Analysis And Control Methods In Vehicular Fuel Consumption On Intersections Of Urban Roads

It is of great importance to reduce vehicular fuel consumption and make road traffic more efficient and sustainable around the world. A great deal of energy of vehicles is lost due to braking behaviour and a large amount of gasline is wasted by idling vehicles during the road intersection; the effects on optimizations of traffic design and signal timing made by rearchers are effective to decrease vehicular delay and to enhance capacity of the signalized intersection. Since these models can collectively improve the vehicle motion and the operation efficiency of the intersection, it should be possible to optimize the vehicle trajectory to minimize its fuel consumption. Consequently, the chief contents are as below in this research effort.For a start, the experiment scheme was designed considering the data base of the following research demand, including the flow chart, the method and the requirements. On this basis, a fuel consumption data collecting system was constructed and a conbined test system in vehicle was proposed to conduct the experiment after analysis on the techniques and methods of fuel consumption data collection of urban roads and intersections. The relevant vehicle operating data were gatherd via field investigation and the corresponding database was costructed after pre-precessing by the method of the Douglas-Peucker algorithm.The next, the computing methods and models on fuel consumption were presented for a single vehicle and traffic flow travelling intersections respectively. Above all, fuel consumption composing and calculating method were put forward, the fuel consumption rates for acceleration, deceleration, idling and cruise were calibrated, and eventually the fuel consumptions for the test vehicles along the test route were computed. The next, vehicular operating time-space ranges infulenced by intersections were defined and surveyed, the fuel consumptions for the test vehicles during the areas of intersections were calculated and there characteristics were analyzed. In the end, three kinds of modes of vehicular operating states were brought forward and their relationships with fuel consumption were discussed.Once again, the process of traffic flow arrival and departure on signalized intersections were analyzed based on wave theory of traffic flow, and thus a conclusion of recovery of traffic operating state mainly depended on the red time and the ratio of initial flow density to maximum density was drawn. Fuel consumption affected by stochastic characteristics of traffic flow arrival was analyzed. Significantly, fuel consumption calculating methods and case studies for traffic flow on over-saturation, low-aturation and critical-saturation signalized intersections were presented, which considered the limitation condition of the distance between two adjacent intersections after analysis on the indexes of the average delay, stop frequency and queue length.Fourth, in the fuel consumption and energy respects, energy coefficients of vehicular operating on singnalized intersections were defined and the correspording calculating methods were proposed, which were fuel consumption proportionality coefficient and energy coefficient based on the analysis on vehicular operating resistances composition and vehicular operation formula. And the analysis on energy coefficients under different modes of vehicular operating states was performed in view of former data and the vehicular operating speed ranges were suggested. Thus, a dynamic operating speed control model was built and approved by the numerical simulation.In the end, three popular signal control strategies for intersections were analyzed and more importantly a signal timing optimization method was brought up and was verified through a verification case which chose the optimization objective of minization of the average fuel consumption for the traffic flow of the intersection. The setting types and application conditions for waiting areas of intersections were concluded at home and abroad, the methods of optimization settings for left-turn waiting areas, through waiting areas and comprehensive waiting areas were proposed which considered the optimization goal of fuel consumption. At last, the improvement effects effected by herein countermeasures on signal timing and waiting areas were validated from the simulation analysis through the softwares of TRANSYT-7F and VISSIM.Following are the primary findings:above all, the average fuel consumption of the test vehicle along the test route was 11.8 L/100km,50.65% of the fuel consumption for the test vehicle was used at the area of intersections,79.2% of the fuel consumption on intersections was burnt at the stages of acceleration and idling, and the principal influence factors for the fuel consumption under mode (Ⅰ), mode (Ⅱ) and mode (Ⅲ) of vehicular operating states were identified for the travel time and acceleration and acceleration time duration, travel speed and travel time length, travel time and stop frequency respectively. The next, the ratio of volume to capacity of the lane groups of the intersection approachs was of great importance for the fuel consumption. It was a low level when the traffic flow was under low-saturation condition, while it had a rapid growth under the critical-saturation traffic flow and it had an agglomeration growth under the over-saturation traffic flow. Once more, fuel consumption proportionality coefficient was influenced by vehicular operating states seriously. The value was 7.2 for mode (Ⅰ), the value was 2.0 for the mode (Ⅱ), the value was 13.9 for mode (Ⅲ) and the average is 7.4. Meanwhile, the coefficients would be optimal under the deceleration state and be decisively influenced by the initial speed and the speed difference. While the energy coefficient was 18.1% for the mode (Ⅰ) and the value is 59.1% for the mode (Ⅱ). And the proposed dynamic speed control method could be effective to reduce the fuel consumption. In the end, fuel consumption-based signal timing method could save fuel consumption about 3.1%, enlarge capacity about 1%, and incrase average delay around 0.8%. Fuel consumption was influenced by waiting areas greatly, which depended on the length of waiting areas, traffic demand, traffic organization and signal time scheme.