere.

The torque converter 22 of the automatic transmission 18 includes a pump 221 directly connected to an output shaft of the engine, and a turbine 2 which receives rotational energy of the pump via oil.
22, a stator 223 for increasing torque transmitted from the pump 221 to the turbine 222, and a turbine 222
And a gear pump 225 driven by a pump 221 to serve as a supply source of oil (ATF). The forward / reverse switching mechanism 23 includes a forward clutch 231 and a reverse brake 23 which are friction engagement means for restricting the driving of a planetary gear train (not shown) and each rotating element of the planetary gear train.
2 and an oil supply circuit 24 for supplying and discharging pressure oil to and from these friction engagement means. The forward / reverse switching mechanism 23
When only the forward clutch 231 is engaged, the turbine shaft 224
And an output shaft 2 integrated with a carrier in a planetary gear train (not shown)
The rotation of the turbine shaft 224 is performed by the transmission mechanism (not shown) while the rotation of the turbine shaft 224 is output to the output shaft 233. It is inverted in the column and output to the output shaft 233 side.

The oil supply circuit 24 includes a gear pump 225
From the forward clutch 231 and the reverse brake 232
And a lubrication and cooling mechanism in a planetary gear train (not shown). The pressure oil from the gear pump 225 is adjusted to a predetermined line pressure irrespective of engine speed fluctuations, and the pressure oil is selectively switched in an oil path by a manual valve 25, and is hydraulically controlled to respectively control the forward clutch 231 or the reverse drive. It is supplied to the brake 232 in a predetermined refueling mode. The manual valve 25 is connected to a manual shift lever 26 via a link system 261 and is switched and held at a shift position of the shift lever, for example, a shift range such as P, R, N, D, 3, 2, L. Here, when it is held in the forward range D, 3, 2, L, the circuit for supplying the pressure oil to the forward clutch 231 side is opened, and when it is held in the reverse range R, the pressure oil is supplied to the reverse brake 232 side. Is released and the pressure oil of the forward clutch 231 and the reverse brake 232 is eliminated, the drive wheel 21 side and the turbine shaft 224 side are cut off, and the turbine shaft 224 side is closed. Hold free.

The control unit 6 controls the hydraulic pressures of the step motor 5 and the step motor 11 and the automatic transmission 18 which constitute the output adjusting means of the engine E. The control unit 6 is a CPU that performs various controls.
The CPU 601 includes a ROM (read only memory) 602, a RAM (random access memory) 603, and input / output ports 604 and 605 via a bus line such as a data bus. Each is connected. ROM 602 has input port 6
CPU 60 based on various signals input through
1 stores various programs and data for judging an operation state and the like and appropriately controlling each part.

The control unit 6 here
Is the engine control function, power transmission path control function,
In particular, when the selector lever 26 is switched between the neutral range N and the travel ranges R, D, 3, 2, L, the oil temperature O
If t is equal to or greater than a predetermined value Ot1, switching of the shift range 26 is detected. If t is less than the predetermined value Ot1, it is detected that a change Δnt has occurred in the turbine speed Nt. It has a function as idle control means for controlling the operation of the engine output adjusting means (step motor 11) so as to perform the engine output correction ΔDt corresponding to the fluctuation. Here, the predetermined value Ot1
Is set in advance as an oil temperature which is considered to be in a state where each friction engagement means in the oil supply circuit 24 does not cause a significant delay in operation due to the flow resistance of the cryogenic oil. A RAM 603 is a working memory for the CPU 601 to perform processing, and temporarily stores various signals and control signals.

The input port 604 has a shift lever 26
The shift lever position signal S (ON when in the P and N ranges, OFF otherwise) from the inhibitor switch 27 as a lever position detecting means provided to the turbine shaft 224 and the throttle opening θs from the throttle sensor 7 From the installed turbine speed sensor 28, the turbine speed Nt
(Equivalent value of vehicle speed V), oil temperature Ot from oil temperature sensor 29 disposed in oil supply circuit 24, target position (opening position) Poi of ISC valve 9 from ISC position sensor 13, engine rotation sensor The engine speed Ne from 30 and the water temperature Wt from the water temperature sensor 31
The opening degree θa of an accelerator pedal (not shown) is input from the accelerator opening sensor 32 and the intake air temperature At is input from the intake air temperature sensor 33.

An output port 605 is provided with a step motor 5 or a step motor 1 serving as an output adjusting means of the engine E.
1 or forward clutch 231 or reverse brake 232
(Not shown) are connected via respective drive circuits (not shown). The operation of the engine idle control device 1 configured as described above will be described with reference to the control program of FIGS. 3 and 4 and the block diagram of FIG. The control unit 6 executes a main routine in response to turning on of the engine key. As shown in FIG.
In step 1, functions such as initial value and flag setting are set, and in step a2, data from each sensor is read. In step a3, a well-known ignition timing control process is performed in step a4.
In step a5, a well-known fuel injection amount control process is performed, and in step a6, an idle speed control process described later is sequentially performed. In step a6, other engine control processes are sequentially performed, and the process returns.

The control processing when the idle control routine in the main routine is reached will be described with reference to FIG. In step b1, each operation data, each idle control parameter, and the like are taken in. Subsequently, in step b2, it is determined whether or not a cranking switch (not shown) is turned on. If it is the cranking time, the process proceeds to step b3. , Water temperature W
The starting basic target position Po (Wt) corresponding to t is calculated using the map m1, the position Po (Wt) is set as the target position Poa here, and the process proceeds to step b4. In steps b4 and b5, clipping of upper and lower limits is performed for disturbance regulation of the target position Poa, and a clipped target position Pob is calculated.
The step motor 11 is feedback-controlled to correct the current position Pi of the valve 9 to the clipped target position Pob.

On the other hand, since it is not during cranking in step b2, the process proceeds to step b6, where the selector lever 26 sets the neutral ranges N, P and the running ranges R,
It is determined whether or not switching has been made between D, 3, 2 and L, based on the shift lever position signal S from the inhibitor switch 27. If not, the process proceeds to step b7, and if it is switched, the process proceeds to step b8. At step b7, the selector lever 26 is in a stable state, and the position feedback control is started based on the current engine operation information. Here, the water temperature Wt
And each basic target position P (W
t) and P (At) are read from the maps m2 and m3, and the maximum value among them is set as the target position Poa here. Then, the process proceeds to steps b4 and b5, where the upper and lower limits of the target position Poa are clipped, the clipped target position Pob is calculated, and the stepper for correcting the current position Pi of the ISC valve 9 to the target position Pob. The feedback control of the motor 11 is performed.

It is assumed that the selector lever 26 has been switched between the neutral ranges N and P and the running ranges R, D, 3, 2 and L in step b6, and that step b8 is reached. Here, it is determined whether or not the oil temperature Ot obtained from the oil temperature sensor 29 is equal to or higher than a predetermined value Ot1.
Go to step b9, otherwise go to step b10. When the oil temperature Ot in the oil supply circuit 24 is lower than the predetermined value Ot1, the process proceeds to steps b10, b11, b12, and b13. Here, first, while sequentially obtaining the maximum value Ntmax of the turbine speed Nt after step b8, the change in the turbine speed Nt obtained from the turbine speed sensor 28 is calculated as a change value from the difference between the current value and the maximum value Ntmax. Δnt [= Ntm
ax−Nt (n)], and then the change value Δnt
Waits for the threshold value to exceed the change determination threshold value Δnt1. That is, the friction engagement means in the oil supply circuit 24 may cause a significant delay in operation due to the flow resistance of the cryogenic oil. Is detected when the change value Δnt exceeds the threshold value Δnt1.

When the change value Δnt of the turbine rotation speed Nt exceeds the threshold value Δnt1, the process reaches step b9, where the rotation speed feedback control is started. In step b9,
The basic target rotation speed Ne (Wt) corresponding to the water temperature (Wt) is read from the map m4, and is calculated as the target rotation speed Neoa. Further, in steps b14 and d15, a deviation ΔNe between the actual engine rotation speed Nei and the target rotation speed Neoa is obtained, and a target deviation correction gain I corresponding to the deviation ΔNe is obtained from the map m5. Next, the target position P here
oa is obtained by adding the target deviation correction gain I (ΔNe) and the previous target position Pob, and steps b4 and d
Go to 5. Then, the upper and lower limits of the target position Poa are clipped, the latest target position Pob after clipping is calculated, and feedback control is performed to correct the current position Pi of the ISC valve 11 to the target position Pob.

In step b8, the oil temperature Ot is set to a predetermined value O
If it is determined that it is equal to or greater than t1, that is, if it is determined that each friction engagement means in the oil supply circuit 24 is in a temperature atmosphere in which operation delay does not occur due to oil flow resistance, P, N As soon as switching of the selector lever between the range and the R, D, 3, 2, L ranges is detected, the rotation speed feedback control of steps b9, b14, d15, b4, and d5 is started, and the same as described above. The basic target rotation speed Ne (Wt) is set as the target rotation speed Neo, and the deviation ΔNe between the actual engine rotation speed Nei and the target rotation speed Neoa is obtained. The target deviation correction gain I (ΔNe) corresponding to the deviation ΔNe is obtained.
, The target position Poa is obtained by adding the gain I and the current target position Po, and the clipped target position Pob is calculated by clipping the target position Poa, and the current position Poi of the ISC valve 9 is calculated.
Is adjusted to the target position Pob by feedback control.

After such idle rotation control, if it is determined on the main routine side that the accelerator opening degree θa has changed by a predetermined amount, the routine exits the idle control routine, and
When the current vehicle speed is lower than the predetermined stop determination speed, the process proceeds to a well-known starting process, in which a target throttle opening that can generate a target torque corresponding to the accelerator opening θa and the engine speed Ne is calculated, and the same throttle opening is calculated. In order to adjust the actual throttle opening θs to the opening, the step motor 5 as the engine output adjusting means is driven, and the rotation of the throttle valve 3 is controlled.

As described above, in the engine idle control device 1 described above, when the oil temperature Ot is equal to or higher than the predetermined value Ot1, the output correction of the engine corresponding to the load fluctuation due to the range switching is performed immediately after the range switching is detected. Since the rotation speed feedback control is performed in steps b9, b12, d13, b4, and d5, that is, in the oil temperature region where the responsiveness of the automatic transmission 18 is high, the output is corrected earlier so that the output correction of the engine is not delayed. be able to. on the other hand,
If the oil temperature Ot is less than the predetermined value Ot1, the turbine speed changes, and the completion of the switching of the forward clutch 231 and the reverse brake 232 as the friction engagement means is detected from the change value Δnt of the turbine speed Nt. After that (step b13), the output correction of the engine corresponding to the load change due to the switching of the range is similarly performed in steps b9 and b1.
4, d15, b4, and d5 can be performed with a delay by the feedback control, and the output correction of the engine can be prevented from being performed prior to the range change.

As described above, in the engine idle control apparatus 1 described above, the timing of the engine output correction is adjusted in accordance with the difference in responsiveness of the automatic transmission due to the difference in viscosity due to the oil temperature of the automatic transmission. Can be set appropriately. The above-described engine idle control device 1 compares the oil temperature Ot with a predetermined value Ot1, detects the shift range switching when the oil temperature is equal to or higher than the predetermined value, and detects the change value Δnt of the turbine speed Nt when the oil temperature is lower than the predetermined value. Is detected as a change (Δnt> change determination value Δnt1), and then the engine output adjustment means IS performs an engine output correction so as to perform engine output correction corresponding to a load change due to switching of the respective ranges.
The current position Pi of the C valve 9 is corrected to the target position Po. Instead of the oil temperature Ot, other oil temperature detecting means for detecting or estimating a state quantity correlated with the oil temperature such as the cooling water temperature Wt is used. In this case, the same operation and effect as those of the engine idle control device of FIG. 1 can be obtained.

The above-described engine idle control device 1 has an ISC valve 9 driven by a step motor 11 and a throttle valve 3 driven by a step motor 5 as engine output adjusting means for adjusting the output of the engine. Using only the throttle valve 3 driven by the motor 5,
The output of the engine may be adjusted in the entire operation range of the engine. In this case, the same operation and effect as those of the engine idle control device of FIG. 1 can be obtained.

The above-described engine idle control device 1 determines the change in the turbine speed Nt as a change value Δnt [= Ntmax, which is the difference between the current value and the maximum value after passing through step b8.
−Nt (n)], and when the change value Δnt changes by more than a threshold value Δnt1 that is a constant rotation speed, the turbine rotation speed Nt is determined to have changed. When the value Nt (n) changes by more than the set ratio Ntmax × α of the maximum value Ntmax after the start of step b8, it may be determined that the turbine speed Nt has changed, or the change rate Ntt / dt of the turbine speed Nt.
Becomes negative, it may be determined that the turbine speed Nt has changed. Further, it is detected that the turbine speed has changed based on the difference between the current value and the previous value of the turbine speed Nt. In these cases, the same operation and effects as those of the engine idle control device of FIG. 1 can be obtained.

Although the above-described engine idle control system has been described as an electronically controlled throttle + stepper motor type ISC, it is needless to say that the engine may be a normal throttle + bypass solenoid type ISC, which is controlled by a control unit (ECU). Any ISC valve can be used.

[0032]

According to the first aspect of the present invention, when the state quantity correlated with the oil temperature is equal to or more than a predetermined value, the switching of the range is detected, and then the output of the engine corresponding to the load change due to the switching of the range is corrected. Therefore, in the oil temperature region where the response of the automatic transmission is high, the output correction of the engine can be hastened, and when the state quantity correlated with the oil temperature is less than a predetermined value, it is detected that the turbine speed has changed. After that, it is possible to delay the output correction of the engine corresponding to the load change due to the switching of the range. As a result, the timing of engine output correction can be appropriately set in accordance with the difference in responsiveness of the automatic transmission due to the difference in viscosity due to the oil temperature of the automatic transmission, and the engine stall and air blow It is possible to reliably prevent the driver from feeling uncomfortable due to the occurrence.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an engine idle control device as one embodiment of the present invention.

FIG. 2 is a control block diagram of the idle control device for the engine of FIG. 1;

FIG. 3 is a flowchart of a main control routine used by control means in the engine idle control device of FIG. 1;

FIG. 4 is a flowchart of an idle control routine used by control means in the engine idle control device of FIG. 1;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 engine idle control device 6 control unit 9 ISC valve 11 step motor 18 automatic transmission 21 wheels 22 torque converter 26 selector lever 27 inhibitor switch 28 turbine speed sensor 31 water temperature sensor E engine Nt turbine speed Ot oil temperature Ot1 predetermined value PT Power transmission path Δnt change

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3G093 AA05 BA02 BA05 BA06 CA04 DA01 DA05 DA06 DB00 DB09 EA07 EA09 EC02 3G301 JA03 JA31 JA34 KA07 LA03 LA04 LC04 PA10Z PA11Z PA15Z PE01Z PE08Z PF00Z PF03Z PF08Z

Claims (1)

[Claims] An automatic transmission having a fluid torque converter disposed in a power transmission path for transmitting an engine output to wheels, and a lever position detection for detecting an operation position of a selector lever for selecting a shift range of the automatic transmission. Means, oil temperature detecting means for detecting or estimating a state quantity correlated with the oil temperature of the automatic transmission, turbine speed detecting means for detecting the turbine speed of the torque converter, and adjusting the output of the engine. When the selector lever is switched between the neutral range and the traveling range, if the state quantity correlated with the oil temperature is equal to or greater than a predetermined value, the switching of the shift range is detected, and If the value is less than the value, it is detected that a change has occurred in the turbine speed. Idle engine control apparatus characterized by comprising control means for controlling the operation of the engine output adjusting means to perform the engine output correction, a.