Analysis on monofuel: Methane and hydrogen in passive TJI engine using Center of Combustion and lambda-value control

Abstract

The search for new combustion systems makes the two-stage combustion system (TJI) widely used when burning poor mixtures of methane and, increasingly, hydrogen. This paper presents the thermodynamic conditions for the combustion of methane and hydrogen when using a passive pre-combustion chamber. Thermodynamic analyses were carried out on a single-cylinder AVL 5804 research engine at varying values of excess air ratio (CH4: λ = 1.0–1.3; H2: λ = 2.16–2.70) and by changing the position of the center of combustion (CoC = 6; 8; 10; 12; 14; 16 deg TDC). As a result of the analyses carried out, the ignition advance was found to be significantly smaller when burning hydrogen than methane to maintain the same CoC value. A larger range of changes in ignition advance is required to determine CoC when burning hydrogen, indicating hydrogen's greater sensitivity to changes in ignition angle. During the combustion of the two fuels, different values of overall efficiency were determined: about 48% when burning hydrogen, and about 33% when methane combustion (in both cases, the maximum efficiency was obtained at the highest value of the λ, for methane and hydrogen, respectively: 1.3 and 2.7).