Latest Research Has Been Carried Out into the Introduction of a Dual-Combustion Approach to Increase the Heat Efficiency of Internal Combustion Engines While Reducing Their Emissions at the Same Time. Compression Ignition (Ci) Motors Use Double-Fuel Combustion to Facilitate the Use of More Easily Accessible Gas Oils or Modern Combustion Methods. In This Study We Have Studied About the Dual-Fuel Compression-Ignition Engines, Effects of Exhaust Emission, Conventional Dual-Fuel Compression-Ignition Engines, Advanced Dual-Fuel Compression-Ignition Engines, Dual-Fuel Spark-Ignited Engines Which Is Concluded That In Compression Ignition (Ci) Engines, Dual-Fuel Combustion Provides an Efficient Solution For Timing and Extending Engine Load Limits to Regulate Combustion. to This End, Both a High and Low-Reactivity Fuel Is Inducted, the Concentration Is Adjusted to One Another and Hence the Reactivity of the Fuel Mixture Is Optimized Under Various Operating Conditions (On a Cycle-By-Cycle Basis).