Researchers explore effect of combustion chamber diameter on diesel double swirl combustion system

In 2010, scientists from the Beijing Institute of Engineering proposed a new combustion method for diesel engines: the Double Swirl Combustion Program (DSCS) (Li et al. 2010). Inside the DSCS, the Double Swirl (DS) chamber is just one of the most visible elements in the new method.

The configuration of DS chamber is manufactured up of two dishes: the more compact dish is in the heart of the chamber which forms the internal chamber, and the larger one types the outer chamber. The cone encounter (Line o–3 in the diagram underneath) from the nozzle orifices to circular ridge kinds a theoretical interface among the outer and internal chambers. A truncated cone is in the center of the inner chamber.

Double swirl combustion chamber. Li et al. (2010)

The workforce hypothesized that the fuel spray collides with the round ridge, splits into two components, and then sorts double swirls, which tends to make the core of the solitary spray meet the air specifically.

As a outcome, the fuel is dispersed much more evenly than that in an normal sort of chamber, and the air in the chamber—especially the air in the internal element of chamber—can be completely used, and the gasoline-air mixing can be enhanced. The DSCS in a diesel motor can make major efficiency enhancements and emission reductions.

Now, researchers from the Beijing Institute of Technological innovation have investigated the consequences of DSCS combustion chamber diameter on overall performance less than many circumstances. They report their final results in a paper in the journal Gas.

DSCSs with diameters of 83, 91, and 98 mm (DSCS83, DSCS91, and DSCS98) were being made and examined in a solitary-cylinder diesel motor at the greatest torque velocity of 1800 rpm less than numerous loads and numerous extra air coefficients (φ).

Experiments showed that DSCS83 outperformed the other DSCSs, with a 2.1–4.9% decrease in brake distinct fuel usage (BSFC), 12.4–23.1% reduction in soot, and a shortening of the combustion interval by 1.6–3.6 °CA.

Simulation results using AVL-Hearth indicated that the wall-flow-guiding effects and in-cylinder air motion such as air entrainment and reversed squish improved as the combustion chamber diameter reduced, which contributed to quick fuel–air mixing in the outer chamber and the clearance, superior indicated electrical power and reduced soot generation.

Nonetheless, when the combustion chamber further more decreased from 83 to 76 mm, the unutilized air in the internal chamber and the clearance decreased the overall performance.

An assessment of the uniformity index of the equivalence ratio in unique areas of DSCS found that DSCS83 had a 1.2–4.8% improvement in the whole-chamber uniformity index at 60 °CA ATDC at 32% load situation.

These final results could be an crucial reference in the optimization and software of DSCSs in diesel engines.

—Kang et al.


  • Xiangrong Li, Zuoyu Sunshine, Wei Du & Rong Wei (2010) ”Research and Growth of Double Swirl Combustion System for a DI Diesel Engine,“ Combustion Science and Technological innovation, 182:8, 1029-1049, doi: 10.1080/00102200903544271

  • Yuning Kang, Xiangrong Li, Hongji Shen, Yanlin Chen, Dong Liu, Jiang Chang (2022) “Effects of combustion chamber diameter on the efficiency and fuel–air mixing of a double swirl combustion system in a diesel motor,” Fuel,
    Quantity 324, Portion A doi: 10.1016/j.gas.2022.124392