| With the rapid development of China’s economy and the continuous improvement of people’s living standards, car ownership has increased year by year, energy shortage and environmental pollution problems is being increasingly intensified in China. To develop low fuel consumption, low emission vehicles has become the current theme of the automotive industry. In particular, in January 1, 2016, China approved the implementation of fuel consumption regulations GB27999-2014 and GB19578-2014, so called fuel consumption regulations phaseⅣ, which put forward more stringent requirements and challenges for car fuel consumption, and also has an important influence on the survival and development of automobile enterprises.The fuel consumption of one large displacement PFI gasoline vehicle that is on sale developed by FAW independly is 11.2L/100 km. According to the curb weight, the corresponding limit in fuel consumption regulations phaseⅣ is 9.2L/100 km, that means the fuel consumption needs to be reduced by about 18%. In order to make the vehicle meet the fuel consumption regulations phaseⅣ,so that can sale it continually in January 1, 2018, FAW launched project to reduce the vehicle fuel consumption. Under this background, combined with the development of the vehicle energy-saving technologies and the enterprise situation, this paper studied the effect of engine friction reduction, engine coolant temperature dynamic control, start stop technology, variable valve timing technology, clutch water pump, electric energy management to vehicle fuel consumption, statistic and analysed their contributions. The main research works and conclusions are as follows:1. Compared and studied the differences between drag torque and universal performance of prototype and improved engine. Overall, the engine friction reduction and dynamic control of the coolant temperature has small influence on fuel consumption on this vehicle.2. Analyse the composition and structure of ESM start-stop system, clutch water pump and VVT system, established the control logic of the corresponding control unit. Through the NEDC cycle fuel consumption comparison test found: start stop technology reduced fuel consumption of the vehicle up to 9.55%, the clutch water pump reduced 3.77%, VVT reduced 2.37%.3. Optimized shift schedule.After optimization, NEDC cycle fuel consumption can be reduced by about 1.5%, and DCT has nearlly no contribution to fuel consumption reduction.4. The signal interface and each function of the electric energy management system of the vehicle are analyzed.Compared and analysed the influence of traditional generator and the one in energy management system on fuel consumption. The contribution of the electric energy management system to the vehicle fuel consumption under the NEDC cycle can reach 1.87%.5. After integration and optimization of the above technicals, the vehicle fuel consumption is reduced to 9.34L/100 km, but is still 1.5% higher than the limit of 9.2L/100 km.6. For all the fuel consumption related functions, the calibration has done the best, it’s already has no space to optimize further. And it’s also hard to optimize from the energy efficiency of vehicle and accessories. But the contributions to fuel consumption of engine friction reduction, engine coolant temperature dynamic control technology and DCT are not yet showed. So it’s better to find why these measures didn’t reduce fuel consumption and tap their potentials. At the same time to explore whether can reduce the coasting resistance further. |
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