Browse Publications Technical Papers 2012-32-0003
2012-10-23

A Simple Model of Cyclic Variation 2012-32-0003

A simple model to simulate cycle-by-cycle variation that is suitable for use in Monte-Carlo approaches has been developed and validated with a wide range of experimental data. The model is intended to be diagnostic rather than predictive in nature, with a goal of providing realistic in-cylinder pressures. The individual-cycle cumulative rate of heat release was curve fit with a four-parameter Wiebe function. It was found that the distribution of the Wiebe b-parameter was quite small, so its value was obtained from the ensemble-averaged condition. The remaining three Wiebe function parameters, θig, θcomb and m were found to be distributed over a moderate range, and were linearly correlated to each other. Using the cumulative density function of θig, and the linear fit of θcomb and m to θig, with a random component added, a Monte-Carlo scheme was developed. The resulting randomly chosen cycles were found to adequately reproduce the observed cyclic variation at the same condition, and can be used with higher-order models to assess the impact of cyclic variations on other cylinder-pressure-driven phenomena.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 17% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:
TECHNICAL PAPER

PASSENGER-CAR BRAKE PERFORMANCE Limitations and Future Requirements

490175

View Details

TECHNICAL PAPER

PASSENGER-CAR BRAKE PERFORMANCE Limitations and Future Requirements

490175

View Details

TECHNICAL PAPER

The Spray Models and Their Influence on Ignition

950279

View Details

X