High pressure gas injection is a very recent combustion concept for natural gas that injects gaseous fuel into the cylinder at pressure of more than 300 bar with considerable potentials such as diesel-like efficiency and minimum methane slip. Not the least on of the major potentials is the possibility of using synthetic methane and minimize CO2-emission considerably. Together with the capability of high mileages future heavy-duty traffic is due to benefit from this concept to a high degree.
On the development side many similarities with diesel combustion are present but also a lot of specific characteristics like the high gas compressibility and the subsequent sub- and supersonic flow phenomena that influence mixing and ignition of the gas jet. In order to tap into these potentials and to investigate optimal hardware and operation strategies we collaborate with Robert Bosch GmbH on one of our single-cylinder engine test beds. To this end upgrades to the test bed were installed, in particular a high pressure gas supply system for up to 550 bar at the injector and an online gas chromatograph for monitoring natural gas composition.
Three years of successful test bed operation has provided for a lot of data, many insights and many more questions and ideas to further this particular combustion concept and to bring it on the track to series production.