Patent Application
20070220879
This invention relates to electro-hydraulic controls for power transmissions and, more particularly, to pressure regulator valve controls in power transmissions.
Automatic shifting power transmissions include a hydraulic system, which supplies power to operate the various clutches and brakes and other elements within the transmission. The hydraulic pressure is limited or controlled in value to provide the most efficient operation that can be obtained.
In more recent transmissions, the hydraulic controls have been advanced to electro-hydraulic controls wherein electrical or electronic signals are available to assist in transmission controls. The electro-hydraulic controls generally comprise a solenoid valve, which receives various signals from a transmission control module (TCM) to supply a pressure signal to the various operating valves of the transmission. While these electro-hydraulic controls work quite well, there can be some improvement in the pressure regulation within the various systems of the power transmission.
It is an object of this invention to provide an improved electro-hydraulic transmission control.
In one aspect of the present invention, the electro-hydraulic control solenoid supplies signals to a pressure regulator valve such that the proper output pressure is maintained.
In another aspect of the present invention, the pressure regulation valve supplies pressure to a load and a feedback of pressure to a hydraulic control module.
In yet another aspect of the present invention, the output pressure of a pressure regulator is subjected to or is operable on a pressure transducer, which issues an electronic signal to a transmission control module to effect control of a regulated pressure.
In still another aspect of the present invention, a pressure command is issued through a control algorithm to a solenoid valve which issues a pilot pressure through a pressure regulating valve; the output pressure of a pressure regulating valve is sensed by a pressure transducer which supplies a feedback signal to the transmission control module (TCM) to provide adjustment in the signal issued to the solenoid valve and therefore the output pressure of the regulator valve.
In
The TCM includes a plurality of command signals such as throttle position, torque demand, vehicle speed, engine speed, and other characteristics or parameters of the powertrain. The pressure command is issued by a main transmission control 18 to the solenoid valve hardware control algorithm 20. The control algorithm 20 supplies output signals in electronic form to valve drive electronics 22. The TCM also includes some conventional electronics that provide feedback signals to the correction device 18.
The TCM also includes a conventional preprogrammable digital computer, which is the main operating base for the output signals. The valve drive electronics 22 issues signals to the solenoid valve 10, which in turn issues a pressure signal through a passage 26 to the pressure regulator valve 12 In an optional construction, the solenoid and regulator valve can be combined in a conventional high flow solenoid valve. The pressure regulator valve 12 provides an output pressure fluid in a passage 28, which is directed to the transmission element 16 and also to the pressure transducer 14. The pressure transducer 14 directs an electronic signal through the pressure feedback electronics 24 in the TCM. This provides a closed loop control regulator within the transmission control system.
The control algorithm 20 calculates an electronic signal in a conventional manner for the solenoid valve, which in turn provides the pilot pressure to the pressure regulation valve. The pressure regulation valve will respond to the pilot pressure to control the output pressure to the transmission element 16.
The pressure in passage 28 is also directed to the pressure transducer 14, which issues an electronic signal back through the TCM to the solenoid hydraulic control algorithm 20. If the signal received at error correction device 18 suggests that the output pressure of the regulator valve 12 is different from the pressure commanded in the transmission control module, a proper selection signal is generated in the control algorithm 20 to provide an output signal which will change the regulated pressure in passage 28 to a level commensurate or agreeable with the pressure commanded by the TCM.
Referring to
The regulating valve 12A includes a pilot portion 36 and a regulating valve portion 38. The pilot portion 36 includes a shuttle valve or plug valve 40, which is in fluid communication through a passage 42 with a solenoid control valve 10A. The solenoid control valve, as explained above with
The spring 59 imposes a bias on the valve spool 46 such that the valve spool 46 is controlled and positioned to establish the pressure within the main line 32. The port 52 of the main line 32 operates on the right end of the valve spool 46 to balance the spring load established by the pilot valve 40. If the line pressure at passage 32 is greater than the line pressure commanded by the TCM through the solenoid 10A, the valve spool 46 will be urged leftward against the spring to exhaust excess fluid within the system through the passage 58.
The passage 56 supplies fluid pressure through a transmission control at which then directs the fluid to a conventional torque converter, not shown. The fluid in passage 54 is open to the pressure transducer 14 as well as to the control or transmission element 16A. The pressure in passage 54 causes the pressure transducer 14 to issue a signal to the TCM thereby assuring that the pressure in the passage 54 is commensurate with the pressure commanded by the TCM for proper operation of the transmission element 16A. The TCM, as previously explained, receives signals from various vehicle-operating mechanisms or sensors such as engine speed, drive position, vehicle speed, torque command, and other items. The TCM also receives signals from the transmission hydraulic control 16A to assure that the transmission is operating in the desired speed ratio or drive ratio established by the operator.
Referring to
The valve bore 62 is also in fluid communication with a feed passage 80, a clutch apply passage 82, an optional passage 84, an exhaust passage 58B, and a feedback passage 76. The feedback passage 76 communicates with the clutch apply passage 82 to provide a signal to the right end of valve spool 60 to signal that the desired pressure is present at the transmission element 16B.
The passage 82 communicates with the transmission element 16B, which may be a torque-transmitting mechanism such as a clutch or a brake. The passage 82 also communicates with the pressure transducer 14 such that the actual pressure at the transmission element 16B can be communicated with the TCM. The fluid pressure in chamber 72, of course, communicates the command signal from the TCM to the regulator valve 12B. The fluid in passage 84 is an optional signal from another operating device within the transmission, which will reduce the pressure in the transmission element 16B when desired.
As with the pressure regulator valve 12A, the regulator valve 12B issues a pressure control signal to a device within the transmission and the pressure issued thereby is directed through a pressure transducer back to the TCM so that regulation of the pressure in the transmission element 16B can be controlled within the parameters set by the TCM.
A torque converter regulator valve 12C is shown in
The control chamber 112 is in fluid communication with the solenoid valve 10C, which receives a control signal from the TCM. The chamber 114 receives a signal from a separate solenoid control valve, not shown, which supplies signals for purposes other than the regulation. The valve bore 102 communicates with a torque converter apply passage 116 at two ports 116 and 118, and a pressure supply passage 122, which is connected with the transmission element 16A to receive input pressure therefrom. The pressure in passage 122 is controlled by the regulation system shown in
The valve bore 102 is also connected with an exhaust port 120, which will limit or return the excess fluid applied to the valve to the transmission sump. The fluid pressure in port 118 and passage 116 is supplied to a conventional transmission element such as a torque converter clutch 16C. The pressure in passage 116 is also directed to the pressure transducer 14 for controlling the signal issued back to the TCM to establish any change in pressure regulation as required by the transmission system. The pressure in passage 116 is also directed back to the valve bore 102 to operate on the right end of the regulator valve 12C to reduce the output pressure in accordance with the required signal from the TCM.
Those skilled in the art will now recognize that the type of pressure regulating systems shown in
For example,
