Increasing the Effective AKI of Fuels Using Port Water Injection (Part II)
2022-01-0523
03/29/2022
- Event
- Content
- This is part II of the paper on ‘Increasing the Effective AKI of Fuels Using Port Water Injection’ In the United States, the metric used to quantify the anti-knock performance of fuels is Anti Knock Index (AKI), which is the average of Research Octane Number (RON) and Motor Octane Number (MON). Fuels with higher AKI are expected to have a better knock mitigating properties, which enables the engine to be run closer to Maximum Brake Torque (MBT) spark timing in the knock limited region. The work done in part I of the study quantified the amount of water required (as a ratio with fuel and absolute) to increase the performance of low AKI fuels in order to match their performance to that of a higher AKI reference fuel, thus increasing their ‘effective AKI’. This paper builds upon the work done in part I of the study by repeating a part of the test matrix with Primary Reference Fuels (PRFs), with iso-octane (PRF100) as the reference fuel and lower PRFs used to match its performance with the help of port water injection. Tests were also conducted using a reference fuel with a similar AKI to that of C9 (reference fuel in the first part of the study), but a different sensitivity, to determine the effect of sensitivity on the amount of water required. Finally, the unburned gas pressure-temperature trajectories for varying loads, CA50s and water injection values were analyzed to better understand the underlying physics of port water injection in engines.
- Citation
- Gopujkar, S., Worm, J., Barros, S., Bonfochi Vinhaes, V. et al., "Increasing the Effective AKI of Fuels Using Port Water Injection (Part II)," SAE Technical Paper 2022-01-0523, 2022, .