The Contemporary Automatic Gearboxes

doi:10.5937/jaes11-3820 Paper number: 11(2013)2, 253, 89 - 97 THE CONTEMPORARY AUTOMATIC GEARBOXES - REVIEW OF THE CURRENT STATE AND INTERPRETATION OF ADVANTAGES AND DISADVANTAGES OF THEIR USE WITH RESPECT TO VEHICLE PERFORMANCE AND TRAFFIC SAFETY Darko Stanojeviü* University of Belgrade, Faculty of Mechanical Engineering, Belgrade, Serbia Vladimir Spasojeviü SDT Group DOO, Belgrade, Serbia Igor Stevanoviü Porsche Beograd Ada , Belgrade, Serbia Aleksandar Nediü Insurance Company Dunav, Belgrade, Serbia The aim of this paper is to present the current state of development level of contemporary automatic gearboxes in the automotive industry, their level of presence, as well as to bring the concept of a possible positive impact of their use on road safety as a solution designed with a high percentage of electronic components and cybernetics. The fi rst section provides an overview of the types of automatic gearboxes in recent time and a short description of their function principles. The second section provides interpretation of possible positive efects of their using in automotive industry with respect to vehicle performance and traffi c safety. Keywords: Contemporary automatic gearboxes, Traffi c safety, Vehicle performance, Automotive industry INTRODUCTION relationship “man-machine”. The modern age would be almost unthinkable without the high Nowadays motor vehicles have equipment which presence of this transportation asset. Currently, makes driving more comfortable, safer and reli- technical characteristics and performances of able for drivers during exploitation of vehicle. Au- vehicle systems are highly developed and new tomotive manufactures are pressured to deliver technologies provide higher safeness and com- complex products with increased quality in short- fort during driving. Although the drivers percep- er development cycles. Engineering the perfor- tion and reactions during driving still play a key mance of mechanical designs with traditionally role in traffi c safety, thanks to the different new test-based development processes are no lon- age vehicle systems in accordance with their de- ger an option [03]. New technologies include not velopment, safe motion of vehicle increasingly only the systems that have been designed in less depends on driver behavior. Nevertheless, the traditional way, i.e. systems that only include user requirements of motor vehicles are increas- mechanical and electronic components, but also ingly higher in terms of performance, but so that those that include communication models, con- increasing effect does not have infl uence on their trol mechanisms, which work principle is based safeness. The most merit for positive effect of ra- on information theory, computer and transmis- tio perfomances-saffness has high participation sion signal theory, feedback theory. [02] In last of the mechanical, electronic, computing and few decades it can be said that vehicles play a communication components in vehicle systems. key role in theory which explains connection and Among the systems such as Electronic Stability * University of Belgrade, Faculty of Mechanical Engineering, Kraljice Marije 16, 11000 Belgrade, Serbia; 89 [email protected] Darko Stanojeviü - The contemporary automatic gearboxes - review of the current state and interpretation of advantages and disadvantages of their use with respect to vehicle performance and traffi c safety Program (ESP), the adaptive cruise control, the all mentioned qualities and at the same time low lane change warning system, the assisted park- price. First automatic gearboxes have appeared ing system, the multiplexed systems and con- in USA at the end of 40’s of the last century but nectivity could be considered as part of the new during the 50’s, 70 % of vehicles already have vehicle technology, there are also found contem- automatic transmission. At the beginning of porary automatic gearboxes such as intelligent or 2000-ies even 90% of vehicle have automatic auto adaptive gearboxes and Automatic-sequen- gearboxes while their participation in Japan was tial gearboxes (manumatic – tiptronic, geartron- 70% and in Europe only 16%. (Figure 1) ic, touch shift, sporttronic) and others. [02] The question arises: How can the using of automatic transmissions affect traffi c safety? Generally, when the topic is vehicle safety, automatic gearboxes, as part of vehicle transmission, belong to the active elements of vehicle safety, because effect of their failure leads directly to traffi c ac- cident. In terms of vehicle performance, positive effects of using automatic gearboxes are proven Figure 1: Participation of automatic transmission on and well-known [08]: vehicles at the beginning of 2000-ies in the world • increasing lifetime of engine and transmission Till the 80’s automatic gearboxes had no electronic central unit to control the gears. The gear • increasing of dynamic characteristics of shift depended on the accelerator’s position and vehicle the control was done by a set of valves that were • increasing of vehicle patency moved by the oil pressure difference around • increasing of productivity of vehicle them. It was a hydraulic control system. [02] • reduction of toxicity of exhaust gases When electronics came into the market, at the end In terms of relationship „man-machine”, or in this of the 80’s the gear shifts were not done by me- case in terms of ergonomically view of vehicle chanic references any more, but by a set of rules design, there is a different interpretation of posi- established by electronics. Several sensors mea- tive effects of using automatic transmission. In sure the vehicle’s speed, the accelerator´s position this paper beside interpretation of current state and speed, the connected gear, etc. This informa- of development level of contemporary automatic tion is received by the electronic central unit that gearboxes, is also represented one approach of sets the connected gear at every moment. interpretation of using automatic transmissions Intelligent or auto adaptive gearboxes with respect to traffi c safety. The aim of this transmission is to adapt to driver´s CONTEMPORARY AUTOMATIC needs and driving style, in every moment of vehi- GEARBOXES cle movement, learning the driver’s habits during vehicle operation. [02] These types of automatic Words automatism and automatic comes from transmission control use several behavior laws Greek language and denote the science of self- and next installed sensors are responsible for movement, i.e. denote something that works by selecting of the most suitable law: accelerator’s itself. Automatic transmission is one of the most position and action speed, vehicle speed, engine complex subsystems in motor vehicles. Design torque, slope, gearbox temperature, etc. of automatic transmissions demands knowledge of the numerous areas of technology, not only Example of one intelligent or auto adaptive mechanical but also others, especially electronic gearbox is type AL4. [04] This type of automatic area. More than 100 components demand not transmissions can mostly be found on French ve- only the precise manufacture, small masses, hicles of new generation such as CITROEN C5, compact solutions and reliable operation, but PEUGEOT 308, 407 etc. Furthermore, in shorter also the easy and fast maintenance and easy terms will be presented technical description changing of gears in all exploitation conditions. and working principle of this type of automatic The aim of every automatic transmission design- transmissions. er is to realize such components which will have 90 Journal of Applied Engineering Science 11(2013)2 , 253 Darko Stanojeviü - The contemporary automatic gearboxes - review of the current state and interpretation of advantages and disadvantages of their use with respect to vehicle performance and traffi c safety AL4 type includes following mechanical compo- 12. Hydraulic distributor (DH) nents: 13. Manual valve 1. Converter 14. Auxiliary hydraulic distributor (DHA) 2. Input shaft 15. Clutch E1 (Reverse and 1st) 3. Fitted oil pump 16. Clutch E2 (2nd, 3rd, 4th) 4. Secondary pinion of step down gear 17. Hub 5. Park wheel 18. Brake F1 (4th) 6. Secondary shaft 19. Brake F2 (Reverse) 7. Drive pinion 20. Brake F3 (1st and 2nd) 8. Ring 21. Epicyclical gear train 9. Differential unit 22. Primary pinion of step down gear [04] 10. Cover All mechanical components of AL4 automatic 11. Adjustable plate gearbox can be seen on fi gure 2. Figure 2: Cross-section of AL4 automatic transmission [04] Auto adaptive or intelligent control at this type of Gear changing are performed automaticly and automatic gearbox is provided by: depends on vehicle speed and loads of engine. • Hidraulic control unit Laws of gear changing are selected by ECU in • Electronic control unit (ECU) function of 3 driving modes: • Auto adaptive or normal mode, basic mode; • Electronic participation Journal of Applied Engineering Science 11(2013)2, 253 91 Darko Stanojeviü - The contemporary automatic gearboxes - review of the current state and interpretation of advantages and disadvantages of their use with respect to vehicle performance and traffi c safety ECU provides adaptation to the driver gearboxes are using double or multiple clutches. habits, load of engine, road profi le. Manumatic is more useful for everyday use be- Characteristic of this mode is economic cause clutch in fl uid provides smooth and insen- driving or low consumption of gas sibly gear changing. Manumatic and most semi- • Sport mode - fast driving. Characteristic of automatic transmissions

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