Budapest University of Technology and Economics
Faculty of Mechanical Engineering, PhD Committee
Booklet of theses
Written by:
Zsolt József Farkas, M.Sc. in Mechanical Engineering
Analysis and simulation of power split
Continuously Variable Transmissions
Applying for a PhD degree in the topic entitled
Supervisor:
Dr. György Kerényi, associate professor
Budapest
2013
1. Introduction
In technical practice, the purpose of transmissions is to connect the power machine and the machine
tool, synchronize their mechanical parameters and transmitting energy. Said mechanical parameters
such as form of motion, movement frequency, force and torque, are usually formed based on the
requirements of the machine tool. In practice during most work processes the mechanical
parameters – required by the machine tool or given by the power machine – change separately or
together. The optimal power machine – machine tool connection requires changing the number of
sprockets and changing these during the work process. Continuously Variable Transmissions (CVT)
fulfils these requirements, so they are ideal for the power machine – machine tool connection.
A CVT unit can be integrated into a drive train in two ways. One of them is mounting directly into the
power flow (Figure 1.a), the other is mounting into a branch created by power split (Figures 1.b and
1.c). The continuously variable power split transmission mechanisms thus produced can be divided
into two further main groups. One of the main groups consists of single (Figure 1.b), the other of
multiple power split transmission mechanisms (Figure 1.c).
i var
i var
1
Input
Power
V
Input
Power
2
Output
Power
Power
Split
1
V
i var
2
Output
Power
C
i const
Power
Splice
1
Input
Power
Power
Split / Splice
V
2
Output
Power
C
i const 1
Power
Splice / Split
C
i const 2
a, direct integration
b, single power split
c, multiple power split
Figure 1. Options for mounting a CVT unit into the drive train (schematic diagrams)
The rising energy prices and the increasingly stringent emission regulations require the operation of
economical and environment friendly energy systems. Tractors used with agricultural, communal and
forestry cases require varied usability, so during different work processes the driving engine, the
transmission and the implement system must work with optimal parameters.
This dissertation covers analysis and simulation of single power split Continuously Variable
Transmissions, which are widely used in high-performance universal tractors. The goal of these
analyses is to observe the efficiency, operational individualities and to define rpm – gear ratio pairs,
that make it possible for the vehicle – given moving with certain speed – operation of vehicle with
good efficiency and low fuel consumption.
1
2. Literature analysis, overview
Leonardo DaVinci sketched the first CVT (Continuously Variable Transmission) in 1490 [1]. Long time
has passed since the first records and continuously variable transmission technology has been
applied in more and more areas (machine tool, wind power plant, vehicle and tractors). Tractors play
a vital role in agricultural prime movers, because it has the most versatile usage and application
possibility. Different agricultural works such as tillage, operating PTO (Power Take-Off) or
hydrostatic-driven machines, shovel loading or transportation tasks require a wide spectrum, optimal
power train.
The central part of the drive train is the transmission, which is able to modify the revolutions and
torque of the engine to get the optimal speed and drawbar power for the current task. Apart from
driving the mechanism, it must ensure offsetting the engine’s performance for driving PTO or
hydraulic controls. Because of this, the transmission is the most important and expensive part of the
tractor, its cost can reach 25-30% of the machine [2].
In order to analyze agricultural drive trains, I collected parameters from the internal combustion
engine and special needs of interfacing engine and transmission. In the past, development of
continuous variable transmissions were on mechanic chain variators and hydrostatic gears. This is
why I analyze the 10 top decisive mechanical [3], [4], [5], [6], [7] and 12 hydrostatic constructions [4],
[8], [9], [10], [11], [12] in detail.
Studies of prime movers’ continuous variable transmissions were carried out by developing
companies, universities and agricultural laboratories. In the last two decades there is significant
activity in studies of prime movers’ continuous variable transmissions. I also overviewed public
national and international studies that were going on before [4], [13], [14], [15], [16], [17] [18] [19],
[20] and parallel [21], [22], [23], [24] to my study.
Based on operational and experimental results it is observable, that power trains with continuous
variable transmissions do not yield obvious benefits, moreover, they are sometimes performing
worse than discrete geared switchable under load (PowerShift) transmissions.
3. Goals of the research
I declared the following research goals after studying the power split continuously variable
transmission’s construction and public analytic results:
- Observing performance flow in industrial and prototype transmission, modelling of behaviour and
decision of optimal working range.
- After careful analysing of losses in transmission – data gathered from literature – creating the
simulation models of the base power train parts of the input and output coupled systems. Analysing,
and interpreting data from this should be lossless, even in the case of considering losses in the
system.
2
- Modelling the one or multiple speed-range power split continuously variable transmission,
determining total efficiency change in the whole operational region. Analysis of the efficiency change
in range changing process of the multi speed-range power train.
- Analysis of combustion engines and CVT’s for given value sets of lowest fuel consumption and
largest efficiency of transmission, and determination operational parameters for them.
- Gathering and ordering industrial CVT’s technical specifications regarding the power train.
- Working out an analysis method to compare tractors equipped with PowerShift and CVT
transmissions that allows precise, complete comparison of transmissions. With the help of this
method, experiments, analysis and interpretation of results, application benefits and cons and
deciding optimal operational parameters.
4. Description of research method and means
Based on a review of references, test results and the objectives defined, the research method was
founded on theoretical (simulation) and experimental, measurement-based (laboratory and field)
testing.
I performed MIL (Modell in the Loop) simulation tests broken down into each elementary drive
component of the drive gear as well as on the complete assembled transmission itself. I carried out
analyses on drive gears of one as well as multiple speed ranges. I also extended the analyses to the
level of the coupling between the internal combustion engine and the continuously variable
transmission. I used a fuzzy-based CFM (Corrected Fuzzy Mean) method to specify optimum
operational parameters.
In the scope of laboratory measurements, I determined the power and fuel consumption
characteristics of tractor engines. I performed tests at the laboratory of the MGI Hungarian Institute
of Agricultural Engineering (Mezőgazdasági Gépesítési Intézet), using a Sigma 5 mobile and a SCHENK
W-400 type dynamometer, as well as a PIERBURG PLU-116H fuel consumption meter, in compliance
with OECD (Organization for Economic Co-operation and Development) CODE I requirements, by
applying standard braking on the PTO shaft of the tractor.
A program for the field test was developed, which is a first step of the complete comparison. The two
basic level of the examination series are the tractor drawbar test and tractor-implement test. The
tractor-implement test level was also separated to transport test, high power operation - and PTO
operation test. The measurements were performed in Cegléd Cifrakert district of the Dél-Pest County
Agricultural Plc. between 22-25 June 2003 and 9-19 October 2007. Drawbar tests were conducted on
a plane cereal stubble field of loamy soil with no upward or downward slopes, in compliance with
MGI’s internal standard (MGI SZ 39-1-321) established on the basis of the OECD method. Regarding
the power machinery tests, the transport tests were executed on a plane test track covered by
asphalt, using an unloaded tractor as well as towing a HW 8011 type two-axle trailer of 7 tons of
gross weight.
3
Between 22-25 June 2003, the measurements were conducted on Case IH CS 150 and Case IH CVX
150 type tractors. The CASE CS 150 has a SYNCROMESH 4 range gears electro hydraulic controlled
PowerShift transmission, which has 4 range gears with 6 synchro. gears included. The Steyr
hydrostatic-mechanic power split, continuously variable transmission is used in the CASE CVX 150
tractors. The investigated tractors – because of the test methods developed by us – have same
engine power (Pnom.=108 kW), tyre dimension and pressure, and their axial load was also the same by
extra weighting. Due to these specifications the tested tractors were the same only the transmission
was different.
Between 9-19 October 2007, the measurements were conducted on Case IH Puma 195 and Case IH
CVX 195 type tractors. By reason of the different weight and tyre dimensions of these machines, I
performed these measurements for further exploration and verification of the drive chain
characteristics, rather than for the sake of comparison.
I conducted this research in cooperation with ENTAM (European Network for Testing of Agricultural
Machines), more specifically with MGI, a Hungarian member of the European Network for Testing of
Agricultural Machines. In the course of testing procedures, I used the laboratories and equipment of
both MGI and BUTE (Budapest University of Technology and Economics). I conducted simulation tests
in Pro/ENGINEER, Matlab and Matlab SIMULINK systems.
5. Test results
For the purpose of simulation tests, I first modelled basic drive gear components, including the
cylindrical gear drive, the planetary gear, bearings, and the continuous variable transmission unit. In
line with the objectives set, I also analyzed losses on basic components in detail. Rpm ratios and
power flows were determined in case of input coupled (IC) and output coupled (OC) continuous
variable transmission structures of single power branching. I supplemented the three operating
modes described in the literature – PS (Power Split), +PC (+Power Circulation), and -PC (-Power
Circulation) – by the analysis of further two operating modes for the sake of accurate efficiency
analysis and calculation. These two operating modes included GN (Geared Neutral) related to the
stationary output shaft of the gear drive; and PVar=0 PV0, when no power flows in the continuously
variable branch.
With respect to single speed range drive gears, I modelled a drive gear of OC-RSC structure (Figure
2.a). In order to explore differences between OC and IC structures, an IC-RSC structure (Figure 2.b) –
the reverse of the drive gear – was also analyzed by using the parameters
(ZS=50, ZR=110, iC1=-3, iC2=-1) of a Fendt Vario gear drive. Figure 3 shows the changes of the overall
efficiency of the drive gear in the function of the output rpm, at constant input rpm
(nIN = 1900 1/min), by taking into consideration the efficiency of the gear drive unit, the continuously
variable transmission unit and the bearings. Figure 4 shows the changes of the overall efficiency of
the drive gear in the function of the output rpm, at constant input rpm (nIN = 1900 1/min), in case of
different figures of continuously variable transmission efficiency.
4
i var
i var
1
2
V
PIN
POUT
1
2
ib
ib
R
C
ic 1
ic 1
ic 2
R
ic 2
C
PIN
POUT
S
S
b, IC-RSC structure
a, OC-RSC structure
Figure 2. Power split CVT
1,0
1,0
0,9
0,8
Efficiency [-]
Efficiency [-]
0,9
0,8
0,7
0,6
0,7
- PC
PS
+ PC
0,5
- PC
PS
-4500
-3500
-2500
0,6
-500
-1500
Output revolution [1/min]
500
1500
-6500
-4500
-2500
Output revolution [1/min]
GN
+ PC
0,4
-500
1500
3500
GN
a, OC-RSC structure
b, IC-RSC structure
Figure 3. Efficiency changes of the transmissions in function of output revolution
(nIN = 1900 1/min, ηVar=0,87)
η var=0,95
H
η var=0,85
η var=0,90
η var=0,80
1,0
η var=0,75
1,0
0,9
0,8
Efficiency [-]
Efficiency [-]
0,9
0,8
0,7
0,6
0,7
- PC
PS
+ PC
PS
-4500
-3500
-2500
-1500
Output revolution [1/min]
0,6
-500
500
GN
1500
-6500
-4500
-2500
Output revolution [1/min]
0,5
- PC
+ PC
0,4
-500
1500
3500
GN
a, OC-RSC structure
b, IC-RSC structure
Figure 4. The efficiency changes for different constant efficiency values in the variable gear unit in
function of output revolution (nIN = 1900 1/min)
5
I performed the simulation tests of a continuously variable transmission comprising power branching
and various speed ranges on a transmission of IC-SRC structure with four speed ranges. I used the
specifications of a Steyr S-Matic transmission for analysis (Figure 5).
Figure 5. The Steyr S-Matic transmission [13]
I performed tests on a dynamic model generated in the Matlab SIMULINK system, starting from the
stationary position of the vehicle, gearing up to all four speed ranges, and then shifting to lower
gears until the vehicle stopped. Changes in the rpm of drive gear components during testing are
shown in Figure 6, and load changes of drive gear components in the function of time are shown in
Figure 7. Figure 8 shows changes of the overall efficiency of the transmission in the four speed ranges
based on analytic calculations. The efficiency figures of the component with variable gear ratio was
taken into consideration at η Var =0.95 and η Var =0.75, respectively. The highest efficiency of the drive
gear is produced in the third speed range, at vehicle speeds between 15-25 km/h depending on
engine rpm.
Figure 6. Rotation per minute diagram of the IC-SRC transmission components axes (nIN=2580 1/min)
6
Figure 7. Loadings of the IC-SRC transmission components (TOUT=100 Nm)
1,00
0,95
Efficiency [-]
0,90
0,85
0,80
0,75
1. speed
range
2. speed
range
3. speed range
4. speed range
0,70
0
5
10
15
20
25
30
35
40
45
50
Vehicle speed [km/h]
Figure 8. The overall efficiency changes of the IC-SRC transmission in the four speed ranges
(nIN=2300 1/min)
I specified the optimal drive chain parameters on a drive train obtained by connecting a 667TA/EBC
(Cummins) type diesel engine built in a Case IH 195 Puma tractor with a Steyr S-Matic transmission.
Among the drive train parameters, I intended to specify those engine rpm and drive gear ratio pairs,
which ensure that all target values are simultaneously fulfilled, i.e. high-efficiency drive gear
operation and low fuel consumption of the internal combustion engine at a given vehicle speed. I set
vehicle speed at 8 km/h, mostly used for agricultural soil cultivation works. The evaluation by a fuzzybased CFM procedure yielded a parameter range of rpm and drive gear ratio (indicated by purple in
Figure 9), where the target values are best reached.
7
Figure 9. Quality distribution (CFM) in a function of engine seed and transmission ratio
Tables 1 and 2 show the traction test results of Case IH CS 150 and Case IH CVX 150 type tractors. For
a better comparison, I also specified the traction characteristics corresponding to the maximal
drawbar power of the CASE IH CVX 150 type tractor at the travel speeds and drawbar forces which
correspond to the maximal drawbar powers measured in each individual gear of the CASE IH CS 150
tractor. Based on the results – and also taking drive train, rolling and sliding losses into consideration
– the maximal achievable power of the engine at a given rpm can be better exploited by a tractor
with continuously variable transmission.
Table 1. Drawbar test results of the CASE IH CS 150 tractor at the maximal drawbar power in each
gears
No.
Gear
Travel
Speed
Drawbar
Force
Drawbar
power
Slip
Engine
rev.
[km/h]
[kN]
[kW]
[%]
[1/min]
Local.
max. PTO
power
[kW]
Local
power
ratio
[kW/kW]
1
2
II/1
II/2
4,0
4,8
32,9
31,9
37,0
42,1
24,9
24,9
2323
2318
88,8
90,1
0,416
0,467
3
II/3
5,7
32,0
50,8
23,2
2251
92,8
0,547
4
II/4
7,4
27,1
55,9
15,5
2216
94,5
0,591
5
III/2
8,7
23,7
57,4
12,2
2239
93,5
0,614
Table 2. Drawbar test results of the CASE IH CVX 150 tractor at the maximal drawbar power in each
cruise control steps
No.
8
Cruise
Control
Travel
Speed
Drawbar
Force
Drawbar
power
Slip
Engine
rev.
[1/min]
Local.
max. PTO
power
[kW]
Local
power
ratio
[kW/kW]
[km/h]
[kN]
[kW]
[%]
1
2
T1
T2
4,0
4,6
39,5
38,2
43,5
49,1
28,4
28,6
2192
2151
96,9
95,7
0,448
0,513
3
T3
6,0
35,5
59,5
25,7
2055
99,8
0,596
4
T4
8,9
28,0
68,9
12,1
2047
100
0,689
In order to explore and analyze the differences between PowerShift and continuously variable
transmission, I developed a simulation software in Visual Basic (Figure 10) environment, which is
suitable, in addition to processing and displaying transport test measurement data, for calculating
other parameters including the distance covered and the drive gear ratio as well.
Figure 10. The CVT-PowerShift Simulator (v 1.6)
Based on the results yielded by the CVT-PowerShift Simulator, Table 3 shows transport test figures in
case of unloaded and loaded test.
Table 3. Transport test results
No
Pos. of
full
load
Type of Tractors
pot.
meter
Unloaded
Loaded
Travel
speed
Time
Fuel cons.
Travel
speed
Time
Fuel cons.
[s]
[dm3]
[s]
[dm3]
17
18,1
0,130
0,134
[km/h]
33,5
39,1
22,4
10,7
0,138
0,069
1
2
CASE IH CS 150
CASE IH CVX 150
0
[km/h]
42,1
50,0
3
CASE IH CVX 150
0
42,1
13,2
0,095
33,5
7,6
0,045
4
CASE IH CVX 150
10
52,0
17,5
0,131
39,3
12,8
0,071
5
CASE IH CVX 150
10
42,1
10,4
0,088
33,5
9,2
0,047
As indicated by the results, the main reason of the lower fuel consumption by the CASE IH CVX 150
tractor is the continuously variable transmission gear ratio changes at a continuous engine rpm, and
engine rpm reductions at the appropriate moments. In addition to transport operations, power
machinery equipped with continuously variable transmission can also be used most advantageously
for loading operations involving intensive accelerations of short duration.
9
6. New scientific results
Thesis 1. [F1], [F2], [F3], [F7], [F8], [F11], [F12], [F14], [F15], [F16], [F17], [F18]
I developed a new testing method suitable for the simulation of the operating mode of continuously
variable transmission gears of single power branching and of one as well as several speed ranges, as
well as for their operating parameter analysis, simultaneously using the results of laboratory and
field test measurements consisting of engine braking, drawbar and tractor – implement tests and of
simulations based on kinematic, dynamic and CAD models.
I verified the applicability of this method by testing single speed range OC-RSC and IC-RSC, and IC-SRC
structured transmission of four speed ranges.
Thesis 2. [F12], [F15], [F18]
In an OC-RSC structured transmission, equipped with a hydrostatic unit of continuously variable
transmission of primary and secondary control (fitted with an engine not operated as a pump),
operating modes of power split and positive power circulation may occur during functional operation
(based on parameters ZS=50, ZR=110, iC1=-3, iC2=-1).
At the commencement of output shaft rotation, the overall efficiency of the drive gear is determined
by the efficiency of the hydrostatic unit.
By tilting the hydraulic pump from zero angular position (iVar = - ∞) into increasingly negative angular
positions (- ∞ < iVar), the overall efficiency of the drive gear will degrade at an increasing rate due to
higher losses caused by the increasing rpm and the increasing positive power circulation generated.
Therefore, this drive gear cannot be operated economically in this transmission range.
Thesis 3. [F9], [F13], [F14], [F15], [F16], [F17], [F18]
In an IC-SRC structured transmission, equipped with a hydrostatic unit of primary control, the
transmission range of the hydrostatic unit should be restricted in order to ensure the preferred
efficiency, therefore a drive gear of several speed ranges is required (four in the case examined).
I have established that operating modes of power split and negative power circulation can occur
during the functional operation of this transmission. The reason of the difference in the overall
efficiency of the hydraulic pump in the angular positions of the same extent but in the opposite
direction is caused by the difference of the negative power circulation produced in the drive gear and
the loss caused by the power split operating mode.
At the borderlines of range shifts, there is a discontinuity and value change in the trend of the overall
efficiency, caused by the change between the power split and negative power circulation modes, as
well as by the power flow occurring in the drive gear components of different rates of efficiency after
the shift of the operating range.
10
Thesis 4. [F16], [F20]
I used the measurement results of a Cummins 667TA/EBC type diesel engine and a Steyr S-Matic
transmission and applied a fuzzy-based CFM method to determine the range of parameter
combinations of internal combustion engine rpm and drive gear transmission ratio to simultaneously
fulfil the target values of the given vehicle speed, high transmission efficiency and low specific fuel
consumption. Based on the test results, the control mechanism should operate the drive gear as
close to the purely mechanical power transmission as possible in the power split transmission ratio
range, besides the reduction of the motor rpm.
Thesis 5. [F7], [F8], [F9], [F11]
I verified and stated the following on the basis of the results of the comparative research conducted
by the testing method developed by me, using CASE IH CVX 150 and CASE IH CS 150 tractors, and by
ensuring identical parameters:
The tractor with a drive gear of continuously variable transmission has produced a higher drawbar
power. Compared to the drive gear of the power machine with a drive gear of discrete transmission,
the drive train of the power machine equipped with a drive gear of continuously variable
transmission can exploit its maximal achievable power at a given rpm by 3-7% more in respect of
values of identical running speed associated with the maximum drawbar power values in each gear
of the power machine with a drive gear of discrete transmission, and by 4-22% more in case of
identical drawbar power figures.
Based on the measurement results of transport tests and the results yielded by the CVT-PowerShift
Simulator of own development, it can be established that a power machine fitted with a drive train
of continuously variable transmission is characterized by better acceleration and lower fuel
consumption features. It follows from this that tractors equipped with a drive train of continuously
variable transmission can also be preferably applied in case of loading operations requiring phases of
short-term but considerable acceleration.
7. Utilization of results
The created analysis method, and the connecting data processing, data analysis, modelling and
operational experiences and results are applicable to analyse other agricultural power machines as
well.
The results can be used to give improvement suggestions to decide optimal and economic
operational parameter sets for both developers and users.
Further improvents of the simulation model would allow the observation of the change of efficiency
in power split CVT.
Experience gathered from modelling of power split CVT can be adapted to the newly designed hybrid
and electrical power trains.
The method to decide optimal operational parameters can be extended to the transmissions of PTO
and hydraulic systems. The newly designed parts of electrical power trains can be implemented to
simulation models to analyse them.
11
8. References
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[2] Szente M.: Traktorhajtóművek, Vállalkozók tanácsadója 97., Mezőgazdasági Technika, 1999
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developments), Grundlagen der Landtechnik Vol. 24, No. 2: 41-46. 1974
[4] Sauer G.: Grundlagen und Betriebsverhalten eines Zugketten-Umschlingungsgetriebes, VDI Reihe 12 Nr. 293,
Duesseldorf: VDI Verlag, 1996
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Anwendungen des Riemers Kettenwandlers, Grundlagen Landtechnik 16, Nr. 2 S.60-65, 1966
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transmissions, VDI-Berichte Nr.2060 S. 303-308, 2009
[8] CASE IH: CVX 120/130/150/170 Produktleitfaden, Case Steyr Produkt-Training Center St. Valentin, 2000
[9] Renius K. Th., Böhler H.: Motoren und Getriebe bei Traktoren, Jahrbuch Agrartechnik 10 S. 56-60 u. 239/240,
1998.
[10] Teinilä T.: Neue Valtra-Getriebe aus eigener Fertigung, ATZ offhighway, Sonderausgabe ATZ Oktober S. 7078, 2009.
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[14] Resch R.: Leistungsverzweigte Mehrbereichs-fahrantriebe mit Kettenwandlern, Dissertation, Technische
Universität München, 2004
[15] MÉM Műszaki Intézet: Beszámoló jelentés a VARITRAK 4 x 4 univerzális eszközhordozó erőgép és
munkagépeinek vizsgálata című MÜFA témáról, Témaszám:1.22.11.0118.56, 1986
[16] Seeger J.: Entwicklung von Antriebsstrangstrategien eines stufenlosen Fahrantriebs in der Simulation und
am Versuchsstand, Veröffentlich in dem Tagungsband des 2. IFK in Dresden 16./17. März 2000, S. 1-14,
2000
[17] Seeger J.: Untersuchung des Systems „Dieselmotor – Leistungsverzweigtes Getriebe” am Versuchsstand und
in der Praxis, Tagungsband „Hydraulische Leistungsübertragung” der VDI-Tagung 29./30.3.2001, Kassel,
VDI-Berichte Nr. 1592, S. 81-96, 2001
[18] Stufenlos – Ja oder Nein? Getriebe im Vergleich, Profi 12/2001, 2001
[19] Manfred L.: How well do stepless transmissions perform?, AgriFuture Agritechnica Focus, S. 24-25, 2001
[20] Sebestyén Zoltán: Gyakorlati tapasztalatok fokozat nélküli váltóművekkel Magyarországon, Szántóföldi
növénytermelés gépesítése a Pannon térségben, Eisenstadt, 2001
[21] Gruppo G., Cutini M., Bisaglia C.: Mechanical vs. Continuously Variable Transmission (CVT) in Static and
Dynamic Test Conditions, International Conference on Agricultural Engineering, AgEng 2004 Leuven 1216.9.2004, 2004
[22] Frassl F.: Untersuchungen zum Einfluss von Lastschaltgetriebe und "stufenlosen"Getriebe auf den
Kraftstoffverbrauch bei Bodenbearbeitung und Transport, Diplomarbeit Universität für Bodenkultur Wien,
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[23] Racz A., Suntinger P.: Automatisches und Halbautomatisches Getriebe im Vergleich, Diplomarbeit Lehr- und
Forschungszentrum Landwirtschaft Raumberg – Gumpenstein, 2011
[24] Gastinger G.: Untersuchung des Kraftstoffverbrauchs in der 75 kW Traktorenklasse mit einem
leistungsverzweigten und lastschaltbaren Getriebe, Masterarbeit Universität für Bodenkultur Wien, 2011
12
9. Scientific publications of the author
[F1] Farkas Zs., Kerényi Gy.: Szimuláció a hajtástechnikában, Gép, LIII. évf. No.6-7. 18-22p, 2002
[F2] Farkas Zs., Jóri J. I.., Kerényi Gy.: The Application and Modelling Possibilities of CVT in Tractor, 5th
International Multidisciplinary Conference, Baia Mare, Part II 145-150p, 2003
[F3] Farkas Zs.: Fokozatnélküli hajtóművek vizsgálata és optimalizálási lehetőségei, Optimization Possibilities
and Investigation of CVT, XI. International Conference in Mechanical Engineering, OGÉT, Kolozsvár 2003
május 8-11, 76-79p, 2003
[F4] Jóri J.I., Farkas Zs., Szabó R., Szente M., Antos G.: The static and dynamic ground pressure of Case IH
Quadtrac rubber belt type tractor, Hungarian Agricultural Engineering No 16/2003, 12-13p, 2003
[F5] Kerényi Gy., Farkas Zs., Jóri J. I., Soós S.: Comparative Analysis of Reversible Plough’s Frames New Trends in
Engineering Design, Balatonfüred, Mezőgazdasági Technika 2003, Jubileumi különszám 45-47p, 2003
[F6] Farkas Zs., Kerényi Gy., Jóri J. I., Borsa B.: Terhelési modell eke keretszerkezetének vizsgálatához, Load
model for examination of plough’s frames, MTA AMB K+F tanácskozás, Gödöllő, 3. kötet 226-230p, 2003
[F7] Farkas Zs., Kerényi Gy.: Analysis of PowerShift and Continuously Variable Transmissions (CVT) of tractors,
Gépészet 2004, Budapest, Volume 2, 510-513p, 2004 május. 27-28,ISBN 963-214-748-0, 2004
[F8] Farkas Zs., Kerényi Gy.: Analysis and simulation of Powertrain of Case IH Tractors with CVT or PowerShift
Transmission, Traktori I Pogonske Masine 4, Tractors and power machines 2004/12. 38-42p, ISSN 03549496, 2004
[F9] Farkas Zs., Kerényi Gy.: Fokozatnélküli hajtóművet tartalmazó hajtáslánc elemzése, Analysis of Power Train
with Continuously Variable Transmissions (CVT), XII. International Conference in Mechanical Engineering,
OGÉT, Csíksomlyó, 87-90p, 2004. április 22-25, ISBN 973-86097-9-8, 2004
[F10] Kerényi Gy., Farkas Zs., Jóri J. I., Borsa B.: Dinamikus terhelési modell eke keretszerkezetének
vizsgálatához, MTA-AMB K+F tanácskozás, Gödöllő, 3. kötet 184-188p, 2004
[F11] Farkas Zs., Kerényi Gy.: Terhelés alatt kapcsolható és fokozatnélküli hajtóművek összehasonlító
vizsgálatának analízise és szimulációja, MTA-AMB K+F tanácskozás, Gödöllő, 1. kötet 143-147p, 2005
[F12] Farkas Zs., Kerényi Gy.: Teljesítmény elágazásos fokozatmentes hajtómű modellezése, GÉP, LVI. Évfolyam
9-10 szám, 43-46p, ISSN 0016-8572, 2005
[F13] Farkas Zs., Kerényi Gy.: Erőgépek teljesítmény elágazásos fokozatnélküli hajtóműstruktúráinak
rendszerezése, MTA - AMB K+F tanácskozás, Gödöllő, 2. kötet 65-69 p, 2006
[F14] Farkas Zs.: Teljesítmény elágazásos fokozatnélküli hajtómű üzemállapotainak elemzése, Analysis of
Infinitely Variable Transmission in the Different Operational Stages, XIV. International Conference in
Mechanical Engineering, OGÉT, Marosvásárhely, 122-125p, 2006. április. 28-30, ISBN (10) 973-7840-100, ISBN (13) 978-973-7840-10-3, 2006
[F15] Farkas Zs.: Egyszeres teljesítmény elágazásos fokozatmentes hajtóművek elemzése, Analysis of single
power split Infinitely Variable Transmissions, XV. International Conference in Mechanical Engineering,
OGÉT, Kolozsvár, Műszaki szemle 122-125p, 2007. április. 26-29, ISSN 1454-0746, 2007
[F16] Farkas Zs., Hung N. Q., Tóth S., Kerényi Gy.: Modelling of the Multiple Range Infinitely Variable
Transmission, Gépészet 2008, Budapest, 29-30.May 2008. G-2008-K-05, ISBN 978-963-420-947-8, 2008
[F17] Farkas Zs., Jóri J. I.: Virtual Prototype of Power Split Infinitely Variable Tractor Transmission, Synergy and
Technical Development (Synergy2009) Gödöllő, Hungary, 30. August – 02. September 2009
[F18] Farkas Zs., Kerényi Gy.: Power Flows and Efficiency Analysis of out- And input coupled IVT, Periodica
Politechnica, Mechanical Engineering 53: (2) 61-68p, ISSN 0324-6051, 2009
[F19] Farkas Zs., Jóri J. I.: Analysis of Power Flows and Efficiency in Infinitely Variable Transmissions of
Agricultural Power Machines, XVII. 1. Commercial Vehicle Technology Symposium, Kaiserslautern, 163173p, 2010. március. 16-18, ISBN 978-3-8322-9040-5, 2010
[F20] Farkas Zs., Piros A., Bercsey T., Jóri I. J.: Mathematical Modelling and Fuzzy Based Evaluation of a Specific
Engine-CVT Transmission Combination, Commercial Vehicle Technology Symposium, Kaiserslautern,
2012.03.13-15, 2012
[F21] Piros A., Farkas Zs.: Fuzzy based evaluation of a specific drive train. Advances in Mechanical Engineering,
pp. 1-7. Paper doi:10.1155/2012/763171., 2012
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