本SAE推荐规程描述了测量客车和轻型卡车燃油系统蒸发排放的程序。排放量是在一系列实验室测试期间测量的，这些测试模拟了夏季大都市地区的典型车辆使用情况: 一个。1小时浸泡，代表一个日循环，其中车辆油箱中的燃油温度从15.6°C升至28.9°C（60°F至84°F） b.在底盘测功机上行驶17.9公里（11.1英里） c.行驶17.9公里（11.1英里）后立即泡1小时热水澡 本文中描述的方法，通常称为SHED(用于蒸发测定的密封外壳)技术，采用在测试的白天和热浸泡阶段期间将车辆放置在其中的外壳。从燃油系统所有开口逸出的蒸汽--预期和意外-都保留在外壳中，外壳中大气的碳氢化合物（HC）浓度的增加代表蒸发排放。因此，根据燃料系统配置和部件设计，通过封闭方法测量的排放值可能与通过前一种捕集方法获得的排放值显著不同。 用于测量排放的测试序列和方法适用于具有或不具有控制燃料蒸发排放的系统或装置的车辆。尽管它们已成功地用于配备各种控制装置的各种车辆，但它们不应不加区别地应用于新的或独特的车辆或燃料系统。例如，基于停放车辆中燃料箱的温度偏移跟随环境空气的温度偏移的经验，测试序列规定加热燃料箱以模拟白天浸泡。任何旨在改变燃料和环境温度之间关系的控制系统都不能在规定的测试序列中进行适当的评估。 本文件旨在作为标准的指南

This SAE Recommended Practice describes a procedure for measuring evaporative emissions from fuel systems of passenger cars and light trucks. Emissions are measured during a sequence of laboratory tests that simulate typical vehicle usage in a metropolitan area during summer months: a. A 1 h soak representing one diurnal cycle in which temperature of fuel in the vehicle's tank is raised from 15.6 to 28.9 °C (60 to 84 °F) b. A 17.9 km (11.1 mile) drive on a chassis dynamometer c. A 1 h hot soak immediately following the 17.9 km (11.1 mile) drive The method described in this document, commonly known as the SHED (Sealed Housing for Evaporative Determination) technique, employs an enclosure in which the vehicle is placed during the diurnal and hot soak phases of the test. Vapors that escape from all openings in the fuel system--both expected and unexpected--are retained in the enclosure, and the increase in hydrocarbon (HC) concentration of the atmosphere in the enclosure represents the evaporative emissions. Emission values measured by the enclosure method can, therefore, be significantly different than those obtained by the former trap method, depending on fuel system configuration and component design. The test sequence and methods for measuring emissions are applicable to vehicles either with or without systems or devices to control fuel evaporative emissions. Although they have been used successfully with a wide range of vehicles equipped with a variety of control devices, they should not be applied indiscriminately to new or unique vehicles or fuel systems. For example, based on experience that temperature excursions of the fuel tank in parked vehicles follow those of ambient air, the test sequence prescribes heating of the fuel tank to simulate a diurnal soak. Any control system designed to alter the relation between fuel and ambient temperatures will not be properly evaluated in the test sequences prescribed. This document is intended as a guide toward standard