Market globalization necessitates the development of heavy duty diesel engines that can operate at altitudes up to 5000 m without significant performance deterioration. But the current scenario is that existing studies on high altitude effects are still not sufficient or detailed enough to take effective measures. This study applied a single cylinder direct injection diesel engine with simulated boosting pressure to investigate the performance degradation at high altitude, with the aim of adding more knowledge to the literature. Such a research engine was conducted at constant speed and injection strategy but different ambient conditions from sea level to 5000 m in altitude. The results indicated the effects of altitude on engine combustion and performance can be summarized as two aspects. First comes the extended ignition delay at high altitude, which would raise the rate of pressure rise to a point that can exceed the maximum allowable limit and therefore shorten the engine lifespan. The other disadvantage of high-altitude operation is the reduced excess air ratio and gas density inside cylinder. Worsened spray formation and mixture preparation, together with insufficient and late oxidation, would result in reduced engine efficiency, increased emissions, and power loss. The combustion and performance deteriorations were noticeable when the engine was operated above 4000 m in altitude. All these findings support the need for further fundamental investigations of in-cylinder activities of diesel engines working at plateau regions.

市场全球化需要开发可在高达 5000 m 的海拔高度运行且性能不会显着下降的重型柴油发动机。但目前的情况是，现有对高海拔影响的研究仍然不够充分或不够详细，无法采取有效措施。本研究应用模拟增压的单缸直喷柴油机来研究高海拔下的性能退化，旨在为文献增加更多的知识。这种研究发动机是在恒定速度和喷射策略下进行的，但从海平面到海拔 5000 米的环境条件不同。结果表明海拔高度对发动机燃烧和性能的影响可以概括为两个方面。首先是高海拔延长点火延迟，这会将压力上升率提高到可以超过最大允许极限的程度，从而缩短发动机的使用寿命。高空作业的另一个缺点是降低了气缸内的过量空气比和气体密度。喷雾形成和混合物制备恶化，加上氧化不足和延迟，将导致发动机效率降低、排放增加和功率损失。当发动机在海拔 4000 m 以上运行时，燃烧和性能恶化是明显的。所有这些发现都支持对在高原地区工作的柴油发动机缸内活动进行进一步基础研究的必要性。高空作业的另一个缺点是降低了气缸内的过量空气比和气体密度。喷雾形成和混合物制备恶化，加上氧化不足和延迟，将导致发动机效率降低、排放增加和功率损失。当发动机在海拔 4000 m 以上运行时，燃烧和性能恶化是明显的。所有这些发现都支持对在高原地区工作的柴油发动机缸内活动进行进一步基础研究的必要性。高空作业的另一个缺点是降低了气缸内的过量空气比和气体密度。喷雾形成和混合物制备恶化，加上氧化不足和延迟，将导致发动机效率降低、排放增加和功率损失。当发动机在海拔 4000 m 以上运行时，燃烧和性能恶化是明显的。所有这些发现都支持对在高原地区工作的柴油发动机缸内活动进行进一步基础研究的必要性。当发动机在海拔 4000 m 以上运行时，燃烧和性能恶化是明显的。所有这些发现都支持对在高原地区工作的柴油发动机缸内活动进行进一步基础研究的必要性。当发动机在海拔 4000 m 以上运行时，燃烧和性能恶化是明显的。所有这些发现都支持对在高原地区工作的柴油发动机缸内活动进行进一步基础研究的必要性。