Overview

winEVA (EDP-programme for the analysis of consumption and driving performance) is a software package for powertrain simulation for computers running the Windows operating system. It can be linked to programmes for data acquisition, e. g. winADAM (Automated Data Acquisition in Mobile applications)  and to the programmes for fatigue life calculation, e. g. winLIFE (fatigue Life Information by Finite Elements). Different types of vehicles (passenger cars, trucks and special vehicles) can be simulated on different road surfaces (road, off-road). In addition to pure computer simulation, winEVA is used:

• for real-time control of dynamic test rigs
• as a driving simulator

The Vehicle Model

The vehicle model is built up in a block-oriented way (see illustration), as is common today and already realised in many software products.

The system has so far been used for vehicles with the following drive types:

• gearbox with constant ratio in each gear (max. 20 gears, manually shifted or automated)
• automatic transmission
• series-hybrid, parallel-hybrid
• overhead line drive (trolley bus)
• electric drive
• continuously variable transmissions (electric, hydrostatic)

In addition, almost any powertrain configuration can be modelled..

Environment and Traffic

The inclusion of the environment (topography, curvature, visibility) is a crucial parameter for realistic simulations (see figure).

The boundary conditions and obstructions caused by traffic rules and the traffic itself also play an important role. The following figure shows which events are recorded and used as data in the simulation.

Many customers prefer the automatic generation of a track simulation based on measured data (winADAM) because of the otherwise large input effort.

Driver Behaviour

The driver's behaviour can be represented differently depending on the requirements:

• Following a measured speed profile
• Independent speed selection on the basis of the measured environmental data.

The driver's gear selection for manual transmissions is also realised for trucks with up to 18 gears.

The driver's actions are influenced by motivational factors related to person and occurrence Driver behaviour is also influenced by whether an occurrence is foreseeable or not. The figure below shows a driver with very different motorised vehicles on the same track with an identical driver. You can see that the driver model adapts very realistically to the vehicle.

Test Rig Control

By using winEVA to control powertrain test rigs, even measured driving cycles can be simulated realistically and with little effort. winEVA specifies the accelerator pedal position, the brake pedal position and the numbers of revolutions per minute and/or the torques at the electric motors of the test rig. At a major car manufacturer, it could be proven that considerably more realistic stress results are achieved with this test rig control than with conventional test rig controls. The illustration shows the priciple by means of a transmission test rig which simulates the data measured with winADAM in a good approximation.

Solution Strategy

Based on the equations of motion of the vehicle, all essential variables within the powertrain are calculated. Optionally, torsionally elastic components, mass inertias and the real torsional excitation of the combustion engine can be taken into account, which is necessary for the analysis of torsional vibrations.

Also important for realistic simulations is the driver model, which has been verified in tests. This model allows the specification of a target speed profile that is valid for a large number of vehicles. In addition, a measured speed profile can be followed exactly - considering physical limits.

Driver and vehicle model access the data of the simulation track, which is defined by the speed profile, topography, coefficient of friction, rolling resistance coefficient, curvature and visibility for each track section. The length of the individual track sections can range from a few centimetres to several hundred metres, depending on the task.

The components of a vehicle must be described very precisely, which requires extensive data. In the case of analytically known relationships, the equations are used directly (air resistance, hydrodynamic relationships, etc.); in the case of components whose properties can only be represented by characteristic diagrams (consumption characteristic diagram of the engine, efficiency characteristic diagrams of the mechanical parts of the transmission, etc.), these relationships are described in matrix form.

Validation

The comparison of driving tests with simulation results was carried out and published by a customer. The figure shows the results of a driving test at the Nürburgring for different variables of the powertrain based on measurement and calculation.

Stationary Parameters

The characterisation of the vehicle by the following quasi-stationary and stationary parameters helps in the assessment of the vehicle and also in troubleshooting in the input data.

Measurement data transfer from winADAM

Measurement data from the measurement data acquisition system winADAM (Automated Data Acquisition in Mobile applications) can be transferred and processed (smoothing functions, filtering). They are immediately available for simulation. The data structure (ASCII-data) is documented so that the user can write his own interfaces to his own measurement systems, if required.

Data Transfer for Fatigue Life Calculations

A data transfer from the winEVA programme to winLIFE is possible without any problems. For this purpose, a variable determined in the simulation (e.g. torque, force) can be transferred to winLIFE and then a fatigue life calculation can be carried out.

Driving Cycles from Traffic Flow Simulation

The simulation of the traffic flow is integrated in winEVA. Based on a microscopic model for motorways, realistic driving cycles can be generated, which can be used as the basis for a powertrain simulation. In this way, the traffic flow can be taken into account.

Publications

[1] Willmerding, G.: Ein Simulationsmodell für den Autobahnverkehr, Teil 1. ATZ Heft 5 1992

[2] Willmerding, G.: Ein Simulationsmodell für den Antriebsstrang, Teil 2. ATZ Heft 6 1992

[3] Willmerding, G.: Jehlicka, E.: Verbrauch-suntersuchungen an Stadtbussen; Der Nahverkehr Heft 5 1986

[4] Willmerding, G.: A simulation system to study the working conditions of vehicles and to develop fuel efficient drivetrains. publication on the FISITA-congress 1992,  Inst. of mech. Eng. 1992

[5] Willmerding, G.: Ein Simulationsmodell für Kraftfahrzeuge im Verkehrsfluß, publication on ASIM-congress TU-Berlin 1993, Fortschritte in der Simulationstechnik, 8. Symposium 1993, Band 6, ISBN 3-528-06555-9

[6] Böhm, Jehlicka, Willmerding: research of a modern freight traffic-system by using computer simulation, publication for the FISITA-congress in Peking 1994

[7] Willmerding, G; Trübswasser, F; Häckh. .: A simulation system to predict fuel consumption and emissions considering the traffic flow. 5. Aachener Kolloquium Fahrzeug- und Motorentechnik 1995. Tagungsband.

[8] Häckh, Willmerding, G.: Handbuch zum Computerprogramm winLIFE. 155 Seiten, Steinbeis-TZ-Verkehrstechnik Ulm, 1.10.1997

[9] Häckh, J; Willmerding, G.: Handbuch zu winE-VA, 199 Seiten, TZ-Verkehrstechnik. 1998

[10] Willmerding, Dietzel, Körner: Rechnergestützte Entwicklung von Schaltprogrammen für Automatik-getriebe, 3. Stuttgarter Symposium Kraftfahrwesen und Verbrennungsmotoren 1999, Seite 843 - 856, ISBN-Nr. 3-8169-1751-8

[11] Willmerding, G.; Häckh, J; Schnödeweind, K.: Fatigue Calculation using winLIFE, Vortrag auf dem  NAFEMS-Seminar Fatigue Analysis am 8.11.00 in Wiesbaden, Herausgeber: The International Association for the Engineering Analysis Community, www.nafems.de

[12] Willmerding, G; Häckh, J;  Berthold, A.: Vor-hersage von Fahrzyklen, Belastungen und Lebens-dauer auf der Basis von gemessenen Streckenda-ten, Vortrag auf der Tagung Fahrwerktech 2001 am 8. und 9. März in München; Veranstalter: TÜV München Tagungen und Kongresse, Westendstr, 122

[13] Willmerding G.: Vorhersage der Lebensdauer dynamisch belasteter Bauteile durch Kombination von Lebensdauerberechnung mit Finite Element Methode; Vortrag Nr. 14 auf der Tagung Fahrwerk-Tech 99 Adaptive Fahrwerksysteme, 4 bis 5.3.1999, München, Tagungsunterlagen TÜV-Akademie München.

[14] Willmerding, G.: Lebensdauerberechnung dynamisch belasteter Bauteile für den multiaxialen Fall in Kombination mit Mehrkörperdynamik und Finite Element Methode; Vortrag auf der MSC-Anwenderkonferenz am 21. und 22.6.1999 in Weimar, Herausgeber Mac Neal Schwendler Corporation, München

[15] Willmerding, G; Häckh, J; Berthold, A: Driving Cycle, Load and Fatigue Life Predictions based on measured Route Data; Vortrag auf der ATT-Tagung in Barcelona 2001, SAE-Paper 01ATT120

[16] Häckh, J; Willmerding, G; Kley, M; Binz, H; Körner,T.: Rechnerische Lebensdauerabschätzung von Getriebegehäusen unter Einbeziehung realer multiaxialer Belastungen; DVM-Tagung Fulda vom 5. bis 6.6.2002,VDI-Berichte N2. 1689, 2002 Seite 303 - 317

[17] Körner, T; Depping, H; Häckh, J; Willmerding, G; Klos, W.: Rechnerische Lebensdauerabschätzung unter Berücksichtigung realer Belastungskollektive für die Hauptwelle eines Nutzfahrzeuggetriebes; DVM-Tagung Fulda vom 5. bis 6.6.2002, VDI-Berichte N2. 1689, 2002 Seite 275 - 285

[18] Körner, T; Depping, H; Häckh, J; Willmerding, G.: Fatigue Life Prognosis for Transmissions based on critical Component Spectrum; World Automotive Congress FISITA 2002, Helsinki, Paper Nr.F02V091

[19] Willmerding, G.; Häckh, J.; Körner, T.: Ein durchgängiges Antriebsstrang-Simulationssystem im Entwicklungsprozess von Automatikgetrieben; Vortrag auf der Tagung: Dynamisches Gesamtverhalten von Fahrzeugantrieben, Haus der Technik, 11. bis 12.3.2003 in München.

[20] Häckh, J.; Willmerding, G.: Untersuchung der Einsatzverhältnisse unter realistischen Bedingungen durch Kombination von Messdatenerfassung und Computersimulation; Vortrag auf der VDI-Getriebetagung 2006: VDI-Getriebetagung 2006.

[21] Häckh, J.; Willmerding, G.: Load spectrum prediction for Transmissions und realistic use combining tests and computer Simulations, Vortrag auf der FISITA-Tagung Budapest 2007: FISITA-Tagung 2007.

[22] Seifert, C.;Willmerding, G.: Fatigue Life Prediction of Automotive Drive Trains By Combination of Drive Cycle Measurements and Simulation Using WinLife, Vortrag auf der NAFEMS Tagung Vancouver , Mai 2007 NAFEMS-Tagung 2007.

[23] Willmerding, G.; Häckh, J.: Ein System zur Untersuchung von Fahrzeugantrieben zur Vorhersage von Fahrleistung, Kraftstoffverbrauch und Lebensdauer unter realistischen Einsatzbedingungen, Vortrag auf der VDI-Tagung Erprobung und Simulation in der Fahrzeugentwicklung, 24.6.-25.6.2009, Würzburg Erprobung_Simulation_VDI_Würzburg_2009.

Services / Projects

We investigate your powertrain problems on a contact basis. Examples of completed projects:

• Prediction of fuel consumption on a test track for different passenger car powertrain concepts (3-litre car) and investigation of driver influence.
• Savings potential through targeted management of auxiliary consumers
• Savings potential through engine shutdown in passenger cars
• Savings potential through brake energy storage
• Savings potential from tyres with reduced rollling restistance coeffizient
• Simulation of the powertrain management to optimise the brake energy storage
• Comparison of different transmission concepts in terms of fuel consumption
• Influence of the transmission efficiency on fuel consumption
• Comparison of electrically powered trucks with railways for use on the NRLA (New Railway Link through the Alps)
• Fatigue life prediction of a retarder shaft based on measured driving cycles
• Influence of manual gear shifting on transmission fatigue life
• Investigation of innovative shift strategies for automatic transmissions using SIL (Software in the Loop Simulation)
• Fatigue life prediction of transmission components under realistic load spectra
• Investigation of continuously variable transmissions based on power split hydrostatic transmissions
• Driving simulation of CVT concepts for the development of a control strategy
• Simulation of different powertrain concepts for transmission selection
• Temperature development in electric engines under realistic driving cycles in commercial vehicles
• Influence of the traffic density on commercial vehicle speed cycles and its impact on fuel consumption

Further Products for the Powertrain Analysis

winADAM: Acquisition of operational data

winADAM is a mobile measurement and analysis system for vehicles. It records - without a cable connection to the measurement object - extensive operational data such as driving speed, lateral acceleration, yaw rate, track angle, geodetic height, longitudinal inclination of the track..

These variables can be exported to winEVA and used as the basis for a simulation.

winLIFE: Fatigue life calculation in connection with finite elements