Evaluation of a stratified prechamber ignition concept for vehicular applications in real world and standardized driving cycles

The aim of this paper is to evaluate the potential of a prechamber ignition system to reduce the exhaust emissions and fuel consumption of commercial vehicles in the conditions proposed by the standardized and real-world driving cycles. For this purpose, a multi-cylinder engine was mapped in stationary conditions using two different combustion modes. First, the engine was tested under the baseline stoichiometric combustion with a spark plug ignition system. Second, the engine map was obtained using a stratified prechamber ignition system under lean conditions. Later, the experimental data was used as input for a computer model that simulates the vehicle operation with both concepts under different driving cycles. To run the model under real-world driving conditions, experimental data was acquired in a specific region in southern Brazil in conditions of heavy and free flow. Moreover, the conditions of the study were extended including two homologation cycles, the FTP-75 and WLTC. The results for the different cycles show similar average exhaust emissions and fuel consumption between WLTC and the real conditions of free flow traffic, and also between the FTP-75 and the real conditions of heavy flow traffic. The results also point out the potential of the prechamber ignition system to achieve a reduction of the engine-out CO and NOx emissions greater than 50% and 85%, respectively, as compared to the baseline stoichiometric combustion with a spark plug ignition, without penalizing the fuel consumption.