This article presents the problem of the knock combustion in a dual fuel compression engine, in which additional fuel besides diesel oil was compressed natural gas (CNG). CNG was injected into the engine intake system and mixed with air supplying the engine. In this paper described the reasons of knock combustion, which occur with more intensity with the increase of methane content in engine fuel. The phenomenon of knock combustion in the dual fuel engine is difficult to eliminate, often impossible to avoid, and it forms a barrier limiting increase of methane share in the fuel. Also, this article contains the results of engine indicating and discussion on changes in the indicating diagrams caused by knock combustion. Carried out tests included engine indicating and numerical calculation of indicator diagrams with using spectral analysis and filtering cylinder pressure signals with high-pass filters. As a result of this calculation, several parameters describing intensity of knock combustion were determined. They allow to tell taking into account only cylinder pressure analysis if there is knock combustion inside engine combustion chamber or not. Knocking is an undesirable type of combustion in the engine, leading to excessive thermal and mechanical loading of the engine parts, causing premature wear of them. For this reason, this type of combustion should be eliminated from the engine operation and researchers of combustion processes must be provided with tools to detect and determine this kind of combustion.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.