After nearly a decade of research and development, Siemens Automotive says it will be the first supplier to begin volume production of piezohydraulic injectors, opening the door to the second generation of common rail diesel injection for passenger cars.
A Western European customer will be the first to receive the new high-pressure injection system, by the end of next year, followed soon after by a second major vehicle manufacturer. Siemens expects common rail to accelerate the penetration of diesel engines in the European passenger car market and potentially the U.S. car market, which has been less receptive to diesel.
The benefits are numerous: improved fuel consumption, high propulsion power, reduced emissions and only minimal noise generation. In addition, fuel can be metered more accurately, and the start of injection can be determined with greater precision, the company says.
A high-pressure pump generates system pressure of 1,500 bar, compared to 3 bar for solenoid port injectors used today. The system, employing a piezoceramic actuator, responds to each voltage pulse within 0.1 milliseconds, which is more than four times faster than solenoid injectors.
In addition to the injectors and pump, the Siemens system comprises actuators with corresponding sensors, engine control and the rail.
Siemens displayed the system at the recent Frankfurt auto show. The company has invested $80 million in the high-pressure diesel injection project and will produce the system at a new plant in Limbach-Oberfrohna near Chemnitz in the former East Germany.
The plant currently has 300 employees and a production capacity for 2 million units per year. Also, in 2001, the plant will begin producing diesel injection valve nozzles for light- and medium-duty commercial vehicles in the U.S. as a part of Siemens' joint venture with Navistar International Corp.