TASR: Transient Air System Rig

• To measure performance of multi-stage engine air systems under engine-realistic conditions, but without an engine

• To reproduce the unsteady gas dynamics in an IC engine exhaust manifold undergoing a specified transient event

To meet these objectives, TASR will need to be able to generate two timescales of unsteadiness:

1. Transient – timescale of engine acceleration, in the order of 100 Hz

2. Pulsating – timescale of exhaust pulses due to opening and closing of valves, order of 10¹–10² Hz

• Transients are created by a fast-acting pressure regulating valve, which imposes ramps in the mean flow entering the pressure plenum (Figs 2 & 3), to imitate vehicle-level events

• Pulses are generated by a Lotus AVT (Active Valve Train) system [3], comprising six electrohydraulic poppet valve actuators, with corresponding mounting plates, exhaust ports, valves and seats, which are installed on top of the pressure plenum (Fig. 2)

• Our modular design philosophy allows different engine cylinder spacing to be accommodated with a minimum of part changes, while the simple plenum design can be adjusted for overall volume, or be adapted to include internal features

TASR offers numerous advantages over traditional gas stand or engine testing:

• It isolates the air system from combustion effects and associated confounding factors

• The non-combusting flow permits new manifold and turbocharger concepts to be inexpensively and rapidly 3D-printed in plastic, ready for immediate testing

• Its capabilities (Tab. 1) and modular design, which is not restricted to any particular cylinder configuration, allows a wide range of engine air systems to be evaluated