Series Turbocharging for the Caterpillar ^® Heavy-Duty On-Highway Truck Engines with ACERT™ Technology

The engine air system continues to be a critical component in achieving the performance and emissions requirements of the diesel engine for the on-highway truck market. Cat ® ACERT™ engine technology is no exception. The first application of series turbochargers to a Caterpillar on-highway truck application became a significant challenge. Space under the hood is quite limited and the engine had to fit into a variety of different truck chassis. This necessitated a very compact design and the flexibility to accommodate different installation requirements. Since the overall efficiency of the turbocharging system is a strong factor affecting fuel consumption, a 6 Sigma project was launched to optimize the design for highest possible efficiency. Following the 6 Sigma methodologies, the series turbocharging system was evaluated using sub-system testing on steady-flow gas stands, engine dynamometer testing and CFD simulation. Analysis of the data was used to identify the design improvements required to meet the performance targets. The design was then modified and optimized, using CFD simulation, and validated through engine dynamometer testing. In the end, the compact series turbocharging system designed for the heavy-duty engines was able to achieve the critical customer requirements.