Simulation And Experimental Research On Optical Gasoline Engine Combustion Process

Gasoline as the heart of vehicle, is the power source of the car, the significance of its existence is undebatable, its healthy development promote the progress of the entire automotive industry. The combustion process of the gasoline engine is complicated, so many researchers pay attention to the testing for gasoline. Visualization technology is the most effective test method for the present to study the internal combustion of the gasoline engine. The most commonly method is transform the gasoline engine, installation visualization window to the interior of the cylinder and detect the combustion of the in-cylinder by laser. However, by transform a larger number of the gasoline structure to achieve the internal visualization of gasoline engine will inevitably affect the performance of the original gasoline engine. Therefore,this article use the software of AVL FIRE to simulate and compare the traditional gasoline engine and the optical gasoline engine, the differences between the optical gasoline engine and traditional gasoline engine will help us verify the reasonableness of optical experiments.Firstly, transform the Pentium B70 gasoline engine into an optical engine. Extended the piston, cylinder and Liner of the original gasoline engine and installation the 45 ° mirror inside the extended piston so that the laser line source transmission in and out the cylinder of the gasoline engine conveniently, and observe the combustion of in-cylinder as much as possible.Secondly analyzes the principle of the numerical simulation, set up the model of the inlet,exhaust ports and combustion chamber of the engine, the calculation of the numerical simulation is based on the foundation. Use the software of AVL FIRE to simulate the distribution of temperature, velocity and density of the gasoline engine and optical gasoline engine, and analyzes the distribution of the density of NO in the optical gasoline engine.This paper mainly studied the combustion diffusion and mixture of gasoline situation of the gasoline engine at different speed, by analysis the temperature, velocity and concentration field.At the high speed, the formation time of the mixed gasoline is shortened, flame spread faster,wider range resulting in the whole temperature increases in the combustion chamber, it willincrease the overall temperature in the combustion chamber. The optical gasoline engine due to the influence of the pits at the top of the piston, the mixed gasoline relatively high concentrations nearby the pits. Therefore the temperature nearby the pit is higher than the original gasoline. The pit at the top of the optical gasoline engine flow intensifies will form a tumble flow phenomena, so that the fuel in the chamber at high speed nearby the pit, but it has little effect on the velocity field of the cylinder velocity, because of the small proportion of the pit. The tumble phenomenon in the pit at the top of the optical gasoline engine piston makes its high concentration. Since the piston downward, causing the cylinder squish strengthened so that the distribution of the fuel density at the exhaust valve side increased. The generation of NO in the combustion process at the optical gasoline engine is the same with traditional gasoline engines, both in the high temperature stage production. Also, because of the pit at the optical gasoline piston, the density of NO is higher nearby the pit, it makes the overall distribution of NO density slightly different.