MATEC Web of Conferences 184, 01020 (2018) https://doi.org/10.1051/matecconf/201818401020 Annual Session of Scientific Papers IMT ORADEA 2018
Comparative analysis of automatic transmission and manual transmission behaviour on the worldwide harmonized light duty test cycle
Norbert Bagameri1, Bogdan Varga1, Aron Csato1 and Dan Moldovanu1,*
1Technical University of Cluj-Napoca, Automotive and Transport Department, 400641 Cluj-Napoca, Romania
Abstract. The European Commission has been actively involved in the development of the World-wide harmonized Light duty Test Cycle (WLTC). The aim of that project was to develop a harmonized light duty test cycle, that represents the average driving characteristics around the world and to have a legislative world-wide-
harmonized procedure put in place from 2017 and onwards for determining the level of CO2 emissions. This work presents the results of the effect of automatic and manual transmissions as a drivetrain of a light duty
vehicle on WLTC driving cycle. AVL Cruise software was used as simulation platform to analyse the CO2 level and fuel consumption of dynamic vehicle model using different type of drivetrains. At first the simulation tool and the most influential parameters of the driving cycle procedure are described. In the second phase various components and modules for both dynamic models using automatic and manual transmission, as well as the respective input parameters, were defined. Analyses are based on a developed dynamic vehicle model in AVL Cruise. Finally, the simulation results were evaluated and presented for the two dynamic models according to a legislative driving cycle to provide the basis fuel consumption and exhaust gas emissions.
1 Introduction Recently research and development trends in the 2 Driving cycle procedure automotive industry have been focused on developing The European Union has developed a new test, called the vehicles with drivetrains that are strongly driven by Worldwide Harmonised Light Vehicle Test Cycle steadily increasing demands on improvements in fuel (WLTC). The WLTC has been developed with driving consumption, emissions and performance. The profile obtained from in use driving data and a test transportation sector is currently responsible for over 20% procedure more realistic in terms of vehicle mass and of emission of greenhouse pollutants, emissions that resistance to progress. The New European Driving cycle directly affect the climatic conditions of the planet. (NEDC) significantly differs from WLTC characterized Increased emissions in conjunction with achieving the by a shorter duration and distance, longer idling and maximum degree of natural regeneration of the cruising time and lower speed and acceleration. Although environment lead to serious problems related to pollution WLTC driving cycle profile is more transient than NEDC, [1, 2]. Since the early phase of the automotive when these two cycles are tested under the same driving development, the interaction between the environment resistance. In WLTC are taking into account its minimum and the traffic has been represented by an ever-increasing and maximum unladen mass, which is defined as the number of legal standards related to reducing the exhaust vehicle’s standard weight without driver, fluid or any gas pollutants, hazardous substances and waste. The additional equipment, the maximum permissible weight, increasingly high traffic density, high demand of mobility the difference in rolling resistance between different tire and transportation adversely have a significant impact on versions, as well as the difference in aerodynamic the environment, causing the large societal problems such resistance expressed as the product of the drag coefficient as a rapid depleting petroleum resources, an increasing air and the frontal area between vehicle model with the best pollution and global warming [3]. and worst aerodynamics. Because pollutant emissions The European Union automobile industry welcomes the from vehicles are caused by combustion of a fuel shift to WLTC and has actively contributed to the generally fossil fuels, increasing the efficiency and development of this new test cycle. effectiveness of vehicles drivetrain is constantly the focus
* Corresponding author: [email protected]
© The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/). MATEC Web of Conferences 184, 01020 (2018) https://doi.org/10.1051/matecconf/201818401020 Annual Session of Scientific Papers IMT ORADEA 2018
of attention of researchers fro the auto otive industry rans ission ontroller of ual lutch rans ission he o ective of was to rovide a ore ro ust consists of shift state controller, which reselects the gear test asis and a rocedure which is ore re resentative of according to the current and desired vehicle s eed, which actual on road vehicle o eration significantly can e characteri ed y gearshift schedule differs fro , its ain differences affecting fuel consu tion include the test cycle and gear shifting se uence, vehicle ass definition, road load deter ination, chassis dyna o eter reconditioning ,
3 Simulation software package odelling various natural or artificial rocesses and heno ena in engineering is achieved y a lying and erfor ance of co le athe atical odels sing the ruise software si ulations can e develo ed, controlled and coordinated at the sa e ti e to achieve results and solutions to o ti i e and i rove the
performance of vehicle’s technical system and are Fig. 2. AVL Cruise component model of the vehicle. analysed in ter s of erfor ance and o erating efficiency n order to uantify and analyse the effect of This simulation model was developed based on an the drivetrain in the e issions and fuel consu tion on existing vehicle using technical data provided by the driving cycle si ulations were erfor ed on two manufacturer to simulate and to put in evidence the different trans issions Fig. 1 represents the WLTC advantages and disadvantages of the drivetrain powered a driving cycle. front wheel drive vehicle equipped with manual transmission and with automatic dual clutch transmission. After every component of the vehicle model is set up the model is tested on the WLTC driving cycle. The basic parameters of the vehicle model are given in Table 1. Table 1. DCT Vehicle model parameters
Parameters Value ehicle ass g ngine dis lace ent c Fig. 1. WLTC driving cycle. ngine a i u ower ngine a i u s eed r 4 Model description ngine nertia g inal drive ratio In the following paragraph provide a description of the lutch inertia g drivetrains used for vehicles: with manual transmission lutch inertia g and automatic transmission. The vehicle model includes rontal area the various sub-models. The vehicle model is a structure rag coefficient that has been developed to simulate accurately the two types of drivetrains. They are not different in the Final drive is a gear step with fixed ratio. It can be used as arrangement of components of the drivetrain. The a transmission step of the differential also called final developed model consists of components that exist in drive unit. A drive torque will be transferred to a power vehicles, such as the internal combustion engine, take of torque of the transmission step by considering the transmission, control and program of the transmission, transmission, the mass moments of inertia, and the brake system, steering system, wheels and the respective moment of loss [4, 5]. The gear ratios of the transmissions connections among them which can be either mechanical are given in the Table 2. or electrical. Each component is described by several parameters and is configurable in such a way that it can Table 2. ear ratio represent a vehicle for this study. The main components of the simulation model with reference to Fig. 2, are the Gear Gear ratio internal combustion engine and the attached mechanical consumer, manual/automatic transmission together with st the controller that controls the operation of the gearbox nd rd such as the gearshift schedule, the differential together th with the final drive, the brakes, the cockpit, the vehicle th body, the electrical system which includes the battery and th other modules essential for initiating the simulation. he
2 MATEC Web of Conferences 184, 01020 (2018) https://doi.org/10.1051/matecconf/201818401020 Annual Session of Scientific Papers IMT ORADEA 2018
The driver should imitate the behaviour of a real driver as operates fre ent ear chan es more operations over well as possible. Everything that would normally be the cycle than the man al transmission controlled by a real driver, such as turning the steering wheel, stepping on the gas, brake and clutch pedal, shifting gears on the manual transmission is controlled by the virtual driver. s the driver controls the cl tch pedal it is necessary to e press the cl tch position as a f nction of time d rin cl tch en a ement phase
5 Drivetrain of the vehicle o different transmission types ere eval ated one of the is the conventional man al transmission hich has a limited n m er of ears ma im m p to si and the a tomatic transmission sin t o cl tches one for the odd ears and one for the even ears n case of the man al transmission the entire synchroni ation process can e Fig. 4. ariation of the f el cons mption d rin drivin cycle divided in nine sta es ta e free travel from ne tral position hich has no tor e transfer his sta e can also start from a disen a ement from a previo s ear called In the simulation carried out with AVL Cruise WLTC here as start of disen a ement ta e e innin of the regulation fixed points, the total CO emissions were contact amon str t and synchroni ation rin initiatin found higher by 6 % higher for the case using automatic the inde in process or preselectin ta e inde in dual clutch transmission than using the manual process concl ded ta e contact of synchroni ation transmission vehicle when compared to the WLTC CO rin ith the sleeve cone initiatin the synchroni ation emissions curve. phase ta e end of synchroni ation rin loc in and e innin of rin and ear t rn d e to cone friction ta e second free travel ta e tip contact of the sleeve a ainst the ear cl tch asher n this sta e is possi le to detect the do le mp phenomena ta e end of ear an lar movement ta e f ll en a ement n the follo in in i the shiftin sched le is presented for the pshift and do nshift process
Fig. 5. ariaton of emissions over the drivin cycle Fig. 3. hiftin strate y for pshift and do nshift