The ASTM D6424 standard is used for general aviation piston engine knock detection and is tested for unleaded fuel candidates. Issues are discussed regarding the identification of knocking cycles, filtering frequency bands, and the effects of down-sampling for this knock detection technique. The knock tests were performed on the Continental TSIO-520-VB engine at 12,000 ft for take-off and cruise conditions using three different fuels, the standard leaded 100LL avgas and two unleaded fuel candidates. The ASTM D6424 knock detection method has its own particular disadvantages, which are detailed and compared to other knock detection methods including the third derivative of pressure signal and discrete wavelet transform. Updates to the standard include a minimum sampling rate of 0.2 CAD. Additionally, the current standard does not contain recommendations for filtering the cylinder pressure which results in over detection of knocking cycles with the two new aviation fuel candidates tested. Recommendations are provided regarding the pressure signal processing prior to ASTM D6424 knock-characterization.

ASTM D6424标准用于通用航空活塞发动机的爆震检测，并经过测试以检测无铅燃料。讨论了有关爆震周期的识别，滤波频带以及此爆震检测技术的下采样效果的问题。爆震测试是在12,000 ft的Continental TSIO-520-VB发动机上进行的，在起飞和巡航条件下使用三种不同的燃料，标准含铅100LL汽油和两种无铅候选燃料进行了爆震测试。ASTM D6424爆震检测方法有其自身的特殊缺点，这些缺点已被详细介绍并与其他爆震检测方法进行了比较，包括压力信号的三阶导数和离散小波变换。对标准的更新包括最低采样率为0.2 CAD。此外，当前标准不包含过滤汽缸压力的建议，这会导致过度检测爆震循环并测试两种新的航空燃料候选物。提供有关在ASTM D6424爆震表征之前进行压力信号处理的建议。