Enhanced instrumentation of an optical research engine with unique combustion chamber

Abstract

A novel optical engine test facility offers advanced possibilities to examine dual-fuel, respectively multi-mode combustion processes at engine-relevant flow, temperature and pressure conditions. Optical accessibility provided via two axes allows an adaptable application of different optical and spectroscopic methods. Due to the specific test rig concept and the unique combustion chamber design in particular, an advanced measurement technology is necessary in terms of precise operating condition acquisition. Aiming at reduced measurement uncertainty – also in terms of most accurate reference data for simulation tools – led to maximum expansion, interesting appraisals, and finally to an improvement of the measurement technology. During the test bench’s characterization with complementary measurement technologies specific effects could be disclosed and described. In particular, proper sensor selection, signal evaluation progress and sensor thermal conditioning lead to a significantly reduced measurement error. In addition to pressure acquisition, combined in-cylinder/wall temperature with corresponding heat flux measurements were applied simultaneously. The expanded process parameter acquisition with improved accuracy lead to an extended reference data set for modelling and simulation approaches. At last, comprehensive in-cylinder measurements of pressure, temperature and flow field under typical operating conditions completed the characterization of the test rig. Moreover, the general operating ability in view of future experimental investigations can be assessed.