Methanol Cold Start Procedure for a Serial Hybrid Powertrain

2025-24-0074

09/07/2025

Authors Abstract
Content
Methanol obtained from regenerative sources is a renewable fuel with many advantages when used in a spark ignition combustion process. Methanol has a comparatively high enthalpy of vaporization, leading to lower combustion temperatures (compared to gasoline combustion) and, hence, lower wall heat losses as well as a reduced tendency to autoignition. The serial combination of a combustion engine with an electric powertrain provides a disconnection of the load demand of the powertrain and the operating point of the combustion engine. In this case, a high volumetric and gravimetric power density, easy energy storage, and a very cost effective already existing infrastructure of fuel distribution is combined with electric driving, high efficiencies, minimal emissions and a closed carbon cycle for the energy provision. Nevertheless, the high flash point of methanol at 11 °C indicates a challenging cold start. Heating the fuel or intake air or blending lightly boiling components are feasible solutions but are related to additional expenses regarding packaging and cost. The described procedure enables the cold start of pure methanol down to – 20 °C, without the necessity for additional engine components, when using a serial hybrid propulsion system. In this case enough electric starter energy is available to start the engine at high engine speeds, run it with minimal intake air pressure and consequently very low fuel mass, which results in a negative engine torque on the crank. The negative engine torque is electrically compensated during the cold start process. A 3D-CFD simulation accompanies the explored procedure. In addition, the procedure is compared to air and fuel heating.
Meta TagsDetails
DOI
https://doi.org/10.4271/2025-24-0074
Pages
9
Citation
Dobberkau, M., Werner, R., and Atzler, F., "Methanol Cold Start Procedure for a Serial Hybrid Powertrain," SAE Technical Paper 2025-24-0074, 2025, https://doi.org/10.4271/2025-24-0074.
Additional Details
Publisher
Published
Sep 07
Product Code
2025-24-0074
Content Type
Technical Paper
Language
English