Interrelated power delivery controls – including engine control – Transmission control – With clutch control
Reexamination Certificate
2001-09-14
2003-08-05
Estremsky, Sherry (Department: 3681)
Interrelated power delivery controls, including engine control
Transmission control
With clutch control
C192S003550, C192S003570, C477S080000, C477S180000, C701S067000
Reexamination Certificate
active
06602161
ABSTRACT:
CROSS-REFERENCE TO RELATED CASES
This application claims the priority of the commonly owned German patent application Serial No. 199 11 332.7 filed Mar. 15, 1999 and of the International patent application Serial No. PCT/DE00/00800 filed Mar. 13, 2000. The disclosures of the above-referenced priority applications, as well as that of each U.S. and foreign patent and patent application identified in the specification of the present application, is incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to improvements in power trains for motor vehicles. More particularly, the invention relates to improvements in means for automatically controlling or regulating the operation of a component (such as the friction clutch) which, when engaged, is arranged to transmit torque between the rotary output element of a prime mover (such as the camshaft or the crankshaft of an internal combustion engine) and the rotary input element (such as the input shaft of a change-speed transmission, especially a transmission having a plurality of fixed ratios or gears including at least one reverse gear, a neutral gear and several forward gears). A ratio selector member, such as a lever, can be manipulated by the operator of the motor vehicle to select the necessary gear of the transmission. Such power trains are normally further equipped with accelerator pedals which are adjustable to regulate the RPM of the prime mover. The controls for the friction clutch are designed to automatically engage and disengage the clutch, i.e., to disengage the clutch prior to shifting of the transmission into a different gear and to automatically engage the clutch when the shifting into a selected gear is completed.
More specifically, the invention relates to power trains of the type wherein the clutch is operated automatically during the initial stage of operation of the power train, namely while the motor vehicle is being started from zero speed.
European patent No. 0038113 discloses a power train with a clutch control system which is designed to generate an RPM reference signal during starting of the motor vehicle and wherein the engine speed (i.e., the RPM of the rotary output element of the engine) is controlled by engaging the clutch in such a way that the engine speed follows an RPM reference signal. In accordance with the patented invention, the reference RPM is derived from the angle of the pivotable valving element or flap of the throttle valve which regulates the admission of fuel into the engine. The arrangement is such that, when the engine torque increases (i.e., in response to increased rate of fuel admission to the engine), the reference signal is altered in order to correspond (i.e., to be properly related) to the higher speed of the engine. The extent of engagement of the clutch is proportional to the difference between the engine speed and the reference RPM. The extent of engagement of the clutch increases if the difference between the (higher) engine speed and the (lower) reference RPM increases.
European patent No. 0696341 discloses certain modifications of the power train which is disclosed in the aforediscussed European patent No. 0038113. Such modifications take into consideration an increased idling RPM of the engine and the shifting of the transmission into a starting gear when the engine speed is increased (by opening the throttle valve) prior to shifting of the transmission into such.starting gear.
Additional modifications of the power train protected by the European patent No. 0038113 are disclosed in European patent No. 0735957, namely to ensure satisfactory regulation of engagement of the clutch when the motor vehicle is to be started at a low speed of the engine, i.e., when it is necessary to maneuver (operate) the motor vehicle at relatively low speeds of the engine or another suitable prime mover.
The combined teachings of the European patents Nos. 0038113, 0735957 and 0696341 disclose a power train wherein the operation of the clutch is adequately controlled during starting of the motor vehicle if the starting takes place while the throttle valve is open to a relatively small extent (i.e., when the angular position of the flap of the throttle valve is remote from the angular position such flap assumes in the fully open condition of the throttle valve. If the angle of the flap is less than 20% of the angle in the fully open position of the valve, the maximum torque normally develops at engine speeds of less than about 1500 1/min. If the angle is increased above 20% of the maximum angle, e.g., to between 60% and 90%, the engine speed rapidly increases to provide a maximum torque. In presently known power trains, such mode of operation permits for a rapid engagement of the clutch which, however, invariably or frequently entails a choking of the engine. Moreover, even though (under normal circumstances) certain presently known power trains permit for a starting of the motor vehicle from a standstill in a slightly open position of the throttle valve, it is necessary to open the throttle valve to a much greater extent if the vehicle is to be set in motion along a steep road surface and/or while the vehicle carries a substantial load.
International application Serial No. PCT/GB97/03497 (published Jul. 2, 1998) under No. WO 98/28162) discloses a method of determining, during a clutch reengagement stage, the so-called kiss point of the clutch. The latter includes a driven plate which transmits torque from the engine to the wheels by way of a multiple-ratio transmission when the clutch is engaged. The clutch actuating mechanism is controlled by an electronic control unit. The method includes the steps of checking whether or not the throttle valve is closed and the vehicle is in an engine overrun condition, partially reengaging the clutch up to a point where the clutch increases the engine speed to a substantially constant level below the speed of the drive plate, monitoring the position of the clutch actuating mechanism when the clutch is partly engaged, computing on the basis of such condition measurements and the known engagement/torque characteristics of the clutch at the current kiss-point position and completing the engagement of the clutch. The inventors named in the aforementioned U.S. patent state that the object of their invention is to calibrate the clutch and more specifically, to determine “the so-called ‘Kiss-point’ of a clutch when the clutch just begins to make frictional contact during its engagement”. The inventors further state that an object of their invention is to provide a method of determining the kiss-point of a clutch which can be regularly implemented during use of the associated vehicle with the minimal effect on the operation of the vehicle so that the determination is not perceived by the operator or passengers.
Commonly owned U.S. Pat. No. 5,176,234 (granted Jan. 5, 1992 to Reik et al. for “METHOD OF REGULATING THE OPERATION OF AUTOMATIC CLUTCHES”) discloses a method of regulating the operation of an automatic friction clutch, which is installed between a prime mover and a transmission in a power train of a motor vehicle, during at least one of various stages of operation including starting, driving, accelerating, braking, driving in reverse and parking of the vehicle and shifting of transmission into different gears as well as during transitions between such stages. The patented method comprises the steps of monitoring—at least for the purpose of starting the vehicle—at least one selected predetermined parameter including measuring the torque in the power train and/or the angular positions of clutch parts while the condition of the clutch is being changed from clutch-open, with the vehicle at a standstill and with the transmission in a gear other than neutral, at a predetermined speed toward clutch-closed to an extent such that the clutch transmits a torque less than that which is required to set the vehicle in motion, determining the clutch-open condition when the transmitted torque and/or the angular positions of clutch parts
Gunnerud Morten Berger
Hemmingsen Fred Roar
Ring Karl Frode
Sundet Torgeir
Waerp Ole Jonny
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