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Hyundai公司对V6柴油机用于由新8档自动变速器组成的动力总成时的怠速声品质进行了广泛的研究,以便分析机械激励噪声和燃烧激励噪声所起的作用。首先,在发动机研发初期,可以采用试验模态分析及按发动机各功能系统的稳定性设计来改善动态特性。另外,增强发动机的结构阻尼,能在燃烧激励增强时使发动机的燃烧噪声维持在目标值水平。在整个结构阻尼分析的频率范围内,发现有些零件较好,有的零件较差,然后对系统中的薄弱环节进行优化。在本研究中,正时链罩采用被动约束涂层减振处理来改善发动机前端2~3 kHz范围内的辐射噪声,并运用了最大喷射压力为180 MPa的第3代共轨系统,它配装了压电式喷油器,该喷油器有成型消声罩,并能进行充、放电时间控制。为使该发动机达到欧5排放标准,采用新喷油策略的低排放燃烧概念也很重要。然而,这种燃烧模式会产生粗暴的高频噪声,并使怠速稳定性变差。所以,应优化对预喷射和后喷射的控制,以降低和优化燃烧室内的燃烧激励噪声。因此,在发动机研发过程中就应考虑到车内声品质和辐射噪声的最佳化,而且,要确保乘客更易接受的声品质。
Hyundai Company conducted extensive research on the idler sound qualities of the V6 diesel engine used in a powertrain consisting of a new eight-speed automatic transmission to analyze the effects of mechanical excitation noise and combustion-induced noise. First of all, in the early days of engine development, experimental modal analysis and the stability design of each functional system of the engine can be used to improve the dynamic characteristics. In addition, the structural damping of the engine is enhanced to maintain the combustion noise of the engine at a target level while the combustion excitation is enhanced. Throughout the frequency range of structural damping analysis, it was found that some parts were better, others were poor, and then the weaknesses in the system were optimized. In this study, the timing chain cover uses passive damping coating to improve the radiated noise in the range of 2 kHz to 3 kHz at the front of the engine. The third generation common rail system with the maximum injection pressure of 180 MPa is used. Equipped with a piezoelectric fuel injector, the injector has a shaped muffler cover, and can charge and discharge time control. In order for the engine to meet Euro 5 emission standards, the concept of low emission combustion with a new injection strategy is also important. However, this combustion mode produces rough high-frequency noise and worsens idle speed stability. Therefore, control of pre-injection and post-injection should be optimized to reduce and optimize combustion excitation noise in the combustion chamber. Therefore, optimization of sound quality and radiated noise in the vehicle should be taken into account during the development of the engine, and the sound qualities that are more acceptable to passengers are to be ensured.