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In this paper investigations of hydrogen use as a main fuel for a compression ignition engine with pilot injection of diesel fuel will be presented. The experiments were performed in steady state conditions on a single cylinder research compression ignition engine with a bore of 85 mm and piston stroke of 90 mm, coupled with an electric dynamometer. The diesel engine with optimized compression ratio was equipped with a diesel fuel direct injection common rail system. A homogeneous mixture of air and hydrogen was formed using a port fuel injection. The influence of hydrogen share on total fuel energy was systematically investigated between limits given by the pure diesel operation and up to a maximum hydrogen share, reaching 98% by energy. The tested hydrogen share was constrained by practical limits at various loads between 4 and 16 bar of IMEP with simulation of the real turbocharger performance and at three engine speeds.

In this article the development of a combustion system with a fuel-scavenged pre-chamber is described. Such a system is commonly used in large-bore engines operated with extremely lean mixtures. The authors implemented the scavenged pre-chamber into a light duty truck-size engine with a bore of 102 mm. The lean burn strategy is intended to achieve very low nitrogen oxide (NOx) emissions at low load. At full load a stoichiometric mixture strategy is applied to achieve sufficient power density while simultaneously enabling the use of a relatively simple three-way catalytic converter for exhaust gas aftertreatment. This work outlines the pre-chamber design features and introduces the results of an experimental investigation of the effect of pre-chamber ignition on a single cylinder testing engine.

This work presents development and results of experimental and numerical investigations of an advanced ignition system with a scavenged pre-chamber for a natural gas fueled engine with a bore of 102 mm and stroke of 120 mm. Two combustion concepts are taken into account. The lean burn concept is used to minimize engine out emissions of nitric oxides (NOx) and to achieve high thermal efficiency at low load. The in-house designed scavenged pre-chamber enables the engine to be operated up to the air-excess ratio (lambda) of 2. A stoichiometric (lambda=1) operation is also possible. It is compatible with a three-way catalyst concept, at high load and potentially transient modes and can provide as high as possible engine power density. The influence of the scavenged pre-chamber volume on the combustion and performance within the range of the operational points of the naturally aspirated engine is presented in this paper.