Summary and Progress of the Hydrogen ICE Truck Development Project

A development project for a hydrogen internal combustion engine (ICE) system for trucks supporting Japanese freightage has been promoted as a candidate for use in future vehicles that meet ultra-low emission and anti-global warming targets. This project aims to develop a hydrogen ICE truck that can handle the same freight as existing trucks. The core development technologies for this project are a direct-injection (DI) hydrogen ICE system and a liquid hydrogen tank system which has a liquid hydrogen pump built-in. In the first phase of the project, efforts were made to develop the DI hydrogen ICE system. Over the past three years, the following results have been obtained: A high- pressure hydrogen gas direct injector developed for this project was applied to a singlecylinder hydrogen ICE and the indicated mean effective pressure ( IMEP) corresponding to a power output of 147 kW in a 6-cylinder hydrogen ICE was confirmed. In addition, nitrogen oxide (NOx) was reduced with a high thermal efficiency by the optimization of the EGR ratio, the injection timing and the ignition timing. From these results, a DI multi-cylinder hydrogen ICE using this injector was concluded to be highly feasible. A NOx storage-reduction (NSR) catalyst system was applied to the hydrogen ICE. We confirmed that the NOx conversion rate was high and the fuel penalty was low under the limited conditions.