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 gear- boxes, 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 elec- tronic 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 offer ability to work on this mode is higher consumption, but still the same principle as conventional automatic performed automatic gear changing gearboxes, letting the computer to choose the automatic most suitable gear. The most present manumat- ic is Tiptronic. Tiptronic is registered trademark, • Snow mode – mode for driving on surface owned by german sport car manufacure Porshe, with low adhesion [04] which licensed it for other car producers, such Electronic control unit (ECU) automatically acti- as: Land Rover and Volkswagen Group (Audi, vates normal mode, every time when vehicle is SEAT, Škoda and Volkswagen). [08] in that kind of exploatation conditions. Tiptronic transmission is equipped with intel- Electronic control unit (ECU) provides 10 gear ligent electronic program for control which was changing laws during transmission, in accor- developed in cooperation with Bosh. As well as dance with drivers habits, chosen drive mode many automatic transmissions tiptronic automat- and internal and external conditions: ic transmission has got blocking clutch for torque • 6 laws: for autoadaptivity, converter which is switched in second, third and • 1 law: for the snow program, fourth gear, and in fi fth gear in the newest ver- • 1 law: “unlocked” for low temperature sion of tiptronic. Gear lever mode of tiptronic has operation, two parallel trajectories. (Figure 3) • 1 law: for depollution when cold (heating), • 1 law: for automatic transmission temperature protection. So, AL4 automatic gearbox provides precise adaptive control as well as good quality of gear changing. Automatic sequential gearboxes This type of automatic gearbox provides two work principles. First one is completely automat- ic, when gearbox performs itself selected gear, and second one is manual (sequential), when driver decides which gear is the most suitable for current driving, using the selector lever and this is the reason why this automatic gearboxes Figure 3: Lever for automatic or manual selection are also called manumatic, because they pro- of gears in gear box-Tiptronic [08] vide most suitable choice of transmission. [02] Left trajectory corresponds to standard automat- Control of gear selection manumatic is provided ic transmission with positions P, R, N, D while with selector lever implemented behind steering right trajectory have position with tags “+”, “-“ wheel or with modifi ed selector lever implement- and M which is designed for manual transmis- ed in tunnel between two seats, or with buttons sion. Launching the lever gear in direction “+” on steering wheel, which for result gives easier performs shifting to higher gear, while launch- control during driving. Different car producers are ing the lever gear in direction “-“ performs shift- using various names for their manumatic gear- boxes: Tiptronic, Geartronic, Touchshift, Sport- ing to a lower gear. In comparison with earlier tronic and other. Different between manumatic transmissions with electronic control and “rigid” and semi-automatic gearboxes is in mode of program control, Tiptronic control characteristic transmission from engine to gearing. Manumatic is adaptive. At sudden acceleration, electronic is using torque converter as well as convention- device recognize sport ambitions of driver be- al automatic gearboxes, while semi-automatic haviour and allows one extreme characteristic of gear changing. On the other hand, if driver 92 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 drives too “soft”, transmission is programmed to other possibilities of gear changing laws which perform timely changing of gear to higher trans- correspond to all drivers behaviour. The concept mission. [08] of tiptronic control can be seen on Figure 4. Between this two extremes are located three

Figure 4: Concept of tiptronic control [08]

Figure 5: Programs of Tiptronic transmission control [08]

One signifi cant parameter of tiptronic trans- sion that means switching to lower gear. Beside mission control is speed of layoff of gas pedal. this it is very important that an unwanted change If speed of layoff is slow, for tiptronic control to a higher gear does not perform in curvature. system that means further moving with current In curvature, lateral acceleration sensor acts, speed, and switching to higher gear. If speed of which hold the most optimal gear for currently layoff of gas pedal is fast, for tiptronic transmis- drive speed. Also with electronic, which is re-

Journal of Applied Engineering Science 11(2013)2, 253 93 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

sponsible for control of automatic transmission is tronic reacts by switching the higher gear and connected ABS (Anti – lock braking system) sys- prevents inadequately engine braking. If driver tem. A sensor channel of ABS system provides wants to be more active during driving is left pos- traction control through regulation of gear. ABS sibility to shift the lever gear in right trajectory control unit compares rotation number of driven and then to shift gears by itself. However, in this and propulsive wheels and recognizes difference case electronic also protects engine of the large between their traction. [09, 08] At braking, in this number of RPM. Otherwise, during driving the situation, the automatic performs changing in driver has need to return lever gear from manual higher gear, and thus prevents additional block- to automatic mode, because he quickly gets to ing of rear wheels. On fi gure 5, it can be seen conclusion that automatic transmission could do programs of control of Tiptronic transmission. this function by itself. Control unit of tiptronic transmission control is During operation in automatic mode, electronic eight-bit microcontroller with 32 kb of memory. control unit needed 30-100 milliseconds to pro- This microcontroller processes information about cess all information and to task appropriate com- vehicle speed, positions and speed of throttle mands. To switch from KF1 to KF5, it is neces- butterfl y, number of engine rotations (RMP), sary at least 30 seconds. Effi ciency of adaptive lateral and longitudinal acceleration of vehicle. transmission control depends of number of in- Thereby, is mentioned electronic unit connected stalled programs in computer and of number pa- with engine electronic. According to these pa- rameters which are determining them. Because rameters different programs of tiptronic control constant tendency to sequential transmissions are possible. If the shift lever is placed on posi- Porsche for model 911S had launched new ver- tion of automatic gear shifting, the possibilities sion of tiptronic transmission under the name of work principle of automatic transmission are Tiptronic S. Command of this tiptronic version is following: replaced from fl oor to steering wheel. Keys on • At starting the vehicle, the automatic trans- steering wheel showed that they are more practi- mission works at the lowest program mode cal for shifting then commands on the fl oor. On of gear shifting, according to the characteris- the lever gear, on the tunnel between two seats, tic KF1, which provides the most comfort and were left same marks for transmission opera- fuel economy; tions in automatic mode as they have been in • If driver shows increasingly sports behaviour previous version of tiptronic. during driving, automatic transmission will Thanks to the high development programs for gear recognize them, and will perform gear shift- shifting, in practice is creating strong competition ing according to the characteristic KF2, KF3, between automatic and conventional transmis- KF4 up to KF5 (sport characteristic). [08] sions. Better acceleration of vehicle this transmis- In base, electronic device is programmed to work sion does not reach compared with conventional at the lower characteristic, which means earlier transmissions. However, thanks to the many num- gear shifting to a higher gear and later gear shift- ber parameters which were placed in electronic, ing to a lower gear. Thus, fuel consumption is tiptronic have numerous benefi ts. The Computer optimised, noise and exhaust emissions are re- program is open for learning and it is able to “Re- duced. At quickly layoff of gas pedal, ahead of member” driver’s behaviour, among other things, the curve, previous automatic transmissions re- also when driver manually shift gears. acted inadequately, performing gear shifting to GPS - controlled automatic transmission a higher gear. Tiptronic transmission is better It is good to mention the newest design solu- informed and do not react like that. Additional tion of control of automatic transmissions. It has benefi t includes possibilities of engine braking in been launched this year, 2013, and it is GPS - current gear, which means absent of gear shift- controlled transmission. Rolls-Royce engineers ing in lower gear, when is exiting the curve. To created this solution of control of automatic the value of 0.4 G of lateral acceleration, which transmissions and call “Satellite Aided Transmis- were measured by sensor of lateral acceleration, sion” (SAT). Control unit of eight-speed auto- automatic transmission do not react in curve and matic transmission is linked to Global Position that means continual driving. Also, at surface with System (GPS) receiver. Vehicle with this kind of snow, ice i.e. at surface with low adhesion, elec- automatic transmission control uses satellites

94 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 to constantly determine conditions of road pro- due to the own automatic transmission, driver fi le. It then uses this data to anticipate how and can more pay attention to the acceleration, steer- when to shift gears. For example, if GPS deter- ing and braking , which for results gives improve mines twisty road and vehicle coming into a turn, safeness in driving. Table 1 presents review of this system holds currently gear, which is better advantages and disadvantages of using auto- than upshifting. GPS fi gures out what upcoming matic transmissions. stretches of road look like, and pre-shifts accord- ingly. For example, it can downshift the moment Table 1: Comparation of advantages and disadvantages of using automatic transmissions a hill or curve is approached, which helps with both performance and fuel economy. Quite liter- Advantages Disadvantages ally, it can be said, that Satellite Aided Transmis- Increasing of increasing of comfort sion uses GPS data and the navigation system to maintenance costs scan the road. The navigation system compiles Increasing of simplicity of using real-time traffi c data and uses the data to update fuel consumption the travel route every three minutes. [05] Reducing presence of limited transmission shock loads ADVANTAGES AND DISADVANTAGES OF USING THE AUTOMATIC TRANSMISSION TRAFFIC SAFETY IN TERMS IN TERMS OF VEHICLE PERFORMANCE OF AUTOMATIC TRANSMISSIONS When the topic is automatic transmission it Driving in complex traffi c environments could be means transmission which work principle is com- very diffi cult for drivers, especially in conditions pletely opposite from manual. Automatic trans- of traffi c where is present often interaction with mission works without often interruptions, with other drivers. In that condition, it is concluded minimal appearance of shock loads, which for that older drivers increasingly lose power of result gives comfortable driving. It is clear that quickly perception and reasoning. One of the transmission is performed automatically, and de- prerequisites for safe driving is attention. When pends of vehicle speed, where hydraulic torque mental resources are not suffi cient to meet all converter provides absence of clutch pedal, the impose tasks, the driver will see only the lim- which for driver means relief of often suppres- ited set of information which he will use for decision sion of clutch pedal, and therefore it increases making and response to the demanding tasks [07]. comfortable in driving. [05] According to the performed statistic, older drivers In terms of fuel consumption, due to the com- crash more frequently in complex traffi c environ- plexity of the system and large energy loss in hy- ments, then younger drivers and especially in inter- draulic torque converter, automatic transmission sections which involve turning, especially turning is not at an enviable level. Because of the men- across the oncoming lane, and in complex traffi c tioned reasons, vehicle with automatic transmis- situations, i.e., when overtaking and merging. Re- sions are vehicles that could be characterized as sults are contradictions about tactical performanc- vehicles with higher fuel consumption. [06] Also, es of older drivers and driving skills. While some in terms of maintenance, i.e. preventive and cor- claim younger drivers make more driving errors rective maintenance vehicles with automatic than older drivers, older drivers have been found transmission could be classifi ed as vehicles with to have more problems with operational driving higher maintenance costs. skills. In this case it was observed and performed Automatic gear shifting, do not give choice of comparison of driving skills of younger and older gear for the driver, so that is why it is possible drivers in aspect of automatic and manually trans- absence of fast drive feeling. In terms of com- missions. More precisely it was compared one fortable, automatic gearboxes are in advantage. particular operational driving skill, gear changing, Automatic transmission provides comfortable at younger and older drivers. during driving, especially in conditions of “traf- Research involved two groups of participants, fi c jams”, which could be described as “go-stop” population of older drivers, between the ages traffi c, because of absents of clutch pedal and of 70 – 90 years, (average age 75.2) and popu- manually gear shifting. Using of automatic gear- lation of younger drivers, between the ages of boxes do not demand special driver skills, and 27 – 48 years (average age 39.2). All partici-

Journal of Applied Engineering Science 11(2013)2, 253 95 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

pants drove the same route, one in vehicle with car with manual transmission and in the automat- manually transmissions and one in vehicle with ic transmission car, compared with the younger automatic transmissions. Each test took 35 min, group. [01] In the older group, driving the auto- in city traffi c, thus to every chosen route had to matic transmission car improved their driving be- be diverse in terms of traffi c complexity, i.e. to in- haviour regarding the number of driving errors. volve many crossroads, left and right turns, traf- However, the car with automatic transmission did fi c signs. For evaluation of driver’s skills during not affect the driving behaviour for the younger the tests, it was used ROA software (Ryd On- group, except for the turning left-task. Road Assessment). [01] ROA software is using Automatic transmission had positive impact on scoring sheet which involve 34 specifi ed items in driver behaviour of older drivers in fi ve driving seven categories (Table 2): speed, position, at- items. The two showing the largest impacts were tention, indicator, manoeuvring, instructions, and Manoeuvring – Change gear, indicating inappropri- traffi c rules showed on fi gure 10. Made errors are ate gear usage and Speed-Too fast for the situa- graded on a 0-2 scale, where 0 implies normal tion relating to problems with controlling the speed driving behaviour, 1 indicates minor error, while according to the situation. The other three items 2 indicates considerable risk-taking behaviour. were Manoeuvring – Handling pedals, Traffi c rules Results of performed tests are showing that the –Exceeding speed limit and Position – To the left. older group made more driving errors, both, in the

Figure 6: Items indicated in italics were the ones in which the automatic transmission car had a signifi cantly positive impact for the older group, which is further displayed in the bar chart in the lower part of the fi gure. The X-axis represents the average number of errors [01]

Table 2: Scoring sheet with 34 specifi ed items in seven categories [01]

96 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

The present study found that the older partici- functional it would need to know about the cam- pants’ driving behaviour improved when driving ber of corners, the inclinometer of hills and to be a car with automatic transmission. As a result of able to sense other vehicles in proximity and how the automatic transmission they displayed safer they are being driven. Generally, it can be said speed adjustments in urban areas, safer lane that automatic transmission is widely accepted, positioning, greater manoeuvring skills and bet- but does this methods of controlling automatic ter attention to the speed regulations while for transmissions is widely accepted remains to be younger drivers, automatic transmission had less answered to above mentioned questions. effect on their driving behaviour. [01] Switching to ACKNOWLEDGMENT automatic transmission may be recommended for older drivers as a means to maintain safe driving This paper is part of research of the project: proj- and thereby the quality of their transport mobility. ect number TR35045 (Scientifi c and technologi- cal support for improving the safety of special CONCLUSION road and rail vehicles, project supported by Min- Contemporary technology is in constant devel- istry of Education, Science and Technological opment. Contemporary automatic transmissions development of Republic of Serbia. and different methods for control automatic gear- REFERENCES boxes such as intelligent or auto adaptive con- trol; automatic sequential control or GPS-con- 1) Falkmer, T., Selander, H., Bolin, I. (2011): “Why drive trolled transmissions are part of development, manual? – Automatic transmission improves driving and present major role. Work principles of these behavior in older drivers”, ARSRPE Conference methods of control of automatic gearboxes are 2) Francisco Gonzales de Prado: “Cybernetics described, and it is clearly that introduction of applications in vehicles”, Master in Cybernetics such controls provides increasing of safeness Research, University of León, September 2012 and proven better performances of motor ve- 3) Glišoviü, J., Demiü, M., Miloradoviü, D. (2011): hicles. But, questions arise: Does such meth- Review of virtual reality applications for re- ods of controlling the automatic transmissions ducing time and cost of vehicle development are better for drivers? Does really make driving cycle, Journal of Applied Engineering Science more comfortable, pleasant and without stress? (Istraživanja i projektovanja u privredi), no. 3, Opinions are divided. Interaction between driv- vol.9, pp. 361-372 ers and system of motor vehicles, in this case 4) http://AL4%20Transmission.pdf: Citroen tech- interaction between drivers and gearboxes could nical training: ”Presentation of AL4 automatic be answer. For some drivers, it is better to have trasnmission” higher physical contact with road profi le and for them that represents better controlling of vehicle 5) http://www.autoblog.com/2013/03/04/rolls- transmission and furthermore better controlling royce-wraith-geneva-2013/ of complete vehicle, while for some drivers ab- 6) Mayur R. Mogre (2012): “Comparative study be- sence of physical contact presents more com- tween Automatic and Manual transmission car”, fortable and pleasant driving. Based on this it International conference on mechanical, Auto- can be said that driving experiences decides mobile and Biodiesel Engineering, pp. 308-312 whether to accept these types of automatic gear- 7) Paviü, N., Popoviü, V., Vasiü, M. (2011): Driv- boxes. Intelligent or auto adaptive control is us- ers age as the dominant demographic factor ing learning of the driver’s habits during vehicle in traffi c accident, Journal of Applied Engi- operation to control transmission. Does driver’s neering Science (Istraživanja i projektovanja habits are always the same for all drivers? That u privredi), no. 3, vol.9, pp. 411-416 could be reason for further research. Also it is 8) V.Spasojeviü (2012): Diplomski MSc rad: “Savre- good to mention one further remark about GPS- mena mehatroniþka rešenja – automatski menjaþki controlled transmissions. Currently road data for prenosnici”, Mašinski fakultet, Beograd car navigation according to the driver’s experi- ences, in many cases, is not complete and this 9) Živanoviü,Z.,Janiüijeviü,N.(1999):Automatske method of controlling of automatic transmissions transmisije motornih vozila, Beograd: Ecolibri would require signifi cantly better road data that Paper sent to revision: 25.04.2013. is currently available. In order to be safe and Paper ready for publication: 23.05.2013.

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