Engine Simulations via KIVA-3

KIVA-3 is a 3-D finite difference computational fluid dynamics code used in the design and analysis of internal combustion engines. Oak Ridge has significantly modified the KIVA-3 code obtained from Los Alamos National Laboratory, to take advantage of a parallel processing environment. KIVA has a large user-body in both Industry and Academia that meets annually at the Society of Automotive Engineers International Congress in Detroit.

KIVA-3 uses a block-structured grid that can conform to arbitrary shapes and follow moving boundaries. The use of ghost cells, connectivity arrays, and cell-face boundary conditions in all directions creates a general recipe for physics, numerics, and boundary conditions that can be applied to a part of the domain or the whole domain. Sub-models for turbulence, combustion, sprays, and heat transfer are also implemented in KIVA.

2-D Analysis- Examining the effects of variation in:

• Spark Energy
  • Production of NOx during piston cycle at spark energy of 1e3
  • Production of NOx during piston cycle at spark energy of 1e4
  • Production of NOx during piston cycle at spark energy of 5e4
  • Production of NOx during piston cycle at spark energy of 1e5
• Engine Speed
  • Production of NOx during piston cycle at 1600RPM
  • Production of NOx during piston cycle at 3200RPM
  • Production of NOx during piston cycle at 4800RPM
  • Production of NOx during piston cycle at 6400RPM
• Geometry - the following examines the effect of geometry on temperature and NOx production.
  • Temperature comparison between circular and rectangular piston top
    • As a function of spark energy
    • As a function of engine speed
  • NOx comparison between circular and rectangular piston top
    • As a function of spark energy
    • As a function of engine speed

3-D Analysis - Presenting Results of:

• Temperature and Pressure in a Dual Piston Configuration
  • Temperature profiles during piston cycles
  • Pressure profiles during piston cycles
• Particle Traces in a single piston baseline engine (in cooperation with A. Uludogan, UW-Madison)
  • Case 1: 12000 rpm, fuel injected at 30 degress
  • Case 2: 4000 rpm, fuel injected at 10 degrees
  • Case 3: 4000 rpm, fuel injected at 20 degrees

Future Plans

Additional enhancements to the numerical and physical models in the code are planned. The initial efforts will include highly accurate spark-ignition and radiative heat transfer models.