Experimental Study Of Vehicle Idling Start-stop System Based On Super Capacitor

In city driving, the engine idling time of cars is about20%of the whole driving circle,the idling start-stop system can avoid the engine’s long idling time. It is of greatsignificance for energy saving and environmental protection. Along with the increase ofautomobile amount, the research of idling start-stop system becomes more and moreimportant. Because of being good at charge and discharge, the super capacitor has beendeveloping rapidly in recent years. This paper developed the test set of the idling start-stopsystem based on super-capacitor; the main content is as following:Calculated the starting and braking energy combining with battery starting analysisand brake energy simulation, on whose basis, designed the parameters of the supercapacitor. With the analysis of the system requirement, determined the structure and modeof super capacitor starting system.Developed idling start-stop test bench, the function of which included：Achieving thecontrol of the engine idling start and stop; Judging system fuel economy by detecting fuelconsumption; Carrying out test of the engine idling start-stop emissions optimization;Switching between the battery and the super capacitor and starting the engine with thesuper capacitor only; Simulating the coasting braking energy and recycling glide energywith the super capacitor.Finally, took some experiments with the test bench. The results show: The startingparameters were similar with battery by using the super capacitor (110F,15V), the startingperformance was good. The idling stop-start system was saving fuel when the idling timeexceeds14s.According to the European ECE+EUDC cycle conditions, the use of theidling start-stop system can fuel32.48mL each cycle and system fuel efficiency is4.4%.Recovered the coasting brake energy with the super capacitor, in a conventional trafficlight junction, a car with the first speed of40Km/h, the energy that recovered by Sliding3.6seconds was enough to provide the engine starting needs. The innovation of this study includes:1) Proposed to use the super capacitor into the engine starting system and start theengine with the super capacitors only, which can adapt to the requirements of enginestarting power discharge.2) Proposed to use the super capacitor recovering the vehicle coasting energy, whichcan improve the energy efficiency and ensure that the super capacitor has sufficient energyfor the next start.3) Proposed the basic controlling method of idling start-stop based on super capacitor,which can effectively achieve the control of the engine idling start-stop and super capacitorcharge and discharge.