Abstract
The main purpose of this study is to optimize engine performance and emission characteristics of off-road engines with retarded spark timing compared to MBT by repurposing the existing passenger engine. This study uses a one-dimensional (1D)-simulation to develop a non-road gasoline MPI turbo engine. The SI turbulent flame model of the GT-suite, an operational performance predictable program, presents turbocharger matching and optimal operation design points. To optimize the engine performance, the SI turbulent model uses three operation parameters: spark timing, intake valve overlap, and boost pressure. Spark timing determines the initial state of combustion and thermal efficiency, and is the main variable of the engine. The maximum brake torque (MBT) point can be identified for spark timing, and abnormal combustion phenomena, such as knocking, can be identified. Spark timing is related to engine performance, and emissions of exhaust pollutants are predictable. If the spark timing is set to variables, the engine performance and emissions can be confirmed and predicted. The intake valve overlap can predict the performance and exhaust gas by controlling the airflow and combustion chamber flow, and can control the performance of the engine by controlling the flow in the cylinder. In addition, a criterion can be set to consider the optimum operating point of the non-road vehicle while investigating the performance and exhaust gas emissions accompanying changes in boost pressure With these parameters, the design of experiment (DoE) of the 1D-simulation is performed, and the driving performance and knocking phenomenon for each RPM are predicted during the wide open throttle (WOT) of the gasoline MPI Turbo SI engine. The multi-objective Pareto technique is also used to optimize engine performance and exhaust gas emissions, and to present optimized design points for the target engine, the downsized gasoline MPI Turbo SI engine. The results of the Pareto optimal solution showed a maximum torque increase of 12.78% and a NOx decrease of 54.31%.
Highlights
Non-road vehicles, such as tractors and utility terrain vehicles (UTVs), which are used in harsh environments, mainly use diesel engines owing to their high power and fuel economy
A multi-point injection (MPI) engine that is categorized as a port fuel injection (PFI) type engine was utilized in this study; we studied the Turbo MPI SI engine
The reference 1D models for use in the study were modeled using specifications and engine test results provided by the original equipment management (OEM)
Summary
Diesel engines installed in non-road vehicles emit air pollution-causing substances such as nitrogen oxides (NOx), carbon monoxide (CO), and particulate materials (PM). Non-road vehicles are subject to lower regulations compared to the commercial automobile industry. Owing to the increasing severity of air pollution, regulations for non-road vehicles are being tightened and are at similar levels as those for the passenger/commercial automobile industry. To reduce diesel engine emissions of exhaust gas pollutants, aftertreatment systems that utilize diesel oxidation catalysts (DOCs), diesel particulate filters (DPFs), and selective catalyst reduction (SCR) are being installed. Gasoline engines for non-road vehicles are drawing attention as a replacement for diesel engines, owing to their lower emissions due to the strong emission reduction capability of a three-way catalytic converter (TWC)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
