1.1 本实验室发动机测试评估了汽车发动机在低速和高负荷工况下缓解汽油、涡轮增压、直喷（GTDI）发动机燃烧室预燃的能力。该测试方法通常称为福特低速预燃（LSPI）测试。 1.1.1 在配备相对较小GTDI火花点火发动机的车辆中，当车辆在低速和高负载条件下运行时，偶尔会发生预点火。不受控制的预燃可能会造成破坏性的发动机损坏。 1.2 以国际单位制表示的数值应视为标准值。 本标准不包括其他计量单位。 1.2.1 例外情况- 如果没有直接的SI等效物，例如螺纹、国家管道螺纹/直径、管道尺寸、线规或指定的单源设备。 1.3 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.4 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 本试验方法评估了汽车发动机在低速和高负荷工况下缓解涡轮增压直喷汽油发动机燃烧室中预燃的能力。 5.2 在制定试验程序的操作条件时，使用了具有已知预燃倾向的不同质量的参考油。 5.3 该试验方法适用于汽油机油规范，预计将用于发动机润滑油的规范和分类，例如: 5.3.1 规格 D4485 . 5.3.2 ILSAC GF-6。 5.3.3 SAE J183分类。

1.1 This laboratory engine test evaluates the ability of an automotive engine to mitigate preignition in the combustion chambers in gasoline, turbocharged, direct-injection (GTDI) engines under low-speed and high-load operating conditions. This test method is commonly known as the Ford low-speed, preignition (LSPI) test. 1.1.1 In vehicles, equipped with relatively small GTDI spark-ignition engines, preignition has occasionally occurred when the vehicles are operated under low-speed and high-load conditions. Uncontrolled, preignition may cause destructive engine damage. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.2.1 Exceptions— Where there is no direct SI equivalent such as screw threads, national pipe threads/diameters, tubing size, wire gauge, or specified single source equipment. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 This test method evaluates the ability of an automotive engine to mitigate preignition in the combustion chambers in turbocharged, direct injection, gasoline engines under low-speed and high-load operating conditions. 5.2 Varying quality reference oils, with known preignition tendencies, were used in developing the operating conditions of the test procedure. 5.3 The test method has applicability in gasoline-engine-oil specifications and is expected to be used in specifications and classifications of engine lubricating oils, such as the following: 5.3.1 Specification D4485 . 5.3.2 ILSAC GF-6. 5.3.3 SAE Classification J183.