JP2004144233A - Vehicle controller and vehicle control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent reduction of line pressure in hydraulic equipment and belt sliding in a belt type continuously variable transmission. <P>SOLUTION: An ECU 100 for controlling a vehicle having an oil pump 500 includes an estimation circuit for estimating a mixing rate of air in oil, a tilt angle sensor 200 for detecting the front or back tilt of the vehicle, a right/left G sensor 300 for detecting the G-value of the vehicle in the right/left direction, a calculation circuit for calculating a corrected flow rate of the oil based on the mixing rate of the air and the position of the vehicle, and a control circuit for controlling the oil pump 500 based on the calculated corrected flow rate. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technique for supplying oil for operating various hydraulic devices, and more particularly to a technique for securing a desired line pressure regardless of the amount of air mixed in the oil or the attitude of a vehicle.
[0002]
[Prior art]
2. Description of the Related Art Various hydraulic devices that operate using hydraulic pressure are mounted on vehicles. There is a transmission as a hydraulic device related to the power train. As this transmission, there is a continuously variable transmission (CVT) that continuously adjusts a transmission gear ratio according to a traveling state of a vehicle. This CVT can efficiently extract the engine output, and is excellent in improving fuel efficiency and running performance. As one of the CVTs put into practical use, there is a CVT that uses a metal belt and a pair of pulleys to continuously change the speed continuously by changing the effective diameter of the pulley by hydraulic pressure. An endless metal belt is used by being wound around an input pulley attached to an input shaft and an output pulley attached to an output shaft. The input pulley and the output pulley each include a pair of sheaves whose groove width can be changed steplessly. By changing the groove width, the winding radius of the endless metal belt around the input pulley and the output pulley changes, As a result, the rotational speed ratio between the input shaft and the output shaft, that is, the gear ratio can be continuously and continuously changed. In such a CVT, the groove width of the input side pulley and the groove width of the output side pulley are changed by hydraulic pressure.
[0003]
Other transmissions include automatic transmissions that combine a torque converter and a planetary reduction gear. Also in this automatic transmission, the state of engagement and disengagement of frictional engagement elements (clutch, brake) is changed by hydraulic pressure.
[0004]
Air may be mixed into oil in such a hydraulic device. If air is mixed, a desired oil pressure may not be obtained. Japanese Patent Laying-Open No. 11-125330 (Patent Document 1) discloses a control device that solves such a problem.
[0005]
A control device disclosed in Patent Literature 1 is a device that controls an automatic transmission that executes a shift by controlling a supply hydraulic pressure to a friction engagement element by a solenoid, and a circuit that calculates a step response of the hydraulic pressure, The circuit includes a circuit for estimating the air mixing ratio in the oil from the calculated step response, and a circuit for correcting the operation amount of the solenoid according to the estimated air mixing ratio.
[0006]
According to this control device, the step response of the hydraulic pressure decreases as the air mixing ratio increases. Therefore, the air mixing ratio is estimated based on the step response of the actual hydraulic pressure when the indicated hydraulic pressure is changed stepwise. Even if an error occurs in the actual oil pressure with respect to the command oil pressure due to the mixing of air into the oil, the error can be suppressed by correcting the solenoid operation amount based on the estimation of the air mixing ratio.
[0007]
[Patent Document 1]
JP-A-11-125330
[Problems to be solved by the invention]
However, when air is mixed into the oil, a large amount of air is mixed into the oil particularly in the surface layer. If the oil pump sucks the oil in the surface layer, the apparent volumetric efficiency of the oil pump decreases, causing the line pressure to decrease. In the CVT, the belt clamping pressure may decrease and belt slippage may occur. There is. Whether or not such surface layer oil is to be sucked depends on the attitude of the vehicle (inclination in the front, rear, left and right directions, etc.). That is, when the vehicle is traveling on a slope and is inclined, the suction port of the oil pump may reach only near the surface layer of the oil accumulated in the oil pan, and the oil pump may contain air. The oil on the surface layer will be sucked.
[0009]
As described above, the control device disclosed in Patent Document 1 corrects the solenoid operation amount based on the air mixing ratio. However, whether or not the oil pump actually sucks the oil mixed with air depends only on the air mixing ratio. I don't know. Further, regardless of the attitude of the vehicle, the oil level can be increased to prevent the intake of oil mixed with air. However, in this case, there are problems such as an increase in stirring loss and occurrence of breather blowing.
[0010]
Further, in the CVT, if the oil pressure is suddenly changed based on a rapid shift command, a large shift flow rate is required, so that line pressure may drop in a situation where air is mixed. There is also.
[0011]
The present invention has been made to solve the above-described problems, and provides a vehicle control device and a vehicle control method for preventing a reduction in line pressure of a hydraulic device and a belt slip of a belt-type continuously variable transmission. It is to be.
[0012]
[Means for Solving the Problems]
A control device according to a first aspect controls a vehicle including an oil pump. The control device calculates an oil correction flow rate based on the air mixing amount and the vehicle attitude based on the estimating means for estimating the oil mixing amount of the oil, the detecting means for detecting the attitude of the vehicle, and the attitude of the vehicle. And a control means for controlling the oil pump based on the calculated corrected flow rate.
[0013]
According to the first aspect, when the estimation unit estimates that the amount of air mixed into the oil is large and the detection unit detects that the vehicle is tilted, the oil pump sucks air in the surface portion of the oil pan. There is a high possibility that the volume efficiency of the oil pump may decrease. For this reason, the calculating means calculates the corrected flow rate of the oil, and the control means increases the rotation speed of the motor that operates the oil pump to increase the discharge amount of the oil from the oil pump so that the corrected flow rate can be satisfied. . Thus, even if the oil pump sucks air, the capacity of the oil pump can be increased to compensate for the reduction in volumetric efficiency of the pump. As a result, it is possible to provide a vehicle control device that prevents the line pressure of the hydraulic equipment from being reduced.
[0014]
A control device according to a second aspect of the present invention controls a vehicle including a belt-type continuously variable transmission to which oil is supplied by an oil pump. The control device includes an estimating unit for estimating an amount of air mixed in the oil, a detecting unit for detecting a posture of the vehicle, and a control unit for the belt-type continuously variable transmission based on the amount of air mixed and the posture of the vehicle. Limit value calculating means for calculating the shift speed limit value, and transmission control means for controlling the belt-type continuously variable transmission based on the calculated shift speed limit value are included.
[0015]
According to the second aspect, when the estimation unit estimates that the amount of air mixed into the oil is large and the detection unit detects that the vehicle is tilted, the oil pump sucks air in the surface portion of the oil pan. There is a high possibility that when the belt-type continuously variable transmission performs a rapid shift in such a state, a large shift flow rate is required, which may cause a decrease in line pressure. For this reason, the limit value calculating means calculates the limit value of the shift speed of the belt-type continuously variable transmission, and the transmission control means gradually shifts the belt-type continuously variable transmission so as to satisfy the shift speed limit value. Let it. Thereby, even if the oil pump sucks air, belt slippage of the belt-type continuously variable transmission can be prevented. As a result, it is possible to provide a vehicle control device that prevents the belt of the belt-type continuously variable transmission from slipping.
[0016]
According to a third aspect of the present invention, in addition to the configuration of the second aspect, the control device further includes a calculating unit configured to calculate a correction flow rate of the oil based on the air mixing amount and the attitude of the vehicle; And control means for controlling the oil pump based on the above.
[0017]
According to the third aspect, when the estimating means estimates that the amount of air mixed into the oil is large and the detecting means detects that the vehicle is tilted, the oil pump sucks air in the surface portion of the oil pan. There is a high possibility that the volume efficiency of the oil pump may decrease. The calculating means calculates the corrected flow rate of the oil, and the control means increases the rotation speed of the motor for operating the oil pump to increase the discharge amount of the oil from the oil pump so that the corrected flow rate can be satisfied. Further, if the belt-type continuously variable transmission performs a rapid shift in such a state, a large shift flow rate is required, which may cause a decrease in line pressure. For this reason, the limit value calculating means calculates the limit value of the shift speed of the belt-type continuously variable transmission, and the transmission control means gradually shifts the belt-type continuously variable transmission so as to satisfy the shift speed limit value. Let it. As a result, even if the oil pump sucks air, it is possible to increase the capacity of the oil pump in order to compensate for the decrease in volumetric efficiency of the pump and to prevent belt slippage of the belt-type continuously variable transmission. As a result, it is possible to provide a control device for a vehicle that prevents the line pressure of the hydraulic device from lowering and that prevents the belt of the belt-type continuously variable transmission from sliding.
[0018]
In the control device according to a fourth aspect, in addition to the configuration of the first or third aspect, the control means includes a means for controlling the rotation speed of the oil pump.
[0019]
According to the fourth aspect, the control means can increase the rotation speed of the motor that drives the electric oil pump to increase the amount of oil discharged from the oil pump.
[0020]
A control method according to a fifth aspect controls a vehicle including an oil pump. The control method includes an estimation step of estimating the amount of oil mixed in the oil, a detecting step of detecting the attitude of the vehicle, and a calculating step of calculating a corrected flow rate of the oil based on the amount of air mixed and the attitude of the vehicle. Controlling the oil pump based on the calculated corrected flow rate.
[0021]
According to the fifth aspect, when the estimation step estimates that the amount of air mixed into the oil is large and the detection step detects that the vehicle is tilted, the oil pump activates the air in the surface layer of the oil pan. Is likely to be sucked, and the volume efficiency of the oil pump may be reduced. For this reason, the correction flow rate of the oil is calculated in the calculation step, and in order to satisfy the correction flow rate, the rotation speed of the motor for operating the oil pump is increased in the control step to reduce the oil discharge amount from the oil pump. increase. Thus, even if the oil pump sucks air, the capacity of the oil pump can be increased to compensate for the reduction in volumetric efficiency of the pump. As a result, it is possible to provide a vehicle control method that prevents a decrease in line pressure of the hydraulic device.
[0022]
A control method according to a sixth aspect controls a vehicle including a belt-type continuously variable transmission to which oil is supplied by an oil pump. This control method includes an estimating step of estimating an amount of oil entrained in oil, a detecting step of detecting an attitude of the vehicle, and a shift speed limit value of the belt-type continuously variable transmission based on the amount of air entrained and the attitude of the vehicle. And a transmission control step of controlling the belt-type continuously variable transmission based on the calculated shift speed limit value.
[0023]
According to the sixth aspect, when it is estimated that the amount of air mixed into the oil is large in the estimation step and that the vehicle is tilted in the detection step, the oil pump is turned on the air in the surface layer of the oil pan. When the belt-type continuously variable transmission performs a rapid shift in such a state, a large shift flow rate is required, which may cause a decrease in line pressure. Therefore, in the limit value calculating step, the limit value of the shift speed of the belt-type continuously variable transmission is calculated, and the belt-type continuously variable transmission is moderated in the transmission control step so as to satisfy the shift speed limit value. Speed. Thereby, even if the oil pump sucks air, belt slippage of the belt-type continuously variable transmission can be prevented. As a result, it is possible to provide a vehicle control method for preventing the belt of the belt-type continuously variable transmission from slipping.
[0024]
The control method according to a seventh aspect of the present invention, in addition to the configuration of the sixth aspect, further comprises: a calculating step of calculating a corrected flow rate of the oil based on the air mixing amount and the attitude of the vehicle; And controlling the oil pump.
[0025]
According to the seventh aspect, when the estimation step estimates that the amount of air mixed into the oil is large and the detection step detects that the vehicle is tilted, the oil pump activates the air in the surface layer of the oil pan. Is likely to be sucked, and the volume efficiency of the oil pump may be reduced. In the calculation step, the corrected flow rate of the oil is calculated, and in the control step, the rotation speed of the motor that operates the oil pump is increased to increase the discharge amount of the oil from the oil pump so that the corrected flow rate can be satisfied. Further, if the belt-type continuously variable transmission performs a rapid shift in such a state, a large shift flow rate is required, which may cause a decrease in line pressure. Therefore, in the limit value calculating step, the limit value of the shift speed of the belt-type continuously variable transmission is calculated, and the belt-type continuously variable transmission is moderated in the transmission control step so as to satisfy the shift speed limit value. Speed. As a result, even if the oil pump sucks air, it is possible to increase the capacity of the oil pump in order to compensate for the decrease in volumetric efficiency of the pump and to prevent belt slippage of the belt-type continuously variable transmission. As a result, it is possible to provide a vehicle control method that prevents a decrease in line pressure of hydraulic equipment and that prevents a belt from slipping particularly in a belt-type continuously variable transmission.
[0026]
In a control method according to an eighth aspect, in addition to the configuration of the fifth or seventh aspect, the control step includes a step of controlling the rotation speed of the oil pump.
[0027]
According to the eighth aspect, the control step can increase the number of rotations of the motor that drives the electric oil pump to increase the amount of oil discharged from the oil pump.
[0028]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. Their names and functions are the same. Therefore, detailed description thereof will not be repeated. In the following, a vehicle having a CVT will be described, but the present invention is not limited to this. Even a vehicle that does not have a CVT may have a hydraulic device that performs control based on line pressure.
[0029]
A control device according to an embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, the vehicle includes an ECU (Electronic Control Unit) 100 which is a control device, an inclination angle sensor 200 connected to the ECU 100 for detecting an inclination angle of the vehicle in the front-rear direction, and a left-right direction of the vehicle. It includes a left and right G sensor 300 that detects acceleration (G value), a CVT 400 that operates based on a control signal from the ECU 100, and a motor 600 of an oil pump 500 that changes the rotation speed based on a control signal from the ECU 100. The suction port of the oil pump 500 is arranged so that the oil accumulated in the oil pan 700 can be sucked. With such an arrangement, when the vehicle is traveling on an inclined road or the like, a suction port may be arranged in the surface layer of the oil accumulated in the oil pan 700. At this time, the mixing ratio of the air is higher in the surface layer of the oil, and the possibility that the oil pump 500 sucks the air is higher.
[0030]
The ECU 100 includes a memory for storing data for estimating an air mixing amount, a mixing amount threshold, an inclination angle threshold, a G threshold, and the like, a program, and a CPU for executing the program stored in the memory. And an interface for communicating with each sensor and device. The threshold value of the mixing amount, the threshold value of the inclination angle, and the threshold value of G may be changed based on the shape of the oil pan 700, the shape of the strainer, the change in the space volume of the V / B section, and the like.
[0031]
ECU 100 gives a shift command value to CVT 400. The shift command value may be a hydraulic command value for changing the groove width of the primary pulley and the secondary pulley of the CVT so that the CVT 400 has a given speed ratio. The ECU 100 detects the actual oil pressure for this oil pressure command value. For example, the ECU 100 calculates a time constant in a step response of the hydraulic pressure from a change in the actual hydraulic pressure when the hydraulic pressure command value is changed in a step-like manner. From the time constant of the step response, the air mixing ratio to oil is estimated.
[0032]
The method of estimating the air mixing ratio into oil is not limited to such a method, and the speed of the vehicle is equal to or higher than a predetermined speed, and the input torque is equal to or higher than the predetermined torque. The determination may be made based on the length of time that a certain state continues.
[0033]
Referring to FIG. 2, a flowchart of a process executed by ECU 100 in FIG. 1 will be described.
[0034]
In step (hereinafter, step is abbreviated as S) 100, ECU 100 executes an air mixing amount detection subroutine. As described above, the air entrainment amount detection subroutine is a process for detecting the air entrapment ratio into oil based on the actual change in oil pressure when the oil pressure command value is changed stepwise.
[0035]
In S110, ECU 100 determines whether or not the air mixing amount detected in S100 is larger than the mixing amount threshold stored in the memory. If the air mixing amount is larger than the mixing amount threshold value (YES in S110), the process proceeds to S120. If not (NO in S110), the process proceeds to S170.
[0036]
In S120, ECU 100 determines whether or not the absolute value of the front-back direction tilt angle detected by tilt angle sensor 200 is larger than the tilt angle threshold value stored in the memory. If the absolute value of the front-back direction inclination angle is larger than the inclination angle threshold value (YES in S120), the process proceeds to S140. If not (NO in S120), the process proceeds to S130.
[0037]
In S130, ECU 100 determines whether the left-right direction G value detected by left-right G sensor 300 is larger than the G threshold value stored in the memory or not. If the G value in the left-right direction is greater than the G threshold (YES in S130), the process proceeds to S140. If not (NO in S130), the process proceeds to S170.
[0038]
In S140, ECU 100 calculates a pump flow rate correction value Q according to the absolute value of the front-back direction inclination angle and the left-right direction G value. This calculation is performed based on a map stored in a memory built in ECU 100, for example.
[0039]
In S150, ECU 100 selects an oil pump rotation speed according to pump flow rate correction value Q. This selection is made based on a map stored in a memory built in ECU 100, for example. The motor 600 rotates at the selected rotation speed, and the flow rate discharged from the oil pump 500 increases by the pump flow rate correction value Q.
[0040]
In S160, ECU 100 changes the CVT shift speed upper limit value to a value lower than usual. In other words, the shift speed is limited even if there is a request for a rapid shift. This change is performed, for example, based on a map stored in a memory built in ECU 100. After this processing, even if there is a request for a rapid shift to the CVT 400, the shift is executed gently so as not to exceed the upper limit of the CVT shift speed.
[0041]
In S170, ECU 100 selects the normal oil pump speed. This selection is made based on data stored in a memory built in ECU 100, for example. The motor 600 rotates at the selected number of rotations, and a normal flow rate of oil is discharged from the oil pump 500.
[0042]
In S180, ECU 100 changes the CVT shift speed upper limit to a normal value. This change is performed, for example, based on data stored in a memory built in ECU 100.
[0043]
The operation of ECU 100, which is the control device according to the present embodiment, based on the above structure and flowchart will be described.
[0044]
When the vehicle travels on a long climbing road, high-load traveling is continuously performed, and the air mixing rate into oil increases (YES in S110). When air is mixed into the oil in this way, the oil mixed in the surface layer has a higher air mixing ratio. If the vehicle is traveling on an uphill road (YES in S120), a pump flow correction value Q corresponding to the inclination angle in the front-rear direction is calculated (S140), and the oil pump 500 discharges only the amount of the pump flow correction value Q. Flow rate increases. Therefore, even if the apparent pump volumetric efficiency is reduced by sucking air, the problem that the line pressure is reduced does not occur because the discharge flow rate from the oil pump 500 is increased. Further, the shift speed upper limit value at the time of sudden shift in CVT 400 is set low. For this reason, the CVT 400 can avoid abrupt shifting, and the line pressure does not decrease due to a large shifting flow rate.
[0045]
Such processing is executed even if the inclination angle in the front-rear direction is smaller than the threshold value (NO in S120), but the G value in the left-right direction is larger than the G threshold value (YES in S130). Is done.
[0046]
As described above, according to the control device of the present embodiment, when the air mixing ratio into the oil increases and the vehicle is inclined, the discharge flow rate of the oil pump is increased or the speed of the CVT is changed. Restrict. As a result, the line pressure does not decrease.
[0047]
The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[Brief description of the drawings]
FIG. 1 is a control block diagram of a vehicle according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating a control structure of a program executed by an ECU of FIG. 1;
[Explanation of symbols]
100 ECU, 200 tilt angle sensor, 300 left and right G sensor, 400 CVT, 500 oil pump, 600 motor, 700 oil pan.

Claims (8)

A control device for controlling a vehicle including an oil pump,
Estimating means for estimating the amount of air entrained in the oil,
Detecting means for detecting the attitude of the vehicle,
Calculation means for calculating a corrected flow rate of oil based on the air mixing amount and the attitude of the vehicle,
A control unit for controlling the oil pump based on the calculated corrected flow rate. A control device for controlling a vehicle including a belt-type continuously variable transmission, wherein oil is supplied to the belt-type continuously variable transmission by an oil pump,
Estimating means for estimating the amount of air entrained in the oil,
Detecting means for detecting the attitude of the vehicle,
Limit value calculating means for calculating a shift speed limit value of the belt-type continuously variable transmission based on the air mixing amount and the attitude of the vehicle;
A control unit for controlling the belt-type continuously variable transmission based on the calculated shift speed limit value. The control device includes:
Calculation means for calculating a corrected flow rate of oil based on the air mixing amount and the attitude of the vehicle,
The control device according to claim 2, further comprising: a control unit configured to control the oil pump based on the calculated correction flow rate. The control device according to claim 1, wherein the control unit includes a unit for controlling a rotation speed of the oil pump. A control method for controlling a vehicle including an oil pump,
An estimating step of estimating the amount of air mixed in the oil;
A detecting step of detecting the attitude of the vehicle,
A calculating step of calculating a correction flow rate of oil based on the air mixing amount and the attitude of the vehicle,
Controlling the oil pump based on the calculated corrected flow rate. A control method for controlling a vehicle including a belt-type continuously variable transmission, wherein oil is supplied to the belt-type continuously variable transmission by an oil pump,
An estimating step of estimating the amount of air mixed in the oil;
A detecting step of detecting the attitude of the vehicle,
A limit value calculating step of calculating a shift speed limit value of the belt-type continuously variable transmission based on the air mixing amount and the attitude of the vehicle;
A transmission control step of controlling the belt-type continuously variable transmission based on the calculated shift speed limit value. The control method includes:
A calculating step of calculating a correction flow rate of oil based on the air mixing amount and the attitude of the vehicle,
The control method according to claim 6, further comprising: a control step of controlling the oil pump based on the calculated correction flow rate. The control method according to claim 5, wherein the control step includes a step of controlling a rotation speed of the oil pump.

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