Hydraulic control system for use in a motor vehicle and method for controlling the hydraulic control system

• US 20080113839A1
• Filed: 11/05/2007
• Published: 05/15/2008
• Est. Priority Date: 11/13/2006
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Honda, Atsushi, Ota, Hirofumi, Nozaki, Kazutoshi
• Granted Patent: US 7,682,276 B2
• Time in Patent Office: Days
• US Class Current: 475/31
• CPC Class Codes: F16H 2059/683 Sensing pressure in control systems or in fluid controlled devices, e.g. by pressure sensors for hydrostatic transmissions F16H2059/6861
• CPC Class Codes: F16H 2061/0288 Relay valve, e.g. valve arranged between shift valve and servo
• CPC Class Codes: F16H 2061/1208 with diagnostic check cycles; Monitoring of failures
• CPC Class Codes: F16H 2200/006 the gear ratios comprising eight forward speeds
• CPC Class Codes: F16H 2200/2048 with seven engaging means
• CPC Class Codes: F16H 2200/2097 comprising an orbital gear set member permanently connected to the housing, e.g. a sun wheel permanently connected to the housing
• CPC Class Codes: F16H 61/0206 Layout of electro-hydraulic control circuits, e.g. arrangement of valves for control of actuators selecting and moving final output members, e.g. shift forks F16H61/2807
• CPC Class Codes: F16H 61/12 Detecting malfunction or potential malfunction, e.g. fail safe in control of hydrostatic gearing F16H61/4192; Circumventing or fixing failures
• CPC Class Codes: F16H 61/143 using electric control means
• CPC Class Codes: F16H 61/686 with orbital gears
• CPC Class Codes: Y10T 137/0396 Involving pressure control
• CPC Class Codes: Y10T 137/5987 Solenoid or electromagnetically operated valve

Abstract

A hydraulic control system that includes a solenoid valve for supplying a prescribed fluid pressure; and a relay valve for selectively switching a destination of the prescribed fluid pressure between a first destination part and a second destination part. The relay valve has an input port supplied with a normally produced fluid pressure and an output port that selectively communicates with the input port. The hydraulic control system further includes a fluid pressure switch, provided in the output port of the relay valve, that is activated when the input port communicates with the output port to allow the normally produced fluid pressure to be supplied to the output port.

Claims

1. A hydraulic control system for use in a motor vehicle, comprising:

a solenoid valve for supplying a prescribed fluid pressure;

a relay valve that selectively switches a destination of the prescribed fluid pressure between a first destination part and a second destination part, the relay valve having an input port that is supplied with a normally produced fluid pressure and an output port that selectively communicates with the input port; and

a fluid pressure switch, provided in the output port of the relay valve, that is activated when the input port communicates with the output port to allow the normally produced fluid pressure to be supplied to the output port.

2. The hydraulic control system of claim 1, wherein the motor vehicle includes a fluid coupling device provided with a lock-up mechanism and an automatic transmission that establishes a plurality of gear steps of different speed ratios by selectively engaging a plurality of hydraulic friction engagement devices, wherein the solenoid valve is a single linear solenoid valve that controls either an engagement pressure of a specific hydraulic friction engagement device or a torque capacity of the lock-up mechanism, and wherein the relay valve selectively switches the destination of fluid pressure of the linear solenoid valve between the first destination part to control the engagement pressure of the specified hydraulic friction engagement device and the second destination part to control the torque capacity of the lock-up mechanism.

3. The hydraulic control system of claim 1, wherein the switching of the destination between the first destination part or the second destination part by the relay valve is controlled based on a control fluid pressure produced from a solenoid switching valve.

4. The hydraulic control system of claim 3, further comprising:

a switching malfunction determination unit that determines whether a switching malfunction has occurred, in which the relay valve cannot be switched and the destination of fluid pressure of the solenoid valve is stuck at the first destination part or the second destination part, wherein the switching malfunction determination unit determines whether the switching malfunction has occurred based on the control fluid pressure produced from the solenoid switching valve and an activation state of the fluid pressure switch.

5. The hydraulic control system of claim 4, wherein the switching malfunction determination unit determines that the switching malfunction has occurred when the fluid pressure switch is activated and the control fluid pressure is not produced from the solenoid switching valve.

6. The hydraulic control system of claim 4, wherein the switching malfunction determination unit determines that the switching malfunction has occurred when the fluid pressure switch is not activated and the control fluid pressure is produced from the solenoid switching valve.

7. The hydraulic control system of claim 4, wherein the switching malfunction determination unit includes:

a fluid pressure switch malfunction determination module that determines whether the fluid pressure switch is operating normally;

a solenoid switching valve determination module that determines whether the control fluid pressure is produced from the solenoid switching valve; and

a fluid pressure switch signal determination module that determines whether the fluid pressure switch is activated.

8. The hydraulic control system of claim 7, wherein the solenoid switching valve determination module detects whether an electronic control unit has sent a drive signal to operate the solenoid switching valve, and, if the drive signal is sent, the solenoid switching valve determination module determines that the control fluid pressure is produced from the solenoid switching valve.

9. A control method of the hydraulic control system according to claim 3, determining that a switching malfunction has occurred, in which the relay valve cannot be switched and the destination of fluid pressure of the solenoid valve is stuck at the first destination part or the second destination part, based on the control fluid pressure produced from the solenoid switching valve and an activation state of the fluid pressure switch.

10. The hydraulic control method of claim 9, wherein it is determined that the switching malfunction has occured when the fluid pressure switch is activated and the control fluid pressure is not produced from the solenoid switching valve.

11. The hydraulic control method of claim 9, wherein it is determined that the switching malfunction has occurred when the fluid pressure switch is not activated and the control fluid pressure is produced from the solenoid switching valve.

12. The hydraulic control method of claim 9, further comprising:

determining whether the fluid pressure switch is operating normally, wherein it is determined whether the switching malfunction has occurred when the fluid pressure switch is operating normally.