Elsevier

Atmospheric Environment

Volume 38, Issue 40, December 2004, Pages 7093-7100
Atmospheric Environment

The influence of air–fuel ratio on engine performance and pollutant emission of an SI engine using ethanol–gasoline-blended fuels

https://doi.org/10.1016/j.atmosenv.2004.01.058Get rights and content

Abstract

Ethanol–gasoline-blended fuel was tested in a conventional engine under various air–fuel equivalence ratios (λ) for its performance and emissions. The amount of fuel injection was adjusted manually by an open-loop control system using a CONSULT controller. It was found that without changing throttle opening and injection strategy, λ could be extended to a leaner condition as ethanol content increased. The results of engine performance tests showed that torque output would increase slightly at small throttle valve opening when ethanol–gasoline-blended fuel was used. It was also shown that CO and HC emissions were reduced with the increase of ethanol content in the blended fuel, which resulted from oxygen enrichment. At an air–fuel equivalence ratio slightly larger than one, the smallest amounts of CO and HC and the largest amounts of CO2 resulted. It was noted that under the lean combustion condition, CO2 emission was controlled by air–fuel equivalence ratio; while under the rich combustion condition, CO2 emission is offset by CO emission. It was also found that CO2 emission per unit horse power output for blended fuel was similar or less than that for gasoline fuel. From the experimental data, the optimal ethanol content in the gasoline and air–fuel equivalence ratio in terms of engine performance and air pollution was found.

Section snippets

1. Introduction

With the rapid development of the industry and society, the requirement of fossil fuels is growing higher and higher, so there is great anxiety about the shortage of energy because of finite reserves or other political reasons (such as petroleum crisis and the Persian Gulf War). Besides designing more efficient engines to save fuel, we need to look for other energy sources to completely or partially substitute the fuels we are using at present. Then the demand and dependence on fossil fuels can

Experimental setup

Our experimental apparatus include four major systems namely, the engine system, power measurement system, exhaust system and injection system. The first three systems can be referred to Hsieh's (Hsieh et al., 2002) experimental equipments. The engine system used in the experiment is a 4-cylinder 8-valve commercial engine New Sentra GA16DE, which is a 1600 cm3 multi-point injection gasoline engine with cylinder bore and stroke 76.0 and 88.0 mm, respectively. The ports arrangements are Dual

Results and discussions

The difference between open- and closed-loop control is that in the closed-loop control, the on-board central unit controls the fuel injection strategy with feedback signal from the oxygen sensor placed in the exhaust pipe, while in open-loop control, injection is adjusted manually to change the air–fuel equivalence ratio. In this study, we use open-loop control to investigate the influence of the air–fuel ratio on engine performance and pollutant emission of ethanol–gasoline-blended fuels.

Conclusion

In this study, engine performance and pollutant emission were measured on the utilization of the ethanol–gasoline-blended fuel under different air–fuel equivalence ratios. The results showed that the air–fuel equivalence ratio and ethanol content play an important role in combustion process. We made the conclusions as follows:

  • 1.

    When air–fuel ratio is slightly smaller than one, maximum torque output and minimum bshc are available. Using ethanol–gasoline-blended fuels improves torque output.

Acknowledgements

This study was financially supported by the Commission on Sustainable Development Research, National Science Council, and the Bureau of Air Quality Protection and Noise Control, Environmental Protection Administration, Taiwan, ROC, under the contract of NSC88-EPA-Z006-008.

References (14)

  • M. Al-Hasan

    Effect of ethanol–unleaded gasoline blends on engine performance and exhaust emission

    Energy Conversion and Management

    (2003)
  • H.R. Chao et al.

    Effect of methanol-containing additive on diesel engine

    Journal of Hazardous Materials

    (2000)
  • Alexandrian, M., Schwalm, M., 1992. Comparison of ethanol and gasoline as automotive fuels. ASME papers...
  • T.R. Aulich et al.

    Gasoline evaporation—ethanol and nonethanol blends

    Journal of Air and Waste Management Association

    (1994)
  • Coelho, E. P.D., et al., 1996. Fuel injection components developed for Brazilian fuels. SAE paper...
  • Furey, R.L., King, J.B., 1980. Evaporative and exhaust emissions from cars fueled with gasoline containing ethanol or...
  • Guerrieri, D.A., Caffrey, P.J., Rao, V., 1995. Investigation into the vehicle exhaust emissions of high percentage...
There are more references available in the full text version of this article.

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