Galindo, J., Serrano, J., Piqueras, P., and Gómez, J., "Description and Performance Analysis of a Flow Test Rig to Simulate Altitude Pressure Variation for Internal Combustion Engines Testing," SAE Int. J. Engines 7(4):1686-1696, 2014, doi:10.4271/2014-01-2582.
Calibration of internal combustion engines at different altitudes, above or below sea level, is important to improve engine performance and to reduce fuel consumption and emissions in these conditions. In this work, a flow test rig that reproduces altitude pressure variation is presented. The system stands out by its altitude range, compactness, portability and easy control. It is based on the use of turbomachinery to provide the target pressure to the engine intake and exhaust lines.The core of the system is composed of a variable geometry turbine (VGT) with a waste-gate (WG) and a mechanical compressor. Given a set of turbomachinery systems, the operation pressure and the air mass flow are controlled by the speed of the mechanical compressor and the VGT and WG position. A simple modification in the installation setup makes possible to change the operating mode from vacuum to overpressure. So that simulating altitude increase or decrease with the same flow test rig components.The installation concept has been validated experimentally based on a demonstrator. The experimental data are complemented with the analysis of computational results obtained from fluid-dynamic modeling. The results allow analyzing in detail the pressure and air mass flow operating range, the dependence on required subsystems characteristics, the potential for temperature regulation, the behavior under engine transient operation and the control strategies.