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China 6 (CN6) emission legislation for light duty vehicles was published in 2016, which introduced real driving emissions (RDE) requirements for new type-approval content. Nitrogen oxides (NOx) and particle number (PN) of RDE test are required to be monitored and reported from July 2020 in CN6a phase, fulfilled from July 2023 in CN6b phase. To meet the PN limitation of CN6 RDE, the optimized engine combustion and advanced emission control system like gasoline particle filter (GPF) are encouraged. Compared to traditional vehicle platform emission compliance which could be done in lab, much more vehicle development and validation efforts are expected on the open road for RDE compliance. High cost and complexity are expected to conduct a complete validation test matrix covering all the RDE critical boundary conditions on the open road.

Changan has upgraded its 1.6 L naturally aspirated GDI engine to meet future fuel economy and emission regulation base on its previous 1.6 L naturally aspirated GDI engine, the major upgrades include a high compression ratio of 13, 35Mpa direct injection system, cooled external EGR, thermo management module,and extensive measures to reduce friction. With this new engine, the vehicle fuel consumption is reduced by 9%, and meet the China 6b emission standard without GPF.

Performance and particulate emissions of a modern common-rail and turbocharged diesel engine fueled with diesel and biodiesel fuels were comparatively studied. An electrical low-pressure impactor (ELPI) was employed to measure particle size distribution and number concentration. Two biodiesel fuels, BDFs (biodiesel from soybean oil) and BDFc (biodiesel from used cooking oil), as well as ultra-low sulfur diesel were used. The study shows that biodiesels give higher thermal efficiency than diesel. Biodiesels give obviously lower exhaust gas temperature than diesel under high engine speed. The differences in fuel consumption, thermal efficiency and exhaust gas temperature between BDFs and BDFc are negligible. The first peaks of heat release rate for biodiesels are lower than that of diesel, while the second peaks are higher and advanced for biodiesels. BDFs show slightly slower heat release than BDFc during the first heat release stage at low engine speed.

Experiments were conducted in a turbocharged, high-pressure common rail diesel engine to investigate particulate emissions from the engine fueled with biodiesel and diesel blends. An electrical low-pressure impactor (ELPI) was employed to measure the particle size distribution and number concentration. Heated dilution was used to suppress nuclei mode particles and focus on accumulation mode particles. The experiment was carried out at five engine loads and two engine speeds. Biodiesel fractions of 10%, 20%, 40%, 60% and 80% in volume were tested. The study shows that most of the particles are distributed with their diameters between 0.02 and 0.2 μm, and the number concentration becomes quite small for the particles with the diameters larger than 0.2 μm. With the increase of biodiesel fraction, engine speed and/or engine load, particle number concentration decreases significantly, while the particle size distribution varies little.

Changan Automobile Company recently develops a new 1.0L turbocharged GDI engine for its future vehicle as an affordable fuel-saving option. Fuel direct injection and turbo-charging are integrated to significantly improve fuel economy and power. Injection spray pattern plays an important role on GDI engine combustion system because of its critical influences on combustion and oil dilution. In this paper, four injector patterns were tested in an optical engine with Planar, double sided Laser Induced Fluorescence (LIF) with fuel & tracer and flame imaging methods to evaluate spray, mixture formation and combustion process in cylinder. Spray pattern and mixture formation are studied using LIF, while flame and combustion characteristics are studied by flame natural luminosity. The pictures of piston crown and glass liner are also evaluated for fuel spray impingement. Four types of multi-hole injectors are prepared.