Title of Invention

"INDEL DRIVE TORQUE CONTROL FOR AUTOMATED VEHICULAR MASTER CLUTCH"

Abstract

A control for a vehicle drive line system (10) including an automated vehicle master clutch (14) drivingly interposed in between a fuel-controlled engine (12) and the input shaft (20) of a mechanical transmission. At sensed idle conditions (THL REF and OS REF), the engine (12) is commanded to generate an output to rque (T fw) equal to a selected idle drive torque (T idle) at idle speed (ES IDLE), the engine is commanded to rotate at idle speed and the clutch, preferably a wet clutch, is caused to engage with a to rque capacity equal to the idle drive torque.

Full Text

FIELD OF THE INVENTION The present Invention relates to controls for vehicular master clutches, preferably wet friction dutches, utilized in partially or fully automated mechanical transmission systems. In particular, the present Invention relates to a control for a vehicle master clutch, preferably a wet clutch, wherein at idle conditions, the master chltch is engaged to a relatively low idle drive torque torque transfer capacity. DESCRIPTION OF THE PRIOR ART Partlally and fully automated vehicular mechanical transmission systems utilizing friction master clutches are known in the prior art, as may be seen by reference to U.S. Pats. No. 4,361,060; 4,596,986; 4,850,236; 4,648,290; 5,389.053; 5,487,004; 5,487,005 and 5,509,867, the disclosures of which are incorporated herein by reference. Controls for automated friction master clutches, usually dry friction dutches, utilized in vehicular automated transmission systems are known, as may be seen by reference to U.S. Pats. No. 4,081,065; 4,646,891; 4,860,861; 5,275,267; 5,293,316; 5,314,050; 5.337,868; 5,337,874; 5,383.823; 5,393,274; 5,411.124; 5,404,301; 5,630,773; 5,624.350 and 5.738,609. the disclosures of which are incorporated herein by reference. 2 SUMMARY OF THE INVENTION According to the present inveniton, a control for an automated master friction clutch, such as a wet frict'on clutch, is provided which utilizes the information available on industry standard electronic vehicular data links, such as data links conforming to the SAE J1922, SAE J1939 and/Or ISO 11898 protocols, to provide improved clutch control and clutch functional features as compared to the prior art. By sensing and controlling engine flywheel torque utilizing an electronically controHed engine connected to an Industry standard data HnL (see U.S. Pat. No. 5,609,867, the disclosure of which is incorporated herein by reference), and controlling the engaged condition of a master motion clutch, a master clutch drive train system providing an Vge to move" at idle conditions is provided. Accordingly, N Is an object of the present invention to provide an Improved control for a vehicle drive line including a master friction clutch which wHJ provide an "urge-to-move" torque at Idle conditions. This and other objects and advantages of the present invention will become apparent from a reading of the following description of the preferred embodiment taken in connection with the attached drawings. ( , BRIEF DESCRIPTION OF ^DRAWINGS li Fig. 1 is a schematic illustration of a vehicular automated mechanical transmission system advantageously utilizing the Idle drive torque master clutch control of the present invention. Fig. 2 Is a schematic lustration of a pressurized fluid-actuated control mechanism for controlling the engaged condition of a vehicular master clutch. Fig. 3 is a partial sectional view of a vehicular wet master friction clutch of the type utilized in the system of Fig. 1. Fig. 4 Is a schematic lustration of the idle drive torque master dutch control system of the present invention, which includes both hardware and software (shown in shadowed blocks). Fig. 5 is a schematic frustration, in flow chart format, of the idle drive torque master clutch control logic of the present invention. DESCERIPTION OF THE PREFERRED EMBODIMENT A vehicular automated mechanical transmission system 10 advantageously utilizing the idle drive torque master clutch control of the present invention is schematically ffiustrated in Fig. 1. System 10 incftides a fuef controfted engine 12, a wet master motion clutch 14 and a multiple-speed mechanical transmission 16. Engine 12 is rypicatty a dlesel or gasoline engine and has an output member or crank shaft 18 which drives friction discs 14A of clutch 14, which are interdigrtated with friction discs 14B, rotationafly fixed to Input shaft 20 of transmission 16. Transmission 16 may be of the simple or compound type, as frustrated in 'T^jU U.S. Pat. No..§,37O£6Oi0 disclosure of which fs incorporated herein by r ^ reference. Transmission 16 has an output shaft 22, which drives a drive shaft 24 ^y connected to the input 26 of a vehicle drive axle mechanism 27. An engine controller 28, which is preferably electronically and microprocessor-controlled, is provided for controlling fueling of the engine and for providing output information to an electronic data link DL, preferably conforming to the industry standard SAE J1939 or a comparable protocol. System 10 also includes a clutch actuator 30 for controlling operation of clutch 14 and a transmission actuator 32 for controlling operation of transmission 16. A sensor 33 is provided for sensing throttle 33A position and providing a signal THL indicative thereof. Throttle position Information also may be obtained from the data link. Electronic engines controlled by an SAE J1939 or simitar data link typically have four modes of operation, (I) fuel according to throttle position, (H) fuel according to requested engine speed, (Hi) fuel according to requested gross engine torque, and (*v) fuel according to requested engine speed and gross engine torque. A microprocessor-based control unit 34 is provided for receiving input signals 36 and processing same according to control logic to generate command output signals 38 to the system actuators. The ECU may be separate or integral with the engine controfler. The various controllers, sensors and/or actuators may communicate over a data link conforming to an Industry standard protocol, such as SAE J1939 or the like. Suitable sensors, such as sensors for sensing engine speed ES, input shafl speed IS and/or output shaft speed OS, and actuators are known to those of ordinary skill in the art and examples thereof, not intended to be limiting, may be seen by reference to U.S. Pats. No. 4,361,060; 4,873,881; 4.974.468; 5,135,218; 5,279,172; 5,305,240; 5,323,669; 5,408,898; 5,441,137; 5,445,126; 5,448,483 and 5,481,170. Clutch 14 is defined as a Vet dutch," as the friction members thereof, 14A and 14B, are exposed to liquid, such as s syn!he& such ss Oe&crt IS or the Hke, for heat transfer and/or lubrication purposes. In the frustrated embodiment, the clutch pack 14C Is contained within a housing 14D, which is connected to source conduit 14E and an exhaust conduit 14F. White a forced coolant system is Illustrated, the present invention also is applicable to wet clutches wherein the friction members are in a relatively static sump or the Hke. While the illustrated preferred embodiment utilizes a multidlsc wet clutch 14, the present invention also is applicable to single-disc wet clutches and/or dry clutches. As is known (see aforementioned U.S. Pat. No. 5,509,867), a data Unlit conforming to the SAE J1939 protocol or a comparable protocol, transmits information by which engine output torque (also called "flywheel torque") may be read or determined. These data links also attow a command to the engine to adjust fueling such that a particular engine speed and/or a particular engine torque is achieved. By utilizing this information and engine control capability, the master clutch 14 may be controlled to provide enhanced system performance. A fluid pressure-operated clutch actuator assembly 30 is schematically Illustrated in Fig. 2. A clutch operator piston 42 is received in a cylinder 44 and Is biased in the disengaging direction by springs 46. Pressurized fluid, such as a hydraulic fluid or pressurized air, introduced into chamber 48 wBI act on piston face 50 to move the piston 42 in the engaged direction against the bias of the springs. A two-position, three-way, solenoid-controlled vafve 52 is provided to selectively pressurize and exhaust chamber 48. A valve controller 54 responding to control signals from system controller 34 controls energizing of the solenoid 52A of valve 52, preferably by pulse width modulation (PWM). M^ Although a pressurized fluid-type actuator assembly 30 is fflusfraled, the present invention also is sppbcabie to dutch controls using other types of clutch actuators, such as ball ramp actuators or the like (see U.S. Pats. No. 5.441,137 and 5,485,903, the disclosures of which are incorporated herein by reference). The friction material of clutch discs 14A and 14B may be of standard material or may be of pyrotytic carbon, as disclosed in U.S. Pat. No. 4,700,823 or the like. The structure of a typical wet master friction clutch 14 may be seen by reference to Fig. 3. Briefly, the engine output 18, shown as a dampened flywheel, Is connected to the transmission input shaft 20 by the engageable and dlsengageable friction disc pack 14C. The clutch Is contained within a housing 14D, which will hotd (he lubricating and cooling fluid, such as a synthetic Oexfron HI or the like. Annular piston 42 Is stidabfy and sealingty contained in a cylinder 44 and is biased in the disengaged direction by springs 46. System 10 also may Include an inertia brake, also known as an Input shaft brake or upshift brake 60, for decelerating or stopping the input shaft 20 for more. ,? A^j^S^ rapid upshlfting. Inertia brakes are known, as may be seen by reference to U.S. Pats. No. 5,086,659 and 5,713,445 Applicants have discovered that, at engine Idle speed (about 850 to 900 RPM) with the transmission engaged in a low ratio, such as first gear, it is desirable that the engine generate at the flywheel, and the master clutch be slightly engaged to transfer, a small amount of torque sufficient to cause slow or creeping movement of the vehicle If the vehicle brakes are not applied. This will provide a mode of operation simitar to that expierienced by drivers of passenger automobiles equipped with torque converter-type transmissions. The advantages of such a provision for an "urge-to-move" feature in a drive line and automatic friction master clutch control Is that the vehicle will feel and act Nke a familiar passenger car equipped with an automatic transmission, the vehicle may be maneuvered at stow speeds using the brake pedal onty, and vehicle launches will be quicker with less lurch as the system backlashes have been taken up. The amount of flywheel or output torque generated by the engine at idle . 6- speed, and transferable by the clutch in the "Urge-to-move" engagement comfition (i.e., the idle drive torque) should be sufficient to allow creeping if the brakes are not applied but small enough to allow the clutch to dissipate the heat energy developed when the dutch is slipped due to application of the vehicle brakes. By way of example, for a medium-duty vehicle (MVMA Class 6 having a GVW of 19,501 to 25,000 pounds), a flywheel torque of about 20 to 30 pound-feet will provide about 3 horsepower, which is sufficient to move the vehicle and which generates an amount of heat at full slipping (900 RPM) that can be substantially continuously dissipated by a wet clutch. Of course, the amount of ¦urge-to-move' torque transferable by the clutch must also be selected so that only acceptable wear is caused during slipping when the vehicle Is maintained tn a stopped condition by application of the brakes. For purposes of explaining an example of the preferred embodiment fo the * _ _. present Invention, H is assumed that the system includes an SAE J1939-type data L$Mb*tM link, that engine speed (ES) and gross engine tofque (T £G)itay~be read and/or d' commanded on the data link and that wngine ftywtwml torqtj* (T rw) is **qual to . _ gross engine torque (T EG) minus certain friction and accessory torques (T P) A UASM Using this reiafionshipoT FW TtG TP),w1th/a known or calculated value for n parasitic torque (T P), the value of gross engine torque to be requested for a ^ ^ desired output or flywheel torque is known. Fig. 4 depicts the entire idle drive torque control system which comprises both hardware and software (shadowed blocks). The function of the engine control loop Is to maintain (or control) the engine speed to a desired speed. To engage the clutch, (he pressure controller will send a PWM command to the solenoid-actuated hydraulic system, which in turn pressurizes the clutch piston 42 to engage the clutch 14. The engaged clutch torque (especially at relatively low values, such as 0 !o 50 pound-feet) is substantially directly proportional to the PWM command. To engage the dutch to the idle drive torque level, the engine controller will first maintain the engine speed at a desired idle RPM by sending the appropriate engine torque request to the engine via the SAE J1939 communication link DL. When the engine control loop achieves its balance, the amount of torque request -7 - will be equal to that of engine friction torque (at desired idle RPM),plus the clutch torque (zero fnot engaged). Tr"e system w$ m©n try to engage the cKitch gradually to the level of desired idle drive torque (26 pound-feet). To do this, the system uses the value of torque request as the feedback reference As the clutch is being engaged graduafty. the k)ad to the engine Increases and, hence, siovys down the engine speed. In response to the speed change, the engine controller win increase the torque request to the engine to maintain the engine speed at the desired idle RPM. When the torque request-reaches the value of 26 pourKWeets-*? % $"Jfr\ above engine parasitic torque (f" EG Tp 26) and 'engine speed stabffizes at Idle speed, the engaged clutch torque wW then be equal to 26 pound-feet. The system witi try to maintain the clutch engagement at this level from this point on. IT for some reason the value of tor qua request changes (due to temperature changes or otherwise), the system will adjust the engine torque (PWM) command accordingly to maintain ttw torque request value at 26 pound-feet above engine parasitic torque and, hence, maintain the flywheel torque constant at 26 pound-feet. Using commands and feedback over the SAE J1939 data link DL, with the clutch 14 disengaged (therefore, toad is zero), the system will cause engine spaed to stabilize at Idle speed (about 850 to 900 RPM). The sensed gross anfline^^^^ J) torque at this point is equal to the parasitic torqu^T C p)/ When at a vehicle-stopped or low-speed condition (OS REF) with the operator throttle position equaling zero, the engine will be commanded to the Idle speed with a gross engine tm^iQ equaling the idle drive torque, plus the parasitic torque (T P Tro), and the clutch will be commanded Into the Idle drive torque capacity condition. The "urge-to move* feature also may require that the transmission be engaged in low gear, an acceptable start geat, or in reverse gear. Acceptable start gears will vary with the number of forward transmission ratios, as is known. 8- Accordingly, it may be seen that a new and improved drive line and master clutch control providing an idle drive torque is provided. Although the present invention has been described with a certain degree of particularity, it is understood that the description of the preferred embodiment is by way o f example only and that numerous changes to form and detail are possible without departing from the spirit and scope of the invention as hereinafter claimed. 9- WE CLAIM: 1. A method for controlling a vehicular drive line system (10) having a fuel-control led engine (12) comprising an output member (18), a multiple-speed change-gear transmission (16) Slaving an input shaft (20) drivingly coupled to said output member by a master friction clutch (14), a clutch operator (30) for selectively engaging and disengaging said clutch to provide a selected torque transfer capacity from said output member to said input shaft, an operator-set throttle device (33A) for manual requesting of fuel supply to said engine, an engine controller (28) for controlling fueling of said engine (12), said engine controller (28) effective to fuel said engine 12 to cause said engine (12) to rotate at a selected engine speed and to develop a selected torque, a system controller (34) for receiving input signals comprising signals indicative of (i) displacement of said throttle device (33A) and (ii) speed of said vehicle, and for processing same according to logic rules to issue command output signals to system actuators having said clutch operator and said engine controller, said method comprising the steps of - 10, (1) selecting an idle drive torque value; (2) comparing throttle device displacement to a first reference value and vehicle speed to a second reference value when the vehicle is stopped or in a low-speed condition; and (3) if throttle device displacement is no greater than said first reference value and vehicle speed is less than said second reference value, (i) causing said engine to rotate at a selected speed and to develop said idle drive torque at the output member thereof and 11. wherein said engine controller is commanded to cause said engine to generate a gross engine torque (TEG ), with said idle drive torque at the engine output (TFW ) equal to gross engine torque minus parasitic engine torque (TFw = TEG - Tp )> and parastic engine torque at a given engine speed is determined by a lookup table which uses the information of engine friction torque as an input to the table. 2. The method as claimed in claim 1 wherein said idle drive torque value is selected to be sufficient to move the vehicle on level ground if the vehicle brakes are not applied, but not sufficient to move the vehicle on level ground if the vehicle brakes are applied. 3. The method as claimed in claim 1 wherein said idle drive torque is less than ten percent (10%) of the rated input torque of the transmission. 12. 4- The method as claimed in claim 1 wherein said transmission has a rated input torque in the range of 554 to 830 Nm (400 to 600 pound-feet) and wherein said idle drive torque is in the range of 27.7 to 55.4 Nm (20 to 40 pound-feet). 5. The method as claimed in claim 1 wherein step additionally requires that said transmission be engaged in a starting gear. 6. The method as claimed in claim 1 wherein step (3) additional ly requires that said transmission be engaged in one of a low speed ratio and a reverse ratio. 7. The method as claimed in claim 1 wherein said first reference value equals about zero throttle displacement. 8. The method as claimed in claim 1 wherein said second reference value equals about 5 KPH (about 3 MPH). 9. The method as claimed in claim 1 wherein said selected speed is the preselected idle speed of said engine. 13. 10. A vehicular drive line system (10) having a fuel-controlled engine (12) comprising an output member (18)" a multiple-speed, change-geartransmission (16) having an iniput shaft (20) drivingly coupled to said output member by a master friction clutch (14), a clutch operator (30) for selectively engaging and disengaging said clutch (14) to provide a selected torque transfer capacity from said output member (IS) to said input shaft (20), an operator-set throttle device (33A) for manual requesting of fuel supply to said engine (12)* an engine fptrontroller (28) for controlling fueling of said engine (12)" said controller effective to fuel said engine (12) to cause said engine (12) to rotate at a selected engine speed and to develop a selected torque, a system controller (34) for receiving input signals comprising signals indicative of (i) displacement of said throttle device and (ii) speed of said vehicle, and for processing same according to logic rules to issue command output signals to system actuators having said clutch operator and said engine controller, said system comprising: 14. means for storing a preselected an idle drive torque value; (2) means for comparing throttle device displacement to a first reference value and vehicle speed to second reference value when the vehicle is stopped or in a low-speed condition; and (3) means for, if throttle device displacment is no greater than said first reference value and vehicle speed is less than said second reference value, causing said engine to rotate at a selected speed and to develop said idle drive torque at the output member thereof and (ii) causing said clutch to be partially engaged to have a torque transfer capacity equal to said idle drive torque" the system being characterized in that said engine controller comprises means causing said engine 15- to generate a gross engine torque 11. The system as claimed in claim 10 wherein said idle drive torque value is selected to be sufficient to move the vehicle on level ground if the vehicle brakes are not applied, but not sufficient to move the vehicle on level ground if the vehicle brakes are applied. 12. The systemf&s claimed in claim 10j wherein said idle drive torque is less than ten percent (1054) of the rated input torque of the transmission. 13. The system as claimed in claim 10 wherein said transmission has a rated input torque in the range of 554 to 830 Urn (400 to 600 pound-feet) and said idle drive torque is in the range of 27.7 to 55.4 Nm (20 to 40 pound-feet). 16. 14. The system as claimed in claim 11 which additionally requires that said transmission be engaged in a starting gear* 15. The system as claimed in claim 10 wherein said transmission is a mechanical transmission uti1izing positive jaw clutches. 16. The system as claimed in claim 10 wherein said clutch is a liquid-coaled wet clutch. 17. The system as claimed in claim 10 wherein said system *' Controller is microprocessor-based and said engine controller communicates with an electronic data link conforming to the protocols of one of SAE J1922, SAE J1939 or ISO 11898. 18. The system as claimed in claim X® wherein said first reference value equals about zero throttle displacement. 19. The system as claimed in claim 10 wherein said second reference value equals about 5KPH 17. 20. The system as claimed in claim 10 wherein said selected speed is the preselected idle speed of said engine. A control for a vehicle drive line system (10) including an automated vehicle master clutch (14) drivingly interposed in between a fuel-controlled engine (12) and the input shaft (20) of a mechanical transmission. At sensed idle conditions (THL REF and OS REF), the engine (12) is commanded to generate an output to rque (T fw) equal to a selected idle drive torque (T idle) at idle speed (ES IDLE), the engine is commanded to rotate at idle speed and the clutch, preferably a wet clutch, is caused to engage with a to rque capacity equal to the idle drive torque.

Documents:

00896-cal-1999-abstract.pdf

00896-cal-1999-claims.pdf

00896-cal-1999-correspondence.pdf

00896-cal-1999-description(complete).pdf

00896-cal-1999-drawings.pdf

00896-cal-1999-form-1.pdf

00896-cal-1999-form-18.pdf

00896-cal-1999-form-2.pdf

00896-cal-1999-form-3.pdf

00896-cal-1999-form-5.pdf

00896-cal-1999-g.p.a.pdf

00896-cal-1999-letters patent.pdf

00896-cal-1999-priority document.pdf

896-CAL-1999-FORM-27-1.pdf

896-CAL-1999-FORM-27.pdf