Heterogeneous combustion in a diesel engine is noisier, uncontrolled and more polluting. This can be achieved with a strategic approach of a reactivity-controlled compression ignition (RCCI) mode engine that operates with low and high reactive fuel combinations. In the present work, a diesel engine is operated in RCCI mode with gaseous fuels viz. CNG as a primary fuel and a blend of diesel and Karanja biodiesel (BD20) as pilot fuel. This research aims to determine the operating limits of CNG fuel for less noisy combustion and clean exhaust.

Further, relative air-fuel ratio (λ), cycle to cycle variations, combustion noise and emissions were studied for full load operation. The CRDI engine is optimized for diesel operation with a split injection strategy. The knock limits for CNG as the primary fuel are obtained. The combustion noise increases at a higher energy share by CNG. Also, higher values of HC and CO emissions are observed. This may be due to higher energy share values, flame speed and octane number of CNG fuel.

Further, NO_x emissions and smoke are decreased. The CNG induction of 10 ms with 90% ES can be noted as a knock limit for 3.5 kW power. The highest BTHE of 24.2% and least BSFC 0.3 kg/kWhr reported by 60%ES of LRF is better than diesel and KBD20 fuel. An optimum 60% energy share of CNG is observed for clean combustion and emissions strategy using the RCCI mode of a modified diesel engine.

柴油发动机中的非均质燃烧噪音更大、不受控制且污染更大。这可以通过使用低反应性和高反应性燃料组合运行的反应性控制压缩点火 (RCCI) 模式发动机的战略方法来实现。在目前的工作中，柴油发动机在 RCCI 模式下使用气体燃料运行，即。CNG 作为主要燃料，柴油和 Karanja 生物柴油 (BD20) 的混合物作为引燃燃料。本研究旨在确定 CNG 燃料的运行限制，以减少噪音燃烧和清洁排气。

此外，还研究了全负荷运行时的相对空燃比 (λ)、循环变化、燃烧噪声和排放。CRDI 发动机针对柴油操作进行了优化，采用分流喷射策略。获得了作为主要燃料的 CNG 的爆震极限。燃烧噪声在 CNG 较高的能量份额下增加。此外，还观察到更高的 HC 和 CO 排放值。这可能是由于 CNG 燃料的能量份额值、火焰速度和辛烷值较高。

此外，减少了NO _x排放和烟雾。90% ES 的 10 ms CNG 感应可以作为 3.5 kW 功率的爆震极限。LRF 的 60%ES 报告的最高 BTHE 为 24.2%，最低 BSFC 为 0.3 kg/kWhr，优于柴油和 KBD20 燃料。使用改进的柴油发动机的 RCCI 模式，对于清洁燃烧和排放策略，观察到 CNG 的最佳能量份额为 60%。