HIGH-PRESSURE HYDROGEN INJECTION FOR INTERNAL-COMBUSTION ENGINES

Manifold induction or low-pressure gaseous hydrogen injection into an engine cylinder can lead to the combustion problems of light-back, preignition and/or autoignition. The most satisfactory way to overcome such problems is to utilize a high-pressure direct injection system that provides fuel injection late in the compression stroke. This paper discusses the development of such an injection valve for hydrogen fuelling of a Ricardo E6 spark ignition research engine. The design and testing of the various major components of the valve is examined in detail. The valve employs the principle of sonic injection, is electromagnetically actuated and is electronically controlled. The lightweight design of the moving element, together with an elastomeric valve seat ensures highly accurate injection down to time durations of 1 ms, and zero valve leakage when closed. Engine performance figures using the injection valve are presented which reveal that the valve performs close to ideal, giving stable engine operation without the combustion problems often associated with hydrogen fuelling.