This paper describes an innovative approach taken in the design of a new common rail injector which uses a piezo stack to directly actuate the needle of the injector nozzle (direct acting concept) instead of using today's servo concepts. The direct acting injector provides a step reduction in engine-out emissions and fuel consumption. A revolutionary rather than evolutionary development path was followed in order to realise new levels of functionality to meet or exceed the customer requirements. After protecting the new concept with patents, throughout the early development cycle intensive use was made of numerical simulation tools to ensure a robust optimisation of dimensional values. This ensured that the number of design iterations required was minimised and shortened the time required to demonstrate proof-of-concept.The result is an injector with radically new configuration compared to existing products, which includes the novel arrangement of how the piezo actuator is placed inside the injector. This inventive step leads the way to improved electrical and hydraulic system efficiency which ultimately offers fuel economy and emissions benefits. Significant innovation was applied in the generation of new electrical drive software and hardware to realise the full potential of the injector.
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