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Air-Fuel Ratio Measurement Diagnostics During Cranking and Startup in a Port-Fuel-Injected Spark-Ignition Engine
ISSN: 0148-7191, e-ISSN: 2688-3627
Published June 08, 2004 by SAE International in United States
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Cranking and startup fuel control has become increasingly important due to ever tightening emission requirements. Additionally, engine-off strategies during idle will require substantially more engine startup events with the associated need for very clean starts. Thus, knowledge of an engine's Air-Fuel Ratio (AFR) during its early cycles is necessary in order to optimize cranking and startup fueling.
This paper examines and compares two methods of measuring an engine's AFR during engine startup (approximately the first second of operation); an in-cylinder technique using a Fast Flame Ionization Detector (FFID) and the conventional exhaust based Universal Exhaust Gas Oxygen (UEGO) sensor method. Engine starts using a Ford Zetec engine were performed at three different temperatures (0, 20 and 90 C) as well as different initial engine starting positions. The results show that, as expected, the UEGO sensor's response time affects how soon it provides reliable AFR data after start, however, the delay is a number of cycles, and not a number of seconds. It is seen that the UEGO sensor provides accurate cycle resolved AFR data starting with the third cycle to seventh cycle after start. This variation in cycle number after start at which the UEGO sensor becomes accurate is a result of the differences in real time between cycles for the different types of starts as well as the fundamental response time of the sensor. Additionally, the above results are independent of starting temperature. Thus, the UEGO sensor can be used as an accurate AFR measurement device approximately one-half second after cranking begins over a wide range of temperatures.
CitationCowart, J., "Air-Fuel Ratio Measurement Diagnostics During Cranking and Startup in a Port-Fuel-Injected Spark-Ignition Engine," SAE Technical Paper 2004-01-1915, 2004, https://doi.org/10.4271/2004-01-1915.
Direct Fuel Injection, Engine Diagnostics, and New Developments in Powertrain Triboligy, Cvt, Atf, and Fuel Economy
Number: SP-1891; Published: 2004-06-08
Number: SP-1891; Published: 2004-06-08
- Shayler, P. J. Issacs, R. M. Ma, T.H. “The variation of in-cylinder mixture ratios during engine cranking at low ambient temperatures” Proc. Instn. Mech. Eng. 206 55 62 1992
- Henein, N.A. Tagomori, M.K. Yassine, M.K. Asmus, T.W. Thomas, C.P. Hartman, P.G. “Cycle-by-Cycle Analysis of HC Emissions during Cold Start of Gasoline Engines” SAE # 952402 1995
- Koenig, M.H. Stanglmaier, R.H. Hall, M.J. Matthews, R.D. “Mixture Preparation during Cranking in a Port-Injected 4-Valve SI Engine” SAE# 972982 1997
- Castaing, B.M. Cowart, J.S. Cheng, W.K. “Fuel Metering Effects on HC Emissions and Engine Stability during Cranking and Startup in a PFI SI Engine” SAE# 2000-01-2836 2000
- Winkler, M. A. Mueller, E. “Determination of the Air/Fuel Ratio of a SI Engine During Transients with a Standard UEGO Sensor” SAE# 2001-01-1955 2001
- Cowart, J. “A Comparison of Transient Air-Fuel Measurement Techniques” SAE# 2002-01-2753 2002
- Yamada, T. Hayakawa, N. Kami, Y. Kawai, T. “Universal Air-Fuel Ratio Heated Exhaust Gas Oxygen Sensor and Further Applications” SAE # 920234 1992
- Almkvist, G. Eriksson “An Analysis of Air to Fuel Ratio Response in a Multi Point Fuel Injected Engine under Transient Conditions” SAE # 932753 1993
- Shayler, P.J. Teo, Y.C. Scarisbrick, A. “Fuel Transport Characteristics of Spark Ignition Engines for Transient Fuel Compensation” SAE # 950067 1995
- Cowart J. S. Cheng W. K. “Throttle Movement Rate Effects on Transient Fuel Compensation in a Port Fuel Injected SI Engine” SAE # 2000-01-1937
- Cowart, J.S. Cheng, W.K. “Intake Valve Thermal Behavior During Steady-State and Transient Engine Operation” SAE # 1999-01-3643 1999
- Personal correspondence with Horiba Technical Staff 2003
- Cheng, W.K Summers, T. Collings, N. “The Fast-Response Flame Ionization Detector” Prog. In Energy and Combustion Science 24 89 124 1998