A Fast Method For Knock Detection Using Wavelet Transform

Fiołka, J.

doi:10.1109/mixdes.2006.1706658

Cited by 5 publications

(1 citation statement)

References 9 publications

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“…Equations and show that the wavelet relative energy P j at level j is defined as the percentage of detail energy E j of the in-cylinder pressure signal over the four levels. , P j = E j E = E j ∑ j = 1 4 E j E j = ∑ k = 1 N j | d j , k | 2 where E is the total detail energy of the pressure signal; k , as the coefficient index, is an integer; and N j is the number of the detail coefficient d j , k at level j .…”

Section: Methodsmentioning

confidence: 99%

Knock Investigation of a Direct Injection−Homogeneous Charge Compression Ignition Engine Fueled with Dimethyl Ether and Liquefied Petroleum Gas

et al. 2009

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An experimental investigation of knock was conducted on a DI-HCCI (direct injection-homogeneous charge compression ignition) engine fueled with DME (dimethyl ether) and LPG (liquefied petroleum gas). The engine's HCCI fuel system provided a homogeneous charge of DME-LPG blend and the DI fuel system injected DME into the cylinder. The in-cylinder pressure was measured and processed using Fourier transform and discrete wavelet transform. The analysis shows that the main frequency band of knock is included between 3.5 and 10 kHz in DI-HCCI combustion with DME as DI and HCCI fuel. As the brake mean effective pressure increases, the main frequency band changes little. With DME as DI fuel and DME-LPG blend as HCCI fuel, the main frequency bands are between 4 and 10 kHz. The cetane number of HCCI fuel has little effect on the main frequency band. With no knock, light knock, and heavy knock, the greatest wavelet relative energy of in-cylinder pressure are at detail D2, D4, and D3, respectively. The distribution of wavelet relative energy over four details does not change with BMEP. As HCCI fuel changes from DME to 60% LPG/40% DME to LPG, the wavelet relative energy distribution remains unchanging. However, the knock intensity plays an important role in determining its distribution. When wavelet relative energy at detail D4 is the greatest, light knock occurs; when wavelet relative energy at detail D3 is the greatest, heavy knock does. Therefore, wavelet relative energy over four details should be monitored for knock detection.

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