Caterpillar Inc. and Isuzu Motors Ltd. have developed a high-pressure fuel injection system for application in Isuzu's 3-L class light-duty diesel engine. The system features Caterpillar's HI90 hydraulically actuated, electronically controlled unit injector (HEUI) fuel system. It is claimed to be the only production fuel injection system that uses a common rail system for high-pressure injection capability regardless of engine speed.