Comparison of pollutant concentrations and engine operating parameters during cold start with petrol and LPG

The cold start of an ICE generates conditions conducive to intensive pollutant emission and reduced thermal efficiency. This study compared the concentrations of selected exhaust components and engine operating parameters during the cold start phase of a dual-fuel vehicle powered by petrol and LPG. The tests were conducted on a chassis dynamometer under identical ambient and load conditions, utilizing a repeatable homologation test. The analysis included HC, CH₄, and NOx concentrations, which were recorded simultaneously with the internal combustion engine's operating parameters: rotational speed, coolant temperature, throttle position, and load. The collected data enabled the development of mathematical models representing the relationships between the dynamics of the start process and pollutant concentrations. The results indicate significant differences in the start characteristics for individual fuels; in particular, LPG exhibits a distinct emission profile during the early phase of engine operation. Conclusions can serve as the basis for designing start control strategies in dual-fuel vehicles, considering environmental requirements and the further development of emission control systems.