Experimental study of heat transfer inside a hydrogen combustion engine: measurements under motored conditions

This paper presents the first stages of an experimental study of heat transfer inside a hydrogen combustion engine. A heat transfer model for hydrogen engines is under development and measurements are carried out for validation. The current paper describes heat transfer measurements in the cylinder under motored conditions. Transient heat flux is evaluated at the cylinder head and liner with a commercially available sensor. The influence of the compression ratio and measuring position is investigated. Results show that the peak of the heat flux trace rises with increasing compression ratio. The position of the peak remains the same for all the compression ratios. The heat flux is negative during the intake and differs from position to position because of differences in the local air flow field. The flux varies less in the compression and expansion stroke but a large cyclic variation is present in that part of the cycle