SIMULATION OF AN UNCONVENTIONAL VEHICLE TRANSMISSION

Transcription

1 SIMULATION OF AN UNCONVENTIONAL VEHICLE TRANSMISSION František BRUMERČÍK 1 Introduction Most of the common used commercial vehicles have regular manual transmission, which works with the ste ratio change via the so called range and slit transmission gear grous. The tendency is to make the work of the driver less comlicated by the automated manual gearboxes (e.g. Volvo I-Shift, Allison gearboxes by Scania, etc.), increasing the efficiency and driving comfort. The common structure of the drivetrain with an automatic transmission is the ower transmission line built in the sequence of the engine - torque converter - automated ste gearbox driven by the electromechanical elements - transaxle. This article resents an unconventional rincile of the ower flow transmission, different from the commonly used drivetrain. It is a combined hydromechanical transmission with hydrostatic units and torque converter in arallel lines with mechanical comonents roviding the continuously gear ratio change. The mathematical model describing this system is quite comlicated, but when correct done, it can increase the quality of the research and develoment rocess significantly. 2 System and model structure The resented transmission contains mechanical arts (gears, shafts, one way clutches), the hydrostatic units and a comlex hydrodynamic torque converter. One of the hydrostatic units is regulated via the roortional derivative (PD) control system, which controls the angle of the unit regulation late inclination β. The ower flow is divided into mechanical, hydrostatic and hydrodynamic line during the continuously ratio change the gearbox works as a continuously variable transmission (CVT). It was develoed for vehicles with the maximum total engine ower of 1 kw. The kinematic structure of the resented gearbox is shown on fig. 1. After the kinematic and dynamic analysis of the transmission structure was done, the block mathematical model was built. It is based on Matlab / Simulink environment. -36-

2 The whole model is assembled from artial subsystems reresented via calculation blocks. The mechanical, hydrostatic and hydrodynamic ower flow line just as well the electronic control system has its own subsystem block that is connected to the other arts of the model. The diagram of the mathematical block model of the whole transmission system is shown on fig. 2. Fig. 1 Kinematic structure of the transmission Source: [2] -37-

3 Fig. 2 Block structure of the mathematical transmission model -1 MCA =-MC u [omegax 1] -K- etac =PX /Pm Abs MC, MT, etahdm etac Poloha lynu alfa omegam -K- -34 /35 -K- ixa omegax 1, omegam, ixa MC omegac Zataz MZS MZS PX 17 /36 omegaxr =omegas.z6/z14 [omegaxr ] Goto 2 MCA Pm MA M1A omegamoz omegaa =-omegam.z9/z1 MT omegat etahdm Komlexny HDM (58 /32 )*.98 MTS =MT.(z8/z7).etavo MTS omegas MrS Hriadel S -19 /47 omegax 1=-omegaS.z11/z12 [omegax 1] Goto 1 Hriadel A -58 /32 omegat =-omegas.z8/z7 MC -81 /75 omega1 M1A MT omega omegaq omega 1=omegaA.z1/z2 beta1 M1 omega -r-q omegamoz iv eta1 MC, MT, M1, M2-17 /46 omegar Mr (17 /46 )*.98 5 oz omegam oz beta1 [beta 1] Goto [beta 1] From beta 1 Hydrorevodnik HP 1 iv omega2 M2 Mq eta2 omegar =-omegas.z6/z5 Mq M MrS=Mr.(z6/z5).etavo PD regulator Hydrorevodnik HP 2 Diferencial DX PA Pm omega1 PT PC beta1 etaq1 omega2 etaq2 iv Generator tlaku eta 1, eta 2, etaq 1, etaq 2 M -r-q P1 P2 Divide -81 /47 Pomerne vykony omega 2=-omegaq.z4/z3 PIred 2 PX1 iv=omega 1/omega 2 -K- etac 1 omegac PIredA PIredS n1, n2, nc, nt etac 2 etac 1, etac 2 omegat -1 MA =-M Source: [1] 3 Simulation rincile The simulation of a vehicle transmission is based on a system resonse to a load set, which reresents the vehicle drive resistance forces or torques. The minimum and maximum resistance torques were calculated according the kinematic structure without the consideration of ower losses along the transmission ower flow line. After the simulation of the system resonse to the constant minimal and maximal load, the ste load change was simulated to test the quality of the control system. The real load changes in the traffic are not so stee, so the robustness of the PD regulator subsystem is tested roerly. The load ste change is shown on fig

4 Fig. 3 Load ste change diagram MIN-MAX-MIN Load ste Load torque Time (sec) Source: [2] 4 Simulation results The initial condition of the simulation rogress from to 3 sec. was the engine idle running and the gas edal ut on 1% by the minimal load alied. After 3 seconds, in which the gearbox outut shaft X reached stabilized seed revolution value, the load stes to maximum and the seed of the outut shaft dros significantly. This is the moment, when the observation of the system behavior starts to be interesting. The achievement of the steady state as a resonse to the load ste in the 3 th and 4 th sec. is monitored and refers to the quality of the PD control system changing the β arameter of the regulated hydrostatic unit. The results of this articular simulation are shown on fig. 4 to

5 Fig. 4 Seed of the engine crank shaft (m), outut gearbox shaft (X) and the gearbox outut / inut shaft seed ratio 23 Engine seed n m (min -1 ) Gearbox outut shaft seed n X1 (min -1 ) Gearbox outut and inut shaft seed ratio i XA Fig. 5 The hydrostatic unit regulation late inclination (β 1 ).8 beta

6 Fig. 6 The global efficiency of the transmission (η c ).9 etac c Fig. 7 Torque on the hydrostatic and hydrodynamic transmission arts (M) 6 MC, MT, M1, M Pum wheel torque M C Turbine wheel torque M T Hydro-unit 1 torque M 1 Hydro-unit 2 torque M 2 2 M (N.m)

7 Fig. 8 Seed of the the hydrostatic and hydrodynamic transmission arts (n) 25 n1, n2, nc, nt n (min -1 ) Hydro-unit 1 seed n 1 Hydro-unit 2 seed n 2 Pum wheel seed n C Turbine wheel seed n T Conclusion The simulation of the ste changes of the load torque allows to check the behavior of the PD regulation and to consider the change fluency of the observed values according the suddenly load changes. These changes cannot haen so short in the real oeration, but they serve a view about the functionality of the hydrostatic control units and thus the whole gearbox by extreme load cases. By the change of the minimal value of 412 N.m to maximum of 299 N.m is visible the notable dro of the engine and outut shaft seed (fig. 4). The torque converter starts to oerate. The engine seed is after about 3 sec. back to the initial value of 22 min-1 (fig. 4). The hydrostatic unit regulation late inclination changes fluently, without interferences by the extreme load change. The control system adats the gearbox oeration according to the desired engine seed and the ressure in the low-ressure ie of the hydrostatic ower flow line (fig. 5). When the load value changes after about 1 sec. back to minimum of 412 N.m, the transmission outut shaft seed starts to rise and the engine crank shaft is released. The PD regulation ut the regulation late inclination and also the engine seed to the value at the start of the ste change at 3 th sec. (fig. 4). The global efficiency of the ower transmission by the minimal load in the stable state is above,8 (fig. 6). This is with regard to usage of hydrostatic and -42-

8 hydrodynamic elements without any ratio ste controllers (automated friction brakes, clutches) quite satisfactory. The collaboration between the engine and the gearbox is ermanent controlled via the PD controller of the regulated hydrostatic unit. By the maximum load, the torque converter is still oerating. Thus, the global efficiency dros, but that is the consequence of the converter characteristics by the torque multilication. The hydrostatic ower flow line works in the field of ower circulation, which is also negative considering the ower transmission efficiency value. The torque demand by this working steady state is so high, that the multilication factor is much more imortant then the efficiency dro. The torque and seed of the other articular transmission arts are shown on fig. 7 and 8. The simulation results show, that the PD controller can regulate the value of the regulating late inclination according the desired engine seed values in the wide range of load cases. This article is ublished within the solution of research roject APVV-87-1 Intelligent diagnostic systems of gearboxes and their comonents References [1] BUKOVÁ, B., DVOŘÁKOVÁ, E.: Využitie hybridných ohonov v železničnej dorave. In: Železničná dorava a logistika - elektronický odborný časois o železničnej dorave a rerave, logistike a manažmente. - ISSN Roč. 4, č. 1 (28), s [2] MRUZEK, M., BARTA, D., KUKUČA, P.: Energy intensity analysis of city hybrid vehicle using the driving simulation. In: TRANSCOM 211 : 9-th Euroean conference of young research and scientific workers : Žilina, June 27-29, 211, Slovak Reublic. - Žilina: University of Žilina, ISBN S [3] DROŹDZIEL, P., KRZYWONOS, L.: The estimation of the reliability of the first daily diesel engine start-u during its oeration in the vehicle. In: Eksloatacja i Niezawodnosc Maintenance and Reliability 1(41)29,. 4 1, ISSN Resume The article resents simulation results of an unconventional vehicle transmission that can be used in commercial vehicles and mobile working machines. The kinematic structure and the dynamic behavior of the system is extracted into the mathematical model. Thus, the simulation of number of load cases can be done and the control system can be tested without the need of number of rototyes to be built. Also, the model rovides the ossibility of all subsystem roerties editation. This allows to -43-

9 shorten the develoment time and to cut the costs in the area of R & D rocess significantly. Key words Simulation, transmission, arallel ower flow, mathematical model, control Ing. František Brumerčík, PhD. Univerzity of Žilina Mechanical Engineering Faculty Deartment of Design and Machine Elements frantisek.brumercik@fstroj.uniza.sk -44-