Reproduction of chassis dynamometer driving cycles on the road as a means of achieving repeatable on-road emissions tests

Projected increases in the cost of conventional fossil energy sources and greenhouse gas emissions caps are among the key drivers for the utilization of various gaseous fuels prepared from biomass in internal combustion engines, primarily in cogeneration units. Due to the low energy content and other poor qualities of many such fuels, they are often intended to be co-fired with diesel fuel, or used in blends with natural gas or other gaseous fuels. Variations in the composition of the biogas, limited capabilities of gas mixing and metering devices, and other factors create challenges in determining the intake charge composition, so that optimal mixture of air and multiple fuels can be maintained. In this study, an experimental device for mixing of two gaseous fuels was tested, with various gases, on a bus engine modified to run on experimental gaseous fuel blends. To evaluate the performance of the mixing device, the composition of the mixture of two fuel gases was continuously analyzed by an inexpensive NDIR ,”garage-grade” exhaust gas analyzer. The focus of this paper is on the adaptation of the analyzer for this purpose, including calibration and linearization techniques, its verification, and performance. Preliminary results show that this analyzer, commonly used for automobile inspection and maintenance purposes, can serve, albeit with precautions and limitations, as a relatively simple tool for field measurements of the composition of a fuel gas mixture, both raw and mixed with air.