JP5999993B2 - Vehicle neutral control device - Google Patents

Description

  According to the present invention, when a predetermined condition is satisfied during traveling of the vehicle, the vehicle drive system is controlled by a fastening force feedback control of a friction transmission element that performs a predetermined rotational difference between the input and output rotational differences of the torque converter in the drive system. The present invention relates to a neutral control device for a vehicle that is in a neutral state in which transmission is limited.

  Conventionally, for example, a neutral control device for a vehicle as described in Patent Document 1 is known.

  This neutral control device is intended for creep torque control when the vehicle is stopped, not when the vehicle is running, but when the neutral control conditions are established when the vehicle is stopped, the wheel drive system is replaced with a torque converter in the drive system. The starting clutch engaging force feedback control is performed so that the input / output rotational difference becomes a predetermined rotational difference, and the neutral state is established when power transmission is limited (neutral control is performed when the vehicle is stopped).

Japanese Patent No. 3606157

By the way, the neutral control may be necessary not only when the vehicle is stopped but also during traveling, for example, during coasting (in coastal) traveling, for example, to increase the fuel efficiency by separating the engine.
However, when the above-described neutral control technology at the time of stopping is directly used for the neutral control at the time of traveling, the following problems occur.

In other words, when feedback control is performed on the starting clutch engagement force so that the input / output rotational difference of the torque converter becomes a predetermined rotational difference, the optimum starting clutch engaging force by the feedback control is the torque to the front and rear shafts of the starting clutch (both The torque to the starting clutch determined by (referred to as starting clutch torque) differs.
However, although the starting clutch torque does not change greatly while the vehicle is stopped, it changes in various ways depending on the vehicle speed, the gear ratio of the wheel drive system, the vehicle deceleration, etc. during traveling. It is difficult to obtain the optimum fastening force of the starting clutch by control.

For this reason, if the neutral control technology at the time of stopping is used as it is for neutral control at the time of driving, the feedback control value cannot follow the vehicle speed, the gear ratio, the vehicle deceleration, etc. that change one by one, and the above feedback control diverges, and at least the control accuracy There is no denying a significant drop in
Therefore, the engagement force of the starting clutch by the feedback control is excessive or insufficient with respect to the optimum engaging force necessary to make the torque converter input / output rotation difference the predetermined rotation difference regardless of the change of the starting clutch torque.

If the starting clutch engagement force is excessive with respect to the above optimum value, fuel consumption may be deteriorated due to the length of time that the engine is used unnecessarily, or engine stall (engine stop) will occur. Cause problems.
On the contrary, when the fastening force of the starting clutch is insufficient with respect to the above-mentioned optimum value, there arises a problem that a response delay at the time of reacceleration after coasting travel becomes large and a reacceleration shock becomes large.

  The present invention can avoid the above problem by prohibiting or restricting the above-mentioned engagement force feedback control of the starting clutch based on the torque converter input / output rotation difference during traveling such that the starting clutch torque changes. It aims at proposing the neutral control apparatus of the made vehicle.

For this purpose, the neutral control device for a vehicle according to the present invention comprises:
When the vehicle is driven by a vehicle drive system including a torque converter and a frictional transmission element, the frictional transmission element performs the vehicle drive system so that an input / output rotational difference of the torque converter becomes a predetermined rotational difference when a predetermined condition is satisfied. A neutral control device for a vehicle having a neutral control means that achieves a neutral state in which power transmission is restricted by fastening force feedback control is a basic premise of the gist configuration,
Provided is a torque change travel detection means for detecting that the torque to the friction transmission element is in a traveled state,
The present invention is characterized in that a fastening force feedback control prohibiting / limiting means for prohibiting or limiting the fastening force feedback control of the friction transmission element by the neutral control means when the torque change traveling is detected by the means .

In the vehicle neutral control device according to the present invention,
When the torque transmission to the friction transmission element is in a running state, if the fastening force feedback control of the friction transmission element diverges or the control accuracy is greatly reduced, the fastening force feedback control of the friction transmission element is prohibited. Or to limit
Even in the running state, the fastening force of the friction transmission element by the feedback control does not cause a large excess or deficiency with respect to the optimum value necessary to make the torque converter input / output rotational difference the predetermined rotational difference.

  Therefore, it is possible to avoid problems such as deterioration of fuel consumption or engine stall due to the length of time that the engine is operated unnecessarily due to excessive fastening force of the friction transmission element. Due to the insufficient fastening force, it is possible to avoid problems such as a large response delay at the time of reacceleration after coasting and a large reacceleration shock.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic system diagram showing a vehicle drive system including a V-belt continuously variable transmission mechanism that includes a neutral control device according to a first embodiment of the present invention. 3 is a flowchart showing a neutral control program executed by the transmission controller in FIG. FIG. 3 is a time chart showing an operation when the neutral control according to FIG. 2 is stopped. FIG. It is a time chart which shows operation | movement at the time of performing the conventional neutral control as it is also at the time of a stop. FIG. 3 is a time chart showing an operation during running of neutral control according to FIG. 2. FIG. FIG. 3 is a flowchart of a neutral control program similar to FIG. 2, showing a neutral control apparatus according to a second embodiment of the present invention. FIG. 7 is a time chart showing an operation during running of neutral control according to FIG. 6. FIG. FIG. 6 is a flowchart of a neutral control program similar to FIG. 2, showing a neutral control device according to a third embodiment of the present invention. FIG. 9 is an explanatory diagram used to explain how to obtain a set vehicle speed and a set gear ratio used in the neutral control in FIG. FIG. 9 is an explanatory diagram used to explain how to obtain a set vehicle speed and a set deceleration used in the neutral control in FIG. 6 is a flowchart of a neutral control program similar to that of FIG. 2, showing a neutral control apparatus according to a fourth embodiment of the present invention. Fig. 11 is a time chart showing the neutral control operation according to Fig. 11. (a) is an operation time chart when the brake pedal depression force exceeds the set value from the middle. (B) is an anti-skid control device activated from the middle. Is an operation time chart.

Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.
<Configuration of the first embodiment>
FIG. 1 shows an outline of a vehicle drive system (wheel drive system) including a V-belt type continuously variable transmission mechanism 1 including a neutral control device according to a first embodiment of the present invention.

This V-belt type continuously variable transmission mechanism 1 has a primary pulley 2 and a secondary pulley 3 arranged so that the pulley V-grooves of both pulleys are substantially aligned in the plane perpendicular to the axis. It is assumed that the terminal V belt 4 is stretched and is well known.
An engine 7 is drivingly coupled to the primary pulley 2 via a starting clutch 5 (friction transmission element) and a torque converter 6 in order.

  The starting clutch 5, the torque converter 6 and the engine 7 are actually arranged coaxially with respect to the primary pulley 2 to form the above drive system. However, in FIG. 1, for the sake of convenience, the starting clutch 5, the torque converter 6 In addition, the engine 7 is shown in a side-by-side arrangement with respect to the primary pulley 2.

A driving wheel (not shown) is coupled to the secondary pulley 3 of the V-belt type continuously variable transmission mechanism 1.
Thus, in the vehicle drive system of FIG. 1, when the start clutch 5 is in the engaged state, the power from the engine 7 is increased by the torque converter 6 while the torque is increased by the torque converter 6 and the V belt type continuously variable transmission mechanism 1 (primary pulley 2 The vehicle can be run by sequentially passing through the endless V-belt 4 and the secondary pulley 3) toward the driving wheel.

During the transmission of the engine power, by changing the V groove width of the primary pulley 2 and the secondary pulley 3 synchronously, the rotational transmission ratio (pulley transmission ratio) between these pulleys 2 and 3 can be changed steplessly. .
The vehicle drive system of FIG. 1 feedback-controls the fastening force of the starting clutch 5 so that the torque converter input / output rotation difference ΔNet (engine rotation speed Ne−turbine rotation speed Nt) becomes the target rotation difference ΔNtgt. It is possible to achieve a neutral state in which power transmission is limited.

The rotation transmission ratio (transmission ratio) between pulleys of the V-belt type continuously variable transmission mechanism 1 includes the engagement / release of the start clutch 5 (including the engagement force feedback control for neutral control that achieves the above neutral state) and the transmission control. Control is performed by the hydraulic circuit 10.
The shift control hydraulic circuit 10 responds to a signal from the transmission controller 11 and performs the control using oil from the oil pump 12 driven by the engine as a working medium.

For this reason, the transmission controller 12
A signal from the primary pulley rotation sensor 13 for detecting the primary pulley rotation speed Npri;
A signal from the secondary pulley rotation sensor 14 for detecting the secondary pulley rotation speed Nsec;
A signal from the accelerator opening sensor 15 for detecting the accelerator opening APO (depressing amount of the accelerator pedal),
A signal from the brake switch 16 that turns on when braking by depressing the brake pedal,
A selection range signal from the inhibitor switch 18 for detecting the select position (parking P range, reverse R range, neutral N range, forward D range) of the transmission shift lever 17 operated by the driver;
A signal from the engine rotation sensor 19 for detecting the engine rotation sensor 19 for detecting the engine rotation speed Ne (input rotation speed of the torque converter 6);
A signal from the turbine rotation sensor 20 for detecting the turbine rotation speed Nt (output rotation speed of the torque converter 6);
A signal (engine speed and fuel injection time) related to the transmission input torque from the engine controller 21 that controls the engine 7 is input.

The engine controller 21 controls the engine 7 as usual based on input information from various sensors (not shown),
When the transmission controller 12 performs the engaging force feedback control (neutral control) of the starting clutch 5 as will be described in detail later, the torque control and the torque return control of the engine 7 for neutral control are also performed in synchronization with this. Shall.

<Neutral control>
The transmission controller 11 executes the control program of FIG. 2 and performs neutral control (engagement force control of the starting clutch 5) of the vehicle drive system as follows.
FIG. 2 is started when a neutral control permission condition such as braking by depressing the brake pedal is satisfied. First, in step S11, neutral control is started in response to the satisfaction of the condition.

Next, in step S12, depending on whether or not the vehicle speed VSP obtained from the secondary pulley rotation speed Nsec exceeds 0 km / h, whether the clutch torque to the start clutch 5 changes or the clutch torque to the start clutch 5 changes Check if the vehicle is stopped.
Therefore, step S12 corresponds to the torque change travel detecting means in the present invention.

When it is determined in step S12 that the vehicle is stopped at VSP = 0 km / h, the engagement force of the starting clutch 5 is determined in step S13 as the input / output rotation difference ΔNet (= Ne−Nt) of the torque converter 6 is the target rotation difference ΔNtgt when the vehicle is stopped. Feedback control is performed so as to achieve a target creep torque equivalent value (for example, a target creep torque equivalent value), and neutral control at the time of stopping by feedback control with excellent disturbance resistance is performed.
Therefore, step S13 corresponds to the neutral control means in the present invention.

However, when it is determined in step S12 that the vehicle is in a traveling state where VSP> 0 km / h (a traveling state in which the clutch torque to the starting clutch 5 changes), in step S14, the feedback control performed in step S13 is prohibited and replaced with this. Neutral control not based on feedback control is performed.
Therefore, step S14 corresponds to the fastening force feedback control prohibiting / limiting means in the present invention.
After the execution of step S14, the control is returned to step S12, so that the neutral control not based on the feedback control is continuously performed by continuously executing step S14 during the traveling.

  Neutral control that does not rely on feedback control is performed by setting the input / output rotation difference ΔNet (= Ne−Nt) of the torque converter 6 to the target rotation difference ΔNtgt (for example, for separating the engine 7 from the vehicle drive system and improving fuel efficiency. There is a feedforward control in which a target engagement force of the start clutch 5 necessary for achieving the target torque converter input / output rotation difference) is obtained in advance as a map and the engagement force of the start clutch 5 is set to this target value.

Hereinafter, the reason why the neutral control that does not depend on the feedback control in the traveling state in which the clutch torque to the starting clutch 5 changes will be described.
FIG. 3 is a time chart of the neutral control at the time of stop by feedback control executed in step S13 in FIG. 2 while the vehicle speed VSP is stopped at 0 km / h.
When neutral control is started at the instant t1 in response to the establishment of the neutral control permission condition, the input / output rotation difference ΔNet (= Ne−Nt) of the torque converter 6 becomes the target rotation difference ΔNtgt (corresponding to the target creep torque) when the vehicle is stopped. The fastening force of the starting clutch 5 is feedback-controlled so that

By the way, if the engaging force control (neutral control) of the starting clutch 5 is performed without feedback of the torque converter input / output rotation difference ΔNet, the torque converter input / output rotation difference is caused by disturbances such as changes in the hydraulic oil temperature of the continuously variable transmission 1. ΔNet greatly deviates from the target rotation difference ΔNtgt within the dashed line in FIG.
However, according to the above-described engagement force feedback control (neutral control) of the starting clutch 5 based on the torque converter input / output rotation difference ΔNet, the torque converter input / output rotation difference ΔNet smoothly converges to the target rotation difference ΔNtgt as shown in FIG. After that, the target rotation difference ΔNtgt is maintained in the vicinity of the target due to disturbance resistance, and high control accuracy can be maintained.

  When the vehicle stops, the input torque to the start clutch 5 (the start clutch torque determined by the input torque from the wheel side and the input torque from the engine side) is substantially constant as shown in FIG. Is compensated without being affected by changes in the starting clutch torque.

However, during traveling at a vehicle speed VSP> 0 km / h, as shown in FIG. 4, the starting clutch torque varies depending on the vehicle speed VSP, the speed ratio i of the wheel drive system, the vehicle deceleration G, and the like.
When the fastening force of the starting clutch 5 is feedback-controlled so that the torque converter input / output rotational difference ΔNet becomes the target rotational difference ΔNtgt even during this traveling, the optimum engaging force of the starting clutch 5 required to satisfy ΔNet = ΔNtgt is Since it varies depending on the starting clutch torque (vehicle speed VSP, speed ratio i of the wheel drive system, vehicle deceleration G, etc.), the fastening force feedback control of the starting clutch 5 Changes such as vehicle speed VSP, wheel drive system speed ratio i, vehicle deceleration G, etc. need to be used as parameters.

However, the response of the starting clutch engagement force feedback control may not reach the changing speed of the starting clutch torque (vehicle speed VSP, wheel drive system speed ratio i, vehicle deceleration G, etc.). The converter input / output rotation difference ΔNet is helped to deviate from the target rotation difference ΔNtgt.
This tendency is particularly noticeable when the starting clutch torque changes suddenly, such as when the vehicle is suddenly braked, and the torque converter input / output rotation difference ΔNet is compared to the target rotation difference ΔNtgt as shown in FIG. As a result, the feedback control is diverged, or at least the control accuracy is greatly reduced.

In this case, the engagement force of the start clutch 5 by feedback control is excessive or insufficient with respect to the optimum engagement force required to make the torque converter input / output rotation difference ΔNet equal to the target rotation difference ΔNtgt regardless of the change of the start clutch torque.
When the fastening force of the starting clutch 5 is excessive, there is a problem that the fuel consumption deteriorates due to a long time for which the engine is used unnecessarily and the fuel consumption deteriorates, or the engine stalls (engine stops). .
On the other hand, when the fastening force of the starting clutch 5 is insufficient, there arises a problem that a response delay at the time of reacceleration after coasting increases and a reacceleration shock increases.

In the present embodiment, the feedback control causes the above-mentioned problem during traveling where the starting clutch torque changes. Therefore, as described above, the engaging force feedback control of the starting clutch 5 based on the torque converter input / output rotation difference ΔNet (step) S13) is prohibited, intends row fastening force control (during running neutral control) of the starting clutch 5 not according to the place of the feedback control in step S14.

<Effects of the first embodiment>
According to the neutral control of the first embodiment described above, in the traveling state in which the torque to the starting clutch 5 changes (step S12), the engagement force feedback control of the starting clutch 5 based on the torque converter input / output rotation difference ΔNet ( (Neutral control in step S13) is prohibited, and the engaging force control of the starting clutch 5 (neutral control in step S14) not based on feedback control is performed.
When the engagement force feedback control of the starting clutch 5 based on the torque converter input / output rotation difference ΔNet is performed in the running state, the neutral control divergence and the control accuracy are not reduced.

Therefore, even during travel where the starting clutch torque changes, the engagement force of the starting clutch 5 does not cause a large excess or deficiency with respect to the optimum value required to make the torque converter input / output rotation difference ΔNet the target rotation difference ΔNtgt. .
Therefore, it is possible to avoid problems such as deterioration of fuel economy due to excessive engagement time of the start clutch 5 and longer engine operation time and engine stall. Due to insufficient fastening force, it is possible to avoid problems such as a delay in response at the time of reacceleration after coasting and a large reacceleration shock.

FIG. 5 is an operation time chart of the first embodiment when the running clutch torque is changed as in FIG. 4.
In this embodiment, even if the torque to the starting clutch 5 changes as shown in the figure, the starting clutch 5 is prohibited from feedback control based on the torque converter input / output rotation difference ΔNet, and the starting clutch not based on feedback control is used. To perform the fastening force control of 5,
The torque converter input / output rotation difference ΔNet can be maintained at a value in the vicinity of the target rotation difference ΔNtgt as shown in FIG. 5 without causing the divergence of the neutral control due to the change of the starting clutch torque and the deterioration of the control accuracy.

In other words, even when the torque to the starting clutch 5 is changing, it is possible to prevent the torque converter input / output rotation difference ΔNet from greatly deviating from the target rotation difference ΔNtgt beyond the deviation width between the alternate long and short dash lines due to disturbance. it can.
1 has a small deviation between the torque converter input / output rotation difference ΔNet and the target rotation difference ΔNtgt, so that the intake can be guaranteed for the maximum engine input torque within the divergence width between the alternate long and short dashed lines due to disturbance. It is sufficient to command the amount to the engine 7.

<Second embodiment>
FIG. 6 shows a control program of the neutral control device according to the second embodiment of the present invention.
Also in this embodiment, the wheel drive system and its control system are the same as in FIG. 1, but the transmission controller 11 executes the control program of FIG. 6 and performs neutral control of the vehicle drive system as follows. (Engagement force feedback control of the starting clutch 5) shall be performed.

  FIG. 6 is started when a neutral control permission condition such as braking by depressing the brake pedal is satisfied. First, in step S21, neutral control is started in response to the satisfaction of the condition.

Next, in step S22, it is checked whether or not the clutch torque of the starting clutch 5 is equal to or greater than a set value.
This set value is the starting clutch torque that causes the above-mentioned engaging force feedback control of the starting clutch 5 performed so that the torque converter input / output rotational difference ΔNet becomes the target rotational difference ΔNtgt causes the problem due to the excessive or insufficient starting clutch engaging force. The lower limit value of the vehicle range (the lower limit value of the starting clutch torque region representing the running state accompanied by the clutch torque change of the starting clutch causing the above-mentioned problem).
Therefore, step S22 corresponds to the torque change travel detecting means in the present invention.

If it is determined in step S22 that the clutch torque of the start clutch 5 is less than the set value, that is, if the start clutch torque range is such that there is no problem due to excessive or insufficient start clutch engagement force, the start clutch 5 of the start clutch 5 is determined in step S23. Low torque by feedback control with excellent disturbance resistance by controlling feedback of fastening force so that torque converter input / output rotation difference ΔNet is a normal gain and target rotation difference ΔNtgt at low torque (for example, equivalent value of target creep torque) When performing neutral control.
Therefore, step S23 corresponds to the neutral control means in the present invention.

However, if it is determined in step S22 that the clutch torque of the start clutch 5 is greater than or equal to the set value, that is, if the start clutch torque range causes a problem due to excessive or insufficient start clutch engagement force, the process is performed in step S23 in step S23. Instead of feedback control with normal control gain, feedback control with a small control gain reduced than normal is used to reduce the engagement force of the starting clutch 5, and the target rotation when the torque converter input / output rotation difference ΔNet is large with the small control gain. Neutral control during large torque is performed in which feedback control is performed to achieve a difference ΔNtgt (for example, a target torque converter input / output rotational difference for reducing fuel consumption efficiency by separating the engine 7 from the vehicle drive system).
Therefore, step S24 corresponds to the fastening force feedback control prohibiting / limiting means in the present invention.
After step S24, control by returning to step S22, by the time of large torque to continue performing the step S24, intends continuously line neutral control by the feedback control using a small control gain.

<Effect of the second embodiment>
According to the neutral control of the second embodiment described above, when the torque to the starting clutch 5 is less than the set value (step S22), that is, when the starting clutch torque is changing, the torque converter input / output rotational difference In order to limit the engaging force feedback control of the starting clutch 5 based on ΔNet (neutral control in step S23), the engaging force control of the starting clutch 5 by the feedback control is performed based on the small gain reduced in step S24.
When the engagement force feedback control of the starting clutch 5 based on the torque converter input / output rotation difference ΔNet is performed based on a large control gain as usual in the traveling state, the neutral control divergence and the control accuracy are not reduced.

Therefore, even during travel where the starting clutch torque changes, the engagement force of the starting clutch 5 does not cause a large excess or deficiency with respect to the optimum value required to make the torque converter input / output rotation difference ΔNet the target rotation difference ΔNtgt. .
Therefore, it is possible to achieve the same effect as the first embodiment described above, and due to excessive fastening force of the starting clutch 5, the time that the engine is used unnecessarily becomes longer, resulting in deterioration of fuel consumption or engine stall. In addition to avoiding problems, it is possible to avoid problems such as a delay in response at the time of re-acceleration after coasting and an increase in re-acceleration shock due to insufficient fastening force of the starting clutch 5.

In addition, based on FIG. 7, in this embodiment, the case where the torque from the neutral control start instant t1 to the starting clutch 5 changes as shown in the figure will be described. When the engagement force feedback control of the start clutch 5 based on a large gain is performed, the above-described start clutch torque range that causes a problem due to excessive or insufficient start clutch engagement force occurs) After the instant t2, the engagement force feedback control of the start clutch 5 To limit the gain by decreasing the gain,
The feedback control amount is reduced by α, so that the neutral control divergence and the control accuracy are not reduced due to the change of the starting clutch torque, and the torque converter input / output rotation difference ΔNet is set to the target as described above with reference to FIG. It can be maintained at a value in the vicinity of the rotation difference ΔNtgt, and the same effect as in the first embodiment can be achieved.

<Third embodiment>
FIG. 8 shows a control program of the neutral control device according to the third embodiment of the present invention.
Also in this embodiment, the wheel drive system and its control system are the same as those in FIG. 1, but the transmission controller 11 executes the control program of FIG. 8 and performs neutral control of the vehicle drive system as follows. (Engagement force feedback control of the starting clutch 5) shall be performed.

  FIG. 8 is started when a neutral control permission condition such as braking by depressing the brake pedal is satisfied. First, in step S31, neutral control is started in response to the satisfaction of the condition.

Next, in step S32, it is checked whether any of the vehicle speed VSP, the vehicle deceleration G, and the gear ratio i is equal to or greater than a set value.
The set values related to the vehicle speed VSP, the vehicle deceleration G, and the gear ratio i are respectively the above-described normal engagement force feedback control of the starting clutch 5 performed so that the torque converter input / output rotation difference ΔNet becomes the target rotation difference ΔNtgt. Vehicle speed VSP causing a problem due to excessive or insufficient starting clutch engagement force, lower limit value of vehicle deceleration G and gear ratio i (vehicle speed range representing a traveling state accompanied by clutch torque change of starting clutch causing the above problem, Lower limit value of vehicle deceleration range and gear ratio range).

  Accordingly, in step S32, it is determined whether or not the normal engagement force feedback control of the start clutch 5 is in a traveling state (feedback control prohibition range) accompanied by a change in the clutch torque of the start clutch 5 that causes the above-mentioned problem. This corresponds to the torque change travel detection means in the present invention.

The above set values will be added below based on FIG. 9 and FIG.
FIG. 9 shows the relationship between the combination of the vehicle speed VSP and the gear ratio i and the load torque to the engine 7, and a constant correlation as shown in the figure between the vehicle speed VSP and the engine load torque for each gear ratio i. Exists.
The engine load region (feedback control prohibition region) in which the above-described normal engagement force feedback control of the start clutch 5 causes a problem due to excessive or insufficient start clutch engagement force is illustrated in FIG. It is a large load range that is greater than the "load torque.

From the above, the lower limit value of the vehicle speed (feedback control prohibited vehicle speed) at which the normal engagement force feedback control of the starting clutch 5 should be prohibited is obtained as shown by VSP1, VSP2, VSP3, and VSP4 in FIG. These are determined as set values relating to the vehicle speed VSP in step S32, and the gear ratio i corresponding to these feedback control prohibited vehicle speeds VSP1, VSP2, VSP3, VSP4 is determined as the set value of the gear ratio i in step S32.
In step S32, based on the combination of the current gear ratio i and the vehicle speed VSP, it is determined that the feedback control is prohibited when either of them is equal to or greater than the set value.

FIG. 10 shows the relationship between the combination of the vehicle speed VSP and the vehicle deceleration G and the load torque to the engine 7, and for each vehicle deceleration G, there is a constant between the vehicle speed VSP and the engine load torque as shown in the figure. Correlation exists.
An engine load region (feedback control prohibition region) in which the above-described normal engagement force feedback control of the start clutch 5 causes a problem due to excessive or insufficient start clutch engagement force is illustrated in FIG. It is a large load range that is greater than the "load torque.

From the above, the lower limit value of the vehicle speed at which normal engagement force feedback control of the starting clutch 5 should be prohibited for each vehicle deceleration G (feedback control prohibited vehicle speed) is shown as VSP1, VSP2, VSP3, VSP4 in FIG. These are determined as the set values for the vehicle speed VSP in step S32, and the vehicle deceleration G corresponding to these feedback control prohibited vehicle speeds VSP1, VSP2, VSP3, VSP4 is set as the set value of the vehicle deceleration G in step S32. Determine.
In step S32, the feedback control prohibition region is determined when either of them is equal to or greater than the above set value based on the current combination of vehicle deceleration G and vehicle speed VSP.

If it is determined in step S32 that the feedback control is not prohibited (feedback control permission), the input / output rotation difference ΔNet (= Ne−Nt) of the torque converter 6 is set with a large gain as usual in step S33. ) Is a target rotation difference ΔNtgt (for example, a value corresponding to a target creep torque) at the time of stopping, and neutral control at the time of stopping by feedback control excellent in disturbance resistance is performed.
Therefore, step S33 corresponds to the neutral control means in the present invention.

However, if it is determined in step S32 that the feedback control is prohibited (traveling state in which the clutch torque to the starting clutch 5 changes), the feedback control performed in step S33 is prohibited in step S34. There is no neutral control.
Therefore, step S34 corresponds to the fastening force feedback control prohibiting / limiting means in the present invention.
After execution of step S34, control by returning to step S32, by subsequently performing the step S34 in the feedback control prohibition area, it intends continuously line the neutral control that is not based on feedback control.

<Effect of the third embodiment>
According to the neutral control of the third embodiment described above, when any of the vehicle speed VSP, the vehicle deceleration G, and the gear ratio i is greater than or equal to the above set value (step S32), that is, the torque converter input / output rotation difference ΔNet is The normal engagement force feedback control (step S33) of the start clutch 5 performed so as to achieve the target rotation difference ΔNtgt causes a feedback control prohibition region (the above-described problem occurs) that causes a problem due to excessive or insufficient start clutch engagement force. (Running state with a change in torque of the starting clutch), the engaging force feedback control of the starting clutch 5 (neutral control in step S33) based on the torque converter input / output rotation difference ΔNet is prohibited, and is not based on the feedback control. In order to perform the engagement force control of the starting clutch 5 (neutral control in step S34),
There is no divergence of neutral control or lowering of control accuracy when the engagement force feedback control of the starting clutch 5 based on the torque converter input / output rotation difference ΔNet is performed in the traveling state.

Therefore, even during travel where the starting clutch torque changes, the engagement force of the starting clutch 5 does not cause a large excess or deficiency with respect to the optimum value required to make the torque converter input / output rotation difference ΔNet the target rotation difference ΔNtgt. .
Therefore, in this embodiment, the same effects as in the first and second embodiments can be obtained, and due to excessive fastening force of the starting clutch 5, the vice-minister in which the engine is operated unnecessarily becomes longer and fuel consumption deteriorates. The problem of engine stall can be avoided, and the problem of increased response delay or increased re-acceleration shock due to re-acceleration after coasting due to insufficient fastening force of start clutch 5 is avoided. be able to.

<Fourth embodiment>
FIG. 11 shows a control program of the neutral control device according to the fourth embodiment of the present invention.
Also in this embodiment, the wheel drive system and its control system are the same as in FIG. 1, but the transmission controller 11 executes the control program of FIG. 11 and performs neutral control of the vehicle drive system as follows. (Engagement force feedback control of the starting clutch 5) shall be performed.

  FIG. 11 is started when a neutral control permission condition such as braking by depressing the brake pedal is satisfied. First, in step S41, neutral control is started in response to the satisfaction of the condition.

  Next, in step S42, it is checked whether or not the anti-skid control device (ABS) for preventing braking slip of the wheel is in operation, or whether or not the brake pedal depression force (braking force) is equal to or greater than a set value.

  During the operation of the anti-skid control device (ABS), the normal engagement force feedback control of the start clutch 5 performed so that the torque converter input / output rotation difference ΔNet becomes the target rotation difference ΔNtgt is This is a running state that causes a problem due to excess or deficiency (running state involving a change in clutch torque of the starting clutch 5), and the feedback control should not be performed.

  The set value relating to the brake pedal depression force (braking force) in step S42 is determined by the above-described normal engagement force feedback control of the start clutch 5 performed so that the torque converter input / output rotation difference ΔNet becomes the target rotation difference ΔNtgt. The lower limit value of the brake pedal depression force that causes a problem due to excess or deficiency of the clutch engagement force (the lower limit value of the brake pedal depression force that causes the running state accompanied by the clutch torque change of the start clutch 5 that causes the above problem).

  Therefore, step S42 determines whether or not the normal engagement force feedback control of the starting clutch 5 is in a traveling state (feedback control prohibition region) accompanied by a change in clutch torque of the starting clutch 5 that causes the above problem. This corresponds to the torque change travel detection means in the present invention.

If it is determined in step S42 that the feedback control is not prohibited (feedback control allowed), the input / output rotation difference ΔNet (= Ne−Nt) of the torque converter 6 is set with a large gain as usual in step S43. ) Is a target rotation difference ΔNtgt (for example, a value corresponding to a target creep torque) at the time of stopping, and neutral control at the time of stopping by feedback control excellent in disturbance resistance is performed.
Therefore, step S43 corresponds to the neutral control means in the present invention.

However, when it is determined in step S42 that the feedback control is prohibited (traveling state in which the clutch torque to the starting clutch 5 changes), in step S44, the feedback control performed in step S43 is prohibited. There is no neutral control.
After the execution of step S44, the control is returned to step S42, so that the neutral control not based on the feedback control is continuously performed by continuing to perform step S44 in the feedback control prohibited area.
Follow step S44 to correspond to the fastening force feedback control inhibition and limitation means in the present invention.

<Effect of the fourth embodiment>
According to the neutral control of the fourth embodiment described above, when the anti-skid control device (ABS) is in operation or the brake pedal depression force (braking force) is greater than or equal to a set value (step S42), that is, a torque converter The above-mentioned normal engagement force feedback control (step S43) of the start clutch 5 performed so that the input / output rotation difference ΔNet becomes the target rotation difference ΔNtgt causes a problem due to the excessive or insufficient start clutch engagement force. In the case of (running state with a change in the torque of the starting clutch that causes the above-mentioned problem), the engagement force feedback control (neutral control in step S43) of the starting clutch 5 based on the torque converter input / output rotation difference ΔNet is prohibited. , Engagement force control of start clutch 5 without feedback control (Neutral at step S44) Control)
There is no divergence of neutral control or lowering of control accuracy when the engagement force feedback control of the starting clutch 5 based on the torque converter input / output rotation difference ΔNet is performed in the traveling state.

Therefore, even during travel where the starting clutch torque changes, the engagement force of the starting clutch 5 does not cause a large excess or deficiency with respect to the optimum value required to make the torque converter input / output rotation difference ΔNet the target rotation difference ΔNtgt. .
Therefore, in this embodiment, the same effects as those in the first, second and third embodiments can be obtained. Due to the excessive fastening force of the starting clutch 5, the time for which the engine is operated unnecessarily becomes longer and the fuel consumption deteriorates. And the problem of engine stalling, and due to insufficient fastening force of the starting clutch 5, there is a problem that response delay at re-acceleration after coasting increases and re-acceleration shock increases. It can be avoided.

In addition, based on FIG. 12, in this embodiment, as shown in FIG. 12 (a), the instant t2 when the brake pedal depression force exceeds the set value, or the anti-skid control device (ABS) starts operating as shown in FIG. 12 (b). After the instant t2, that is, when the engagement force feedback control of the start clutch 5 based on a large gain as usual is performed, the problem of the start clutch engagement force described above occurs after the instant t2 when the start clutch engagement force is excessive or insufficient. In order to stop the engagement force feedback control and control the engagement clutch 5 without using the feedback control,
The torque converter input / output rotation difference ΔNet can be maintained at a value near the target rotation difference ΔNtgt as described above with reference to FIG. 5 without causing the divergence of the neutral control due to the change of the starting clutch torque and the deterioration of the control accuracy. Thus, the above effects can be achieved.

1 V belt type continuously variable transmission mechanism
2 Primary pulley
3 Secondary pulley
4 Endless V-belt
5 Starting clutch
6 Torque converter
7 Engine
10 Shift control hydraulic circuit
11 Transmission controller
12 Oil pump
13 Primary pulley rotation sensor
14 Secondary pulley rotation sensor
15 Accelerator position sensor
16 Brake switch
17 Shift lever
18 Inhibitor switch
19 Engine rotation sensor
20 Turbine rotation sensor
21 Engine controller

Claims (4)

When the vehicle is driven by a vehicle drive system including a torque converter and a frictional transmission element, the frictional transmission element performs the vehicle drive system so that an input / output rotational difference of the torque converter becomes a predetermined rotational difference when a predetermined condition is satisfied. In a neutral control device for a vehicle, including a neutral control means for achieving a neutral state in which power transmission is limited by fastening force feedback control,
Provided is a torque change travel detection means for detecting that the torque to the friction transmission element is in a traveled state,
The vehicle neutral is provided with a fastening force feedback control prohibiting / limiting means for prohibiting or limiting the fastening force feedback control of the friction transmission element by the neutral control means when the torque change traveling is detected by the means. Control device. In the vehicle neutral control device according to claim 1,
The fastening force feedback control prohibiting / limiting means reduces the fastening force feedback control amount of the friction transmission element in accordance with the torque to the friction transmission element when the torque change traveling is detected. Vehicle neutral control device. In the neutral control device for a vehicle according to claim 1 or 2,
The torque change running detection means determines that the running state in which the torque to the friction transmission element changes when at least one of a vehicle speed, a gear ratio of a vehicle drive system, and a vehicle deceleration exceeds a set value. A neutral control device for a vehicle, characterized in that In the neutral control device for a vehicle according to any one of claims 1 to 3,
The torque change travel detection means determines that the vehicle is in a travel state in which the torque to the friction transmission element changes when an operation of a device that increases vehicle deceleration occurs. Neutral control device.

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