US3719107A - Two-stage throttle valve for an automatic transmission - Google Patents

Abstract

A THROTTLE VALVE SYSTEM FOR AN AUTOMATIC POWER TRANSMISSION MECHANISM IN AN AUTOMOTIVE VEHICLE DRIVELINE HAVING AN INTERNAL COMBUSTION ENGINE WITH AN EXHAUST GAS RECIRCULATION CONTROL, SAID THROTTLE VALVE SYSTEM BEING ADAPTED TO PRODUCE A PRESSURE SIGNAL THAT IS RELATED FUNCTIONALLY TO THE MAGNITUDE OF THE ENGINE TORQUE AND INCLUDING A DIAPHRAGM ACTUATOR THAT IS SUBJECTED TO ENGINE INTAKE MANIFOLD PRESSURE AND A SECONDARY THROTTLE VALVE THAT

MODIFIES THE VALVE ACTUATING FORCES OF THE DIAPHRAGM ACTUATOR TO COMPENSATE FOR THE EFFECT OF THE EXHAUST GAS RECIRCULATION CONTROL SYSTEM ON THE ENGINE INTAKE MANIFOLD, THEREBY TENDING TO MAINTAIN THE DESIRED RLATIONSHIP BETWEEN ENGINE TORQUE AND THE OUTPUT PRESSURE SIGNAL OF THE THROTTLE VALVE SYSTEM.

Description

March 6, 1973 E, F, JAGDMANN ET AL 3,719,107

TWO-STAGE THROTTLE VALVE FOR AN AUTOMATIC TRANSMISSION 3 Sheets-Sheet 1 Filed Nov. 2. 1971 March 6. 1973 E, F, AG MANN Em 3,719,107

TWO-STAGE THROTTLE VALVE FOR AN AUTOMATIC TRANSMISSION March 6, 1973 E F. JAGDMANN ,iT AL 3,719,107

TWO-STAGE THROTTLE VALVE FOR AN AUTOMATIC TRANSMISSION United "States Patent O F 3 719,107 TWO-STAGE THROTTLE VALVE FOR AN AUTOMATIC TRANSMISSION Edwin F. Jagdmann, Northville, and George E. Lemieux,

Livonia, Mich., assignors to Ford Motor Company,

Dearborn, Mich.

Filed Nov. 2, 1971, Ser. No. 195,030 Int. Cl. B601; 21/02 US. Cl. 74843 4 Claims ABSTRACT OF THE DISCLOSURE A throttle valve system for an automatic power transmission mechanism in an automotive vehicle driveline having an internal combustion engine with an exhaust gas recirculation control, said throttle valve system being adapted to produce a pressure signal that is related func tionally to the magnitude of the engine torque and including a diaphragm actuator that is subjected to engine intake manifold pressure and a secondary throttle valve that modifies the valve actuating forces of the diaphragm actuator to compensate for the effect of the exhaust gas recirculation control system on the engine intake manifold, thereby tending to maintain the desired relationship between engine torque and the output pressure signal of the throttle valve system.

GENERAL DESCRIPTION OF THE INVENTION The improved throttle valve system of our invention is adapted to be used in the driveline of an automotive vehicle having an internal combustion engine with an airfuel mixture intake manifold controlled by a carburetor throttle valve. In conventional control circuits for transmission in such drivelines it is common practice to use a transmission throttle valve having a diaphragm actuator that is subjected to engine intake manifold pressure. The manifold pressure forces acting on the diaphragm of the actuator are transmitted to a throttle pressure modulator valve element. Control pressure from an engine driven pump is regulated and the regulated pressure is distributed to the throttle valve system where it is modulated by the throttle valve element. Upon an increase in the engine intake manifold pressure, which would correspond to an increase in engine torque, the output signal of the throttle valve is increased. This signal is used to initiate speed ratio changes. It is used also to vary the output pressure of the main regulator valve for the circuit so that a high regulated control pressure will be maintained by the regulator valve system when the engine manifold presure is high. It will reduce the control pressure when the engine is operated at low torque, which would correspond to a reduced manifold pressure.

In certain exhaust gas emission control devices used with internal combustion engines, a portion of the exhaust gases under specific operating conditions is recirculated to the engine intake manifold system where it is cycled a second time through the combustion process. This reduces the engine manifold vacuum, but this loss in vacuum is not accompanied by the usual increase in engine torque. When compensation then is made for the effect of the exhaust gas recirculation controls, the output pressure signal from the transmission throttle valve system will produce a changed shift timing signal on the shift valves 3,719,107 Patented Mar. 6, 1973 of the control circuit. It will also cause an undesirable increase in circuit pressure. These influences cause retarded ratio upshifts during the acceleration period of the vehicle and relatively rough or harsh ratio changes due to the excessive control pressure that is made available to the pressure operated servos for the transmission clutches and brakes.

The improvement of our invention compensates for the effect of the exhaust gas recirculation controls on the output pressure signal of the throttle valve system. This is accomplished by providing in the throttle valve system a secondary valve element that acts upon the primary pressure modulating valve element of the throttle valve system with a precalibrated force. Provision is made for establishing fluid communication between the high pressure portion of the 'valve system and the secondary valve element when the exhaust gas recirculation controls are triggered. This changes the net forces acting on the secondary valve and hence the primary throttle valve actuating forces are also changed, thereby causing a different calibration for the throttle valve system during those instances when the exhaust gas recirculation controls are effective. The optimum ratio shift performance thus is maintained for the entire range of operating conditions of the vehicle engine.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING FIG. 1 shows in schematic form a transmission gearing arrangement with clutches and brakes adapted to be controlled by fluid pressure operated servos which form a part of our improved control system.

FIG. 2 is a schematic representation of a control valve system embodying the improvements of our invention for use with a transmission mechanism of the type shown in FIG. 1.

FIG. 3 is a subassembly view of the throttle valve system included in the schematic circuit of FIG. 2.

FIG. 4 is a graph showing the relationship between manifold pressure and the output pressure signal of the throttle valve system when the exhaust gas recirculation control is effective as well as when it is ineffective.

PARTICULAR DESCRIPTION OF THE INVENTION In FIG. 2 numeral 10 designates the crankshaft of an internal combustion engine 12 in an automotive vehicle driveline. The engine includes a throttle valve controlled carburetor 14, an air-fuel mixture intake manifold 16 and a combustion gas exhaust gas manifold 18. An exhaust gas recirculation control valve 20 is connected at one side to a control pressure line 22. It includes a solenoid actuated shift valve which is adapted to control distribution of pressure from line 22 to line 24, the latter extending to throttle valve system 26. The solenoid actuated shift valve includes a circuit having an electric switch 28, which is actuated by engine intake manifold pressure variations. Switch 28 is connected to the intake manifold through passage 30.

Crankshaft 10 is connected to the impeller 32 of a hydrokinetic torque converter 34. When the switch 28 is actuated, the exhaust gas recirculation control 20 is activated and this in turn activates the solenoid actuated shift valve Which is identified in FIG. 3 by reference character 36.

Converter 34, in addition to the impeller 32, includes a bladed turbine 38 and a bladed stator 40. The impeller, the stator and the turbine are arranged in toroidal fluid flow relationship in the usual fashion. Turbine 38 is connected drivably to turbine shaft 42, which serves as a power input shaft for the gearing illustrated schematically in FIG. 1.

A positive displacement pump 44 is connected drivably to the impeller 32. The output pressure passage for the pump is in communication with passage 22.

The transmission gearing, shown in FIG. 1, includes a first simple planetary gear unit 46 and a second simple planetary gear unit 48. Direct-and-reverse clutch 50 may be engaged and released by a fluid pressure operated clutch servo 52 to establish and diseastablish a driving connection between driven shaft 42 and drive shell 54. Shell 54 is connected directly to sun gear 56, which is common to both of the simple planetary gear units 46 and 48. Gear unit 46 includes, in addition to the sun gear 56, a ring gear 58, a carrier 60 and planet pinions 62 journalled rotatably on the carrier 60 in meshing engagement with the ring gear '58 and sun gear 56. Carrier 60 is connected drivably to power output shaft 64.

Gear unit 48 includes, in addition to the sun gear 56, a ring gear 66, carrier 68 and planet pinions 70, the latter being journalled on the carrier 68 in meshing engagement with ring gear 66 and sun gear 56. Ring gear 66 is connected directly to the power output shaft 64. Carrier 68 is connected to or partly defines a brake drum about which is positioned a low-and-reverse brake band 72. Carrier 68 is adapted to be anchored to the transmission housing 74 through an overrunning brake 76 during operation in the low speed ratio in the automatic drive range.

A forward drive clutch 78 is adapted to establish and disestablish a driving connection between shaft 42 and ring gear 58. Clutch 78 is actuated by a fluid pressure operated servo 80. The clutch 50 defines a brake drum about which is positioned an intermediate speed ratio brake band 82. Brake band 82 is applied and released by fluid pressure operated servo 84. Brake band 72 is applied and released by a fluid pressure operated reverseand-low servo 86.

A compound governor valve assembly 88 is connected drivably to the power output shaft 72. Shaft 72 is connected drivably to road wheels 90 through a suitable driveshaft and difierential-and-axle assembly.

The gearing mechanism of FIG. 1 is capable of establishing three forward drive speed ratios and a single reverse speed ratio. To establish the lowest forward drive speed ratio, the forward clutch 78 is applied. It remains applied during operation in each of the forward driving ratios. Clutch 78 then connects the driven shaft 42 to the ring gear 58. The resistance to rotation offered by the carrier 60 causes a reverse driving torque on the sun gear 56. The torque then is reversed again as it passes through and is multiplied by gear unit 48. Carrier 68 acts as a reaction member since reaction torque on the carrier is transferred through the overrunning brake 76 to the stationary housing. A positive forward driving torque on the ring gear 66 complements the forward driving torque on the carrier 60.

To establish intermediate speed ratio operation, intermediate speed ratio brake band 82 is applied while the clutch 78 remains applied. This anchors the sun gear 56. With the ring gear 58 acting as a torque input element of the gearing, sun gear 56 acts as a reaction member and carrier 60 acts as a driven member. Output shaft 64 then is driven at an increased speed ratio greater than the lowest speed ratio but less than unity. overrunning brake 76 freewheels under these conditions.

Direct drive, high speed ratio operation is achieved by engaging simultaneously both clutches T8 and 50 and releasing both brakes. All of the elements of the gearing then are locked together for rotation in unison.

Brake band 72 is engaged during continuous low speed ratio'operation and during reverse drive. It is capable of transferring reaction torque under these driving conditions from the carrier 68 to the housing.

Direct and reverse drive clutch 50 is applied and brake band 72 is applied. Clutch 78 is released and brake band 82 is released. Torque from shaft 42 then is distributed through the clutch 50 to the sun gear 56. With the carrier 68 acting as a reaction member, ring gear 66 is driven in a reverse direction. The reverse motion of ring gear 66 is transferred to the output shaft 64.

The actuation and release of the clutches and the brakes is achieved by the control system shown in FIG. 2. The clutches and brakes are applied by fluid pressure operated servos which receive control pressure from pump 30. This pressure is regulated by a main pressure regulator valve 92. The regulated line pressure is distributed from the regulator valve to a driver-operated manual valve 94. This valve can be moved by the operator to any one of several drive range positions. These are indicated by the symbols R, N, D, 2 and 1, which respectively identify the reverse position, the neutral position, the automatic drive range position, intermediate speed ratio drive position and low speed ratio drive position. When the manual valve is shifted to the R position or to the 1 position, passage 96, extending from the output side of the main regulator valve 92, is connected to passage 98. This in turn extends to the reverseand-low servo 86.

Manual valve 94 connects passage 96 with passage 100 whenever it assumes one of the forward driving range positions. This passage 100 extends in turn to direct-andreverse clutch 50.

When the manual valve is shifted to the 2 position, passage 96 is connected to passage 102, which extends to the apply side of the intermediate servo 84. This servo includes a piston 10-4 situated in a cylinder 106. It defines a pressure chamber on either side of the cylinder. When both pressure chambers are pressurized, the brake is released.

If the left-hand apply pressure chamber is pressurized, the brake is applied. Thus, during automatic operation of the control valve system, the intermediate speed ratio brake band may be applied and released by selectively pressurizing and exhausting the release pressure chamber of the servo 84. Pressure is distributed to the release side of the servo 84 through a 1-2 shift valve 108. This valve receives control pressure from the manual valve 94 through passage 110. It is triggered to the upshift position by the force of governor pressure distributed to one side of the shift valve through passage 110, which in turn extends to the speed signal pressure source which is the governor 8 8. The upshift signal from the governor 88 is opposed by a downshift throttle valve signal from the TV boost valve 112. Valve 112 is applied when an input signal through passage 114 extends to throttle valve assembly 26. This assembly will be described with reference to FIG. 3.

Valve 112 receives the output signal from 'valve system 26 to modulate control pressure distributed to it from passage 22. This amplifies the pressure signal that is an indicator of engine torque so that engine manifold pressure may be relied upon as an accurate indicator of engine torque demand.

Line pressure is distributed also to 2-3 shift valve 116 through passage 118, the latter communicating with the manual valve. Passage 118 is pressurized during operation in the automatic drive range position D. Governor pressure from passage acts on one side of the 23 shift valve 116, and the output signal of the TV boost valve acts in the opposite direction. The signal is distributed to the 2-3 shift valve through pass-age 120. When an upshift occurs in response to opposing influences of the pressures in passages 120 and 110, pressure is distributed from passage 118 to passage 122, which extends to direct-and-reverse clutch 50.

The output signal for valve 26 is distributed also to cutback valve 124 through passage 114. One side of valve 124 is subjected to the governor pressure in passage 110. After a predetermined output speed is achieved, valve 124 is triggered by the governor pressure to distribute pressure from passage 114 to passage 126, which in turn extends to the main regulator valve. The cutback valve 124, by selectively pressurizing and exhausting passage 126, causes the main regulator valve 92 to regulate at a higher pressure at lower vehicle speeds-and at a relatively low pressure at higher vehicle speeds for any given throttle pressure.

It is apparent from FIG. 2 that the output signal of valve system 26 is used both for controlling the shift points during automatic speed ratio changes as well as the circuit pressure level.

FIG. 3 shows in more detail the characteristics of the valve system 26. It includes a secondary valve 128 and a primary valve 130. The primary valve 130 includes a pair of spaced valve lands 132 and 134. These are slidably situated in valve chamber 136 which is formed with ports that register with the lands. A first port 138 communicates with the regulated line pressure passage 96. A third valve land 140 of relatively large diameter defines with the land 132 a differential area that communicates with port 142. This may be pressurized with line pressure that is distributed to passage 100 during reverse drive operation thereby providing for an augmentation in the magnitude of the output pressure signal of valve system 26 during reverse drive which produces an augmentation of the main regulator valve pressure.

Passage 114 communicates with the output pressure port of the valve 130, which receives modulated pressure from the valve 130. This modulated pressure is distributed to the left-hand side of the land 140 to provide the necessary pressure feedback. The force acting on the valve 130 to produce modulation is provided by actuator spring 144 located in actuator housing 146. A flexible diaphragm 148 is located in the housing 146, and it cooperates with the housing 146 to define a manifold pressure chamber 150. A force transmitting stem 152 connects mechanically the valve 130 with the diaphragm 148. The left-hand side of the diaphragm 148 is exposed to atmospheric pressure.

A vacuum pressure fitting 154 establishes communication between chamber 150 and manifold pressure passage 156 shown in FIG. 1. Passage 156 extends to the engine intake manifold at a location on the downstream side of the carburetor throttle illustrated schematically in FIG. 1 by reference character 158.

The secondary valve 128 includes a pair of valve lands 160 and 162. These define a differential area that is in fluid communication with passage 164. That area is pressurized with line pressure, which is distributed to it through solenoid actuated shift valve 166 when valve 166 is deactuated. It is deactivated whenever the EGR system is deactivated. If the EGR system is effective, the valve 166 connects passage 164 to the exhaust passage illustrated schematically at 168.

The right-hand side of the land 162 is exposed to the feedback pressure in passage 114. This pressure complements the pressure in passage 164 to oppose the force of valve spring 170. Valve 128 engages the left-hand end of the valve 130. Thus when passage 164 is exhausted, the force of spring 170 opposes the force of spring 144. This reduces the magnitude of the throttle valve signal. The amount of the reduction is calibrated to correspond to the reduction in engine torque that results from the introduction of exhaust gas through the exhaust gas recirculation system into the intake manifold. The calibration is achieved by controlling the spring rate of spring 170 and by controlling the diameter of land 162, which is exposed to throttle pressure in passage 114.

The variation in engine intake manifold pressure, which occurs for each value of the throttle valve signal, is illustrated by curve A in FIG. 4. This curve A shows a relationship between these two variables when the EGR system is deactivated. Curve B, on the other hand, represents the relationship between these two variables when the EGR system'is actuated. The change from curve A to curve B in FIG. 4 is achieved by triggering the solenoid actuated shift valve, which either activates or deactivates the secondary throttle valve 138..

Having thus described a preferred embodiment of our invention, what we claim and desire to secure by U.S. Letters Patent is:

1. A control valve circuit for an automatic power transmission mechanism in an automotive vehicle driveline having an internal combustion engine with an air-fuel mixture intake manifold, said transmission comprising gearing adapted to establish multiple torque delivery paths between a driving member and a driven member, fluid pressure operated clutches and brakes for controlling the relative motion of elements of said gearing, a fluid pressure source, conduit structure connecting said pressure source to said clutches and brakes, shift valve means in said conduit structure for establishing and disestablishing a fluid connection between said source and said clutches and brakes. a source of the speed signal pressure drivably connected to a driven member, a pressure signal passage extending from said signal source to said shift valve means for imposing on the latter an upshifting tendency, a throttle valve system connected hydraulically to said shift valve means for imposing on the latter a downshifting tendency, a main pressure regulator valve means for regulating the pressure supplied by said pressure source, said throttle valve system including a flexible diaphragm defining in part a manifold pressure chamber, a manifold pressure passage connecting the intake manifold of said engine with said manifold pressure chamber, spring means acting on said diaphragm whereby changes in manifold pressure cause deflection of said diaphragm, a modulator valve element in said throttle valve system connected mechanically to said flexible diaphragm, means for supplying pressure from a high pressure portion of said circuit to said modulator valve, modulated output pressure of said modulator valve being related in magnitude to the engine intake manifold pressure, and a secondary throttle valve in said throttle valve system, said secondary throttle valve including a valve spring acting on it in one direction, a fluid pressure area on said secondary throttle valve, the force created by pressure on said area urges said secondary throttle valve in the opposite direction, the net forces acting on said secondary throttle valve being distributed to said modulator valve element whereby the modulating characteristics of the latter may be changed, said engine having exhaust gas recirculation control whereby engine exhaust emissions may be recirculated to the intake manifold, said control including an automatically operated shift valve in fluid communication with said pressure area on said secondary throttle valve whereby the pressure forces on said secondary throttle valve may be applied and released in response to the activation and deactivation of said control.

2. The combination as set forth in claim 1 wherein the pressure area on the secondary throttle valve element is in fluid communication with a high pressure portion of said circuit whereby said secondary throttle valve element is urged in said opposite direction against the opposing force of the spring acting thereon thereby interrupting the transfer of forces from said secondary throttle valve element to said modulator valve element.

3. The combination as set forth in claim 1 wherein said exhaust gas recirculation control includes a solenoid actuated shift valve, said solenoid actuated shift valve defining in part a fluid connection between a high pressure region of said circuit and said pressure area on said secondary valve element, said solenoid actuated shift valve 7 being actuated to exhaust the pressure area on said secondary valve element when the exhaust gas recirculation control is activated whereby the spring acting on said secondary valve element opposes the spring acting on said flexible diaphragm.

4. The combination as set forth in claim 2 wherein said exhaust gas recirculation control includes a solenoid actuated shift valve, said solenoid actuated shift valve defining in part a fluid connection (between said high pressure region of said circuit and said pressure area on said secondary valve element, said solenoid actuated shift valve being actuated to exhaust the pressure area on said secondary valve element when the exhaust gas recirculation control is activated whereby the spring acting on said secondary valve element opposes the spring acting on said flexible diaphragm.

References Cited UNITED STATES PATENTS 3,688,606, 9/1972 Lemieux et a1. 74-863 CHARLES J. MYHR-E, Primary Examiner m T. C. PERRY, Assistant Examiner U .8. Cl. X.R. 74864

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