Post-Injection Strategies for Combustion Optimization in Diesel Engines
Summary
Post-injection, the deliberate delivery of a secondary fuel pulse after the main injection event, has emerged as a pivotal means of refining in-cylinder combustion in modern diesel engines. By introducing a controlled quantity of fuel into the late combustion phase, post-injection promotes localised soot oxidation, moderates peak temperatures to curb nitrogen oxide formation and shapes the late heat-release profile. The precise timing, fuel quantity and dwell interval between main and post-injection critically govern spray–air mixing, turbulence levels and flame propagation. When combined with exhaust gas recirculation and variable valve timing, post-injection facilitates a more homogeneous charge and tailored combustion phasing, thus striking an improved balance between particulate and NOx emissions while maintaining or even enhancing fuel efficiency. Both transient engine tests and one-dimensional simulations have demonstrated that optimally phased post-injection can achieve substantial reductions in soot mass and number concentrations under low-load, part-load and rapid-acceleration conditions. Against a backdrop of tightening global emission standards, post-injection strategies offer a cost-effective retrofit pathway to cleaner diesel operation without extensive hardware overhaul.
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Post-Injection Strategies for Combustion Optimization in Diesel Engines publication trend
The graph below shows the total number of articles in post-injection strategies for combustion optimization in diesel engines across all publications each year (not limited to Nature Index journals).
Technical terms
Post-injection: A secondary fuel injection event occurring after the main combustion pulse, aimed at enhancing soot oxidation and influencing late-cycle temperature profiles.
Exhaust Gas Recirculation (EGR): A method of returning a portion of exhaust gases to the intake to reduce peak combustion temperatures and decrease NOx formation.
Brake Specific Fuel Consumption (BSFC): The mass of fuel consumed per unit of brake power output, used to evaluate engine efficiency.
Brake Mean Effective Pressure (BMEP): A measure of engine load derived from torque and displacement, representing the average in-cylinder pressure during the power strokes.
References
- Study on the Effects of Exhaust Gas Recirculation and Fuel Injection Strategy on Transient Process Performance of Diesel Engines. Sustainability (2023).
- Research of Post Injection Strategy of an EGR Diesel Engine to Improve Combustion and Particulate Emissions Performance: Application on the Transient Operation. Symmetry (2020).
- Numerical Investigation and Multi-Objective Optimization of Internal EGR and Post-Injection Strategies on the Combustion, Emission and Performance of a Single Cylinder, Heavy-Duty Diesel Engine. Energies (2020).
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