JP5109855B2 - Gradient estimation device - Google Patents

Description

  The present invention belongs to the technical field of a gradient estimation device that estimates or detects a road gradient when a vehicle is stopped.

As an apparatus for estimating a road surface gradient, for example, a technique described in Patent Document 1 is known. In this publication, the difference between the acceleration sensor value before the vehicle slips and the acceleration sensor value when the vehicle slips is obtained, and the acceleration change amount ΔG is calculated from this difference. Then, based on the characteristic diagram in which the acceleration change amount ΔG and the road surface gradient are related one-to-one, the road surface gradient is estimated based on the acceleration change amount ΔG.
JP 2008-145151 A

  By the way, the acceleration change amount ΔG accompanying the slip-down depends on the magnitude of the transmission output shaft torque at the time of the slip-down. In other words, even if the road surface gradient is the same, the higher the transmission output shaft torque, the more difficult it is to slide down, so the acceleration change amount ΔG is small, and the road surface gradient is also estimated to be small depending on the magnitude of the transmission output shaft torque. End up. Therefore, it can be said that the relationship between ΔG and the gradient is not a one-to-one relationship, but a relationship that changes depending on the magnitude of the transmission output shaft torque at the time of sliding down.

  However, in the above prior art, since the estimated gradient value is calculated based on the characteristic diagram in which ΔG and the gradient are related on a one-to-one basis, the magnitude of the transmission output shaft torque when the estimated gradient value decreases. There was a problem that it was not an appropriate value depending on the situation.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a gradient estimation device capable of estimating a road surface gradient with high accuracy even if there is an influence of torque acting on drive wheels. It is in.

In order to achieve this object, in the gradient estimation device of the present invention, the drag torque of the engagement element of the automatic transmission when the vehicle slips in estimating the road surface gradient based on the amount of change in acceleration accompanying the vehicle slip. The larger the is, the greater the road surface gradient is.

When the drag torque of the engagement element of the automatic transmission is large, the amount of acceleration change due to vehicle drag is calculated smaller than when the drag torque is zero. In other words, the acceleration change amount is calculated to be smaller as the drag torque is larger. Therefore, it is considered that the amount of change in acceleration is larger as the drag torque of the engagement element of the automatic transmission is larger, and it is possible to estimate a road surface gradient with high accuracy by estimating that the road surface gradient is large.

  Hereinafter, the best mode for carrying out the present invention will be described based on the first embodiment.

First, the configuration will be described.
FIG. 1 is a system configuration diagram illustrating a neutral control device to which the acceleration detection device according to the first embodiment is applied. The output of the in-vehicle engine 1 is output from the output shaft 3 (output shaft of the transmission) after being subjected to a predetermined change by the automatic transmission 2 connected to the engine 1.

  In the automatic transmission 2, a clutch 2a (engagement element) that is engaged when starting is provided. The clutch 2a is a multi-plate clutch, and the piston is operated by the fastening pressure supplied from the control valve unit to ensure a fastening capacity corresponding to the fastening pressure. In addition, drive plates and driven plates are alternately arranged in the clutch 2a, and cooling grooves through which cooling oil flows are formed in the facing of each clutch plate. Since these configurations are general configurations of an ordinary multi-plate clutch, detailed description is omitted.

  The vehicle is provided with an engine controller (ECU) 4 and an automatic transmission controller (ATCU) 5 for controlling the engine 1, the automatic transmission 2 and the like based on detection values of various sensors described later. Both controllers 4 and 5 are communicably connected to each other and constitute a neutral control means.

  Various sensors such as an accelerator opening sensor 6, a brake switch 7, a vehicle speed sensor 8, an acceleration sensor (G sensor) 9, and a shift sensor 10 are mounted on the vehicle.

  The accelerator opening sensor 6 outputs an accelerator opening signal to the ECU 4. The brake switch 7 outputs to the ECU 4 a brake switch signal indicating whether or not a brake (not shown) provided on each wheel is depressed. The vehicle speed sensor 8 detects the traveling speed (vehicle speed) of the vehicle based on the rotation speed of each wheel obtained by the wheel speed sensor provided on each wheel, and outputs a vehicle speed signal to the ECU 4. The G sensor 9 detects acceleration acting on the vehicle and outputs an acceleration signal to the ECU 4. The shift sensor 10 detects the shift position of the automatic transmission 2 and outputs a shift position signal to the ATCU 5. The oil temperature sensor 21 detects the oil temperature in the automatic transmission 2 and outputs an oil temperature signal to the ATCU 5.

  In the neutral control means (ECU4, ATCU5) shown in FIG. 1, the shift position of the automatic transmission 2 is the forward travel position, the accelerator operation is not performed, the vehicle is stopped by the brake operation, and the road gradient is When the angle is equal to or smaller than the predetermined angle, neutral control is performed to reduce the engagement capacity of the clutch 2a of the automatic transmission 2 that is engaged when the vehicle starts to obtain a predetermined engagement capacity.

  That is, in the neutral control means, the shift position signal from the shift sensor 10 is the forward travel position, the accelerator opening signal from the accelerator opening sensor 6 is zero, and the brake switch signal from the brake switch 7 is ON (brake Is depressed), the vehicle speed signal from the vehicle speed sensor 8 is a predetermined value (≈0), and the acceleration signal from the G sensor 9 is an acceleration corresponding to a slope with a predetermined angle or less. carry out. Further, the neutral control means cancels the neutral control and shifts to complete engagement when the above-described neutral control execution condition such as brake switch OFF is not established. When shifting to complete fastening, the fastening capacity may be increased at once, or the fastening capacity may be increased according to the accelerator opening, etc., and there is no particular limitation.

  FIG. 2 is a control block diagram showing the configuration of the acceleration detection device built in the ECU 4 of the first embodiment. The acceleration detection device 11 of the first embodiment is a vehicle that slides down when neutral control is canceled on a slope. Is used to correct the deviation from the zero point due to the temperature change or the time change of the G sensor 9 (zero point correction).

  The acceleration detection apparatus 11 according to the first embodiment includes a first filter 12, a zero point correction unit (zero point correction unit) 13, a second filter 14, and a G calculation unit when N control is entered (acceleration detection unit during slope stop). 15, N control missing G calculation unit 16, ΔG calculation unit (acceleration change detection unit) 17, acceleration estimation unit (slope stop acceleration estimation unit) 18, drift amount calculation unit (drift amount calculation unit) 19 and a G calculation unit 20.

  The first filter 12 removes a noise component (for example, about 6 Hz) included in the G sensor signal (acceleration signal).

The zero point correction unit 13 corrects the drift amount from zero of the G sensor signal after passing through the first filter 12 based on the drift amount calculated by the drift amount calculation unit 19, and the corrected G sensor signal is 2 is output to the G filter 16 and the G calculator 20 when the N control is lost (zero point correction). Here, the correction method is arbitrary, and a method using the most recent drift amount or several drift amounts, a method using an average value of all drift amounts calculated in the past, and the like are conceivable.
In the first embodiment, the zero point correction is performed only when the road surface gradient based on the G sensor signal is detected too small relative to the actual road surface gradient.

The second filter 14 removes a vehicle spring vibration component (for example, about 1 to 2 Hz) included in the G sensor signal after the zero point correction.
When the N control is entered, the G calculation unit 15 calculates the acceleration detection value at the time of hill stop based on the G sensor signal after the zero point correction at the time of neutral control start, that is, at the time of hill stop.

  Based on the G sensor signal after the zero point correction, the N control missing G calculation unit 16 and the acceleration detection value with the most opening (when the vehicle slips immediately after the end of neutral control) Acceleration detection value at the time of sliding) is calculated.

  As shown in FIG. 3, the ΔG calculation unit 17 determines that the neutral control is canceled when the vehicle transitions from the slope stop state to the running state based on the difference between the slope stop acceleration detection value and the slippage acceleration detection value. Immediately after that, an acceleration change amount ΔG accompanying the vehicle slip is calculated.

  The acceleration estimation unit 18 calculates an estimated value of acceleration at a hill stop when the hill is stopped based on the acceleration change amount ΔG and the oil temperature signal. Here, the acceleration estimation unit 18 includes a slope stop acceleration estimated value calculation map in which the slope stop acceleration estimated value corresponding to the acceleration change amount ΔG accompanying the vehicle slip is preset according to the vehicle characteristics. . FIG. 4 is an acceleration estimated value calculation map when stopping on a slope according to the first embodiment. The estimated acceleration value at the time of stopping on the hill, that is, the road surface gradient [%], can be obtained in advance by an experiment or the like from the acceleration change amount ΔG immediately after canceling the neutral control on the hill, the oil temperature signal, and the vehicle characteristics. A plurality of set characteristics shown in the map of FIG. 4 will be described later.

The drift amount calculation unit 19 is a comparator that outputs a difference value between two input values. The drift amount from the zero point of the acceleration detection value is calculated based on the difference between the acceleration detection value when the hill is stopped and the estimated acceleration value when the hill is stopped. Is calculated.
The G calculation unit 20 calculates an acceleration detection value from the G sensor signal after the zero point correction. The output of the G calculation unit 20 is used for neutral control.

Next, the operation will be described.
[Zero point correction action based on the amount of acceleration change when sliding down]
In the acceleration detection device 11 according to the first embodiment, the acceleration is determined based on the deviation between the estimated acceleration value when stopping on the slope estimated from the acceleration change amount ΔG when the vehicle slips and the detected acceleration value when stopping on the slope based on the G sensor signal. The drift amount from the zero point of the detected value is calculated, and the zero point correction of the acceleration detected value is performed based on the drift amount.

  That is, when a drift error is caused in the G sensor 9 due to a change with time or a temperature change, the acceleration detection value calculated based on the G sensor signal is shifted from the true value by the drift amount. However, the acceleration change amount ΔG can be accurately calculated from the G sensor signal when the vehicle slides down and the G sensor signal when the hill stops, regardless of the drift error of the G sensor 9.

  Therefore, by calculating the accurate acceleration change amount ΔG at the time of sliding down, it is possible to obtain a highly reliable acceleration estimate value when stopping on a hill from the vehicle characteristics. Then, by comparing this slope stop acceleration estimated value and the slope stop acceleration detection value based on the G sensor signal, an accurate drift amount can be calculated and optimal zero point correction can be realized.

  Furthermore, as shown in the map of FIG. 4, on the uphill road, a plurality of characteristics are set according to the oil temperature in the automatic transmission, and the road surface gradient [%] is set to increase as the oil temperature decreases. ing. During neutral control, the engagement capacity of the clutch 2a is reduced, and relative rotation due to slip occurs in the clutch 2a. Since the clutch 2a is a multi-plate type, and oil is supplied to the clutch facing portion for cooling, when the oil temperature decreases, the viscosity of the oil increases, thereby increasing the drag torque of the clutch 2a. Due to the increase in the drag torque, the torque of the output shaft 3 is increased, so that it becomes difficult for the vehicle to fall down. That is, the acceleration change amount ΔG becomes small.

  Therefore, the road surface gradient is estimated by assuming that the lower the detected oil temperature, the greater the torque of the output shaft 3 of the automatic transmission.

  Thereby, the estimated value of the road surface gradient can be calculated with a value corresponding to the magnitude of the torque of the output shaft 3 at the time of sliding down, and the accuracy of the gradient estimation can be improved. Moreover, the accuracy of the correction control can be improved by performing zero point correction using the estimated gradient value.

  Further, since the road surface gradient is estimated according to the drag torque of the clutch 2a, the power transmission state inside the transmission can be taken into account, and the magnitude of the torque of the output shaft 3 can be accurately grasped.

  Further, by considering that the drag torque is larger as the oil temperature in the automatic transmission 2 is lower, the drag torque can be easily estimated from the oil temperature.

  FIG. 5 shows an example of zero point correction. For example, when an acceleration detection value corresponding to a gradient of 3% is detected on an uphill road, and then the vehicle slides down the uphill road by releasing the brake, an estimated acceleration value (gradient 5) corresponding to a gradient of 5% is calculated from the acceleration change amount ΔG. Suppose that the reverse amount equivalent to% is calculated. In this case, the difference (2%) between the estimated gradient 5% and the detected gradient 3% is calculated as the drift amount, and the zero point correction unit 13 offsets the G sensor signal in the positive direction by an amount corresponding to the gradient 2% ( When correcting with only the most recent drift amount).

  Further, in the first embodiment, the acceleration estimation unit 18 has a slope stop acceleration estimated value calculation map in which the slope stop acceleration estimated value corresponding to the acceleration change amount ΔG accompanying the vehicle slip is preset according to the vehicle characteristics. Is provided. When the driver releases the brake on the slope, the vehicle slips above a certain slope.At this time, the vehicle acceleration change ΔG that occurs according to the magnitude of the slope is determined in advance from experiments and simulations. You can ask for it. Therefore, by mapping the slope stop acceleration estimation value according to the acceleration change amount ΔG, the calculation load can be reduced and the estimated value calculation speed can be increased.

[Noise component elimination]
In Example 1, the 1st filter 12 which removes the noise component contained in a G sensor signal is provided in the front | former stage of each G calculation part 15,16,20. Since the noise components are always mixed in the sensors mounted on the vehicle, the first filter 12 that removes these noise components is arranged in front of each G calculation unit 15, 16, 20. It is possible to acquire a G sensor signal that is not affected.

[Vehicle spring vibration component removal action]
In the first embodiment, the second filter 14 for removing the vehicle spring vibration component included in the G sensor signal is provided in the preceding stage of the N control entering G calculation unit 15. In general, the vibration of the vehicle is large immediately before and after the stop of the vehicle, so that a large amount of spring vibration components accompanying the vibration of the vehicle are included in the G sensor signal. Therefore, by removing the vehicle spring vibration component included in the G sensor signal in the previous stage of the G calculation unit 15 at the time of entering the N control, it is possible to acquire the G sensor signal excluding the influence due to the vibration of the vehicle.

[G sensor signal correction action of neutral control device]
In a vehicle equipped with an automatic transmission, the creep force transmitted from the automatic transmission to the wheels via the torque converter is not necessary when the vehicle is stopped and held. Therefore, the fuel consumption of the engine is reduced accordingly.

  Therefore, in the forward travel position, in a state where the brake pedal is depressed and the brake is actuated and the accelerator is almost fully closed and the vehicle is stopped, the neutral for reducing the engagement capacity of the clutch 2a remains in the forward travel position. It has been proposed to improve fuel efficiency by executing control.

  Here, in the neutral control, since it takes time until the clutch 2a is completely engaged immediately after the control is released and the wheels generate driving force, the vehicle slips down the slope. Therefore, in order to prevent this slipping, as a neutral control start condition, a method of determining the road surface gradient using the G sensor and carrying out neutral control only within the range of the slope that allows the slipping is devised. Yes.

  On the other hand, if the output value (zero point) shifts due to temperature drift of the G sensor, the gradient cannot be accurately determined, so the neutral control is started despite the unacceptable slope of the vehicle, There was a problem of unexpected sliding down when the control was released.

  On the other hand, in the neutral control device of the first embodiment, the acceleration detection device 11 shown in FIG. 2 is used as the road surface gradient detection means, and the neutral control means (ECU4, ATCU5) detects the acceleration detected by the acceleration detection device 11. When the detected value is less than or equal to the predetermined angle, the engagement capacity of the clutch 2a is reduced.

  As a result, even if a drift error due to deterioration, temperature change, or the like has occurred in the G sensor 9, the true road surface gradient can be detected by the zero point correction by the acceleration detection device 11, so that the expectation It is possible to reliably avoid slipping down the vehicle.

  Further, in the neutral control device of the first embodiment, the zero point correction unit 13 is an area indicated as a correction symmetry area in the road gradient map corresponding to the acceleration change amount ΔG in FIG. Only when the value is larger than the absolute value of the acceleration detection value when the hill stops, the zero point correction is performed.

  In other words, if the detected value of the road surface gradient is smaller than the estimated value, neutral control may be started with a gradient that cannot allow the slip down, but if the detected value is larger than the estimated value, the slip down Neutral control will not start with an unacceptable slope. Therefore, by correcting the zero point only when the detected value of the road surface gradient is smaller than the estimated value, correction of the drift error that does not affect the neutral control can be omitted, and excessive zero point correction can be prevented. it can.

FIG. 7 is a time chart illustrating the zero point correction operation when the hill is stopped according to the first embodiment.
At time t1, the brake switch (BRKSW) is turned on, the vehicle stops (vehicle speed VSP zero and accelerator opening zero), and the start condition that the road gradient is less than the predetermined angle is satisfied, so neutral control is started and the engagement capacity of the clutch 2a decreases. To do. Immediately after this, in the N control entry G calculation unit 15, the acceleration detection value at the time of hill stop is calculated.

Here, immediately after the vehicle stops, the vehicle vibrates greatly and the G sensor signal is also affected. However, since the spring vibration component of the vehicle is removed by the second filter 14, the G sensor signal excluding the influence of the vibration is removed. Based on this, it is possible to calculate the acceleration detection value at the time of stopping on the slope. Further, the noise component included in the G sensor signal is also removed by the first filter 12.
In the section from the time point t1 to t2, since the vehicle is stopped, a constant G sensor signal corresponding to the road surface gradient is output.

  At time t2, since the driver removes his / her foot from the brake pedal, the neutral control is canceled by turning off the brake switch, and the clutch of the automatic transmission 2 starts to shift from the half clutch state to the fully engaged state. At this time, the N control missing G calculation unit 16 starts calculating the acceleration detection value based on the G sensor signal and comparing the calculated acceleration detection value with the acceleration detection value when the hill stops.

At time t3, the vehicle starts to move down the slope, and at time t4, the difference between the acceleration detection value and the acceleration detection value at the time of stopping on the slope is maximized. Therefore, the ΔG calculation unit 17 calculates the acceleration change amount ΔG from the difference between the two. Calculated. As a result, the acceleration estimation unit 18 selects a predetermined characteristic from the map of FIG. 4 based on the oil temperature, and uses the selected characteristic to calculate the estimated acceleration value at the time of hill stop based on the acceleration change amount ΔG. Is done. The drift amount calculation unit 19 calculates the zero point correction drift amount from the difference between the estimated acceleration value when the hill is stopped and the detected acceleration value when the hill is stopped.
At time t5, the clutch of the automatic transmission 2 is engaged, and the neutral control loss is completed.

Next, the effect will be described.
In the acceleration detection device according to the first embodiment, the following effects can be obtained.

  (1) An acceleration sensor 9 mounted on a vehicle having an automatic transmission, and a G calculation unit 15 with N control (acceleration detecting means when stopping on a hill) that detects an acceleration detection value when stopping on a hill that is an acceleration sensor signal when stopping on a hill ) And a ΔG calculation unit 17 (acceleration change detection means) that detects an acceleration change ΔG that accompanies the vehicle sliding down when the vehicle transitions from the slope stop state to the running state based on the acceleration sensor signal. The oil temperature is low based on the oil temperature sensor 21 (output shaft torque detecting means) that detects or estimates the torque of the output shaft 3 (output shaft) of the automatic transmission 2 at the time of sliding down and the acceleration change amount ΔG. The slope stop acceleration estimated value calculation map (gradient estimation means) for estimating that the road surface gradient is large (as the output shaft torque is large) is provided.

  When the torque of the output shaft 3 is large, the acceleration change amount ΔG due to the vehicle slippage is calculated smaller than when the torque of the output shaft 3 is zero. In other words, the acceleration change amount ΔG is calculated to be smaller as the torque of the output shaft 3 is larger. Therefore, it is assumed that the acceleration change amount ΔG is the same as the torque of the output shaft 3 of the automatic transmission 2 is large, and it is possible to estimate the road surface gradient with high accuracy by estimating that the road surface gradient is large.

  (2) In the forward travel position, the accelerator operation is not performed, the vehicle is stopped by the brake operation, and the road surface gradient detected by the slope stop acceleration estimated value calculation map (gradient estimation means) is less than the predetermined gradient The neutral control means for reducing the engagement capacity of the clutch 2a (the engagement element of the automatic transmission 2) that is engaged when the vehicle starts, and the drag torque detection means that detects or estimates the drag torque of the clutch 2a. The slope stop acceleration estimated value calculation map (gradient estimation means) assumes that the torque of the output shaft 3 is larger as the detected drag torque is larger.

  Therefore, the power transmission state inside the automatic transmission can be taken into account, and the magnitude of the torque of the output shaft 3 can be accurately grasped.

  (3) An oil temperature sensor 21 (oil temperature detection means) for detecting the oil temperature of the automatic transmission is provided, and the slope estimated acceleration calculation value map (gradient estimation means) indicates that the output shaft decreases as the detected oil temperature decreases. It was decided that the torque of No. 3 was large. Therefore, the drag torque can be easily estimated from the oil temperature.

  Next, Example 2 will be described. Since the basic configuration is the same as that of the first embodiment, only different points will be described. FIG. 8 is a system configuration diagram illustrating a neutral control device to which the acceleration detection device according to the second embodiment is applied. In the first embodiment, the oil temperature sensor 21 is provided, but instead, the second embodiment is different in that the engine speed sensor 22 is provided. The engine speed sensor 22 detects the speed of the engine 1 and outputs an engine speed signal to the ECU 4.

  FIG. 9 is a control block diagram showing the configuration of the acceleration detection device built in the ECU 4 of the second embodiment. In the first embodiment, the acceleration estimation unit 18 inputs an oil temperature signal and selects a characteristic according to the oil temperature. On the other hand, the second embodiment is different in that the engine speed signal is input and the characteristics are selected according to the engine speed.

  FIG. 10 is an acceleration estimated value calculation map when stopping on a slope according to the second embodiment. The acceleration estimator 18 estimates the slope stop acceleration estimation value, that is, the road surface gradient, based on the characteristics selected according to the engine speed.

Next, operations unique to the second embodiment will be described.
[Zero point correction action based on the amount of acceleration change when sliding down]

  As shown in the map of FIG. 10, on the uphill road, a plurality of characteristics are set according to the engine speed, and the road surface gradient [%] is set to increase as the engine speed increases. When idling up during warm-up, or when the accelerator pedal is depressed suddenly, the engine speed is set higher. At this time, the torque of the output shaft 3 also increases, making it difficult for the vehicle to slide down.

  Accordingly, the road surface gradient is estimated by assuming that the torque of the output shaft 3 of the automatic transmission 2 is larger as the detected engine speed is higher.

  Thereby, the estimated value of the road surface gradient can be calculated by a value corresponding to the magnitude of the output shaft torque at the time of sliding down, and the accuracy of the gradient estimation can be improved. Moreover, the accuracy of the correction control can be improved by performing zero point correction using the estimated gradient value. Further, the torque of the output shaft 3 can be easily estimated from the engine speed.

(Other examples)
The best mode for carrying out the present invention has been described based on the first and second embodiments. However, the specific configuration of the present invention is not limited to the first and second embodiments. Design changes and the like within a range not departing from the gist are included in the present invention.

  For example, in the first embodiment, the example in which the acceleration detection device of the present invention is used as the road surface gradient detection means of the neutral control device has been shown. As a device for performing the above, it can be applied to other vehicle control devices.

  Moreover, in Example 1, although the example which set the several characteristic according to temperature in the acceleration estimated value calculation map at the time of one hill stop was shown, it provided with the some map by which the characteristic was set for every temperature, The map may be appropriately selected according to the situation.

  Further, in the first embodiment, although set according to the oil temperature in the automatic transmission 2, the characteristics of the torque converter (speed ratio, torque ratio, torque capacity coefficient, differential speed between the engine speed and the turbine speed) The characteristics may be switched according to the above. This is because these parameters change from moment to moment, and the change affects the output shaft torque.

  In the first and second embodiments, when switching a plurality of characteristics according to the temperature and the engine speed, for example, the characteristic 1 is within a predetermined temperature range, or the characteristic 1 is within a predetermined engine speed range. Set the area to the parameter and select the characteristic. At this time, hysteresis may be provided in each parameter area to prevent control hunting or the like associated with a change in environmental conditions.

  Further, although the characteristics are selected according to the oil temperature in the automatic transmission 2 in the first embodiment and the engine speed in the second embodiment, the characteristics may be selected from a combination of these two parameters.

1 is a system configuration diagram illustrating a neutral control device to which an acceleration detection device according to a first embodiment is applied. FIG. 3 is a control block diagram illustrating a configuration of an acceleration detection device built in the ECU 4 according to the first embodiment. It is explanatory drawing which shows the calculation method of the acceleration variation | change_quantity (DELTA) G of Example 1. FIG. It is a figure which shows an example of the acceleration estimated value calculation map at the time of a hill stop of Example 1. FIG. It is a figure which shows the zero point correction method of Example 1. FIG. The area | region which performs zero point correction | amendment of Example 1 is shown on the acceleration estimated value calculation map at the time of a hill stop. 3 is a time chart showing a zero point correction operation when the hill road of Example 1 is stopped. It is a system block diagram which shows the neutral control apparatus to which the acceleration detection apparatus of Example 2 is applied. FIG. 5 is a control block diagram illustrating a configuration of an acceleration detection device built in an ECU 4 according to a second embodiment. It is a figure which shows an example of the acceleration estimated value calculation map at the time of a hill stop of Example 2. FIG.

Explanation of symbols

1 Engine 2 Automatic transmission 3 Output shaft 4 ECU
5 ATCU
6 Accelerator opening sensor 7 Brake switch 8 Vehicle speed sensor 9 Acceleration sensor 10 Shift sensor 11 Acceleration detection device 12 First filter 13 Zero point correction unit 14 Second filter 15 N control entering G calculation unit 16 N control missing G calculation unit 17 ΔG calculation unit 18 acceleration estimation unit 19 drift amount calculation unit 20 G calculation unit 21 temperature sensor 22 engine speed sensor

Claims (3)

An acceleration sensor mounted on a vehicle having an automatic transmission;
A slope stop acceleration detecting means for detecting a slope stop acceleration detection value which is a signal of the acceleration sensor at a slope stop;
Based on the acceleration sensor signal, an acceleration change amount detecting means for detecting an acceleration change amount associated with the vehicle sliding down when the vehicle transitions from the slope stop state to the running state;
Output shaft torque detecting means for detecting or estimating the output shaft torque of the automatic transmission at the time of the sliding down;
Gradient estimation means for estimating that the road surface gradient is larger as the output shaft torque is larger, based on the acceleration change amount;
In the forward travel position, when the accelerator operation is not performed, the vehicle is stopped by the brake operation, and the road surface gradient detected by the gradient estimation means is equal to or less than a predetermined gradient, the vehicle is engaged when the vehicle starts. Neutral control means for reducing the fastening capacity of the engagement element of the automatic transmission;
Drag torque detecting means for detecting or estimating the drag torque of the engaging element;
Have
The gradient estimation device is characterized in that the gradient estimation unit considers that the output shaft torque is larger as the detected drag torque is larger . The gradient estimation device according to claim 1,
Oil temperature detecting means for detecting the oil temperature of the automatic transmission is provided,
The gradient estimating device is characterized in that the output shaft torque is considered to be larger as the detected oil temperature is lower . The gradient estimation apparatus according to claim 1 or 2,
An engine which is an internal combustion engine and an engine speed detecting means for detecting the engine speed;
The gradient estimation device is characterized in that the output shaft torque is considered to increase as the engine speed increases .

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