0
Research Papers: Internal Combustion Engines

Prediction of Combustion Parameters, Performance, and Emissions in Compressed Natural Gas and Gasoline SI Engines

[+] Author and Article Information
Mirko Baratta, Andrea E. Catania, Stefano d’Ambrosio, Ezio Spessa

IC Engines Advanced Laboratory, Dipartimento di Energetica, Politecnico di Torino, C.so Duca degli Abruzzi, 24 10129 Torino, Italy

The modulation of $Sb∕SL$ is defined as $(Sb∕SL,max∕Sb∕SL,min−1)×100%$.

J. Eng. Gas Turbines Power 130(6), 062805 (Aug 21, 2008) (11 pages) doi:10.1115/1.2943193 History: Received January 28, 2008; Revised February 08, 2008; Published August 21, 2008

Abstract

The simulation of heat release, flame propagation speeds, and pollutant formation was carried out in both a turbocharged compressed natural gas (CNG) engine and a multivalve naturally aspirated bifuel engine running on either CNG or gasoline. The predictive tool used for investigation is based on an enhanced fractal geometry concept of the flame front, which is able to capture the modulation of turbulent to laminar burning speed ratio throughout the overall combustion phase without introducing flame kernel growth or burnout submodels. The prediction model was applied to a wide range of engine speeds, loads, relative air-fuel ratios, and spark advances, and the obtained results were compared to experimental data. These latter were extracted from measured in-cylinder pressure by an advanced diagnostics technique that was previously developed by the authors. The results confirmed a quite accurate prediction of burning speed even without any kind of tuning, with respect to different currently available fractal as well as nonfractal approaches for the simulation of flame-turbulence interaction. Furthermore, the computational code proved to be capable of capturing the effects of fuel composition, different combustion-chamber concepts, and operating conditions on engine performance and emissions.

<>

Figures

Figure 1

Burned (Vb) and unburned (Vu) region volumes in the 2000cc16V engine combustion chamber

Figure 2

Distributions of experimental and predicted Sb∕SL, for gasoline (left column) and CNG (right column) fueling under different engine loads, at the indicated operating conditions

Figure 3

Overview of model performance when applied to the 2000cc16V NA engine (test cases in Table 2)

Figure 4

Overview of model performance when applied to the 1200cc8V TC engine (test cases in Table 3)

Figure 5

Distributions of experimental and predicted combustion-related quantities for different engine speeds

Figure 6

Distributions of experimental and predicted combustion-related quantities for different engine speeds

Figure 7

Distributions of experimental and predicted combustion-related quantities for different A∕F ratios

Figure 8

Distributions of experimental and predicted combustion-related quantities for different bmep values

Figure 9

Measured, diagnosed, and predicted exhaust NO (upper row) and CO (lower row) concentrations at the indicated operating conditions for gasoline (left column) and CNG (right column) fueling

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related Proceedings Articles
Related eBook Content
Topic Collections