Analysis of Wall impingement Spray and Film Formation Process of Direct Injection SI Engines under Low Temperature Conditions

‐Controlled Fuel and Wall Temperature as Experimental Parameters‐

Abstract

In a direct injection spark ignition engine, strict control of pollutant emissions at cold start is required to comply with new regulations. Fuel temperature and wall temperature are especially important parameters because they are closely related to the fuel film formed by spray impingement on the wall. The purpose of this study is to clarify the mixture and fuel film formation process with wall impingement spray under low temperature fuel and wall conditions. Construction of a spray experiment equipment that can simultaneously cool fuel temperature and wall temperature, and Total internal reflection laser induced fluorescence (TIR-LIF) method was applied to the fuel film formed by wall impingement spray. TIR-LIF method can measure fuel film thickness by fluorescence from fuel film during the spray injection without the influence of the spray droplet. In this paper, the fuel and wall temperatures were controlled from 293 K to 253 K to investigated film formation process during spray injection. In addition heat of evaporation considering heat capacity of fuel film was estimated.