WO2006110946A1 - Fluid flow control apparatus and valve system - Google Patents
Fluid flow control apparatus and valve system Download PDFInfo
- Publication number
- WO2006110946A1 WO2006110946A1 PCT/AU2006/000508 AU2006000508W WO2006110946A1 WO 2006110946 A1 WO2006110946 A1 WO 2006110946A1 AU 2006000508 W AU2006000508 W AU 2006000508W WO 2006110946 A1 WO2006110946 A1 WO 2006110946A1
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- WO
- WIPO (PCT)
- Prior art keywords
- fluid
- pressure
- clutch device
- constrictor
- control apparatus
- Prior art date
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D25/00—Fluid-actuated clutches
- F16D25/06—Fluid-actuated clutches in which the fluid actuates a piston incorporated in, i.e. rotating with the clutch
- F16D25/062—Fluid-actuated clutches in which the fluid actuates a piston incorporated in, i.e. rotating with the clutch the clutch having friction surfaces
- F16D25/063—Fluid-actuated clutches in which the fluid actuates a piston incorporated in, i.e. rotating with the clutch the clutch having friction surfaces with clutch members exclusively moving axially
- F16D25/0635—Fluid-actuated clutches in which the fluid actuates a piston incorporated in, i.e. rotating with the clutch the clutch having friction surfaces with clutch members exclusively moving axially with flat friction surfaces, e.g. discs
- F16D25/0638—Fluid-actuated clutches in which the fluid actuates a piston incorporated in, i.e. rotating with the clutch the clutch having friction surfaces with clutch members exclusively moving axially with flat friction surfaces, e.g. discs with more than two discs, e.g. multiple lamellae
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D48/00—External control of clutches
- F16D48/02—Control by fluid pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/02—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used
- F16H61/0202—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used the signals being electric
- F16H61/0204—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used the signals being electric for gearshift control, e.g. control functions for performing shifting or generation of shift signal
- F16H61/0206—Layout of electro-hydraulic control circuits, e.g. arrangement of valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/12—Detecting malfunction or potential malfunction, e.g. fail safe; Circumventing or fixing failures
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D48/00—External control of clutches
- F16D48/02—Control by fluid pressure
- F16D2048/0209—Control by fluid pressure characterised by fluid valves having control pistons, e.g. spools
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/12—Detecting malfunction or potential malfunction, e.g. fail safe; Circumventing or fixing failures
- F16H2061/1244—Keeping the current state
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/12—Detecting malfunction or potential malfunction, e.g. fail safe; Circumventing or fixing failures
- F16H2061/1256—Detecting malfunction or potential malfunction, e.g. fail safe; Circumventing or fixing failures characterised by the parts or units where malfunctioning was assumed or detected
- F16H2061/126—Detecting malfunction or potential malfunction, e.g. fail safe; Circumventing or fixing failures characterised by the parts or units where malfunctioning was assumed or detected the failing part is the controller
- F16H2061/1268—Electric parts of the controller, e.g. a defect solenoid, wiring or microprocessor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H63/00—Control outputs from the control unit to change-speed- or reversing-gearings for conveying rotary motion or to other devices than the final output mechanism
- F16H63/40—Control outputs from the control unit to change-speed- or reversing-gearings for conveying rotary motion or to other devices than the final output mechanism comprising signals other than signals for actuating the final output mechanisms
- F16H63/48—Signals to a parking brake or parking lock; Control of parking locks or brakes being part of the transmission
Definitions
- This invention relates to a fluid flow control apparatus and a valve system, and more particularly, though not exclusively, to a valve system for providing a "limp-home" function to an Automated Manual Transmission (AMT), Double Clutch Transmission (DCT), Continuously Variable Transmission (CVT) or other transmission having a wet or dry clutch whereby a vehicle fitted with the transmission can be driven in the event of electrical power failure.
- AMT Automated Manual Transmission
- DCT Double Clutch Transmission
- CVT Continuously Variable Transmission
- a recent wave of transmission inventions which incorporate wet (or dry) clutches have a common downfall in that, in the event of an electrical power failure, a "limp home” function is not available.
- the ability for a transmission to provide a "limp home” function is an inherent advantage in that it enables the driver to keep the vehicle mobile, with some loss of function, so as to be able to "limp home" to a location where the transmission can be diagnosed and repaired.
- Preferred examples of the present invention seek to provide a valve system which enables the above devices to perform in a similar manner to a normal automatic transmission (ie. one with a torque converter) when electrical power to the transmission is lost. That is, to provide such devices with a "limp home" function which enables a vehicle propelled by way of the transmission to be driven to a location where the transmission can be diagnosed and repaired.
- a fluid flow control apparatus including a fluid supply line having a flow constrictor, the fluid flow control apparatus being adapted for receiving fluid at pressure from a pump driven by an engine, a section downstream of the constrictor being adapted for fluid communication with a clutch device, wherein the flow constrictor reduces pressure of fluid from the pump so that when the engine is at idle fluid downstream of the constrictor is at a pressure below an activation pressure required to engage the clutch device, and wherein the pressure of fluid downstream of the constrictor is able to be raised to the activation pressure by increasing engine speed.
- the fluid flow control apparatus is in the form of a unitary device.
- the clutch device is operated by fluid via a first flow path when electrical power is available, and via the fluid flow control apparatus when electrical power is not available. More preferably, a valve automatically switches operation to the fluid flow control apparatus in response to a loss of electrical power.
- a valve system for controlling engagement of a hydraulically actuated clutch device, the valve system including a valve and a fluid supply line, wherein the valve is movable between a normal condition in which engagement of the clutch device is controlled by way of an electrically powered control and a power-loss condition in which engagement of the clutch device is controlled by controlling pressure of fluid from said fluid supply line, wherein the pressure of fluid from said fluid supply line is controlled independently of the electrically powered control, and wherein the valve is moved from the normal condition to the power-loss condition in response to loss of electrical power.
- fluid is fed to the fluid supply line by a pump, and pressure of fluid from said fluid supply line is controlled by controlling the pump. More preferably, the pressure of fluid from said fluid supply line is controlled by varying rotational speed of an input of the pump.
- the clutch device is for transmitting drive from an engine to a drive train of a vehicle, the pump is driven by the engine, and the pressure of fluid from said fluid supply line is controlled by increasing/decreasing engine speed.
- the fluid supply line includes a feed orifice for constricting fluid flow to the clutch device.
- the valve system includes a bleed orifice for constricting fluid flow from the clutch device.
- the feed orifice and bleed orifice are selected such that, when the engine is at idle the clutch device is disengaged and, when throttle of the engine is increased the clutch device engages progressively.
- the clutch device is a friction clutch.
- Figure 1 is a diagrammatic sketch of a valve system in accordance with a first example
- Figure 2 is a graph of fluid pressure versus current for the valve system of Figure 1;
- Figure 3 is a diagrammatic sketch of an engine coupled to a friction device controlled by the valve system of Figure 1;
- Figure 4 is a diagrammatic sketch of a valve system in accordance with an alternative example.
- Figure 5 is a diagrammatic sketch of an engine coupled to a typical existing automatic transmission having a torque converter.
- the valve system 10 shown in Figure 1 is for controlling engagement of a hydraulically actuated clutch device 12, and includes a valve 14 and a fluid flow control apparatus 15 having a fluid supply line 16 incorporating a pair of flow constrictors in the form of a feed orifice 38 and a bleed orifice 40.
- the valve 14 is movable between a normal condition (as shown) in which engagement of the clutch device 12 is controlled by way of an electrically powered control, and a power-loss condition in which engagement of the clutch device 12 is controlled by controlling pressure of fluid from the fluid supply line 16.
- the pressure of fluid from the fluid supply line 16 is controlled independently of the electrically powered control.
- the valve 14 Upon loss of electrical power, the valve 14 is moved from the normal condition to the power-loss condition so as to provide a limp home function.
- the clutch device 12 may form part of a transmission for transmitting drive from an engine of a vehicle to a drive train of the vehicle. Electrical power to the transmission may be lost by way of system failure or by default by a computer of the vehicle sensing a fault and switching off power to the transmission. In the case of the valve system 10 shown in Figure 1, loss of electrical power to the transmission will result in a solenoid 18 being denied electrical power.
- the solenoid 18 controls a line pressure regulator 20 which, in turn, controls pressure of hydraulic fluid in fluid line 22 which feeds the valve system 10.
- Figure 2 shows a graph of pressure of fluid in the fluid line 22 downstream of the line pressure regulator 20 on the vertical axis, against current supplied to the solenoid 18 on the horizontal axis.
- the normal operating range is between the broken lines, as indicated by arrow 24 however, in the event of loss of electrical power, the current supplied to the solenoid 18 will drop below the normal operating range 24 such that pressure of fluid in the fluid line 22 will rise into the power-loss range, as represented in the graph by arrow 26. On loss of electrical power, the solenoid 18 also toggles the valve
- valve 14 is shown in the normal condition and movement of the valve 14 to the power-loss condition will involve movement of the valve 14 to the right, as depicted by arrow 32. Movement of the valve 14 may also be controlled by way of a spring 34 which biases the valve 14 toward the normal condition.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Hydraulic Clutches, Magnetic Clutches, Fluid Clutches, And Fluid Joints (AREA)
Abstract
A fluid flow control apparatus including a fluid supply line (16) having a flow constrictor (38), the apparatus being adapted for receiving fluid at pressure from a pump (42) driven by an engine, a section downstream of the constrictor (38, 40) being adapted for fluid communication with a clutch device (12), wherein the flow constrictor (38, 40) reduces pressure of fluid from the pump (42) so that when the engine is at idle, fluid downstream of the constrictor (38, 40) is at a pressure below an activation pressure required to engage the clutch device (12), and wherein the pressure of fluid downstream of the constrictor (38,40) is able to be raised to the activation pressure by increasing engine speed. In an other embodiment a valve system for controlling engagement of a hydraulically actuated clutch device is disclosed, the valve system including a valve and a supply line, wherein the valve is movable between a normal condition and a power-loss condition in which the engagement of the clutch device is controlled independently of an electrically powered control and wherein the valve is moved to power-less condition in response to loss of electrical power.
Description
FLUID FLOW CONTROL APPARATUS AND VALVE SYSTEM
Field of the Invention
This invention relates to a fluid flow control apparatus and a valve system, and more particularly, though not exclusively, to a valve system for providing a "limp-home" function to an Automated Manual Transmission (AMT), Double Clutch Transmission (DCT), Continuously Variable Transmission (CVT) or other transmission having a wet or dry clutch whereby a vehicle fitted with the transmission can be driven in the event of electrical power failure.
Background of the Invention
A recent wave of transmission inventions which incorporate wet (or dry) clutches have a common downfall in that, in the event of an electrical power failure, a "limp home" function is not available. The ability for a transmission to provide a "limp home" function, as has been provided already in a normal automatic transmission (ie. an automatic transmission having a torque converter - see Figure 5) is an inherent advantage in that it enables the driver to keep the vehicle mobile, with some loss of function, so as to be able to "limp home" to a location where the transmission can be diagnosed and repaired.
With new automated manual transmissions, friction launch devices, decouplers and wet start clutches, it has not been possible to incorporate a limp home function.
Preferred examples of the present invention seek to provide a valve system which enables the above devices to perform in a similar manner to a normal automatic transmission (ie. one with a torque converter) when electrical power to the transmission is lost. That is, to provide such devices with a "limp home" function which enables a vehicle propelled by way of the transmission to be driven to a location where the transmission can be diagnosed and repaired.
Summary of the Invention
In accordance with one aspect, there is provided a fluid flow control apparatus including a fluid supply line having a flow constrictor, the fluid flow control apparatus being adapted for receiving fluid at pressure from a pump driven by an engine, a section downstream of the constrictor being adapted for fluid communication with a clutch device, wherein the flow constrictor reduces pressure of fluid from the pump so that when the engine is at idle fluid downstream of the constrictor is at a pressure below an activation pressure required to engage the clutch device, and wherein the pressure of fluid downstream of the constrictor is able to be raised to the activation pressure by increasing engine speed.
Preferably, the fluid flow control apparatus is provided with a second flow constrictor downstream of the first flow constrictor, and said section downstream of the first constrictor is between the first constrictor and the second constrictor. More preferably, the second flow constrictor is upstream of an exhaust, and the second flow constrictor slows flow of fluid through the fluid flow control apparatus.
Preferably, the fluid flow control apparatus is in the form of a unitary device.
Preferably, the clutch device is operated by fluid via a first flow path when electrical power is available, and via the fluid flow control apparatus when electrical power is not available. More preferably, a valve automatically switches operation to the fluid flow control apparatus in response to a loss of electrical power.
In accordance with another aspect, there is provided a valve system for controlling engagement of a hydraulically actuated clutch device, the valve system including a valve and a fluid supply line, wherein the valve is movable between a normal condition in which engagement of the clutch device is controlled by way of an electrically powered control and a power-loss condition in which engagement of the clutch device is controlled by controlling pressure of fluid from said fluid supply line, wherein the pressure of fluid from said fluid supply line is controlled independently of the electrically powered control, and
wherein the valve is moved from the normal condition to the power-loss condition in response to loss of electrical power.
Preferably, fluid is fed to the fluid supply line by a pump, and pressure of fluid from said fluid supply line is controlled by controlling the pump. More preferably, the pressure of fluid from said fluid supply line is controlled by varying rotational speed of an input of the pump.
Even more preferably, the clutch device is for transmitting drive from an engine to a drive train of a vehicle, the pump is driven by the engine, and the pressure of fluid from said fluid supply line is controlled by increasing/decreasing engine speed.
Preferably, the fluid supply line includes a feed orifice for constricting fluid flow to the clutch device. More preferably, the valve system includes a bleed orifice for constricting fluid flow from the clutch device. Even more preferably, the feed orifice and bleed orifice are selected such that, when the engine is at idle the clutch device is disengaged and, when throttle of the engine is increased the clutch device engages progressively.
Preferably, the valve system includes a solenoid which automatically moves the valve from the normal condition to the power-loss condition in response to loss of electrical power.
Preferably, the clutch device is a friction clutch.
Brief Description of the Drawings
The invention is described, by way of non-limiting example only, with reference to the accompanying drawings in which:
Figure 1 is a diagrammatic sketch of a valve system in accordance with a first example;
Figure 2 is a graph of fluid pressure versus current for the valve system of Figure 1;
Figure 3 is a diagrammatic sketch of an engine coupled to a friction device controlled by the valve system of Figure 1;
Figure 4 is a diagrammatic sketch of a valve system in accordance with an alternative example; and
Figure 5 is a diagrammatic sketch of an engine coupled to a typical existing automatic transmission having a torque converter.
Detailed Description
The valve system 10 shown in Figure 1 is for controlling engagement of a hydraulically actuated clutch device 12, and includes a valve 14 and a fluid flow control apparatus 15 having a fluid supply line 16 incorporating a pair of flow constrictors in the form of a feed orifice 38 and a bleed orifice 40. The valve 14 is movable between a normal condition (as shown) in which engagement of the clutch device 12 is controlled by way of an electrically powered control, and a power-loss condition in which engagement of the clutch device 12 is controlled by controlling pressure of fluid from the fluid supply line 16. The pressure of fluid from the fluid supply line 16 is controlled independently of the electrically powered control. Upon loss of electrical power, the valve 14 is moved from the normal condition to the power-loss condition so as to provide a limp home function.
For example, the clutch device 12 may form part of a transmission for transmitting drive from an engine of a vehicle to a drive train of the vehicle. Electrical power to the transmission may be lost by way of system failure or by default by a computer of the vehicle sensing a fault and switching off power to the transmission. In the case of the valve system 10 shown in Figure 1, loss of electrical power to the transmission will result in a solenoid 18 being denied electrical power. The solenoid 18 controls a line pressure regulator 20 which, in turn, controls pressure of hydraulic fluid in fluid line 22 which feeds the valve system 10.
Figure 2 shows a graph of pressure of fluid in the fluid line 22 downstream of the line pressure regulator 20 on the vertical axis, against current supplied to the solenoid 18 on the horizontal axis. The normal operating range is between the broken lines, as indicated by arrow 24 however, in the event of loss of electrical power, the current supplied to the solenoid 18 will drop below the normal operating range 24 such that pressure of fluid in the fluid line 22 will rise into the power-loss range, as represented in the graph by arrow 26. On loss of electrical power, the solenoid 18 also toggles the valve
14 to the power-loss condition so as to prevent flow from a clutch regulator valve 30 to the clutch device 12, and to enable flow from the fluid supply line 16 to the clutch device 12.
With reference to Figure 1, the valve 14 is shown in the normal condition and movement of the valve 14 to the power-loss condition will involve movement of the valve 14 to the right, as depicted by arrow 32. Movement of the valve 14 may also be controlled by way of a spring 34 which biases the valve 14 toward the normal condition.
When in the normal condition, engagement of the clutch device 12 is controlled by way of the clutch regulator valve 30, which in turn is controlled by way of a solenoid 36.
In the event of electrical power loss to the transmission, electrical power will also be lost to the solenoid 36 which, in the present example, is arranged to default to disabling passage of fluid through the clutch regulator valve 30.
Once the valve 14 is toggled to the power-loss condition, hydraulic fluid from the . clutch regulator valve 30 to the clutch device 12 is bypassed by the fluid supply line 16. Engagement of the clutch device 12 and, in particular control of slip of the clutch device 12, will instead by controlled by controlling pressure of fluid supplied by the fluid supply line 16 to the clutch device 12. More particularly, the amount of clutch pressure will depend on the pressure of fluid in the fluid supply line 16 between the feed orifice 38 and the bleed orifice 40. The feed orifice 38 reduces the fluid pressure to a level which is useable so as to selectively operate the clutch device 12 by varying fluid pressure provided by a pump 42 feeding the system 10.
The bleed orifice 40 is provided downstream of a junction 41 feeding the clutch device 12 such that fluid is exhausted through the bleed orifice 40. The exhaust may be fed to a lubrication circuit as may be required to provide additional cooling in view of heat generated by clutch slippage. As well as having an effect on the pressure at junction 41 used for controlling the clutch device 12, the bleed orifice 40 also serves to slow flow of hydraulic fluid through the exhaust 43 thus reducing the need for a high volume pump to supply the valve system 10 with hydraulic fluid. The flow rates of the orifices 38 and 40 will be tuned along with a capacity of the pump 42 to achieve useable control of clutch engagement and disengagement.
For the purpose of illustration of the function of the feed orifice 38 and bleed orifice 40, Figure 3 shows a diagrammatic sketch of an engine 39 coupled to a friction clutch 12 controlled by pressure of fluid supplied from between a feed orifice 38 and a bleed orifice 40. A feed line 44 is branched from the fluid supply line 16 at a junction 41 between the orifices 38, 40. A valve 45 which defaults to an open condition in the event of electrical power failure is located along the feed line 44, and pressure fed by the feed line 44 to the friction clutch 12 controls engagement/disengagement and slippage of the clutch 12. As described with reference to Figure 1, the pressure of fluid in the feed line 44 may be controlled by varying pressure of fluid fed to the feed orifice 38, for example by adjusting throttle of the engine 39 where the supply pump 42 is driven by the engine 39.
In the inset of Figure 2, there is shown a sketched graph representing the change in fluid pressure as the fluid flows through the feed and bleed orifices 38, 40, for four different supply pressures 46, 48, 50, 52, corresponding to four speed positions of the engine 39. The sketched graph is aligned with the feed orifice 38 and bleed orifice 40 shown below the graph, in order to demonstrate the fluid pressures before the feed orifice 38, between the feed orifice 38 and the bleed orifice 40, and after the bleed orifice 40. The supply pressure 46a, 48a, 50a, 52a (ie. before the feed orifice 38) is indicative of the fluid pressure upstream of the feed orifice 38, and corresponds to the maximum pressure supplied by the line pressure regulator 20.
Because the bleed orifice 40 is open to exhaust, a demand is placed on the pump 42 thus causing supply pressure to drop, hence causing a low fluid pressure between the feed
orifice 38 and the bleed orifice 40 which is insufficient to engage the clutch device 12 at idle (see line 46 in the graph of Figure 2). Once output of the pump 42 is increased, for example by increasing the throttle of the engine 39 driving the pump 42, the pump flow arid pressure increases (see lines 48, 50 and 52 in the graph of Figure 2) and the clutch 12 begins to apply thus causing the engine to drive the transmission, and thus the vehicle. Accordingly, a limp home mode with controllable clutch slip is achieved.
Because of this slip, as mentioned above, it may be advantageous to allow the oil escaping from the orifice 40 to be dumped into a transmission lubricant circuit, thus providing additional lubrication flow to keep the clutch 12 lubricated and cool.
If a driver of the vehicle wishes to disengage the limp home function, he or she simply disengages the manual valve 28 by moving the gear selector device to a different position (for example "Neutral" or "Park"), or may simply reduce the throttle to prevent transmission of drive. The gear selector device may be in the form of, for example, a T- bar, column shift, push-button selector, or the like.
The limp-home function of the valve system 10 will be performed whenever electrical power is lost to the transmission with the gear selector in a "Drive" or "Reverse" range.
An alternative valve system 10 is shown in Figure 4, with like features being indicated with like reference numerals.
The above valve systems have been described by way of example only and modifications are possible within the scope of the invention. For example, in one form the fluid flow control apparatus 15 may be provided in a unitary solenoid type device which is connected to receive electrical power and which, in the absence of receiving electrical power, routes fluid flow through the fluid flow control apparatus 15 so as to activate the limp home function.
Claims
1. A fluid flow control apparatus including a fluid supply line having a flow constrictor, the fluid flow control apparatus being adapted for receiving fluid at pressure from a pump driven by an engine, a section downstream of the constrictor being adapted for fluid communication with a clutch device, wherein the flow constrictor reduces pressure of fluid from the pump so that when the engine is at idle fluid downstream of the constrictor is at a pressure below an activation pressure required to engage the clutch device, and wherein the pressure of fluid downstream of the constrictor is able to be raised to the activation pressure by increasing engine speed.
2. A fluid flow control apparatus as claimed in claim 1, wherein the fluid flow control apparatus is provided with a second flow constrictor downstream of the first flow constrictor, and said section downstream of the first constrictor is between the first constrictor and the second constrictor.
3. A fluid flow control apparatus as claimed in claim 2, wherein the second flow constrictor is upstream of an exhaust, and the second flow constrictor slows flow of fluid through the fluid flow control apparatus.
4. A fluid flow control apparatus as claimed in any one of claims 1 to 3, wherein the fluid flow control apparatus is in the form of a unitary device.
5. A fluid flow control apparatus as claimed in any one of claims 1 to 4, wherein the clutch device is operated by fluid via a first flow path when electrical power is available, and via the fluid flow control apparatus when electrical power is not available.
6. A fluid flow control apparatus as claimed in claim 5, wherein a valve automatically switches operation to the fluid flow control apparatus in response to a loss of electrical power.
7. A fluid flow control apparatus as claimed in any one of claims 1 to 6, wherein the clutch device is a friction clutch.
8. A valve system for controlling engagement of a hydraulically actuated clutch device, the valve system including a valve and a fluid supply line, wherein the valve is movable between a normal condition in which engagement of the clutch device is controlled by way of an electrically powered control and a power-loss condition in which engagement of the clutch device is controlled by controlling pressure of fluid from said fluid supply line, wherein the pressure of fluid from said fluid supply line is controlled independently of the electrically powered control, and wherein the valve is moved from the normal condition to the power-loss condition in response to loss of electrical power.
9. A valve system as claimed in claim 8, wherein fluid is fed to the fluid supply line by a pump, and pressure of fluid from said fluid supply line is controlled by controlling the pump.
10. A valve system as claimed in claim 9, wherein the pressure of fluid from said fluid supply line is controlled by varying rotational speed of an input of the pump.
11. A valve system as claimed in claim 9 or claim 10, wherein the clutch device is for transmitting drive from an engine to a drive train of a vehicle, the pump is driven by the engine, and the pressure of fluid from said fluid supply line is controlled by increasing/decreasing engine speed.
12. A valve system as claimed in any one of claims 8 to 11, wherein the fluid supply line includes a feed orifice for constricting fluid flow to the clutch device.
13. A valve system as claimed in claim 12, wherein the valve system includes a bleed orifice for constricting fluid flow from the clutch device.
14. A valve system as claimed in claim 13, wherein the feed orifice and bleed orifice are selected such that, when the engine is at idle the clutch device is disengaged and, when throttle of the engine is increased the clutch device engages progressively.
15, A valve system as claimed in any one of claims 8 to 14, wherein the valve system includes a solenoid which automatically moves the valve from the normal condition to the power-loss condition in response to loss of electrical power.
16. A valve system as claimed in any one of claims 8 to 15, wherein the clutch device is a friction clutch.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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AU2005901904 | 2005-04-18 | ||
AU2005901904A AU2005901904A0 (en) | 2005-04-18 | Fluid Flow Control Apparatus and Valve System |
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Publication Number | Publication Date |
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WO2006110946A1 true WO2006110946A1 (en) | 2006-10-26 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/AU2006/000508 WO2006110946A1 (en) | 2005-04-18 | 2006-04-13 | Fluid flow control apparatus and valve system |
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Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1991013266A1 (en) * | 1990-02-24 | 1991-09-05 | Automotive Products Plc | A clutch control system |
EP0982512A2 (en) * | 1998-08-26 | 2000-03-01 | Honda Giken Kogyo Kabushiki Kaisha | Clutch hydraulic controller |
US20020148310A1 (en) * | 2001-04-16 | 2002-10-17 | Satoshi Uchino | Hydraulic control system of automated manual transmission |
US20040149535A1 (en) * | 2003-01-30 | 2004-08-05 | Thilo Schmidt | Device for the control of a hydraulically actuated clutch of an automatic transmission |
-
2006
- 2006-04-13 WO PCT/AU2006/000508 patent/WO2006110946A1/en active Application Filing
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1991013266A1 (en) * | 1990-02-24 | 1991-09-05 | Automotive Products Plc | A clutch control system |
EP0982512A2 (en) * | 1998-08-26 | 2000-03-01 | Honda Giken Kogyo Kabushiki Kaisha | Clutch hydraulic controller |
US20020148310A1 (en) * | 2001-04-16 | 2002-10-17 | Satoshi Uchino | Hydraulic control system of automated manual transmission |
US20040149535A1 (en) * | 2003-01-30 | 2004-08-05 | Thilo Schmidt | Device for the control of a hydraulically actuated clutch of an automatic transmission |
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