Study On Diesel Ignition Time In N-butanol/diesel Composite Combustion System

The growing demand for energy,the depletion of oil reserves,the rapid decline of the remaining oil resources as a non-renewable energy source,has stimulated the interest in finding clean alternative fuels.As a new alternative fuel,n-butanol has received extensive attention due to its excellent physical and chemical properties.This article is based on a modified singlecylinder dual fuel engine,the inlet pressure and inlet temperature constant,through the inlet jet n-butyl alcohol,in cylinder direct injection diesel,realization of n-butanol/diesel dual fuel combustion process,and to redefine the diesel burning method,ignition delay period,butanol in proportion to the amount of combustion and combustion in advance in advance,To establish the evaluation system of chemical reaction suitable for diesel ignition time,mixing process and after diesel ignition.The results show that:1.Redefine the ignition starting point of diesel oil through the intersection of the internal energy change rate and the thermal change rate of working medium;The evaluation system of diesel mixture in dual fuel was established by the lag period of diesel fuel.The chemical reaction evaluation system suitable for diesel ignition was established by the amount and proportion of advance combustion of butanol.2.Influence of key parameters on the starting point of diesel ignition: When the diesel injection amount is 35 mg,the butanol injection amount increases,and the mixture temperature of butanol decreases before ignition.At-8DEG ATDC,the ignition Angle of diesel starts from the initial TDC and then away from the TDC.At 0DEG ATDC,there is little difference in the starting point of diesel ignition.When the injection amount of butanol is 35 mg,with the delay of the injection Angle,the increase of the injection amount of diesel and the increase of the mixture temperature of butanol,the ignition Angle of diesel is first close to TDC and then far away from TDC.At 4DEG ATDC,the ignition starting point of 50 mg diesel is relatively forward.3.Influence of key parameters on diesel combustion delay period: when the diesel injection amount is 35 mg and the butanol injection amount increases,the cylinder pressure growth rate decreases and the average temperature in the cylinder decreases.The delay combustion period increases first and then decreases at-8deg ATDC,increases continuously at0 deg ATDC,and decreases first and then increases at 4deg ATDC.When the n-butanol injection amount is 35 mg,the diesel injection amount increases,and the average compression temperature in the cylinder rises.With the increase of the diesel injection amount,the temperature difference before ignition increases.At-8deg ATDC,the delay combustion period first increases and then decreases,and at 0deg ATDC,the trend of first decreases and then increases.The combustion retardation period of 50 mg diesel at 4DEG ATDC is relatively long.4.Influence of key parameters on the chemical reaction after diesel ignition: when the diesel injection amount is 35 mg and the butanol injection amount increases,the average temperature and total heat in the cylinder increase with the n-butanol injection amount,and the peak heat release rate is away from the top dead center first and then close to the top dead center.When the n-butanol injection amount is 35 mg,the diesel injection amount increases,the average temperature and the total heat in the cylinder increase,and the peak value of heat release rate increases and is close to the dead center.