WO2008064640A1 - Multifunctional torque converter for disconnecting the turbine from the idling engine and control method for disconnecting a multifunctional torque converter from the idling engine - Google Patents

Abstract

The invention relates to a torque converter which comprises the following components: a damper assembly that is connected to a hub of the torque converter, a turbine clutch that is connected to a turbine and the damper assembly, and a converter clutch that is connected to a housing of the torque converter and the damper assembly. In an idle mode, the turbine clutch and the converter clutch are disengaged, and the converter housing can freely rotate in relation to the hub. In a converter mode, the turbine clutch is engaged, the converter clutch is disengaged, and the turbine clutch non-rotatably connects the turbine and the damper assembly. In a lock-up mode, the converter clutch is engaged, and the converter clutch non-rotatably connects the converter housing and the damper assembly.

Description

 Multifunctional torque converter for separating the turbine from the engine in the

Idle and control method for disconnecting a multifunctional

Torque converter from engine idling

FIELD OF THE INVENTION

The invention relates to improvements in a device for transmitting power between a rotary drive unit (for example, the engine of a motor vehicle) and a rotationally driven unit (for example, the automatic transmission in the motor vehicle). In particular, the invention relates to a multi-functional torque converter with a turbine that can be controlled to be connected to an output hub of the torque converter. In particular, the turbine may be disconnected from the hub while the engine is idling.

BACKGROUND OF THE INVENTION

FIG. 1 illustrates a general block diagram showing the relationships between the engine 7, the torque converter 10, the transmission 8, and the differential / axle assembly 9 in a typical vehicle. It is known that a torque converter is used to transmit torque from an engine to a transmission of a motor vehicle.

The pump 37, the turbine 38 and the stator 39 are the three major components of the torque converter. When the pump is welded to the lid 11, the torque converter becomes a sealed chamber. The cover is connected to the converter driver disk 41 (flexplate), which in turn is bolted to the crankshaft 42 of the engine 7. The lid may be connected to the transducer driver disc using lands or pegs welded to the lid. The welded connection between the pump and the cover transfers the motor torque to the pump. Therefore, the pump always rotates at the engine speed. The function of the pump is to use this rotational movement to move the fluid radially outward and axially to the turbine. Therefore, the pump serves as a centrifugal pump, which conveys the liquid from a small radial inlet to a large radial outlet and so increases the energy of the liquid. The pressure for engaging the transmission clutches and the torque converter clutch is generated by an additional pump in the transmission, which is driven by the pump hub.

In the torque converter 10, a fluid circuit is formed by the pump (sometimes referred to as an impeller), the turbine and the stator (sometimes referred to as a reactor). The fluid circuit allows the engine to continue rotating when the vehicle stops and to accelerate the vehicle again when desired by a driver. Similar to a gear reduction, the torque converter supports engine torque through a torque ratio. The torque ratio is the ratio of output torque to input torque. The torque ratio is highest when the turbine speed is low or zero (also referred to as stalling). The stall torque ratios are usually in the range of 1.8 to 2.2. That is, the output torque of the torque converter is 1, 8 to 2.2 times as large as the drive torque. The output speed, however, is much lower than the input speed because the turbine is connected to the output side and does not rotate while the drive side is running at engine speed.

The turbine 38 utilizes the energy received by the fluid from the pump 37 to drive the vehicle. The turbine housing 22 is connected to the turbine hub 19. The turbine hub 19 transmits the turbine torque to the drive shaft 43 of the transmission via a sprocket connection. The drive shaft is connected via gears and shafts in the transmission 8 and an axle differential 9 with the wheels of the vehicle. The force of the liquid acting on the turbine blades is output by the turbine in the form of a torque. Axial thrust bearings 31 absorb the axial forces applied to the components by the fluid. Once the output torque is sufficient to overcome the inertia of the stationary vehicle, the vehicle starts moving.

After the energy of the liquid has been converted into a torque by the turbine, the liquid still contains residual energy. The liquid emerging from the small radial outlet opening 44 normally enters the pump in such a way that it counteracts the rotation of the pump. The stator 39 serves to redirect the liquid to contribute to the acceleration of the pump and thereby the Increase torque ratio. The stator 39 is connected by a freewheel 46 with the stator 45. The stator shaft is connected to the transmission housing 47 and does not rotate. Free wheel 46 prevents stator 39 from rotating at low speed ratios (when the pump is turning faster than the turbine). The liquid entering the stator 39 from the turbine outlet 44 is deflected by the stator blades 48 so that it enters the pump 37 in the direction of rotation.

The inlet and outlet angles of the blades, the shape of the pump and turbine housings, and the overall diameter of the torque converter affect its performance parameters. As a design parameter, the torque ratio, efficiency, and ability of the torque converter to take in engine torque without allowing the engine to "spin." This occurs when the torque converter is too small and the pump can not decelerate the engine.

At low speed ratios, the torque converter works satisfactorily by letting the engine rotate while the vehicle is stationary and assisting engine torque to increase performance. At speed ratios less than 1, the torque converter has an efficiency of less than 100%. As the speed of the turbine equals the speed of the pump, the torque ratio of the torque converter gradually decreases from a high level of approximately 1.8 to 2.2 to a torque ratio of approximately one. The speed ratio when reaching a speed ratio of 1 is referred to as Einkuppelpunkt. At this point, the liquid entering the stator does not need to be redirected, and the free-wheel in the stator allows for rotation in the same direction as the pump and turbine. Since the stator does not deflect the fluid, the torque output by the torque converter is equal to the torque absorbed. The entire fluid circuit turns as a unit.

Due to losses in the liquid, the maximum efficiency of the torque converter is 92 to 93%. Therefore, a torque converter clutch 49 is used for mechanical connection of the drive side with the output side of the torque converter, which increases the efficiency to 100%. The clutch piston plate 17 becomes hydraulic by commands from the transmission control - A -

actuated. The piston plate 17 is sealed at its inner diameter by an O-ring 18 against the turbine hub 19 and at its outer diameter by a ring 51 made of friction material against the lid 11. These seals form a pressure chamber and connect the piston plate 17 with the lid 11. This mechanical connection bypasses the fluid circuit of the torque converter.

The mechanical connection of the torque converter clutch 49 transmits significantly more torsional variations to the powertrain. Since the powertrain is basically a spring-mass system, torsional variations from the engine can excite resonant vibrations of the system. To remove the resonance vibrations of the drive train from the driving range, a damper is used. The damper includes springs 15 arranged in series with the motor 7 and the transmission 8 to reduce the effective spring rate of the system and thus the resonant frequency.

The torque converter clutch 49 generally comprises four components: a piston plate 17, cover plates 12 and 16, springs 15 and a flange 13. The cover plates 12 and 16 transmit the torque from the piston plate 17 to the compression springs 15. On the cover plate are around the springs 15 around Noses 52 formed to support the springs in the axial direction. The torque is transmitted via a riveted connection from the piston plate 17 to the cover plates 12 and 16. The cover plates 12 and 16 allow the torque to act on the compression springs 15 by contact with an edge of a recess for the spring. The two cover plates together support the spring on both sides of its central axis. The spring force is transmitted to the flange 13 by contact with an edge of the recess for the flange spring. Sometimes, the flange also has a tongue or a slot in the direction of rotation, which engages in a part of the cover plate in order to prevent excessive compression of the springs during the transmission of high torques. The torque is transmitted from the flange 13 to the turbine hub 19 and to the drive shaft 43 of the transmission.

If necessary, the energy can be absorbed by friction, which is sometimes referred to as hysteresis. The hysteresis results from the torsion and the relaxation of the damping plates and is thus twice as large as the actual friction torque. The hysteresis assembly generally consists of a diaphragm spring (or Belleville spring) 14 between the flange 13 and one of the Cover plates 16 to press the flange 13 against the other cover plate 12. By controlling the force exerted on the diaphragm spring 14, the magnitude of the friction torque can also be controlled. Typical hysteresis values are in the range of 10 to 30 Nm.

It is desirable to reduce the fuel consumption of an engine connected to a torque converter while the engine is idling. Thus, there has long been a need for a torque converter to reduce the moment of inertia of an engine when idling. In particular, there has long been a need for a torque converter with parts, such as e.g. turbine, which can be disconnected from the engine when idling.

BRIEF SUMMARY OF THE INVENTION

The present invention generally includes a torque converter, comprising: a damper assembly connected to a hub of the torque converter; a turbine coupling connected to a turbine and the damper assembly; and a converter clutch connected to a cover of the torque converter and the damper assembly. When the engine is in idle mode, the turbine clutch and converter clutch are disengaged, and the converter cover and turbine are freely rotatable with respect to the hub. In converter mode, the turbine clutch is engaged, the converter clutch disengaged, and the turbine and damper assembly rotatably connected by the turbine clutch. In lock mode, the converter clutch is engaged, and the converter cover and damper assembly are non-rotatably connected by the converter clutch.

In some aspects, the turbine clutch includes a first piston plate, and the converter clutch includes a second piston plate. The torque converter includes an impeller; a turbine housing; a first chamber containing the turbine and the impeller and being at least partially defined by the first and second piston plates; a second chamber defined at least in part by the first piston plate and the turbine housing; and a third chamber defined at least in part by the converter cover and the second piston plate. In the idling mode of the engine, the fluid pressure in the first chamber is then adjusted to is less than the pressure of the corresponding liquids in the second and third chambers.

In some aspects, the turbine clutch includes a first piston plate, and the converter clutch includes a second piston plate. The torque converter includes an impeller; a turbine housing; a first chamber containing the turbine and the impeller and being at least partially defined by the first and second piston plates; a second chamber defined at least in part by the first piston plate and the turbine housing; and a third chamber defined at least in part by the converter cover and the second piston plate. In the converter mode, the fluid pressure in the first chamber is then set to be less than the fluid pressure in the third chamber, and the fluid pressure in the first chamber is set to be greater than the fluid pressure in the second chamber. The liquid in the first chamber is arranged to flow through the first chamber for cooling the turbine and the impeller.

In some aspects, the turbine clutch includes a first piston plate, and the converter clutch includes a second piston plate. The torque converter includes an impeller; a turbine housing; a first chamber containing the turbine and the impeller and being at least partially defined by the first and second piston plates; a second chamber defined at least in part by the first piston plate and the turbine housing; and a third chamber defined at least in part by the converter cover and the second piston plate. In the lock mode, the fluid pressure in the first chamber is set to be greater than the fluid pressure in the third chamber.

Further, the present invention includes a torque converter having a damper assembly connected to a hub of the torque converter; a turbine clutch in a first torque path between a turbine and the damper assembly; and a converter clutch in a second torque path between a torque converter cover and the damper assembly. In the idle mode of the engine, the turbine clutch and the converter clutch are disengaged and thus the first and second torque paths are broken. In converter mode, the turbine clutch is engaged and the converter clutch disengaged so that the first torque path is continuous and the second torque path is interrupted. In lock mode, the converter clutch is engaged and the second torque path is engaged.

Further, the present invention generally includes a torque converter having a reduced moment of inertia in the idling mode of the engine, wherein an output hub and a turbine are arranged to rotate independently of the output hub. In some aspects, the torque converter includes a damper assembly connected to the hub and the converter cover and a turbine coupling connected to a turbine and the damper assembly. The turbine clutch is arranged to be open in the idle mode of the engine.

The present invention generally includes a method of operating a torque converter including the steps of: varying the hydraulic pressure in the first, second, and third chambers; and varying respective torque transfer paths between a torque converter cover and a hub-connected damper assembly, on the one hand, and between a turbine and the damper assembly, on the other hand, in response to varying hydraulic pressure.

In some aspects, varying the hydraulic pressure includes maintaining the pressure in the first chamber at a value lower than the corresponding pressures in the second and third chambers, and changing the corresponding torque transmission paths includes opening the corresponding torque-transmitting paths.

In some aspects, varying the hydraulic pressure includes maintaining the pressure in the first chamber at a value lower than the pressure in the third chamber and maintaining the pressure in the second chamber at a value lower than the pressure in is the first chamber, and changing the respective torque transmission paths involves opening the

Torque transmission path between the cover and the damper assembly and the closing of the torque transmission path between the turbine and the damper assembly. Then, the method includes flowing the liquid into and through the first chamber. In some aspects, varying the hydraulic pressure includes maintaining the pressure in the first chamber at a value higher than the pressure in the third chamber, and changing the corresponding torque-transmitting paths includes closing the torque-transmitting path between the cover and the damper assembly.

A general object of the present invention is to provide a means for disconnecting an output hub of a torque converter when the engine is idling.

Another object of the present invention is to provide a torque converter with a turbine clutch and a converter clutch, both of which transmit torque via a damper assembly.

Another object of the present invention is to provide a torque converter that disconnects an output hub when the engine is idling and supplies coolant to the loop while hydraulically actuating the clutches in the converter mode.

These and other objects and advantages of the present invention will be apparent from the following description of preferred embodiments of the invention and from the accompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed description, the nature and operation of the present invention will be described in detail in conjunction with the accompanying drawings, in which:

1 is a general block diagram of power flow in a motor vehicle intended to assist in explaining the relationships and operation of a torque converter in the powertrain of the motor vehicle;

FIG. 2 is a cross-sectional view of a prior art torque converter in an installed position on an engine of a motor vehicle; FIG. Fig. 3 is a view of the torque converter shown in Fig. 2 taken along the line 3-3 in Fig. 2 from the left side;

Fig. 4 is a cross-sectional view of the torque converter shown in Figs. 2 and 3 taken along section line 4-4 in Fig. 3;

Fig. 5 is an exploded view of the torque converter shown in Fig. 2 as viewed from the left side of a viewer;

Fig. 6 is an exploded, second view of the torque converter shown in Fig. 2 as viewed from the right-hand side of the viewer;

Fig. 7A is a perspective view of a cylindrical coordinate system illustrating the spatial terms used in the present application;

Fig. 7B is a perspective view of an object in the cylindrical coordinate system of Fig. 7A illustrating the spatial terms used in the present application;

Fig. 8 is a partial cross-sectional view of a torque converter according to the present invention;

Fig. 9 is a partial cross-sectional view of the torque converter of Fig. 8, showing the loading chamber of the impeller;

Fig. 10 is a partial cross-sectional view of the torque converter of Fig. 8, showing the inner chamber; =

Fig. 11 is a partial cross-sectional view of the torque converter of Fig. 8, showing the outer chamber; and

FIG. 12 is a partial cross-sectional view of the torque converter of FIG. 8 showing the torque transfer paths. FIG. DETAILED DESCRIPTION OF THE INVENTION

It should be understood from the beginning that like reference numerals in different drawing views designate identical or functionally similar structural elements of the invention. Although the present invention will be described with reference to the aspects presently considered to be preferred, it should be understood that the claimed invention is not limited to the aspects described.

It will also be understood that this invention is not limited to the particular methods, materials, and modifications described, and to that extent, of course, may vary. It is further understood that the terms used herein are for the purpose of describing particular aspects only and are not to be construed as limiting the scope of the present invention, which is limited only by the appended claims.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. Although any methods, devices, or materials similar or equivalent to those described herein may be used to make or test the invention, the preferred methods, devices, and materials are described below.

Fig. 7A is a perspective view of a cylindrical coordinate system 80 illustrating the spatial terms used in the present invention. The present invention will be described, at least in part, in connection with a cylindrical coordinate system. The system 80 has a longitudinal axis 81 which serves as a reference for the following directional and spatial terms. The attributes "axial,""radial," and "circumferential" refer to an orientation parallel to axis 81, to radius 82 (which is perpendicular to axis 81), and to circumference 83, respectively. The attributes "axial,""radial" and "perimeter" also refer to an alignment parallel to corresponding planes. To illustrate the position of the various planes are the objects 84, 85 and 86. The surface 87 of the object 84 forms an axial plane. That is, the axis 81 forms a line along the surface. The surface 88 of the object 85 forms a radial plane. That is, the radius 82 forms a line along the surface. The surface 89 of the object 86 forms a peripheral plane. That is, the periphery 83 forms a line along the surface. Another example shows that an axial movement or position is parallel to the axis 81, a radial movement or position is parallel to the radius 82 and a circumferential movement or position on the circumference is parallel to the circumference 83. A rotation occurs with respect to the axis 81.

The attributes "axial," "radial," and "circumferential" refer to an orientation parallel to axis 81, radius 82, and circumference 83, respectively. The attributes "axial," "radial," and "circumference" also refer to an alignment parallel to corresponding planes.

FIG. 7B is a perspective view of an object 90 in the cylindrical coordinate system 80 of FIG. 7A illustrating the spatial terms used in the present application. The cylindrical object 90 is representative of a cylindrical object in a cylindrical coordinate system and should not be understood as limiting the present invention. The object 90 includes an axial surface 91, a radial surface 92, and a peripheral surface 93. The surface 91 is part of an axial plane, the surface 92 is part of a radial plane, and the surface 93 is part of a peripheral surface.

8 is a partial cross-sectional view of the torque converter 100 according to the present invention. The torque converter 100 includes a damper assembly 102, a torque converter or lockup clutch 104, and a turbine clutch 106. The assembly 102 is rotationally connected to the hub 108. Under rotatably connected or fixed is to be understood that the assembly and the hub are connected to each other such that the two components rotate together, that is, that the two components are firmly connected with respect to the rotation. The non-rotatable connection of two components does not necessarily restrict their relative movement in other directions. For example, two non-rotatably interconnected components can also axially move with respect to each other via a sprocket connection. It should be understood, however, that a non-rotatable connection does not necessarily mean the presence of movement in other directions. For example, two non-rotatably interconnected components may also be axially secured together. The above explanation of the rotational connection can also be applied to the following discussions.

The clutch 104 is rotatably connected to the assembly 102. In some aspects, the clutch 104 includes a piston plate 110 that may be replaced by any one of in FIG the art known means, for example, connected to the plate 112 extruded rivets 111, rotatably connected to the assembly 102 is connected. The clutch 104 also includes a pressing member 113 that presses against the plate 110 in the axial direction. The pressure element allows axial movement of the plate 110 independently of axial movement through the assembly 102. As the pressure element 113, any element known in the art may be used, for example a leaf spring. The clutch 106 is rotatably connected to the assembly 102 and the turbine 114. In some aspects, the coupling 106 includes a piston sheet 116 that is connected to the assembly by any means known in the art, such as rivets 118. In some aspects, the coupling 106 includes a plate rotationally connected to the turbine by any means known in the art, such as welds 122 and 123.

FIG. 9 is a partial cross-sectional view of the torque converter of FIG. 8, showing an impeller loading chamber 124.

Fig. 10 is a partial cross-sectional view of the torque converter of Fig. 8, showing the inner chamber 126; and

11 is a partial cross-sectional view of the torque converter of FIG. 8, showing the outer chamber 128.

FIG. 12 is a partial cross-sectional view of the torque converter of FIG. 8 showing the torque transfer paths 130 and 132. The following description will be seen in conjunction with FIGS. 8-12. The clutch 104 is disposed in a torque transmission path between the torque converter cover 134 and the assembly 102. In some aspects, this path is path 130. Clutch 106 is disposed in a torque transmission path between turbine 114 and assembly 102. In some aspects, this path is the path 132. As will be described below, changing the hydraulic pressure in the respective chambers 124, 126, and 128 causes the clutches to open and close, thereby opening and closing the torque transfer paths. That is, the path can not transmit the torque over its entire length. In other words, the path is broken. For example, torque may be at one end of the torque transfer path which is transmitted to its other end. The closing of the torque transmission path is understood to mean that it is made continuous and thereby can transmit the torque over its entire length.

The chamber 124 includes the turbine 114 and the impeller 135 and is at least partially defined by the plates 110 and 116. By partially defined, it is meant that the plates form at least part of the boundary or enclosure of the chamber. The chamber 126 is at least partially defined by the plate 116 and the turbine housing 136. The chamber 128 is at least partially defined by the plate 110 and the lid 134.

To operate the torque converter 100 when the engine is idling, that is, when an engine (not shown) connected to the converter 100 is idling, the two clutches 104 and 106 are opened. For this purpose, the liquid pressure in the chamber is maintained at a value smaller than the liquid pressure in the chamber 128, so that the plate 110 is displaced in the direction 137 and the clutch 104 is opened. Further, the fluid pressure in the chamber 126 is maintained at a value higher than the fluid pressure in the chamber 124, so that the plate 116 is axially displaced in the direction 138 and the clutch 106 is opened. In this arrangement, no torque is transmitted to the hub 108 which is rotationally fixedly connected to the drive shaft 140 of a transmission (not shown) in the converter 100 installed in a vehicle (not shown). That is, the turbine and the converter cover are separated from the hub.

In other words, the non-rotatably connected to the transmission hub is separated from the parts of the torque converter, which absorb the torque from the engine, in particular from the converter cover and the turbine housing. Thus, the parts of the transducer connected directly or indirectly to the engine are separated from the hub. This reduces the moment of inertia perceived by the engine due to the connection of the engine to the torque converter, thereby reducing the fuel consumption of the engine.

To operate the torque converter 100 in a converter mode, that is, such that the turbine 114 boosts the torque received by the impeller 135, the clutch 104 is opened and the clutch 106 is closed. For this purpose, the Fluid pressure in the chamber 124 held at a value which is lower than the liquid pressure in the chamber 128, so that the plate 110 is axially displaced in the direction 137 and the clutch 104 is opened. The fluid pressure in the chamber 124 is maintained at a value higher than the fluid pressure in the chamber 126 such that the plate 116 is axially displaced in the direction 137 and the clutch 106 is closed. In this arrangement, the path 132 is closed, the path 130 is opened, and torque is transmitted from the turbine to the assembly 102 and hub 108. That is, the turbine 114 is rotatably connected to the hub 108.

The clutch 106 must be constructed to withstand the increased engine torque (due to the turbine boost effect). In some aspects, the plates 142 and 144 are used to strengthen the clutch to allow it to absorb the greater torque. It should be understood, however, that the clutch 106 is not limited to the torque amplification arrangement shown and that other means for increasing the torque capacity of the clutch 106 are included within the spirit and scope of the claimed invention. During operation in converter mode, heat is generated by the turbine and impeller. The transducer 100 is advantageously arranged so that in the converter mode, a liquid flows through the chamber 124 to cool the turbine and the impeller.

Although the coupling 106 is illustrated with a particular arrangement of interlocking components, it should be understood that the coupling is not limited to this arrangement and that other arrangements are included within the spirit and scope of the claimed invention. Thus, the hydraulic pressure is changed using the same chamber so that the clutches in a

Operate torque amplification mode and a liquid flow for cooling the loop is provided. In some aspects, the liquid flows from the chamber 128, which is under a higher hydraulic pressure than the chamber 124, into the chamber 124 and through the channel 145.

To operate the torque converter 100 in a lock-up mode, that is, to connect the housing 134 to the assembly 102, the clutch 104 is closed. In some aspects, the converter 106 closed clutch remains closed while the clutch 104 is closed. According to some Aspects, the clutch 106 is opened in the lock-up mode. More specifically, as soon as the clutch 104 is closed, the clutch 106 is opened. This sequence will be described in more detail below. If the clutch 106 remains closed, the moment of inertia of the impeller is transmitted in the torque transmission path. The moment of inertia of the impeller may be used to affect the natural frequency of the torque converter in lock-up mode and thus to prevent unwanted resonances.

To close the clutch 104, the fluid pressure in the chamber 124 is maintained at a value higher than the fluid pressure in the chamber 128 so that the plate 110 is displaced axially in direction 138. To open the clutch 106, the fluid pressure in the chamber 124 is maintained at a value lower than the fluid pressure in the chamber 126, so that the plate 116 is displaced axially in the direction 138. In this arrangement, the torque from the motor is transmitted along the path 130 from the housing to the assembly 102 and on to the hub 108. That is, the lid 134 is rotatably connected to the hub 108. When the clutch 106 is open, the path 132 is also open. When the clutch 106 is closed, the path 132 transmits the moment of inertia of the pump to the path 130.

It should be understood that the above-noted pressures are relative values that are not limited to any particular value or range, except for the values or ranges characteristic of the overall construction, arrangement, or operation of a particular torque converter 100 ,

The lid 134 may be connected to the motor by any means known in the art. In some aspects, pins 146 are used. In some aspects, leaf spring 102 includes a plurality of coil springs 148 that are secured to flange 150 and plates 152 and 154.

Axially between the lid 134 and the plate 110, a friction material is attached. The clutch 104 is not limited to any particular type or arrangement of friction materials. In some aspects, the friction material is fixedly connected to the lid or to the plate 110. According to some aspects (not shown), a clutch plate is disposed axially between the cover and the plate. The friction material 158 is axially between the plates 116, 120, 142 and 144 arranged. The clutch 106 is not limited to any particular type or arrangement of friction materials. In some aspects, the friction materials are firmly bonded to the plates. According to some aspects (not shown), clutch plates are disposed axially between the plates.

In some aspects, torque converter 100 includes a three-way hydraulic system. In this system, the channels 145, 160, and 162 convey fluid to and from the chambers 124, 128, and 126, respectively. The channel 160 is located within the shaft 140 and communicates with the chamber 128 via the fluid. The channel 162 is located radially between the shaft 140 and the stator shaft 166 and communicates with the chamber 126 via the fluid. The channel 145 is located radially between the shaft 166 and the flange 168 and is in communication with the chamber 124 via the fluid.

The present invention also includes a torque converter having a reduced moment of inertia when the engine is idling. The converter includes an output hub and a turbine arranged to rotate independently of the output hub. In some aspects, the torque converter includes a damper assembly connected to the hub and a converter cover and a turbine coupling connected to a turbine and the damper assembly. The turbine clutch is arranged to open in idle mode of the engine. In contrast to the torque converter shown in Fig. 4, the turbine is thus not rotatably connected to the output hub in the idle mode of the engine. In the torque converter according to the present invention, in the idling mode of the engine, there is no rotationally fixed connection between the turbine and the hub, and the turbine can rotate independently of the rotational state of the hub.

In some aspects, the torque converter is the torque converter 100, the hub around the hub 108, the turbine around the turbine 114, the damper assembly around the damper assembly 102, the converter cover about the converter cover 134, and the turbine clutch around the turbine clutch 106.

The clutches 104 and 106 and the damper assembly 102 have been illustrated with certain shapes, dimensions and arrangements. It should be understood, however, that a torque converter according to the present invention is not limited to those shown Shapes, dimensions and arrangements is limited and that other shapes, dimensions and arrangements according to the above descriptions are included within the spirit and scope of the claims. The torque converter 100 has been shown with a particular arrangement of accessory components. It should be understood, however, that a torque converter in accordance with the present invention is not limited to the particular accessories and their arrangement shown in the figures and that other accessories and arrangements are within the spirit and scope of the claimed invention.

The present invention also includes a method of operating a torque converter. Although the method of illustration has been described as a series of steps, no particular order should be inferred from it unless specifically stated. In a first step, the hydraulic pressure in the first, second and third chambers is varied. In a second step, in response to varying the hydraulic pressure, the torque transfer paths between a torque converter cover and a hub-connected damper assembly and between a turbine and the damper assembly are changed. In some aspects, the torque converter is the torque converter 100 and the first to third chambers are the chambers 124, 126, and 128, respectively.

In some aspects, varying the hydraulic pressure includes maintaining the pressure in the chamber at a value lower than the corresponding pressures in the chambers 126 and 128, and changing the corresponding torque transmission paths involves opening the hydraulic pressure

Torque transmission path between the cover 114 and the damper assembly 102 and the opening of the torque transmission path between the turbine and the damper assembly. This is the case in the idle mode of the engine in which no torque is transmitted to the shaft 140 because both clutches 104 and 106 are open. This mode advantageously reduces the moment of inertia and thus the fuel consumption of the vehicle engine.

In some aspects, varying the hydraulic pressure includes maintaining the pressure in the chamber 124 at a value lower than the pressure in the chamber 128 and maintaining the pressure in the chamber 126 at a value lower than that Pressure in the chamber 124 is. Then, changing the torque transfer paths includes opening the torque transfer path between the cover and the damper assembly and closing the torque transfer path between the turbine and the damper assembly. This is the case in converter mode where the clutch 104 is open and the clutch 106 is closed and the turbine 114 boosts the torque received by the impeller 135. The method also includes flowing the liquid in the chamber 124 through the chamber to cool the turbine and the impeller.

In some aspects, varying the hydraulic pressure includes maintaining the pressure in the chamber 124 at a value higher than the pressure in the chamber 128. Then, changing the respective torque-transmitting paths involves closing the torque-transmitting path between the cover and the damper assembly. This is the case in the lock-up mode, in which the clutch 104 is closed and the torque is transmitted from the cover to the transmission shaft.

Thus, it will be appreciated that the objects of the present invention will be effectively attained, although those skilled in the art may conceive of modifications and variations of the invention which are within the spirit and scope of the claimed invention. It is further understood that the above description is only illustrative of the present invention and is not intended to be limiting. Therefore, other embodiments of the present invention are possible without departing from the spirit and scope of the present invention.

Claims

claims A torque converter comprising: a damper assembly connected to a hub; a turbine coupling connected to a turbine and the damper assembly; and a converter clutch connected to a cover of the torque converter and the damper assembly. 2. A torque converter according to claim 1, wherein the turbine clutch and the converter clutch are disengaged in an idling mode of the engine and in which the turbine and the converter cover are freely rotatable with respect to the hub. 3. The torque converter of claim 2, wherein the turbine clutch comprises a first piston plate and the converter clutch comprises a second piston plate; and wherein the torque converter further comprises: an impeller; a turbine housing; a first chamber containing the turbine and the impeller and being at least partially defined by the first and second piston plates; a second chamber defined at least in part by the first piston plate and the turbine housing; and a third chamber defined at least in part by the converter cover and the second piston plate, wherein the fluid pressure in the first chamber in the idling mode of the engine is set to be lower than the pressures of the corresponding fluids in the second and third chambers. 4. The torque converter of claim 1, wherein the turbine clutch is engaged in a converter mode and the converter clutch is disengaged and the turbine clutch rotatably interconnects the turbine and the damper assembly. 5. The torque converter of claim 4, wherein the turbine clutch comprises a first piston plate and the converter clutch comprises a second piston plate; and wherein the torque converter further comprises: an impeller; a turbine housing; a first chamber containing the turbine and the impeller and being at least partially defined by the first and second piston plates; a second chamber defined at least in part by the first piston plate and the turbine housing; and a third chamber defined at least in part by the transducer cover and the second piston plate, the fluid pressure in the first chamber in the transducer being adjusted to be lower than the fluid pressure in the third chamber and higher than the fluid pressure in the second chamber is. 6. The torque converter of claim 5, wherein the liquid in the first chamber is directed to flow through the first chamber. 7. The torque converter of claim 1, wherein the converter clutch is engaged in a lock-up mode and the converter clutch rotatably connects the converter cover and the damper assembly together. 8. The torque converter of claim 7, wherein the turbine clutch is engaged. 9. Torque converter according to claim 7, wherein the turbine clutch is open. 10. The torque converter of claim 7, wherein the turbine clutch comprises a first piston plate and the converter clutch comprises a second piston plate; and wherein the torque converter further comprises: an impeller; a turbine housing; a first chamber containing the turbine and the impeller and being at least partially defined by the first and second piston plates; a second chamber defined at least in part by the first piston plate and the turbine housing; and a third chamber defined at least in part by the converter cover and the second piston plate, wherein the fluid pressure in the first chamber in the bypass mode is set to be higher than the fluid pressure in the third chamber. 11. The torque converter of claim 1, wherein the damper assembly comprises a plurality of flange-mounted coil springs. 12. A torque converter comprising: a damper assembly connected to a hub of the torque converter; a turbine clutch in a first torque transmission path between a turbine and the damper assembly; and a converter clutch in a second torque transmission path between a torque converter cover and the damper assembly. 13. The torque converter of claim 12, wherein the turbine clutch and the converter clutch are disengaged in an idle mode of the engine and the first and second torque transmission paths are interrupted. 14. The torque converter of claim 12, wherein in a converter mode, the turbine clutch is engaged, the converter clutch is disengaged, the first torque transmission path is continuous, and the second torque transmission path is broken. 15. The torque converter of claim 12, wherein in a lockup mode, the converter clutch is engaged and the second torque transmission path is continuous. 16. The torque converter of claim 15, wherein the turbine clutch is engaged and the first torque transmission path is continuous. 17. The torque converter of claim 15, wherein the turbine clutch is disengaged and the first torque transmission path is broken. 18. A torque converter having a reduced moment of inertia in the idling mode of the engine and comprising: an output hub; and a turbine arranged to rotate independently of the output hub. 19. The torque converter of claim 18, further comprising a damper assembly connected to the hub and a converter cover, and a turbine clutch connected to a turbine and the damper assembly, the turbine clutch arranged to be in the idle mode of the engine is opened. 20. A method of operating a torque converter, the method comprising the steps of: Varying the hydraulic pressure in the first, second and third chambers; and Changing the respective torque transfer paths between a torque converter cover and a damper assembly connected to a hub and between a turbine and the damper assembly in response to varying the hydraulic pressure. 21. The method of claim 20, wherein varying the hydraulic pressure further comprises maintaining the pressure in the first chamber at a value lower than the corresponding pressures in the second and third chambers, and changing the corresponding one Torque transmission paths further, the opening of the corresponding ^; Includes torque transmission paths. 22. The method of claim 20, wherein varying the hydraulic pressure further comprises maintaining the pressure in the first chamber at a value lower than the pressure in the third chamber and maintaining the pressure in the second chamber at a value , which is lower than the pressure in the first chamber, and wherein changing the respective torque transmission paths further comprises opening the torque transmission path between the cover and the valve Damper assembly and the closing of the torque transmission path between the turbine and the damper assembly comprises. 23. The method of claim 22, further comprising flowing the liquid through the first chamber. 24. The method of claim 20, wherein varying the hydraulic pressure further comprises maintaining the pressure in the first chamber at a value higher than the pressure in the third chamber, and changing the corresponding torque transmission paths further closing the Torque transmission path between the lid and the damper assembly comprises. 25. The method of claim 24, wherein varying the hydraulic pressure further comprises maintaining the pressure in the second chamber at a value higher than the pressure in the first chamber, and changing the corresponding torque transmission paths further to open the Torque transmission path between the turbine and the damper assembly comprises.