DETERMINING FUEL TRANSFER CHARACTERISTICS FOR MIXTURE CONTROL DURING TRANSIENT OPERATION

This paper investigates the fuel transfer characteristics of the intake port of a fuel-injected spark ignition engine. These characteristics were examined for engine warm-up conditions, following cold starts at temperatures down to -30 degrees Celsius, and extending to fully warm states. The engine was cooled down to soak temperature, by circulating an antifreeze/water coolant mixture from a chiller tank through three parallel paths. During engine running, the coolant system was configured as in a vehicle, with a heat exchanger replacing the vehicle radiator. The general form of a test sequence was: (1) cold-soaking to the desired initial temperature; (2) engine starting; (3) stabilise load, speed, and mixture supply air-fuel ratio (AFR) as quickly as possible; and (4) performance of a sequence of tests in a repeating pattern, where each test disturbs the engine operating state and records the AFR response, as indicated by a UEGO sensor exposed to the exhaust gas stream. The interpretation of signal characteristics and the model-fitting procedure are described. Some illustrative results are given for: (1) typical values of time constant and fraction of fuel delivered to the intake system; and (2) compensated transient tests. For the covering abstract see IRRD 873243.

Language

  • English

Media Info

  • Features: References;
  • Pagination: p. 81-8

Subject/Index Terms

Filing Info

  • Accession Number: 00713385
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • ISBN: 0-85298-847-8
  • Files: ITRD
  • Created Date: Nov 22 1995 12:00AM