Two-phase VOF flow simulations in an electric vehicle gearbox
Title: Two-phase VOF flow simulations in an electric vehicle gearbox
SNIC Project: SNIC 2021/22-921
Project Type: SNIC Small Compute
Principal Investigator: Valery Chernoray <>
Affiliation: Chalmers tekniska högskola
Duration: 2021-11-19 – 2022-12-01
Classification: 20306


Trucks, buses, and coaches are responsible for about a quarter of CO2 emissions from road transport in the EU and for 6% of total EU emissions. Despite some improvements in fuel consumption efficiency in recent years, these emissions are still rising, mainly due to increasing road freight traffic. The first-ever EU-wide CO2 emission standards for heavy-duty vehicles, adopted in 2019, set targets for reducing the average emissions from new trucks for 2025 and 2030. From 2025 on, manufacturers will have to meet the targets set for the fleet-wide average CO2 emissions of their new trucks registered in a given calendar year. Stricter targets will start applying from 2030 on. The targets are a 15% reduction from 2025 and a 30% reduction from 2030 expressed as a percentage reduction of emissions compared to the EU average in the reference period from 1 July 2019 to 30 June 2020. This means that for a truck manufacturer AB Volvo any marginal efficiency gains in every component are considered beneficial for the total reduction of CO2 emissions. Truck transmission is one of the components where the losses can be decreased. The main idea of the current project is to perform numerical simulations of the oil flow in a Volvo truck transmission and to compare the simulation results to the experimental data from a newly built test rig at Chalmers. The experimental work will be performed in Chalmers Laboratory of Fluids and Thermal Sciences The simulations will be performed in the commercial CFD software Star CCM+. The validation results will be used for the improvement of CFD simulations of oil flow in a truck gearbox and for optimization of gearbox design.