MXPA96006265A - Cooling bypass control compensated by hydraulic temperature for a transmission autumn - Google Patents

Abstract

The present invention relates to a system for controlling fluid flow in a hydraulic circuit of an automatic transmission, comprising: a source of fluid having a varying temperature, a cooler communicating with the fluid source, adapted to transfer heat between the fluid from the fluid source, to a second fluid, a circuit, a bypass valve to supply fluid from the fluid source to the circuit and to the cooler, in accordance with the temperature of the fluid, wherein the bypass valve comprises: a fluid drain, a moving reel in a chamber, communicating the chamber with the fluid source, the cooler and the circuit, a first ledge formed on the reel, pushing the pressure of the fluid source on the first ledge the reel for a connection between the fluid source and the circuit, a spring that pushes the reel to close a connection between the fluid source and the circuit, a first hole adapted to the The fluid flow rate through it, which is relative independent of the temperature of the fluid, is regulated by a second orifice adapted to produce a fluid flow rate through it, which depends relatively on the temperature of the fluid, placed in the fluid. series with the first hole, between the chamber and the drain, and a second shoulder separated from the first sessile along the reel, the pressure of fluid being measured between the first hole and the second hole to the second shoulder that pushes the reel to close the conxi

Description

"COOLING BYPASS CONTROL COMPENSATED BY HYDRAULIC TEMPERATURE FOR A TRANSMISSION AUTOMATION " BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION This invention relates to the field of hydraulic circuits for automatic transmission control. 2. DESCRIPTION OF THE PREVIOUS TECHNIQUE A hydrokinetic torque converter, which forms a hydrokinetic torque flow path from the engine crankshaft to the input elements of a gear ring of an automatic transmission includes a turbine and a propeller placed in a flow circuit of toroidal fluid. It also includes a friction bypass clutch adapted to connect the impeller to the turbine in order to establish a mechanical torque flow path in parallel with respect to the hydrokinetic torque flow path of the torque converter.

The hydrokinetic torque converter of our invention includes a bypass embedment controlled by a hydraulic valve system. The bypass clutch has features that are common to the control system described in U.S. Patent No. 5,029,087 and the control system of the hydrokinetic torque converter of U.S. Patent Number 5,303,616. These patents have been assigned to the concessionaire of our present invention. Patent Number '087 discloses a torque converter control system having a latching clutch to establish a controlled mechanical torque flow path between the motor and the transmission gear and to modify the capacity of the clutch of derivation during displacement intervals. That patent gives to cococer an electronic control strategy to effect a control slip in a bypass clutch of the torque converter whereby the bypass clutch is actuated by pressure of the modulated converter clutch solenoid from a valve of clutch solenoid so as to effect variable clutch capacity so that the resulting control slip results in a real slip approaching the reference slip determined by the operating parameters of the driving line. Patent Number '616 discloses a torque converter control system having a latching clutch to establish a controlled mechanical torque flow path between the motor and the transmission gear and to modify the clutch capacity bypass during gear shift intervals. The system of this invention allows two fixed displacement pumps to operate in several different modes: combined supply, supercharged secondary pump, and reinforced clutch pump. A particularity or characteristic of this system is the supercharging circuit that regenerates the residual hydraulic energy to raise the inlet pressure of the secondary pump above the atmospheric pressure. In a conventional hydraulic circuit for an automatic transmission, the fluid from the torque converter and the cooler provides most of the fluid to the lubrication system, because the converter, cooler and lubrication system are placed in series. In some conventional hydraulic systems, one or more separate circuits are fed from a line pressure source so that during periods when the flow demand of the pump is high, such as when the torque converter and the flow of the Cooler chokes or chokes, not all fluid directed to the lubrication system is throttled or closed.

COMPENDIUM OF THE INVENTION An object of this invention is to provide a system that ensures the flow of continuous lubrication fluid suitable in the mechanical transmission components, and fluid supply in a manner compatible with the requirements of the lubrication flow rate in response to the operating gear scale, the inlet speed and the rate of fluid flow through the cooling system. The system conserves the flow during a cold and moderate fluid temperature operation, thus preserving the pumping power, but nevertheless, it increases the flow rate during a high temperature operation to help heat transmission from the box of gear. This object is achieved through the operation of a cooler bypass valve that responds to changes in oil viscosity or oil temperature, to alter the proportion of oil directed to a cooler and the lubrication circuit. In obtaining these objects and advantages of the system of this invention for controlling the flow of fluid in a hydraulic circuit of an automatic transmission, it includes a source of fluid having a variable temperature.; a cooler communicating with the fluid source and adapted to transmit heat between the fluid from the fluid source to the second fluid; a circuit; and a bypass valve for supplying fluid from the fluid source to the circuit and the cooler, in accordance with the temperature of the fluid. The bypass valve, which supplies the fluid to the first and second portions of the hydraulic circuit, includes a reel movable in a chamber, the chamber communicates with the fluid source and the first and second portions of the circuit; a first shoulder formed on the reel, the pressure of the fluid source at the first shoulder and pushing the reel to open a connection between the fluid source and the first portion of the circuit; and a spring that pushes the spool to close a connection between the fluid source and the first portion of the circuit.

BRIEF DESCRIPTION OF THE DRAWINGS Figures IA, IB and 1C, in combination, show a schematic diagram of a hydraulic control circuit for an automatic transmission. Figure 2 shows the variation of the flow rate through a sharp-edged orifice and a laminar orifice as changes in temperature. Figure 3 is a schematic diagram of the symbols of ANSI for a valve of the modified line to include a sharp-edged orifice and a laminar orifice. Figure 4 is a schematic diagram of the symbols of ANSI to reduce the modified valve to include a sharp-edged hole and a laminar orifice. Figure 5 is a schematic diagram of the microprocessor, the emitters, the solenoid controlled valves used to control the operation of the transmission. Figure 6 is a schematic diagram of a cooler bypass valve.

DESCRIPTION OF THE PREFERRED MODALITY With reference to Figures IA and IB, the hydraulic system for controlling and actuating the components of an automatic transmission for an automotive vehicle, includes a drain 10 wherein the hydraulic fluid is contained and from where it is attracted by a purifying pump 12 and supplied to a reservoir 14. The inlet of a high flow rate pump 16 is connected through the holding valve 18 to the reservoir. The output of the pump 16, the secondary regulated pressure SRP is maintained at about 8.44 kilograms per square centimeter gauge or greater, through the operation of the SRP regulator valve 52. The pump inlet 22 is partially attracted from the reservoir 14 through a supercharging nozzle 24, which carries the fluid through the system from the various components of the transmission. The output of the pump 22 in line 24 is maintained at a regulated line pressure through the control of a pressure signal produced by a valve 25 operated by a variable force solenoid and is applied to a pressure regulating valve 212 The clutch capacity line. The torque converter 20 includes a propeller wheel 26 with vanes, driven permanently by a case of the propeller 28 with the crankshaft of an internal combustion engine 30. A turbine wheel 32 with vanes and a wheel 34 of the stator with vanes are mounted in relation to the propeller so as to form a toroidal flow path within which the fluid of the torque converter circulates and rotates about the axis of the converter of torque. The stator wheel 34 is mounted on a unidirectional clutch 36 to provide a unidirectional drive connection to the transmission case. A bypass clutch 38 of the torque converter, when engaged, produces a mechanical drive connection between the turbine and the impeller and, when disengaged, allows the hydrokinetic drive connection between the turbine and the propeller. The clutch 38 disengages or disengages and the torque converter opens when the CBY pressure in line 40 is applied to the space between the propeller housing and the friction surface of the clutch 38 which engages the case 28. The pressure of CBY is greater than the pressure of Cl in line 46. Line 44 at a pressure of CT, is drained through the oil cooler 126, and the pressure of Cl in line 46 is supplied to the torque converter boiler. torque through the hole 122 when the clutch 38 is disengaged.

Secondary Regulated Pressure Valve A temperature-compensated pressure-limiting valve 52 produces an output, the SRPX pressure carried in line 82 to the anti-consumption back pressure valve 78, whose output, supply TCF pressure of the torque converter The torque is carried on line 88 to the regulator valve 86 of the converter. Secondary regulated pressure, controlled by the valve 52, is carried through the line 54. The valve 52 includes a spool 56 pushed by a spring 58 to the right in the valve bore, whose movement to the right is limited by contact of the projections 60 control against the valve body. The SRP feedback pressure on line 62 enters the valve through a hole 64 with sharp edges. The radial space between the shoulders 60 and the perforation of the valve defines a laminar orifice extending along the axis of the valve 52 from the feedback orifice, which extends along the axis of the valve 52 from the feedback hole, connected through the line 62 with the vent hole 66. Preferably, the diameter of the orifice 64 is 1.0 millimeter, the diameter of the ridges 60 is 14,994 millimeters, and the diameter of the perforation adjacent the ribs 60 is 15,019 millimeters.

Through this discussion, a sharp-edged or fixed hole means a restricted hydraulic passage through which the flow rate varies non-linearly with a pressure drop through the hole, approximately as the square root of the pressure drop, and the flow rate varies almost linearly with the temperature of the fluid, such as the commercially available hydraulic transmission fluid flowing through the orifice. A laminar orifice means a restricted passage through which the flow rate varies linearly and directly with the pressure drop through the orifice, and exponentially (or logarithmically), with the temperature of the fluid flowing through the orifice. The valve 52 further includes control projections 68, 70; the input port 80 of SRP, the output port 81 of SRPX; the supercharge output hole 74 connected via line 76 with the supercharging relief valve 78. The relief valve 52 is usually. it closes by the spring 58, which causes the spool 56 to move toward the right-hand end of the valve, while the flow rate from the pump 16 is so low that the SRP pressure is relatively low. In that position, the line 76 is closed by the ledge 68 from the SRP line 54 and the converter power line 82 is closed by the ledge 70 from the SRP line 54. The power line 82 of the converter is connected through the hole 75 with the line 54 of SRP. As the flow rate is raised from the pump 16 and the SRP pressure, the control pressure at the right-hand end of the spool 56 first opens the output port 81 of SRPX, thereby connecting line 54 of SRP with anti-consumption back pressure valve 78, through line 82. SRPX pressure on line 82 moves a spool 84 of anti-consumption back pressure valve 78 to the left thus connecting the TCF pressure of torque converter on line 82 with converter regulator valve 86 through line 88. As the SRP still rises further, the projection 68 chokes the SRP in hole 74, of so that the fluid in the SRP is connected to the line 76, the nozzle 24, the check valve 18 and the line 144. The feedback chamber at the right-hand end of the bore of the valve 52 is exhausted through one hole 60 the Mining of high resistance and is fed through a fixed hole 64 insensitive to viscosity. At automatic transmission fluid temperatures less than 66 ° C, the flow through the laminar orifice is negligible; therefore, the constant state differential pressure through the fixed orifice is negligible. At fluid temperatures greater than 93 ° C, the exhaust through the laminar orifice 60 increases. In this way, a pressure divider is established and the flow of the feedback pressure through the valve 52 is reduced in this way as the temperature rises above 93 ° C in proportion to the hydraulic resistance values. of the two holes 60, 64.

Regulator Valve of the Converter The regulator valve 86 of the converter clutch controls three modes of operation: the operation of the open convector or the clutch disengaged; the operation of the clutch engaged or the drive locked; and the modulated slider or partial coupling of the clutch 38 of the torque converter. A variable pressure TCC signal is carried on the line 90 to the right-hand end of the valve 86 from a solenoid-operated valve 92 of the converter clutch. The magnitude of this pressure signal is proportional to a predetermined clutch torque capacity and a pulse width modulated PWM service control signal, produced by a microprocessor and applied to the solenoid of valve 92. valve 86 modulates the differential pressure through the friction surface of the clutch 38, in proportion to the imposed TCC pressure and the magnitude of the PWM service cycle. The valve 86 includes a spool 94 movable within the valve bore and bearing four control projections 96, 98, 100 and 102. The valve sleeve 104 is fixed in position in the valve chamber by a retainer, the sleeve holding a booster 106, which is pushed by the feed TCF pressure of the torque converter to the right against the end. on the left hand side of the reel 94. A ventilation hole 108 communicates with the valve chamber and is opened and closed by the control projection 102. A compression spring 110 pushes the spool 94 to the right inside the valve chamber. The line 88 carries the feed pressure of the torque converter to the passage 112 and through the hole 114, towards the bore or chamber of the valve. The passages 112, 118 and 120 connect the line 88 to the valve chamber, in mutually separated positions. The line 40 connects an outlet orifice of the valve 86 with the passage through which the clutch 38 disengages. The line 44 connects the return line from the torque converter directly with the discharge lines 113, 114 of the torque converter and through the lines 116, 119 which are connected to the orifices of the valve 86. The line 46 carries the fluid at the supply pressure of the converter to the torque converter 20, through the valve 86. The torque converter 20 is opened, that is, the bypass clutch 38 is released when the PWM duty cycle supplied to the solenoid of the valve 92 driven by the clutch solenoid of the converter is zero, reducing the in this way the pressure to zero on line 90 and on the right-hand end of spool 94. In this case, the supply pressure of the torque converter operating at the left hand end from spool 106, forces spool 94 towards the right-hand end of the valve chamber. In this position, the valve 86 connects the line 118 with the line 40, thereby pressurizing the space between the cover 28 of the propeller and the friction surface of the clutch 38. The valve 86 connects the line 120 through the orifice 122. with line 46, through which, the hydraulic fluid is supplied to the torsion converter bocel. The fluid at the outlet of the nozzle, carried on line 44, enters the valve chamber through lines 116, 119 and is carried on discharge line 113 of the converter TCX to the oil cooler 126, through of the counter-pressure valve 78 for supercharging consumption. The spool 84 of the valve 78 will have moved towards the left-hand end of its chamber against the effect of the compression spring, due to the presence of the SRPX pressure at the right-hand end of the spool 84, as described in the foregoing with reference to the operation of the valve 52. A displacement valve 200 1-2 connects a source of the regulated line pressure IX with the line 128, when the first gear ratio is selected. A valve 130 for increasing lubrication and latching the converter includes a spool 132, which moves to the left inside the valve chamber due to the effect of the compression spring 134, and a pressing force developed in the shoulder 136 when the press line 128. With valve 130 in this position, fluid to SRP carried on line 54 from valve 52 and through line 138 to lock valve 130 of the converter, is connected through valve 130 with a FLANGING line 140 that connects to the chamber of the regulator valve 86 of the converter in a hole placed between the reels 106 and 94. When the lines 140 and 88 are pressed, there is no pressure differential across the spool 106 and the spool 94 moves towards the right-hand end of the valve chamber due to a pressing force applied to the large pressure area at the left-hand end of the shoulder 102 This action moves the spool 94 to the right to the same position as that described above with respect to the operation of the open torque converter. In this condition, the clutch 38 of the torque converter is disengaged and the torque converter 20 operates in an open condition. In this way the valve 86 provides an independent interlocking force on the large diameter of the projection 102 to ensure that the vehicle can be started or driven in the first gear with the converter open, even when an obstruction is present in a valve orifice. 86, whose obstruction could otherwise prevent the spool 94 from sliding to the right-hand end or from the valve chamber. This interlocking feature also allows the torque to operate in an open condition even when there is a failure of the solenoid 92 or the microprocessor control system causes the pressure in line 90 to be elevated. The low pressure in line 90 would be to be expected during normal operation, as mentioned above. In that case, the SRP pressure operating on a larger projection on the left hand side of the reel 94, overcomes the effect of the pressure present in the line 90 and allows the reel 94 to move to the open condition in the end to the right of the camera. This prevents the loss of motor speed in the reverse gear or driving conditions in the low gear ratio. In order to operate the torque converter 20 in the locked encoder, the clutch 38 is coupled due to the presence of a larger pressure in the torque converter than the pressure in the space between the propeller housing and the surfaces Clutch friction 38. The torque converter operates in the locked condition when the solenoid-operated valve 92 produces a pressure of approximately 3.52 kilograms per square centimeter gauge on the line 90, thereby moving the spool 94 toward the left hand end of the valve chamber. The spool 94 moves towards the left-hand end of the chamber when the UNLOCKING pressure line 140 closes in the valve 130 due to the absence of the pressure of IX from the displacement valve 1-2 and due to the force of larger pressure acting on the right-hand end of the projection 96, compared to the pressing force on the left-hand end of the booster 106 produced by the TCF pressure. With the valve positioned at the left-hand end of the chamber, line 88 is connected directly through lines 118 and through lines 120 and hole 122 with the torsion converter bocel through the line 46. Fluid placed between the case 28 of the impeller and the clutch 38 is discharged into the reservoir through the line 40 and the vent hole 108, thereby producing a differential pressure across the friction surfaces of the clutch 30. , forcing the same towards the locked or hooked condition. The fluid from the torque converter returns through line 44 to line 113, which directs the TCX discharge of the torque converter to the cooler 126 through the valve 78.

Microprocessor Controller Figure 6 shows a microprocessor that is used to control the valve circuits which in turn control the distribution and discharge of drive pressure to the clutches and servo-brakes for transmission. The processor is shown at 170 in Figure 6. As depicted schematically in Figure 6, an air charge temperature sensor 172 is adapted to develop an ambient air temperature that is used by the processor to develop commands sent to the system. of the control valve. The processor also responds to an air conditioning clutch signal from the sensor 174 which indicates whether the air conditioning system is connected or disconnected. An on / off brake switch 176 is activated by the vehicle brakes, and the on / off signal is supplied to the processor. An engine speed sensor 178 measures the speed of the crankshaft. The engine coolant temperature is detected by the temperature sensor 180. The drive scale that is selected by the operator is indicated by the manual lever position sensor 182. A speed sensor 184 of the transmission output arrow provides an indication of the speed of the driven arrow of an output shaft. This speed is related to the vehicle speed signal developed by the sensor 86. An oil temperature signal is supplied from the transmission to the processor via the sensor 188. A throttle position signal is supplied from the engine to the processor via the sensor 190. The control valve circuit includes solenoid-operated displacement valves that receive displacement signals. These are the variable force signals from the processor. They are received by the displacement solenoid 192-195. Sensor inputs, such as motor-related sensor signals indicative of engine coolant temperature, absolute barometric pressure, etc. they are used by the processor to develop more accurate outputs as the load and climate conditions change. Other inputs are based on impeller controls, such as the throttle position of the motor. Still other inputs to the processor are developed by the transmission itself, such as the speed sensor signal of the output shaft, the position signal of the manual lever and the oil temperature signal of the transmission. The processor will develop the appropriate displacement time and conditions for the displacements in the relationship as well as the control of the application and release of the clutch. A line pressure is also developed by the processor to provide an optimum displacement sensation. The processor is an integrated central processor that converts signals, such as signals from the vehicle's speed sensor and a throttle position sensor, engine temperature sensor, turbine speed sensor and manual selector lever , in electrical signals for the solenoid-operated valves 192-196, the solenoid valve for the bypass clutch 92 of the variable-force solenoid converter for the electronic pressure control. The processor receives the signals from the sensor and operates with respect to them in accordance with the programmed control algorithms. The processor includes gates and appropriate driver circuits to supply the operation output of the algorithms to the hydraulic solenoid control valves. The processor 170 includes a central processing unit (CPU); a read-only memory (ROM), wherein the control unit that includes the read / write memory or RAM; and the internal buses between the memory and the arithmetic logic unit of the central processor.

The processor performs the program that is obtained from the memory and provides the appropriate control signals to a valve circuit while the input signal conditioning portions of the processor read the input data and the logical portions of the calculation provide the calculation results to the output drive system under program control. The memory includes both a random access memory (RAM) and a memory that reads only (ROM), the latter storing the information comprising the control logic. The result of the calculations carried out in the input data are stored in the RAM where it can be addressed, erased, rewritten or changed, depending on the operating conditions of the vehicle. The data that is stored in the ROM can displace the program information or the functions in which the two variables, such as the throttle position and the vehicle speed, are related to one another, in accordance with a displacement function. The data may also be in the form of information in a table containing three variables or data, such as a synchronizer value and values for the other two pieces of data or variables.

The control strategy for the transmission is divided into several routines and control modules that are carried out in sequence in a known manner during each background step. The strategy for each module is carried out in addition in a sequential manner, just as the modules themselves are executed in a sequential manner. The different data registers are initialized as an input data of the aforementioned sensors and are input to the input signal conditioning portion of the processor. The information resulting from the admission of the sensor data, together with the information that is stored in the memory and learned from an internal bottom step, is used to carry out the control functions of the displacement solenoid valves, the throttle pressure solenoid valve and the bypass clutch solenoid valve. The modules and submodules are carried out in sequence in each background circuit. Each module or logical portion is independent of the others and carries out a specific function. They are carried out as they are directed separately by a processor pointer. The functions occur after the input signals are received through the input gates and the signal conditioning portions of the processor and after the conditioning of the input signal has occurred. The capacity of the clutches and brakes to transmit the torque depends, of course, on the level of the pressure maintained in the control circuit by the main pressure regulator. This control is different to the TV pressure controls of conventional transmissions that depend on the mechanical throttle valve links to maintain a desired throttle valve pressure to a vacuum diaphragm that is operated by the manifold pressure of engine intake. The TV control in the present design is achieved by a variable force solenoid valve, which responds to a signal developed by the electronic microprocessor. The electronic TV strategy for the processor includes the step of seeking the torque of the motor of a frame and appropriately varying the signal supplied to the variable force solenoid to adjust the transmission capacity of the transmission torque.

Converter Interlock Valve A converter lubrication and interlock increase valve 130 is supplied through line 128 with pressure IX of displacement valve 200 which connects a source of regulated line pressure to the line 128, in accordance with the control pressure from the solenoid valve 195, when operation is required at the first forward gear change. The supercharging pressure SPS is carried on line 144 to an orifice located near the left-hand end of the valve chamber 130. The supercharging pressure is regulated by the supercharging relief valve 79 to approximately 3.56 kilograms per square centimeter gauge and is applied to a control shoulder of the valve 130 which is approximately five times larger than the other control projections formed on the spool 132, where the other pressure signals function to control the position of the spool 132. The pressure of secondary regulated SRP is carried on lines 54 and 138 to valve 130. Valve 130 is also supplied through lines 142, 204 and with the pressure of D321 from a manual valve 202, which connects a source of pressure Line regulated LP on line 24 to line 204, when the manual valve is moved by the operator movement of the scale selector vehicle (PRNDL) to any of the forward driving positions. The absence of pressure from D321 is an indication of the reverse drive operation of the transmission, i.e., the low pressure in line 142 indicates that the vehicle operator has placed the scale selector lever of PRNDL on the R scale. The fluid exit from the valve 130 is carried on the line 146 through the orifice 148 and the filter 152 to the various lubrication circuits 147-150, deviating from a temperature compensated orifice 154 toward which the fluid is taken from the valve 130 through the line 156. The line 140 brings the pressure of UNLOCKING towards a valve orifice 86 positioned between the booster 106 and the projection 102 of the spool 94. The compression spring 134 pushes the spool 132 and the Large control projections on spool 206 to the left, in the valve chamber. An object of the valve 130 is to prohibit the coupling of the clutch 38 for an inappropriate period of time, such as when the forward or reverse couplings are initiated, but nevertheless, to allow engagement of the clutch 38 on all advancement scales and speeds. of low engine when the transmission is running during the second, third, fourth and fifth changes. Essentially, the interlocking valve 130 compares three hydraulic pressure signals D321, IX and SPS and produces a high pressure or low pressure signal on the line 140, which is applied with the regulator valve 86 of the converter, representing the high pressure signal. a UNLOCK control signal. During conditions when the manual selector is in the reverse or neutral parking positions, and the engine speed is at idle speed or at a speed lower than 2,000 revolutions per minute, the pressures of D321, IX and SPS are at low magnitude; therefore, the spool 132 moves towards the left hand end of the valve chamber, thereby opening a connection between the secondary regulation pressure line 138 in the UNLOCKING line 140. The UNLOCKING pressure causes the spool 94 of the converter regulator valve 86 to move to the right-hand end of its valve chamber thereby opening a connection between the power line 88 of the torque converter and the line 40, through which the pressure is applied to the space between the propeller cover and the friction surfaces of the clutch 38. This action disengages the clutch and opens the torque converter. When the transmission is operating within the D-scale at the first change at an idle engine speed or at engine speed less than 2,000 revolutions per minute or at a ratio of the first change that is manually selected with the engine speed less than 2,000 revolutions per minute, the pressure D321 tends to cause the spool 132 to move to the right and the pressure IX tends to move the spool to the left. Therefore, since the pressure D321 and IX are essentially at the same line pressure magnitude and the pressure SPS is low, the position of the spool 132 is determined by the effect of the spring 134, thereby opening the line 138 of SRP to the UNLOCKING line 140, and the clutch 138 is decoupled as described immediately above. With the transmission running on the reverse scale or R with the engine speed above 3,000 revolutions per minute or within the D scale or thruster on the first shift with the engine speed greater than 3,000 revolutions per minute, the pressure of D321 and IX have an essentially equal magnitude and virtually no net effect on the position of the spool 132. But the SPS pressure (of about 3.52 kilograms per square centimeter gauge or greater) operating in the rests 206 moves the spool 132 clockwise against the effect of the spring 134. As the engine speed rises to more than 3,000 revolutions per minute, the SPS pressure increases in order to save energy; therefore, the pressure force related to SPS at the end of the shoulder 206 increases and moves the spool 132 toward the right-hand end of the valve chamber. This action closes the communication between the SRP 138 line and the UNLOCK line 140; therefore, the regulator valve 86 of the converter operates as described above when the UNLOCKING pressure is absent from the left-hand end of the reel 94. With the transmission operating at the first change, either within the manual scale or the driving scale and with a motor speed greater than about 3,000 revolutions per minute, the pressure D321 tends to move the spool 132 to the right and the pressure IX tends to move the spool 132 to the left, canceling in a manner effective, therefore, the pressure force acting in the opposite direction caused by the pressure D321 at the left-hand end of the spool 132. In this case, the pressure SPS works against the effect of the spring 134, moves the spool towards the right-hand end of the valve chamber and closes the SRP line 138 to the UNLOCKING line 140. Therefore, the regulator valve 86 of the converter operates as described above when the UNLOCKING pressure is absent from the left-hand end of the reel 94.

With the transmission running at the second shift until the fifth change in the driving scale with the engine speed above 3000 revolutions per minute, the pressure IX is absent at the right-hand end of the reel 132, the pressure D321 is present at the left-hand end of the spool, and the SPS pressure operates on the shoulders 206 to move the spool 132 towards the right-hand end of the valve chamber, thereby closing the line 138 of pressure SRP opening towards the line 140 of UNLOCKING. When the manual gear selector is on the D scale and the transmission operates at the second to fifth forward speed ratios, with the engine speed within the range of 800 to 1200 revolutions per minute, the SPS and IX pressures are low or absent in the valve 130, but the pressure D321 forces the spool 132 against the spring 134 towards the right-hand end of the valve chamber, thereby closing the connection between the line of SRP 138 and the line 140 of UNLOCKING . In this position, the TC regulating valve 86 operates as described above in the absence of the UNLOCK pressure so that the converter clutch opens or closes according to the pressure control signals on the valve 86. The Unlocking line 140 is discharged through port 160 when spool 132 moves to the right-hand end of its valve chamber. The flow rate for lubricating circuits 147-150 is relatively low at vacuum motor speeds but as the speed of the output shaft of the transmission increases, the lubrication requirement increases. An object of the control strategy is to prevent the interlocking of the torque converter when the lubrication requirement is low. To produce this effect, when the spool 132 is moved to the left, such as when the engine speed and the SPS pressure are low, the flow of the fluid through the line 156 is closed by the spool 132 from a connection with the spool 132. line 146, thereby preventing any increase in lubrication flow through line 146 to lubrication circuits 147 to 150. In this condition, the interlocking of the torque converter is prohibited. However, when the engine speed and SPS pressure increase, the spool 132 moves to the right-hand end of the valve chamber, thereby opening a connection between the lubrication line 156 and line 146. The action increases the flow to the lubrication circuits 147-150. In this condition, the torque converter will operate either in the latched or unlocked mode, depending on the effect of the various pressure control signals on the valve 86, but with the unlatching pressure discharged to the sump.

Clutch Capacity Pressure Regulator The solenoid-driven line pressure valve 25 produces a line pressure control LPC pressure signal, preferably in the form of several sudden changes in magnitude or alternatively as a magnitude that increases linearly carried on line 210 to the left-hand end of clutch capacity pressure regulator valve CCPR. The LPC is regulated by applying a variable voltage to the solenoid of the valve 25, a signal produced as an output by the microprocessor 170, in response to the result of a control algorithm carried out by the microprocessor. The pressure D321, a control pressure signal, is carried on the line 204 to the differential area of the control projections 214, 216, and produces a pressing force tending to move the spool 218 counterclockwise against the effect of the spring 220. The fluid in SRP is carried on line 222 to valve 212, and on line 224 to solenoid-operated line pressure valve 25.

The line pressure is brought to the valve 212 through the line 226 towards a hole that is opened and closed by the ledge 228 towards the SPS excess relief line 230 which is connected through the valve 52, the line 76, the supercharging relief valve 79 and the nozzle 24, with the suction side of the pump 22. The check valve 231 alternately opens a connection between the SRP line 222 and the line 226 when the spool 218 and the highlight 28 move to the right inside the valve chamber, or close that connection when the line pressure exceeds the magnitude of the SRP. During operation, when the vehicle operator moves the scale selector to the driving scale from the neutral or reverse scales, several friction elements, possibly from 1 to 3 clutches or hydraulically operated brakes, must be filled and operated quickly at approximately pressures. 2.81 kilograms per square centimeter gauge in order to place the clutch elements to complete the change of the gear ratio in approximately 250 to 500 milliseconds. As the friction elements are filled and operated, the line pressure decreases due to the high flow requirement; therefore, the spool 218 moves towards the right-hand end of the valve chamber because the line pressure fed back toward the end of the spool is lower than the effect of the other forces acting on the spool. valve, including spring force 220. When this occurs, valve 212 is stopped by releasing line pressure by closing the connection between lines 226 and 230 by moving shoulder 228 through the corresponding holes. Then, virtually all of the flow produced by the pump 22 is directed to the friction elements which include a forward clutch, a reverse-clutch, an intermediate clutch, a direct clutch, and an overdrive clutch. However, the friction elements require more volume than can be supplied from the pump 22 so that the magnitude of the line pressure continues to decrease enough for the forces acting on the valve spool 218 to be insufficient to prevent the spring 220 moves the spool 218 entirely towards the right-hand end of the valve chamber. With the valve positioned in this manner, the boss 228 continues to close the connection between the lines 226 and 230, but opens a connection between the SRP line 222 and the line 226 through the check valve 231. After this connection is opened, the flow demand of the friction element is connected to the output of the pump 16 which produces a high flow rate. In this way, the flow produced by the pumps 16 and 22 is combined to supply the friction elements. As a consequence, of the SRP that is being supplied to the friction elements, the magnitude of the SRP pressure decreases, thereby allowing the spool 56 of the secondary regulated pressure valve 52 to move towards the right end of the chamber of the valve to close the connection between lines 54 and 88 through which is supplied to clutch 38 torque converter. This action decreases the flow rate of fluid carried on line 88 through valve 86 and line 40 into the space between the thruster housing and clutch 38. As the pressure on the friction elements of Inlet, the line pressure rises and the spool 214 moves to the left inside its valve chamber, first closing the connection between the lines 226 and 222 so that the flow rate from the pump 16 is then supplied to the regulator valve 86 of the torque converter through lines 54, 82 and 88. Eventually, as the pressure in the input friction elements and line pressure rise sufficiently high, the spool 214 moves towards the left hand end of the valve chamber until the shoulder 222 opens a connection between line 226 and 230 allowing excessive flow to be released and supplied to the inlet of the valve. bomb 22 Solenoid Feed Pressure The solenoid feed pressure SF is regulated by valve 232, which balances the pressure forces due to SRP on line 236 against the force of spring 234. The solenoid feed pressure, fed again and applied to differential areas in the valve spool through the hole 238, a fixed hole insensitive to viscosity, develops a force in opposition to that of the spring 234. A temperature compensated laminar orifice formed in the annular space between the shoulder 244 and the piercing 240 of the valve, connects the vent hole 242 and the orifice 238. A relatively low fluid temperature, flowing through the laminar orifice is small and the flow through the fixed orifice 238 is negligible. A high fluid temperature, which escapes through the laminar orifice, increases. As the temperature rises, the flow of the feedback pressure through the valve 232 is reduced in proportion to the hydraulic resistance of the fixed hole 238 and the laminar orifice.

Lubrication Circuit Power Flow Control Valve When the transmission is operating within the parking, reverse, neutral and 1 scales, the flow rate of the fluid to the lubrication circuits 147-150 is determined by the hole 250 of sharp edges and the flow control valve 248. That valve includes a spool having control projections 252, 254; a compression spring 256; and an exit orifice that opens and closes by projection 254. A first pressure signal LBF, detected on the upstream side of the orifice 250, acts on a left hand side surface of the shoulder 254, tending to move the reel to the right thus closing a connection between lines 236 and 156. The second signal, detected on the downstream side of the hole 250, acts on a surface on the right-hand side of the projection 252, tending to move the valve spool to the left, thereby opening a connection between lines 156 and 236. Spring 256 pushes the valve spool to the left, also tending to open the valve, which is normally open. The valve 248 begins to throttle or regulate the fluid, i.e. move to the right to close the line marked LBF, when the net force on the valve spool resulting from the differential pressure through the orifice 250 and the spring force are balanced . The valve 248 moves to the right in response to the pressure forces and the force of the spring 256. Therefore, the valve maintains a constant differential pressure through the orifice 250 and a constant flow through that orifice, regardless of the supply pressure or the load pressure of the lubrication system. In this way, valve 248 is compensated by pressure. When the engine speed increases to approximately 2000 revolutions per minute, one mode of the energy pump shifts to an overload. The supercharging pressure SPS carried through line 144, develops a pressure force on the projection placed on the right-hand end of the valve spool, in whose projection the force of the spring 256 is applied. The force of the pressure SPS it is added to the force of the spring, thus increasing the differential pressure through the orifice 250 which is required to balance the valve 248. Therefore, the flow rate through the orifice 250 increases in proportion to the increased differential pressure. through hole 250. As the engine speed increases above the supercharging threshold pressure, towards its maximum magnitude, the SPS pressure and the lubricating fluid flow control differential pressure increase exponentially. Accordingly, the lubrication fluid flow increases exponentially. An additional circuit directs the fluid to the lubrication circuits 147-150 through a laminar orifice 260. This fluid enters the lubrication system downstream of the sharp-edged hole 250, but the flow is not compensated by the flow control valve 248.; therefore, the flow through the orifice 260 is added to the flow through the orifice 250. The effect of this is to increase the volume of the fluid to the lubrication circuits 147-150 during high temperature operating conditions, when the fluid The hydraulic fluid flows freely through the laminar orifice 260. The increase in the flow to the lubrication circuits is proportional to the temperature of the hydraulic fluid and results in a lubrication fluid flow rate that increases exponentially as the engine speed increases, similar to that described in FIG. the foregoing with respect to operations at normal or low temperature. During the operation of the transmission at the second to fifth speed scales, the spool 132 of the relay valve 130 of the lubrication increase / interlock moves to the right hand of its chamber, in accordance with the hydraulic logic detailed in which precedes in the subsection called "Converter Interlock Valve". When the spool 132 of the valve is positioned at the right-hand end of its chamber, the line 156 is connected through the valve 130 with the line 146 through a hole 148 with sharp edges. With the system positioned in this manner, the line 140 and the hole 148 are placed in parallel with the line 150 and the hole 250, between the outlet of the valve 248 and the lubrication circuits 147-150. The orifice 148 then connects to the outlet of the valve 248, as well as the orifice 250. This arrangement effectively increases the size of the orifice 250, thereby increasing or increasing the volume of fluid flow to the lubrication system.

Temperature Compensated Cooler Bypass The cooler bypass valve of Figure 6 can be replaced by a corresponding valve of Figure IB, to provide temperature compensated operation. Referring now to Figures IB and 6, the fluid exiting the torque converter carried on line 262 from valve 79, whose spool is located at the left end of its chamber due to the effect of the supply pressure of the The converter passes either through the coolant bypass valve 264 to the lubrication circuits 147-150 enters the cooler 126 or is directed partially to the cooler and partly to the valve 264 depending on the condition of that valve. The line 262 applies pressure to a feedback rib 262 formed on the spool 268, and carries the fluid directly to the cooler 126 when the valve 264 is closed. The valve chamber is connected through a hole 270 with sharp edges to the valve. 274 oil drain, where the pressure is maintained at an essentially atmospheric pressure. A laminar orifice 284, formed in the annular space between the shoulder 276 and the internal diameter of the valve body, allows fluid to pass through the valve chamber towards the orifice 270 and the drain 274, when the viscosity of the valve Hydraulic fluid is relatively low, but prevents the flow of hydraulic fluid when its viscosity is relatively high. A control projection 278 alternately opens and closes a connection between line 262 and line 280, which is connected through hole 260 with the downstream side of hole 250 and with the upstream side of that hole, through of the retention variable 282. The position of the spool 268 within the valve chamber is controlled by the force balance established by the feedback pressure operating at the left hand end of the control shoulder 266, the force of the spring 284 acting on the hand side of the spool, and the back pressure developed within the spring chamber through the viscosity-sensitive hydraulic pressure divider comprising the laminar orifice and the sharp-edged hole 270. This pressure divider is created by the series arrangement of the laminar orifice 286 which is sensitive to the viscosity, and the fixed orifice 270, which is insensitive to viscosity. During a cold temperature operation, such as when the temperature of the transmission fluid is less than 38 ° C, the flowability of the laminar orifice 284 is small compared to that of the fixed orifice; therefore, the spring chamber is discharged. The pressure acting on the left-hand end of the shoulder 266 overcomes the force of the spring and the spool 268 to the left to the position of the bypass mode where the valve 264 directs essentially all of the fluid flow in the line 262 to the Lubrication circuit through line 280, effectively deriving the oil cooler and ensuring an adequate fluid flow to the lubrication circuit. Without the transmission of heat from the transmission fluid to the environment through the operation of the oil cooler, the operating temperature of the transmission increases, the drag by viscosity decreases and the parasitic losses decrease. During a high temperature operation, such as when the temperature of the fluid is greater than 82 ° C, the spool 268 moves towards the right-hand end of the valve chamber due to the presence of the back pressure operating on the face of the valve. left end of the control projection 276. When the temperature is relatively high, the flowability through the laminar orifice 294 is high relative to that of the fixed orifice 270; therefore, the back pressure in the spring chamber operating on the shoulder 276 increases. This pressure creates a force that is added to the force of the spring 284 and helps move the spool to the cooling mode position at the right-hand end of the chamber. In this position, essentially all the flow in line 262 is directed through the oil cooler 126, thereby maximizing the transmission of heat from the oil to the environment.

At temperatures between 38 ° C and 82 ° C, or some other predetermined calibration scale, the valve modulates the bypass flow of the cooler as a function of oil viscosity. This viscosity has a fixed relation to the temperature, the effective control highlight areas, the spring force and the orifice sizes will determine the minimum and maximum points of the calibration temperature scale. In this way, the valve maintains the temperature of the transmission oil within an optimum range for minimum parasitic loss and maximum fluid service life. At fluid temperatures between the minimum and maximum points of the calibration scale, the valve will settle in a certain intermediate position directing a certain amount of fluid to the cooler and diverting the rest. Although the form of the invention shown and described herein constitutes the preferred embodiment of the invention, it is not intended to illustrate all possible forms of the invention. The words used here are words of description rather than limitation. Various changes may be made in the form of the invention without departing from the spirit and scope of the invention as disclosed.

Claims (22)

CLAIMS:

1. A system for controlling the flow of fluid in a hydraulic circuit of an automatic transmission, comprising: a fluid source having variable temperature; a cooler communicating with the fluid source, adapted to transmit heat between the fluid and the fluid source to a second fluid; a circuit; and a bypass valve for supplying fluid from the fluid source to the circuit and the cooler, in accordance with the fluid temperature. The system according to claim 1, wherein: the bypass valve directs the fluid from the fluid source to the circuit; and the cooler is adapted to transmit heat from the fluid to the ambient air passing through the cooler, the flow resistance of the fluid through the cooler is high with respect to the resistance to flow of the fluid through the bypass valve. 3. The system according to claim 1, wherein the bypass valve directs the fluid from the fluid source to the circuit when the fluid temperature is relatively low and directs the fluid from the fluid source to the cooler when the fluid is relatively high. The system according to claim 3, wherein the bypass valve directs a first portion of the fluid from the fluid source to the circuit and a second portion of the fluid from the source of fluid to the cooler when the fluid temperature It is at a predetermined temperature scale. The system according to claim 1, wherein the bypass valve comprises: a reel movable in a chamber, the chamber communicates with the fluid source, the cooler and the circuit; a first projection formed on the reel, the pressure of the fluid source at the first projection pushes the reel to open a connection between the fluid source and the circuit; a spring that pushes the spool to close a connection between the fluid source and the circuit. The system according to claim 1, wherein * the bypass valve comprises: a fluid sump; a movable reel in a chamber, the chamber communicates with the fluid source, the cooler and the circuit; a first projection formed on the reel, the pressure of the fluid source at the first projection pushes the reel to open a connection between the fluid source and the circuit; a spring that pushes the spool to close a connection between the fluid source and the circuit; a first orifice adapted to produce a fluid flow rate therethrough that is relatively independent of the fluid temperature; a second orifice adapted to produce a flow regime of the fluid therethrough, which depends relatively on the temperature of the fluid, placed in series with the first hole between the chamber and the drain; and a second projection spaced apart from the first projection along the spool, the fluid pressure between the first orifice and the second orifice is applied to the second projection that pushes the reel to close the connection. The system according to claim 6, wherein the bypass valve comprises: an outlet orifice communicating with the circuit; a surface of the first projection communicating with the fluid source, a surface of the second control projection communicating with the fluid between the first port and the second port and which is placed on an opposite axial side of the second port from the location of the surface of the first control projection, the position of the reel in the chamber is determined by the pressure forces developed on the surfaces of the first and second control projections, and a spring force applied to the reel, opening and closing the reel a Connection between the camera and the exit hole as the spool moves. The system according to claim 7, wherein the spool of the flow control valve further comprises a third control shoulder adapted to open and close a connection between the chamber and the outlet orifice. 9. A system for controlling fluid flow in a hydraulic circuit, of an automatic transmission comprising: a fluid source having variable viscosity; a cooler communicating with the fluid source, adapted to transmit heat from the fluid to the fluid source to the second fluid; a circuit; and a bypass valve for supplying fluid from the fluid source to the circuit and to the cooler, in accordance with the viscosity of the fluid. The system according to claim 9: wherein: the bypass valve directs the fluid from the fluid source to the circuit; and the cooler is adapted to transmit heat from the fluid to the ambient air passing through the cooler, the resistance to the flow of the fluid through the cooler being high relative to the resistance of the fluid flow through the bypass valve. The system according to claim 9, wherein the bypass valve directs the fluid from the fluid source to the circuit when the fluid temperature is relatively low and directs the fluid from the fluid source to the cooler when the fluid is relatively high. The system according to claim 9, wherein the bypass valve directs a first portion of the fluid from the fluid source to the circuit, and a second portion of fluid from the source of fluid to the cooler, when the fluid temperature It is within a scale of predetermined viscosity. The system according to claim 9, wherein the bypass valve comprises: a reel movable in a chamber, the chamber communicates with the fluid source, the cooler and the circuit, a first protrusion formed in the reel, the pressure from the fluid source in the first projection pushes the reel to open a connection between the fluid source and the circuit; a spring that pushes the spool to close a connection between the fluid source and the circuit. The system according to claim 9, wherein the bypass valve comprises: a fluid sump; a movable reel in a chamber, the chamber communicates with the fluid source, the cooler and the circuit; a first projection formed on the reel, the pressure of the fluid source at the first projection pushes the reel to open a connection between the fluid source and the circuit; a spring that pushes the spool to close a connection between the fluid source and the circuit; a first orifice adapted to produce a fluid flow rate therethrough that is relatively independent of fluid viscosity; a second orifice adapted to produce a fluid flow rate therethrough which is relatively dependent on the viscosity of the fluid, which is placed in parallel with the first hole between the chamber and the drain; and a second shoulder separated from the first shoulder along the spool, the fluid pressure between the first hole and the second hole applied to the second shoulder pushes the reel to close the connection. The system according to claim 14, wherein the bypass valve comprises: an outlet orifice communicating with the circuit; a surface of the first projection communicates with the fluid source, a surface of the second control projection communicates with the fluid between the first orifice and the second orifice and is placed on an axial side opposite the second projection from the location of the surface of the first control projection, the position of the reel in the chamber is determined by pressure forces developed on the surfaces of the first and second control projections and a spring force applied to the reel, the reel opens and closes a connection between the camera and the exit hole as the reel moves. 16. The system according to claim 15, wherein the spool of the flow control valve further comprises a third control shoulder adapted to open and close a connection between the chamber and the outlet orifice. 17. A bypass valve for supplying fluid from the fluid source to a hydraulic circuit comprising: a first and second portions of the hydraulic circuit; a movable reel in the chamber, the chamber communicates with the fluid source and the first and second portions of the circuit; a first projection formed on the reel, the pressure of the fluid source in the first projection pushes the reel to open a connection between the fluid source and the first portion of the circuit; a spring that pushes the spool to close a connection between the fluid source and the first portion of the circuit. 18. The bypass valve according to claim 17, comprising: a fluid sump; a movable reel in a chamber, the chamber communicates with the fluid source and the first and second portions of the circuit; a first projection formed on the reel, the pressure of the fluid source at the first projection pushes the reel to open a connection between the fluid source and the first portion of the circuit; a spring that pushes the spool to close a connection between the fluid source and the first portion of the circuit; a first orifice adapted to produce a fluid flow rate therethrough that is relatively independent of the fluid temperature; a second orifice adapted to produce a rate of fluid flow therethrough that depends relatively on the temperature of the fluid, placed in parallel with the first hole between the chamber and the drain; and a second projection spaced apart from the first projection along the spool; the fluid pressure between the first hole and the second hole that is applied to the second protrusion pushes the reel to close the connection. 19. The bypass valve according to claim 18, comprising: a fluid sump; a movable reel in a chamber, the chamber communicates with the fluid source and the first and second portions of the circuit; a first projection formed on the reel, the pressure of the fluid source at the first projection pushes the reel to open a connection between the fluid source and the first portion of the circuit; a spring that pushes the spool to close a connection between the fluid source and the first portion of the circuit; a first orifice adapted to produce a fluid flow rate therethrough that is relatively independent of fluid viscosity; a second orifice adapted to produce a fluid flow rate therethrough that depends relatively on the viscosity of the fluid, which is placed in parallel with the first hole between the chamber and the drain; and a second projection detached from the first projection along the reel the fluid pressure between the first hole and the second orifice is applied to the second projection pushes the reel to close the connection. 20. The bypass valve according to claim 19, further comprising: an outlet orifice communicating with the circuit; a surface of the first projection communicates with the fluid source, a surface of the second control projection communicates with the fluid between the first orifice and the second orifice and is placed on an opposite axial side of the second projection from the location of the surface of the first control projection, the position of the reel in the chamber is determined by the pressure forces developed on the surfaces of the first and second control projections, and a spring force applied to the reel, the spring opens and closes a connection between the camera and the exit hole as the reel moves. The system according to claim 17, wherein the bypass valve directs the fluid from the fluid source to the first portion of the circuit when the fluid temperature is relatively low and directs the fluid from the fluid source to the fluid source. second portion of the circuit, when the temperature of the fluid is relatively high. The system according to claim 17, wherein the bypass valve directs a first portion of the fluid from the fluid source to the first circuit portion, and the second portion of the fluid from the fluid source to the second portion of the circuit when the temperature of the fluid is within a predetermined temperature range. SUMMARY OF THE INVENTION A cooler bypass valve, placed in a hydraulic circuit between the discharge side of a torsion and lubrication torque converter circuit, includes a valve spool pushed by the feedback pressure acting in opposition to the force of a compression spring to a position of Bypass cooling mode where the flow of the converter discharge fluid is connected to the lubrication circuit by deviating from the oil cooler. The bypass valve includes a viscosity-sensitive pressure divider that includes a serial arrangement of a laminar orifice and a sharp-edged hole placed between the converter discharge and the oil drain. As the temperature of the oil increases, the flow through the laminar orifice produces a control pressure as opposed to the feedback pressure and is added to the spring force, which combine to move the valve spool to a position of cooling mode where essentially all the converter discharge is directed through the oil cooler. On a predetermined temperature scale, the valve maintains a position where the portion of the converter discharge is directed towards the oil cooler, and the residue towards the lubrication circuit.