On the Design and Optimization of a Clean and Efficient Combustion Mode for Internal Combustion Engines through a Computer NSGA-II Algorithm

Abstract

In order to address typical problems due to the huge demand of oil for consumption in traditional internal combustion engines, a new more efficient combustion mode is proposed and studied in the framework of Computational Fluid Dynamics (CFD). Moreover, a Non-dominated Sorting Genetic Algorithm (NSGA-II) is applied to optimize the related parameters, namely, the engine methanol ratio, the fuel injection time, the initial temperature, the Exhaust Gas Re-Circulation (EGR) rate, and the initial pressure. The so-called Conventional Diesel Combustion (CDC), Homogeneous Charge Compression Ignition (HCCI) and the Reactivity Controlled Compression Ignition (RCCI) combustion modes are compared. The results show that RCCI has a higher methanol ratio and an earlier injection timing with moderate EGR rate and higher initial pressure. The initial temperature increases as the methanol ratio increases. In comparison, CDC has the lowest hydrocarbon and CO emissions and the highest combustion efficiency. At different crankshaft rotation angles corresponding to 50% of the combustion amount (CA50), the combustion temperature and boundary layer temperature of HCCI change significantly, while those of RCCI undergo limited variations. At the same CA50, the exergy losses of HCCI and RCCI are lower than that of the CDC. On the basis of these findings, it can be concluded that the methanol/diesel RCCI engine can be used to obtain a clean and efficient combustion process, which should be regarded as a promising combustion mode.

A Study on the Relationship between Anodic Oxidation and the Thermal Load on the Aluminum Alloy Piston of a Gasoline Engine

“…The internal heat transfer coefficient of the piston was affected by the temperature at the top of the piston and the airflow movement of the crankcase [9], which was generally expressed by Eq. ( 3)…”