← Back to Publications

Methodology To Reduce Diesel Engine Pollutant Emissions

Author: Dr. Ahmad Saylam

Document type: Published research article

Journal: International Journal of Petrochemistry & Natural Gas

Publication details: Volume 1, Issue 1, pages 04–08, 2022

Publication date:

Scientific status: Numerical feasibility and screening study based on detailed chemical kinetics and homogeneous reactor modelling. The reported emission and power trends require experimental validation before practical engine application.

Persistent identifier: No DOI is stated in the published article. The bibliographic record should therefore be cited by journal, volume, issue, pages and publication date.

Abstract

The study proposes blending a conventional diesel fuel with a selective additive mixture as a possible route to reducing carbon monoxide, nitrogen oxides and unburned hydrocarbons from diesel-engine operation.

Feasibility was investigated numerically using a diesel-fuel surrogate containing 77 vol% n-dodecane and 23 vol% m-xylene. Detailed chemical-kinetic mechanisms were coupled with a homogeneous multi-zone representation of a two-stroke diesel-type HCCI engine. Additional single-zone Cantera calculations were used to examine exhaust-gas-recirculation effects.

The study covered air–fuel ratios from 9.8 to 29.4 and engine speeds from 1000 to 2000 rpm. The principal multi-zone cases used an intake temperature of 323 K, intake pressure of 1 bar and compression ratio of 15.

Under the simulated conditions, the additive blend produced the strongest reductions in carbon monoxide and unburned hydrocarbons for the rich case at an air–fuel ratio of 9.8. Reductions of up to about 60% were reported for selected cases. Nitrogen-oxide reduction was generally slight, while predicted engine power decreased by approximately 4–11% depending on the additive-blending ratio.

The work concludes that additive blending may be considered together with established emission-control measures, including exhaust-gas recirculation, selective catalytic reduction, diesel oxidation catalysts and particulate filters. Experimental validation remains necessary.

Model and operating framework

  • diesel-fuel surrogate: 77 vol% n-dodecane and 23 vol% m-xylene;
  • homogeneous multi-zone model for a two-stroke diesel-type HCCI engine;
  • detailed chemistry implemented in ANSYS Chemkin-Pro;
  • supplementary homogeneous single-zone calculations in Cantera;
  • air–fuel ratios of 9.8, 14.71 and 29.4, corresponding in the paper to equivalence ratios of approximately 1.5, 1.0 and 0.5;
  • engine-speed range of 1000–2000 rpm;
  • principal intake conditions of 323 K and 1 bar;
  • baseline compression ratio of 15.

Engineering interpretation

The calculations indicate an emission–performance trade-off rather than a universal improvement. The largest predicted benefits concern carbon monoxide and unburned hydrocarbons under selected rich conditions, whereas nitrogen-oxide reduction is modest and engine power declines as the additive fraction increases.

The study also suggests that the altered reactivity of the blended fuel may permit operation at a lower compression ratio, which could offer an additional route to nitrogen-oxide reduction. That proposal was identified as a subject for further work rather than demonstrated experimentally.

Scope and application boundary

The results are derived from homogeneous multi-zone and single-zone simulations. These models do not fully resolve fuel injection, spray breakup, evaporation, local mixture stratification, detailed turbulence–chemistry interaction, wall films, crevice flows, cycle-to-cycle variability or after-treatment behaviour.

The reported percentage reductions should therefore be interpreted as model-dependent trends for the selected fuel surrogate, additive formulation, chemical mechanisms, engine geometry and operating conditions—not as guaranteed reductions for commercial diesel fuel or a production engine.

Experimental validation should include ignition behaviour, heat release, indicated efficiency or torque, regulated emissions, particulate mass and number, additive stability and compatibility, deposit formation, lubricant interaction, material durability, toxicology, fuel-standard compliance and after-treatment performance.

A complete industrial assessment would additionally require fuel-cost analysis, additive supply and blending control, cold-start and transient operation, long-duration durability, life-cycle effects and comparison with alternative in-cylinder and exhaust-after-treatment strategies.

Full text

View the open-access article PDF

Access and licence

The published article states that it is an open-access work distributed under a Creative Commons Attribution License, permitting use, distribution and reproduction when the original author and source are credited. The article does not identify a licence-version number on the displayed copyright statement.

Citation

Saylam, A. (2022). Methodology To Reduce Diesel Engine Pollutant Emissions. International Journal of Petrochemistry & Natural Gas, 1(1), 04–08.