Advanced Heat Transfer and Underhood Airflow Investigation with Focus on Continuously Variable Transmission (CVT) of Snowmobiles

Johannes Wurm, Christoph Hochenauer, Esa Väisänen, Eetu Hurtig, Joonas Mähönen

Research output: Contribution to journalArticleResearchpeer-review

Abstract

The presented paper focuses on the computation of heat transfer related to continuously variable transmissions (CVTs). High
temperatures are critical for the highly loaded rubber belts and reduce their lifetime significantly. Hence, a sufficient cooling system is
inevitable. A numerical tool which is capable of predicting surface heat transfer and maximum temperatures is of high importance for
concept design studies. Computational Fluid Dynamics (CFD) is a suitable method to carry out this task.
In this work, a time efficient and accurate simulation strategy is developed to model the complexity of a CVT. The validity of the
technique used is underlined by field measurements. Tests have been carried out on a snowmobile CVT, where component
temperatures, air temperatures in the CVT vicinity and engine data have been monitored. A corresponding CAD model has been
created and the boundary conditions were set according to the testing conditions. In a first step a simplified study is presented, to gain
basic knowledge about the system, followed by a full underhood airflow simulation. The modelling process is presented in detail and
necessary adaptions are identified.
The results show, that the numerical model is able to predict the surface temperatures within a range of 5 % for different load cases.
Thus, the developed method is validated and can be used for future development processes. The influence of the pulley design on the
underhood airflow will be evaluated to identify optimization potential. Moreover, the presented work is the first of its kind, where a
numerical heat transfer simulation of a CVT is compared to field tests carried out on snow.
Original languageEnglish
Number of pages9
JournalSAE International journal of commercial vehicles
Volume10
Issue number2
Publication statusPublished - 16 Sep 2017

Fingerprint

Heat transfer
Pulleys
Snow
Cooling systems
Temperature
Numerical models
Computer aided design
Rubber
Computational fluid dynamics
Boundary conditions
Engines
Testing
Air

Keywords

  • CVT
  • CFD
  • Snowmobiles
  • Heat transfer

Cite this

Advanced Heat Transfer and Underhood Airflow Investigation with Focus on Continuously Variable Transmission (CVT) of Snowmobiles. / Wurm, Johannes; Hochenauer, Christoph; Väisänen, Esa; Hurtig, Eetu; Mähönen, Joonas.

In: SAE International journal of commercial vehicles, Vol. 10, No. 2, 16.09.2017.

Research output: Contribution to journalArticleResearchpeer-review

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AU - Mähönen, Joonas

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AB - The presented paper focuses on the computation of heat transfer related to continuously variable transmissions (CVTs). Hightemperatures are critical for the highly loaded rubber belts and reduce their lifetime significantly. Hence, a sufficient cooling system isinevitable. A numerical tool which is capable of predicting surface heat transfer and maximum temperatures is of high importance forconcept design studies. Computational Fluid Dynamics (CFD) is a suitable method to carry out this task.In this work, a time efficient and accurate simulation strategy is developed to model the complexity of a CVT. The validity of thetechnique used is underlined by field measurements. Tests have been carried out on a snowmobile CVT, where componenttemperatures, air temperatures in the CVT vicinity and engine data have been monitored. A corresponding CAD model has beencreated and the boundary conditions were set according to the testing conditions. In a first step a simplified study is presented, to gainbasic knowledge about the system, followed by a full underhood airflow simulation. The modelling process is presented in detail andnecessary adaptions are identified.The results show, that the numerical model is able to predict the surface temperatures within a range of 5 % for different load cases.Thus, the developed method is validated and can be used for future development processes. The influence of the pulley design on theunderhood airflow will be evaluated to identify optimization potential. Moreover, the presented work is the first of its kind, where anumerical heat transfer simulation of a CVT is compared to field tests carried out on snow.

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