SE518960C2 - Power units for motor vehicles - Google Patents

Abstract

Drive unit for motor vehicles, comprising an internal combustion engine (1) and a non-synchronized auto-shift gearbox (9), which has an intermediate shaft 850) and is connected to the engine via an automated clutch (3). The clutch and the gearbox are controlled by an electronic control unit (45), to which there are fed signals representing the selected gear from a gear selector (46) and signals representing various engine and vehicle data. The control unit is disposed, when the gear selector is in the neutral position, the clutch is engaged and the vehicle speed is so low the synchronisation by means of the engine requires an engine rpm lower than the enging idle rpm, to first disengage the clutch, then brake the intermediate shaft to a standstill, thereafter engage the clutch slowly and finally engage the selected gear, when the input shaft has reached a suitable rpm range for engagement of the selected gear.

Description

'25 nous », nu ne. N '" eo: a oc *,., Unon: zi, uo I: _..,,. U 0 vxo. Vun... _ _ E' O .iuv _ ": c _ na. J. __, nu n. e e 2 possible to make the gearbox shorter or alternatively to with a given length make the gears wider than in a synchronized gearbox with a corresponding length to thereby enable the transmission of higher torques.

When the vehicle is stationary and the gear selector is in the neutral position, the clutch is normally engaged, so that torque is transmitted from the engine via the clutch to the input shaft of the gearbox and thereby also to its intermediate shaft. This is often used to drive the gearbox lubricating oil epump, which means that the gearbox bearing in this way is supplied with lubricating oil even in the neutral position of the gearbox when the clutch is engaged. When starting the vehicle, the clutch must first be disengaged before a starting gear can be engaged. If the gear to be engaged is an asynchronous gear, the interlocking gears on the main axle and the intermediate axle must first be decelerated to at least the next stationary position before The gearbox of the type in question usually has very small losses, which means that it would take too long from the time the clutch was disengaged until the rotating parts of the gearbox stopped, unless the rotating parts were actively braked. somehow.

A known way is to use an intermediate shaft brake, which quickly slows down the intermediate shaft to a standstill when the clutch is disengaged.

In the case of drive units of the type in question, however, problems arise in being able to comfortably load an unsynchronized gear at low speed without receiving scratching sound in the gearbox. Namely, if the speed of the vehicle is so low that a lower speed of the engine would be required than its idle speed in order to be able to synchronize with the engine the speed of the input shaft with the speed of the selected gear but so high that the intermediate axle brake can not be used to brake down the intermediate shaft, the transmission of the gear unit can only take place a number of seconds after disengagement, when the speed of the input shaft has been reduced to a suitable speed, if the loading is to be possible without scraping. Depending on the inertia of the rotating masses and the temperature of the oil in the gearbox, the required time before the gearing could be carried out without scraping would amount to between five and ten seconds. The object of the present invention is to provide a drive unit of the type indicated in the introduction, which obviates the above-mentioned problems by enabling quick and convenient loading without a scraper of a gear, when the vehicle's speed is so low that synchronization by speed control of the motor is not possible, but so high that shifting immediately after braking of the intermediate shaft to a stop by means of the intermediate shaft brake cannot be carried out without scraping.

This is achieved according to the invention in that the control unit is arranged that - when the gear selector is in the neutral position, the clutch is engaged and the vehicle speed is so low that synchronization with the engine requires lower engine speed than the engine idle speed for the selected gear - when moving the gear selector to the selected gear position in turn disengage the clutch, activate said well means to quickly decelerate the intermediate shaft to at least almost stationary, engage the clutch so that the input shaft is accelerated slowly and finally activate said clutch means to engage the selected gear, when the input shaft has reached a speed range suitable for the loading of the selected gear.

In a preferred embodiment, the control unit is arranged to, under said conditions, first set the clutch in the pulling position and then slowly increase the clutch force, so that the input shaft is accelerated up to a suitable speed range. For the identification of the traction position and the control of the connection, a control unit of the type shown and described in SE 9903117-1 is preferably used.

The invention is described in more detail with reference to exemplary embodiments shown in the accompanying drawings, in which fi g. 1 shows a schematic representation of an embodiment of a drive unit according to the invention, fi g. 2 clutch and gearbox in fi g. 1 on an enlarged scale and fi g. 3 is a diagram of the speed of the input shaft depending on the engagement and disengagement process of the clutch when the gear is engaged at low speed.

I fi g. 1 denotes a six-cylinder internal combustion engine, for example a diesel engine, the crankshaft 2 of which is coupled to a single-disc dry single-clutch coupling generally denoted by 3, 10 15 20 '-ß: unng sn; va u 518 960 ëäu fi faseavwnua 4 which is enclosed in a coupling housing 4. Instead of a single-disc slat coupling, a two-disc coupling can be used. The crankshaft 2 is non-rotatably connected to the coupling housing 5 of the clutch 3, while its lamella disc 6 is non-rotatably connected to an input shaft 7, which is rotatably mounted in the housing 8 of a gearbox generally designated 9. In the housing 8, a main shaft 10 and an intermediate shaft 11 are rotatably mounted.

As most clearly shown by fi g. 2, a gear 12 is rotatably mounted on the input shaft 7 and lockable on the shaft by means of a coupling sleeve 13 provided with synchronizing means, which is rotatably but axially displaceably mounted on a hub 14 inextricably connected to the input shaft. By means of the coupling sleeve 13 also a gear wheel 15 rotatably mounted on the main shaft 10 lockably relative to the input shaft 7. The gears 12 and 15 engage with gears 16 and 16, respectively. 17, which are non-rotatably connected to the intermediate shaft 1 1. On the intermediate shaft 11, further gears 18, 19 and 20 are rotatably arranged, which engage with gears 21, 22 and 22, respectively, rotatably mounted on the main shaft 10. 23, which are lockable on the main shaft by means of coupling sleeves 24 resp. 25, which in the embodiment shown do not have synchronizing devices. On the main shaft 10, a further gear 28 is rotatably mounted and engages with an intermediate gear 30 rotatably mounted on a separate shaft 29, which in turn engages with the intermediate shaft gear 20. The gear 28 is lockable on its shaft by means of a coupling sleeve 26.

The gear pairs 12, 16 and 15, 17 and the clutch sleeve 13 form a split gear with a low gear stage LS and a high gear stage HS. The pair of gears 15, 17 together with the pair of gears 21, 18, 22, 19, 23, 20 and 28, 30 also form a basic gearbox with four forward gears and a reverse gear. At the output end of the main shaft 10, a gear 31 is arranged rotatably, which forms the sun gear in a planetary type two-speed gearbox designated 32, whose planet gear carrier 33 is rotatably connected to a shaft 34, which forms the output shaft of the gearbox. The planetary gear 35 of the range gear 32 engages with a ring gear 36, which by means of a coupling sleeve 37 is lockable relative to the gearbox housing 8 for low-range LR and relative to the planetary gear carrier 33 for high-range HR. The coupling sleeve 37 also has a neutral position NR lying between the gear positions LR and HR, in which the output shaft 34 is disengaged from the main shaft 10.

The coupling sleeves 13, 24, 25, 26 and 37 are displaceable as the arrows show in fi g. 2, whereby the gear steps shown in connection with the arrows are obtained. The displacement is effected in fi g. 2, schematically indicated servos 40, 41, 42, 43 and 44, which may be pneumatically actuated piston-cylinder devices of the type used in a gearbox of the type described above, which is marketed under the name Geartronic®. The servo unit is controlled by an electronic control unit 45 (fi g. 1), comprising a microcomputer, depending on signals input into the control unit representing different engine and vehicle data, which includes at least engine speed, vehicle speed, clutch and accelerator pedal position and, where applicable, engine brake to -from, when an electronic gear selector 46 connected to the control unit 45 is in its automatic position. When the selector is in the position for manual shifting, the shifting takes place at the driver's command via the gear selector 46. The control unit 45 also controls the fuel injection, ie the engine speed, depending on the accelerator pedal position and the air supply to a pneumatic piston-cylinder device 47.

The control unit 45 is programmed in a known manner so that it keeps the clutch 3 engaged when the vehicle is stationary and the gear selector 46 is in the neutral position. This means that the motor drives the input shaft 7 and thus also the intermediate shaft, while the output shaft 34 is disengaged. Any attachments driven by the intermediate shaft, such as an oil pump for gearbox lubrication, are operated in this position. The control unit 45 is further programmed to, when the vehicle is stationary and the gear selector fl is moved from the neutral position to a gear position, either to a position for automatic transmission or to a position with the starter selected by the driver, first disengage the clutch 3, then brake the intermediate shaft ll to stop using of it in fi g. 2, which may be a per se known brake device controlled by the control unit 45. With the intermediate shaft 11 braked to a stop or in any case at least almost to a stop, the control unit 45 now initiates shifting in the base gearbox to a gear which is given by the automatic or by the driver selected total gear. When the driver after loading the gear »rush 1st: - 10 15 20,. u In a u 518 960 f 6 provides gas, the accelerator pedal acts as a reverse clutch pedal, which via the control unit gradually increases the clutch engagement with increasing throttle.

If the vehicle is not completely stationary when the gear selector 46 fl is shifted from the neutral position to a gear position, but its speed is so low that synchronization of the selected gear by means of the motor would require an engine speed below the engine idle speed, the shifting process takes place in the manner illustrated in the diagram in fi g. 3, where the solid line 7, 7, line a marks the idle speed of the engine, which in the example shown is assumed to be 600 rpm. The area between the dashed lines “b” and “c”, approx. 350-450 rpm, marks the speed range within which the speed of the input shaft 7 must be in order for shifting to the selected gear to take place without scraping. When moving the gear selector 46 from the neutral position, the control unit 45 initiates disengagement of the clutch 3. Then the control unit activates the intermediate shaft brake 50, which quickly brakes down the intermediate shaft 11 to stop, as illustrated by the line "d". Thereafter, the control unit initiates engagement of the clutch 3 by first setting it in the traction position and then successively increasing the engagement until the speed of the input shaft 7 reaches the desired speed range between lines "b" and "c", as illustrated by line " e ”. With the speed of the input shaft within the specified range, the control unit 45 initiates the loading of the selected gear. The control unit can, for example, be programmed to control the engagement process, so that the coupling 3 transmits such a low torque that the acceleration of the input shaft 7 from stop to 350-450 rpm takes about 0.3-0.6 s.

Claims (3)

10 15 20 f '25 .Ivan Ina). 518,960 Patent claims A drive unit for a motor vehicle, comprising a combustion engine (1) and an input shaft (7) connected via an automated vane coupling (3) to the engine crankshaft (2) to a stepped gearbox (9) having at least one housed in a housing between shaft (11), which has at least one gear (16, 17) in engagement with a gear (12, 15) on the input shaft and brake means (50), by means of which the rotation of the intermediate shaft can be rapidly slowed down to zero when disengaging the clutch, a main shaft (10) mounted in the housing with gears (1 5,2l, 22,23), which engages with gears (17,18, 19,20) on the intermediate shaft, the at least one gear in each pair engaging with each other gears on the intermediate shaft and the main shaft are rotatably mounted on their shaft and lockable by means of coupling means (13,24,25), of which at least the coupling means for some forward gears lack synchronizing function, and cooperating actuators (40,41,42) cooperating with the coupling means, which are controlled by one connected to a gear selector (46) n control unit (45), in which signals representing the selected gear are entered and various engine and vehicle data, which at least include engine speed, input shaft speed, vehicle speed, clutch position and accelerator pedal position, characterized in that the control unit (45) is arranged that - when the gear selector (46) is in the neutral position, the clutch (3) is engaged and the vehicle speed is so low that synchronization with the engine requires lower nine-torque than the engine idle speed for the selected gear - when moving the gear selector to the selected gear position in turn and order disengage the clutch, activate said brake means (50) to quickly brake the rotation of the intermediate shaft to at least almost stationary, engage the clutch so that the input shaft (7) is accelerated slowly, and activate said clutch means (13 , 24,25) to load in the selected gear, when the input shaft has reached a speed range suitable for the loading of the selected gear. Drive unit according to claim 1, characterized in that the control unit (45) is arranged to, under said conditions when coupling the coupling (3), first quickly set the coupling in the pulling position and then slowly increase the coupling force. 518 960 8 Drive unit according to claim 1 or 2, characterized in that the control unit (45) is arranged to control the clutch (3), so that under said conditions the input shaft is accelerated up to a suitable speed range of about 0.3 - 0.6 s . »Upon 11 :: -