JP3429453B2 - Creep force control method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle equipped with a continuously variable transmission, which is configured to creep using a clutch mechanism capable of freely changing transmission torque. About. 2. Description of the Related Art Recently, a continuously variable transmission (Continuously Varia
BLE Transmission (hereinafter referred to as CVT), and a transmission that can smoothly change the gear ratio steplessly has been developed. In a vehicle or the like equipped with this CVT, similar to a torque converter vehicle, Japanese Patent Application Laid-Open No. 62-216842 discloses a method for causing creep to cause the vehicle to travel slowly without depressing the accelerator pedal when the shift lever is in the traveling position.
As shown in the publication, a hydraulically controlled type that can freely change the transmission torque to the clutch mechanism is adopted,
There is known a clutch mechanism which operates a predetermined initial set amount to generate a creep force. [0003] However, when a creep force is generated by using this type of clutch mechanism, the clutch mechanism and the controller that controls the clutch mechanism may vary due to variations in products. Even if the mechanism is operated by the same amount, a difference occurs in the transmission torque. As a result, a phenomenon that the creep force differs for each vehicle may occur, which may adversely affect drivability and the like. According to the present invention, in order to solve the above-mentioned problems, a creep force generated while a brake is stopped acts as a reaction force to lower the engine speed.
The control value by the idle speed control means for maintaining the engine speed in this state at the target idle speed and the control value by the idle speed control means in the normal state where no creep force is applied, that is, the learning value The deviation from the above is intended to indirectly indicate the creep force, and the result of the idle speed control by the idle control means is effectively used as a sensor for indirectly indicating the creep force. An object of the present invention is to make it possible to automatically adjust a creep force that varies for each product with a simple configuration without adding any dedicated sensor or actuator. [0005] That is, a creep force control method according to the present invention provides an internal combustion engine and feedback by increasing or decreasing the amount of intake air to maintain the idle speed of the internal combustion engine at a target idle speed. Idle speed control means for performing control; a continuously variable transmission interposed between the internal combustion engine and the drive wheels for continuously changing the gear ratio; and a transmission interposed between the internal combustion engine and the drive wheels. A vehicle comprising: a clutch mechanism capable of freely changing torque; and clutch control means for automatically controlling the clutch mechanism. Under certain conditions, the clutch control means controls the clutch mechanism to cause creep. The idle speed control means for maintaining the target idle speed at least in a state where no creep force is applied. The control value is learned and stored as a learning value, and at least under a predetermined condition including a condition that the brake is actuated and the vehicle is stopped, the clutch control means operates the clutch mechanism by a predetermined amount to generate a creep force. In this state, feedback control by the idle speed control means is performed to maintain the target idle speed in this state, and the deviation between the control value by the idle speed control means and the learning value at this time falls within a predetermined range. Change the control amount of the clutch mechanism by the clutch control means to fit, and use the result of idle speed control
By doing so, the creep force is automatically adjusted . According to such a configuration, the control amount of the clutch mechanism is changed by the clutch control means so that the deviation between the control value by the idle speed control means and the learning value falls within a predetermined range. The creep force that varies from product to product can be automatically adjusted to a constant value with a simple configuration without adding a dedicated sensor or actuator. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram mainly showing a portion according to the present embodiment in an automobile as a traveling vehicle.
As shown in FIG. 1, the vehicle uses an engine 1 as an internal combustion engine as a power source, and connects the engine 1 and driving wheels 3 via a clutch mechanism 4 and a continuously variable transmission (hereinafter referred to as CVT) 2. It is made. The engine 1 is electrically controlled by the engine controller 5 to control ignition timing, fuel injection amount, and the like. For the electric control, a throttle sensor 91 for detecting a throttle opening and an intake pipe pressure are controlled. At least an intake pipe pressure sensor 92 to be detected, an engine speed sensor (not shown), and the like are provided. In addition, this engine 1
ISC (Idle Speed C) is an idle speed control means that can freely control the idle speed by changing the intake air amount.
ontroler) 11 is provided. This ISC11 is
In principle, the IS output from the engine controller 5
Automatic control is performed by the C control signal e to set the idle speed to a predetermined target idle speed. The vehicle further includes a vehicle speed sensor 93 for detecting the vehicle speed and a brake sensor 94 for detecting the on / off state of the brake. The CVT 2 only needs to be capable of continuously and continuously changing the speed ratio. The mechanism is not limited as long as this function is satisfied. For example, in this embodiment, the input sheave 21 and the output Belt 2 with sheave 22
The one connected by 3 is adopted. The input sheave 21 and the output sheave 22 are
3 is configured to be freely changeable, and the sheave driving means 7 for changing the diameter of each of the sheaves 21 and 23 is used to change this diameter to continuously and continuously change the gear ratio. . The sheave driving means 7 is controlled by a CVT control signal g output from the CVT controller 6. [0010] The clutch mechanism 4 is provided with a CVT from the engine 1.
2 is a hydraulic control type that can freely change the transmission torque transmitted to the clutch 41.
And a hydraulic cylinder 43 connected to the clutch operating lever 42, and an electromagnetic control valve 44 for adjusting the flow rate and direction of hydraulic oil flowing into the hydraulic cylinder 43. This working oil is supplied by a hydraulic pump P driven by the engine 1. Then, for example, the electromagnetic control valve 44 is controlled by a clutch control signal f from the engine controller 5 serving as a clutch control means to move the hydraulic cylinder 43 forward and backward,
The clutch operating lever 42 is moved to a desired position to realize the intermittent or half-clutch state of the clutch 41. When the shift lever is in the running position and the accelerator pedal is not depressed, the clutch operating lever 42 of the clutch mechanism 4 is operated, as in the case of the torque converter vehicle.
Is moved to a predetermined position to bring the vehicle into a half-clutch state, thereby causing creep in which the vehicle travels slowly. However, simply moving the clutch operating lever 42 to a predetermined position will cause the generated creep force to differ from vehicle to vehicle due to variations in the clutch mechanism 4 including the hydraulic circuit between products. Therefore, in the present embodiment, the creep force acting while the brake is stopped acts as a force that is not used for running the vehicle but decreases the engine speed in a reactive manner. The control value DFB of the ISC 11 for maintaining the idling speed and the ISC stored and learned in the normal state where no creep force is applied.
Paying attention that the deviation from the control value of 11, ie, the learning value DLRN, indirectly indicates the creep force,
We try to keep the creep force constant. More specifically, a program as shown in the flowcharts of FIGS. 2 and 3 is stored in the memory of the engine controller 5, and is repeatedly executed at a constant period (for example, 8 msec) to automatically control the clutch mechanism 4. By doing so, the variation in creep force for each vehicle is kept within an allowable range. Here, this flowchart called the creep learning routine will be described with reference to FIGS. In brief, steps S1 to S6 in this flowchart are for determining whether or not a predetermined condition including at least a condition that the brake is operated and the vehicle is stopped is satisfied. If all of these predetermined conditions are satisfied, the process proceeds to step S7, and the creep force is automatically adjusted to be within a predetermined range. First, at step S1, the intake pipe pressure PA
It is determined whether RM is 743 mmHg or more.
Note that the intake pipe pressure PARM is calculated from the value of the output signal d of the intake pipe pressure sensor 92. And 743mmH
If it is equal to or more than g, the process proceeds to step S2, otherwise, the creep learning routine ends without doing anything. In step S2, it is determined whether or not the state where the clutch mechanism 4 is operated by a predetermined amount to apply the creep force and the brake is ON has been continued for a predetermined time KTCVTKG or more. If this condition is satisfied, the process proceeds to step S3, and if not, the creep learning routine is terminated without doing anything. In step S3, it is determined whether or not the vehicle has stopped using the value of the vehicle speed signal a input from the vehicle speed sensor 93. If stopped, the process proceeds to step S4; otherwise, the creep learning routine ends without doing anything. In step S4, it is determined whether the electric load of the air conditioner or the like is off. If it is off, the process proceeds to step S5, and if not, the creep learning routine ends without doing anything. In step S5, the counter CCVTDF
Count up B. In step S6, the value of the counter CCVTDFB is set to a predetermined value KTCVTDF.
It is determined whether it is B or more. If this condition is satisfied, the process proceeds to step S7, and if not, the creep learning routine ends without doing anything. Step S7 is a part called a creep learning processing routine, the contents of which will be described in detail below with reference to FIG. In step S71, a control value DF obtained by idling speed control performed in another routine (not shown)
It is determined whether or not B is smaller than a value obtained by subtracting the lower limit constant KDFBCVTL from the learning value DLRN. If it is smaller, the process proceeds to step S75; otherwise, the process proceeds to step S72. In step S72, it is determined whether or not the control value DFB is larger than a value obtained by adding an upper limit constant KDFBCVTH to the learning value DLRN. If it is larger, the process proceeds to step S73; otherwise, the process proceeds to step S74. Here, the learning value DLRN is a value obtained by learning and storing a control value by idle speed control for maintaining a target idle speed under a certain condition including at least a condition in which no creep force is applied. Yes, a reference value. In step S73, the control value DFB
Is large, it is determined that the creep force is too strong, and the value of the clutch control signal f is set and output so as to reduce the creep force. In step S74, since the control value DFB is within the predetermined range, it is determined that the creep force is appropriate, and the value of the clutch control signal f is set and output so as not to change the creep force. In step S75, since the control value DFB is small, it is determined that the creep force is too weak, and the value of the clutch control signal f is set and output so as to increase the creep force. Then, this routine ends. The present embodiment configured as above operates as follows. That is, as shown in FIG. 4, after the creep force is applied for a certain period of time while the vehicle is stopped, the control value DFB is reduced to the lower limit (DLRN-K) at the timing shown by t1 in FIG.
If the value is smaller than (DFBCVTL), it is determined that the creep force is too small, and the creep force is increased (step S75). Also, as shown in FIG. 5, when the control value DFB is larger than the upper limit (DLRN + KDFBCVTH), it is determined that the creep force is too large, and the creep force is reduced (step S73). Therefore, according to the present embodiment, by effectively utilizing the result of the idle speed control, the creep force that varies for each product can be reduced without adding a dedicated sensor or actuator, and a very simple software only. With the change, it can be adjusted automatically within the allowable range. The present invention is not limited to the embodiment described above. For example, the same effect can be obtained by applying the present invention to a powder clutch type clutch mechanism or the like. The automatic adjustment of the creep force may be performed only at the time of product shipment or at the time of vehicle inspection at a dealer or the like. In addition, the present invention is not limited to the illustrated example, but can be variously modified without departing from the gist thereof. As described in detail above, according to the present invention,
Focusing on the fact that the creep force generated while the brake is stopped acts as a force that lowers the engine speed in a reactive manner, makes effective use of the fact that the result of idle speed control is an indirect indication of the creep force. This makes it possible to automatically adjust the creep force that varies for each product to a constant value with a very simple configuration without adding a dedicated sensor or actuator.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic schematic configuration diagram of an automobile showing one embodiment of the present invention. FIG. 2 is a flowchart showing a creep learning routine in the embodiment. FIG. 3 is a flowchart showing a creep learning processing routine in the embodiment. FIG. 4 is an operation explanatory view in the embodiment. FIG. 5 is an operation explanatory view in the embodiment. [Description of Signs] 1 ... internal combustion engine (engine) 11 ... idle speed control means (ISC) 2 ... continuously variable transmission 3 ... drive wheel 4 ... clutch mechanism 5 ... Clutch control means (engine controller) DFB: Control value DLRN: Learning value

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F16D 48/06 B60K 41/28 F02D 29/00

Claims (1)

(1) An internal combustion engine and idle speed control means for performing feedback control by increasing or decreasing an intake air amount so as to maintain the idle speed of the internal combustion engine at a target idle speed. A continuously variable transmission interposed between the internal combustion engine and the drive wheels and capable of continuously changing the gear ratio, and a clutch interposed between the internal combustion engine and the drive wheels and capable of freely changing the transmission torque A vehicle having a mechanism and clutch control means for automatically controlling the clutch mechanism, wherein under a certain condition, the clutch control means controls the clutch mechanism to cause creep. At least in a state where no creep force is applied, the control value of the idle speed control means for maintaining the target idle speed is learned and stored as a learning value, Under predetermined conditions including at least the condition that the brake is operated and the vehicle is stopped, the clutch control unit operates the clutch mechanism by a predetermined amount to apply a creep force, and in this state, the target idle speed is reduced. Feedback control is performed by the idle speed control means to maintain the clutch mechanism, and the clutch mechanism is automatically controlled by the clutch control means such that the deviation between the control value of the idle speed control means and the learning value at this time falls within a predetermined range. By using the result of idle speed control.
A creep force control method characterized by automatically adjusting the creep force.