In this paper, physical property parameters including density, viscosity and surface tension of different contents of diesel-gasoline blend fuel were measured and analyzed. The experiments were performed on the dieselgasoline blend fuels with 4 different volume fractions of diesel (20%, 40%, 60% and 80%) at temperature from 5 • C to 65 • C. The influence of temperature and diesel content on the blends' properties was summarized based on experimental data, formulas about the material parameters were established, and the accuracy of these formulas was verified. Besides, saturated vapor pressure, freezing point and flash point of the blend fuel have also been measured and analyzed, and a database of the material parameters of the blends was also established. Key words: internal combustion engine, diesel-gasoline blend fuel, physical property CLC number: TK 407.9Document code: A
IntroductionWith the widespread use of internal combustion engine (ICE), environment has been damaged due to the harmful substances released from the ICE, which are also harmful to human health, therefore it is of great significance to develop more efficient and lower emission combustion mode for ICE. Compared with traditional ICE combustion mode, homogenous charge compression ignition (HCCI) is considered as a promising technology, which can simultaneous reduce the harmful emissions and improve combustion efficiency of ICE. The biggest challenge of HCCI combustion is how to control the starting point of ignition and the burning rate effectively when the operating condition of engine changes. Besides, the narrow operation range of HCCI engine is also a big problem [1] .Due to high viscosity and low volatility of diesel fuels, one of the primary problems for the HCCI diesel engine is how to form a homogeneous mixture quickly [2] , for gasoline engine, however, because of the high octane number and auto-ignition temperature of gasoline fuels, it is not so easy for the mixture to achieve its auto-ignition temperature in different operating conditions [3] . Bessonette et al. [4] investigated different kinds of fuels used in HCCI engine, the results showed that in order to make the engine operate in HCCI mode with better performance, the physical properties of the ideal HCCI fuel should between diesel-and gasoline-like fuels.Turner et al. [5] first employed the Diesel-Gasoline blend fuel in a gasoline direction injection (GDI) engine, and the blend fuel was named after "dieseline". Han et al. [6] carried out series researches on the combustion and emissions characteristics of a single-cylinder diesel engine using the Diesel-Gasoline Blend Fuel, their research results showed that by employing a proper ratio of diesel to gasoline, the operation range of HCCI engine could be greatly broadened, meanwhile a lower emission level could be achieved. A reduced gas-phase chemical mechanism of "dieseline" was developed by Kokjohn et al. [7] , then the mechanism was coupled with the KIVA code to establish the "dieseline" HCCI mode, based on this mode, lots of...
