A Numerical Investigation of Gas Exchange Modeling and Performance Prediction of a Camless Two-Stroke Hydrogen Engine
Paper in proceeding, 2023

Heavy-duty vehicles are primarily powered by diesel fuel, emitting CO2 emissions regardless of the exhaust after-treatment system. Contrastingly, a hydrogen engine has the potential to decarbonize the transportation sector as hydrogen is a carbon free, renewable fuel. In this study, a multi-physics 1D simulation tool (GT-Power) is used to model the gas exchange process and performance prediction of a two-stroke hydrogen engine. The aim is to establish a maximum torque-level for a four-stroke hydrogen engine and then utilize different methods for two-stroke modeling to achieve similar torque by optimizing the gas exchange process. A camless engine is used as base, enabling the flexibility to utilize approximately square valve lift profiles. The preliminary step is the GT-Power model validation, which has been done using diesel and hydrogen engines (single-cylinder heavy-duty) experiments at different operating points (871 rpm, 1200 rpm, 1259 rpm, and 1508 rpm). Thereafter, the validated model is used to simulate four-stroke hydrogen engine performance at different intake and exhaust pressures. The last step was to modify the model to operate in two-stroke mode. The intake and exhaust valve closing timings, pressure differential, and air-fuel equivalence ratio were varied to investigate the delivery ratio, charging efficiency, trapping efficiency, and scavenging efficiency for perfect displacement and perfect mixing modes. The variable valve-actuated camless two-stroke hydrogen engine achieved similar torque to that of a conventional cam-operated four-stroke hydrogen engine by optimizing valve timings, pressure differential, and in-cylinder air-fuel mixture proportions.

Author

Srinibas Tripathy

Energy Conversion and Propulsion Systems

Lucien Koopmans

Energy Conversion and Propulsion Systems

Stina Hemdal

Volvo Group

Claes Kuylenstierna

Volvo Group

SAE Technical Papers

01487191 (ISSN) 26883627 (eISSN)

SAE 2023 World Congress Experience, WCX 2023
Detroit, USA,

Subject Categories

Energy Engineering

DOI

10.4271/2023-01-0232

More information

Latest update

6/20/2023