TW201606216A - A device to control a continuously variable transmission - Google Patents

Abstract

The various embodiment of the present disclosure provides a device to control a CVT. The device comprises an actuator 112, a memory element 120 and a control unit 118. The actuator 112 is operatively coupled to a movable sheave 110 of a secondary pulley of the CVT. The memory element 120 is adapted to store desired engine speed corresponding to BSFC and belt 106 efficiency for at least one operating condition corresponding. The control unit 118 controls the actuator 112 to adjust the position of the movable sheave 110. The control unit 118 measures an actual engine speed from at least one engine speed sensor, retrieves a desired engine speed from the memory element 120 and determines a difference between the same. The control unit 118 then computes a required clamping force of the belt and controls the actuator 112 based on the determined difference and the belt efficiency.

Description

Device for controlling a stepless transmission

The present disclosure relates to a device for controlling a continuously variable transmission (CVT).

A Variable Diameter Pulley (VDP) type CVT includes a main pulley, an auxiliary pulley, and a V-belt. The main pulley includes a fixed and a movable sheave coupled to an engine crankshaft and a variator (which is a disc with a roller) having a specific weight and Configured to surround the center of the crankshaft). The rollers move outwardly within the transmission at an increasing engine speed, which moves the movable sheave in a centrifugal fashion toward the fixed sheave sheave. The auxiliary pulley includes a fixed and a movable sheave coupled to a drive side shaft leading to the wheel, and a compression spring (having a specific rigidity), commonly referred to as a contra spring, supports the movable sheave It is free of removal from the auxiliary pulley retaining sheave and has a centrifugal clutch that also opens and connects the driver to the wheels at a particular speed. A V-belt or a wedge-shaped belt surrounds the two sheaves between the main pulleys and is connected to the two sheaves of an auxiliary pulley. The main source of the V-belt drive.

Mechanical variable diameter pulley (VDP) for CVT is designed for all The effective CVT ratio (CVT ratio) maintains the engine speed in the optimum region by driving the driven components. However, since the mechanical CVT does not have any feedback on the operating conditions, the engine speed in the VDP-CVT slips from the optimum area. The design of the CVT component and its mechanical capabilities (eg, roller weight, spring stiffness) are adjusted to be most suitable for flat road conditions and become inefficient when operating at higher speeds and suddenly encountering other uphill conditions. Preferably, during this time, the load on the wheel is not sensed correctly, and the engine speed drops due to not switching to the lower gear. Other inefficient operating conditions include, but are not limited to, braking to lower speeds and sudden opening of the throttle, as the CVT ratio is still at a higher gear ratio and torque is insufficient, resulting in undesirable accelerate.

According to an embodiment of the present disclosure, a controlless transmission is provided (CVT) device. The device includes an actuator operatively coupled to one of the auxiliary sheaves of the CVT. A memory component is configured to store an expected engine speed corresponding to a Brake Specific Fuel Consumption (BSFC) of at least one operating condition. The memory element is further configured to store a belt efficiency corresponding to at least one operational condition. The apparatus further includes a control unit configured to control the actuator to adjust the position of the movable sheave of the CVT. The control unit is configured to measure an actual engine speed from at least one engine speed sensor and to draw an expected engine speed from the memory element. The control unit then determines a difference between the expected engine speed and the actual engine speed. The control unit is further configured to calculate a required clamping force of one of the belts based on the difference between the expected and actual engine speeds and the belt efficiency, and control the movable sheave of the auxiliary pulley according to the required clamping force .

According to another embodiment of the present disclosure, a controlless transmission is provided (CVT) method. The method includes the step of measuring an actual speed of an engine from at least one engine speed sensor. In the next step, the method includes extracting, from a memory component, an expected speed of the engine based on at least one operating condition of the BSFC. The method also includes determining a difference between the expected engine speed and the actual engine speed. The method further includes extracting the belt efficiency of the operational condition from the memory component. Additionally, the method includes calculating the required clamping force of one of the belts from the difference between the expected and actual engine speeds and the belt efficiency. The method in addition includes controlling the actuator to achieve a desired gear ratio based on the desired clamping force of the belt.

102‧‧‧Fixed sheaves for main pulleys

104‧‧‧Removable sheave of the main pulley

106‧‧‧Belt

108‧‧‧Fixed sheaves for auxiliary pulleys

110‧‧‧Removable sheave of auxiliary pulley

112‧‧‧Actuator

114‧‧‧ Spring

116‧‧‧Clutch

118‧‧‧Control unit

120‧‧‧ memory components

202‧‧ The first step of the method

204‧‧ The second step of the method

206‧‧ The third step of the method

208‧‧ The fourth step of the method

210‧‧ The fifth step of the method

212‧‧ The sixth step of the method

The description of the embodiments of the present disclosure is made with reference to the following drawings: FIG. 1 illustrates a schematic diagram of an apparatus for controlling a CVT according to an embodiment of the present disclosure, and FIG. 2 illustrates an embodiment according to an embodiment of the present disclosure. A flow chart of a method of controlling a CVT.

1 illustrates an overview of an apparatus for controlling a CVT in accordance with an embodiment of the present disclosure. The apparatus includes an actuator 112 operatively coupled to one of the auxiliary pulleys of the CVT to move the sheave 110. One of the auxiliary sheaves of the fixed sheave 108 is mounted on a suitable fixed portion of a vehicle. Actuator 112 is an electromechanical electromagnetic actuator such as, but not limited to, an electromagnetic clutch. The device is associated with a memory component 120 that is configured to store an expected engine speed corresponding to a brake fuel consumption rate (BSFC) of at least one operating condition. The memory component 120 is further configured to store a belt effect corresponding to the at least one operating condition rate. Memory element 120 is an internal (built-in) or external component. The apparatus further includes a control unit 118 configured to control the actuator 112 to adjust the position of the movable sheave 110 of the CVT. Prior to controlling the actuator 112, the control unit 118 is configured to measure an actual engine speed from at least one engine speed sensor (not shown in FIG. 1) and is further tuned to draw an expectation from the memory component 120. The engine speed and the difference between the expected engine speed and the actual engine speed. In addition, control unit 118 is configured to calculate the required clamping force of one of belts 106 based on the difference between the expected and actual engine speeds and the belt efficiency. The calculated required clamping force is modulated by control unit 118 to control the movement of movable sheave 110 in the auxiliary sheave. This required clamping force is configured to determine a consistent power to control the actuator 112. It displays a clutch 116 such as, but not limited to, a centrifugal clutch to apply torque to the wheels of the vehicle.

In accordance with an embodiment of the present disclosure, the actuator 112 is operatively coupled to a primary One of the pulleys can move the sheave 104 and control the movable sheave 104 to maintain an optimal engine speed in accordance with at least one operating condition of the BSFC. One of the main pulleys, the fixed sheave 102, is mounted on a fixed portion of the vehicle.

In accordance with an embodiment of the present disclosure, the belt 106 between the primary pulley and the auxiliary pulley is a metal belt or a non-metallic belt 106 such as rubber.

In accordance with an embodiment of the present disclosure, the at least one operating condition is selected from one including, but not limited to, a speed ratio, a belt tension, a rotational speed, an external load, a diameter of the pulley, a throttle position, a surface gradient, and A group of similar projects.

In accordance with an embodiment of the present disclosure, the at least one engine speed sensor is selected from the group consisting of, but not limited to, a flywheel tooth sensor, an alternator based sensor, and an inductive Inductance based sensor and similar projects Group.

In accordance with an embodiment of the present disclosure, the actuator 112 is configured to pull and/or Or push the movable sheave 110 in the auxiliary pulley to achieve an optimum gear ratio. The belt 106 connecting the main pulley and the auxiliary pulley does not slide when the force on the main pulley is balanced by controlling the movable sheave 110 in the auxiliary pulley. Instead of individually controlling the primary and secondary pulleys, the control unit 118 provides an appropriate additional correction force to maintain the auxiliary pulleys at an efficient gear ratio. The clamping force applied to the auxiliary pulley by the electromechanical actuator 112 is corrected.

In accordance with an embodiment of the present disclosure, the actuator 112 provides a help at the auxiliary pulley force. By connecting the actuator 112 to the auxiliary pulley, less assistance is provided under partial load conditions to change the gear ratio to overdrive, meaning that gain is provided for belt efficiency. Moreover, it increases the rate of acceleration under local load conditions because the boost is applied directly above the auxiliary side.

According to an embodiment of the present disclosure, the device is retrofitted to an existing mechanical type The auxiliary side of the VDP-CVT. The electromagnetic actuator 112 operates only when the pulley position requires correction. Thus, the position of the belt 106 on the pulley is corrected, thereby contributing to the optimum CVT speed ratio for maintaining engine speed. The device is housed inside a spring 114, such as a pin spring, and controls the actuator 112 in accordance with the required clamping force. Alternatively, the device is housed outside of the spring 114.

In accordance with an embodiment of the present disclosure, the disclosed apparatus is capable of controlling a belt slip The overall efficiency of the CVT is extracted under local load conditions. Local load conditions refer to low torque conditions. The device maintains a lower engine speed to achieve an optimal BSFC point such as one of the throttle positions corresponding to at least one operating condition. The device ensures optimal or necessary belt 106 tension for local throttle power transfer. The device controls the engine speed and the rate of change of the CVT gear ratio to the gear ratio Improved fuel consumption. Thus, it optimally controls one of the belts 106 that is very inefficient under localized load conditions, such as, but not limited to, a rubber belt.

In accordance with an embodiment of the present disclosure, the disclosed apparatus is capable of controlling at full load The drivability of the vehicle under conditions and its fuel efficiency. In addition, the unit provides improved loading/acceleration characteristics and sufficient traction for the wheels by delivering high value engine torque. The device also maintains the speed in an optimum area where the engine power balances the resistance of the pedal action on the steering surface.

2 illustrates a method for controlling a CVT according to an embodiment of the present disclosure. One of the flowcharts. The method includes the step of measuring an actual speed of the engine from at least one engine speed sensor. It uses an existing engine speed sensor or an external engine speed sensor (202). The method further includes extracting, by the BSFC according to at least one operational condition, an expected speed of the engine from a memory component (204). A control unit is configured to determine a difference between the expected engine speed and the actual engine speed (206). Additionally, at least one operational condition of the belt efficiency (208) is drawn from the memory component. The control unit is similarly configured to calculate the required clamping force (210) for one of the belts from the determined difference between the expected and actual engine speeds and the belt efficiency. After calculating the required clamping force, the same control unit is configured to control the actuator connected to the movable sheave of the CVT to achieve the desired optimum gear ratio (212) for the at least one operating condition.

According to an embodiment of the present disclosure, the required clamping force is configured to determine the motion Force to control the actuator. The actuation force is obtained by controlling the current to the electromagnetic clutch actuator.

According to an embodiment of the present disclosure, the required clamping force is applied to the actuator Maintain one of the best operating conditions for at least one operating condition.

According to an embodiment of the present disclosure, the device is capable of maintaining the engine at a specific reference The speed zone provides better performance and fuel consumption between different transmission ratios of the CVT. The device overcomes the efficiency slip under local load conditions by only correcting the gear ratio to improve belt efficiency. The control unit controls the CVT to achieve the optimum gear ratio, wherein the belt efficiency is highest at least one operating condition and there is no sacrifice in drivability. The electromechanical linear actuator is controlled in a manner that provides the force required to move the sheave in the auxiliary sheave with reasonable speed and accuracy. Also, at least one limit switch is provided to the actuator to avoid overdriving the sheaves. The control mechanism used is the force required to move the sheave in the auxiliary sheave relative to the percentage of the duty cycle that is scheduled to be implemented, with the expected engine speed as input to complete the upward and downward movement.

It is to be understood that the embodiments described in the above description are merely illustrative and not limiting the scope of the invention. Many other modifications and variations of the embodiments described herein and the embodiments described herein are contemplated. The scope of the invention is limited only by the scope defined by the scope of the patent application.

102‧‧‧Fixed sheaves for main pulleys

104‧‧‧Removable sheave of the main pulley

106‧‧‧Belt

108‧‧‧Fixed sheaves for auxiliary pulleys

110‧‧‧Removable sheave of auxiliary pulley

112‧‧‧Actuator

114‧‧‧ Spring

116‧‧‧Clutch

118‧‧‧Control unit

120‧‧‧ memory components

Claims (9)

A device for controlling a stepless transmission (CVT), the device comprising: an actuator operatively coupled to a movable sheave of one of the auxiliary pulleys of the CVT; a memory component configured to be stored Corresponding to an expected engine speed of a brake fuel consumption rate (BSFC) of at least one operating condition, the memory component is further configured to store a belt efficiency corresponding to the at least one operating condition; and a control unit configured to control the Actuating to adjust the position of the movable sheave in the CVT, the control unit being configured to measure an actual engine speed from at least one engine speed sensor, the control unit being configured to draw from the memory element An expected engine speed and determining a difference between the expected engine speed and the actual engine speed, the control unit being further configured to calculate one of the belts based on the difference between the expected engine speed and the actual engine speed and the belt efficiency The required clamping force is used to control the movable sheave of the auxiliary pulley according to the required clamping force. The device of claim 1, wherein the actuator is an electromechanical actuator. The device of claim 1, wherein the actuator is configured to pull and/or push the movable sheave of the auxiliary pulley to achieve an optimum gear ratio. The apparatus of claim 1, wherein the at least one operating condition is selected from the group consisting of a speed ratio, a belt tension, a rotational speed, an external load, a pulley diameter, a throttle position, a surface gradient, and the like. The device of claim 1, wherein the at least one engine speed sensor is selected from the group consisting of a flywheel tooth sensor, an alternator sensor, an inductive sensor, and the like. The device of claim 1, wherein the required clamping force is configured to determine a An actuation force is used to control the actuator. A method of controlling a stepless transmission (CVT), the method comprising: measuring an actual speed of an engine from at least one engine speed sensor; extracting one of the engines from a memory component according to at least one operating condition of the BSFC Speed; determining a difference between the expected engine speed and the actual engine speed; extracting one of the operating conditions from the memory component; calculating the belt from the difference between the expected engine speed and the actual engine speed and the belt efficiency a desired clamping force; and controlling the actuator to achieve a desired gear ratio based on the desired clamping force of the belt. The method of claim 7, wherein the required clamping force is configured to determine a consistent power to control the actuator. The method of claim 7, wherein the required clamping force is applied to the actuator to maintain an optimum engine speed of the at least one operating condition.