本SAE推荐实施规程描述了测量乘用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试验期间测量的，这些试验模拟了夏季大都市地区的典型车辆使用情况:a.浸泡1小时，代表一个白天循环，在此循环中，车辆油箱中的燃油温度从15.6°C升高至28.9°C（60至84°F）；b.在底盘测功机上行驶17.9公里（11.1英里）；C.在行驶17.9公里后立即热浸泡1小时（11.1英里）驾驶本文件中描述的方法，通常被称为SHED（蒸发测定用密封外壳）技术，使用了一个在试验的日间和热浸阶段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- -预期的和意外的——都保留在密封室内，密封室内大气中碳氢化合物（HC）浓度的增加代表了蒸发排放。因此，根据燃料系统配置和部件设计，采用封闭式方法测得的排放值可能与采用前一种捕集器方法测得的排放值存在显著差异。测量排放的试验顺序和方法适用于配备或不配备控制燃油蒸发排放系统或装置的车辆。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型或独特的车辆或燃油系统。例如，根据驻车燃油箱温度随环境空气温度变化的经验，试验顺序规定对燃油箱进行加热，以模拟日间浸泡。 任何设计用于改变燃油和环境温度之间关系的控制系统都不会在规定的测试顺序中进行正确评估。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