An air-flow meter, developed primarily for the measurement of air intake into an internal combustion engine, is described. The well-known process of corona ion deflection in a gas flow together with proper electrode geometry and a detection scheme provides the conceptual basis for a humidity-insensitive ionic air-flow sensor. Output characteristics of the sensor, such as response time and range of operation, are discussed and compared to those of a production hot-wire meter of the type that is currently used with electronic fuel injection systems. Unlike the hot-wire transducer, the proposed sensor is shown to allow for bidirectional measurement of the air flow. The transient response time of the ionic sensor is shorter than that of the hot-wire transducer. >

An ion-drag air mass-flow sensor for automotive applications

To contrast the phenomenon of HC formation in a Diesel and a spark ignition engine, a chapter is included on the latter. The absorption and desorption of fuel by cylinder lubricating oil films has been modelled using principles of mass transfer in this Chapter. Henry’s Law for a dilute solution of fuel in oil is used to relate gas to liquid phase fuel concentrations. Mass transfer conductances in gas and liquid phases are considered, the former via use of Reynolds’s Analogy to engine heat transfer data, the latter through assuming molecular diffusion through an effective penetration depth of the oil film. Oxidation of desorbed fuel is assumed complete if the mean of burned gas and lubricating oil film temperatures is greater than 100 K. Below this value, the desorbed fuel is considered to contribute to hydrocarbon emissions. Comparison with engine test data corroborates the absorption/desorption hypothesis. The model indicates the equal importance of gas and liquid phase conductance.

Hydrocarbon Emissions from Spark Ignition Engines

To contrast the phenomenon of HC formation in a diesel and a spark-ignition engine, a chapter is included on the latter. The absorption and desorption of fuel by cylinder lubricating oil films have been modelled using principles of mass transfer in this chapter. Henry’s law for a dilute solution of fuel in oil is used to relate gas to liquid-phase fuel concentrations. Mass transfer conductances in gas and liquid phases are considered, the former via the use of Reynolds’s analogy to engine heat transfer data, the latter through assuming molecular diffusion through an effective penetration depth of the oil film. Oxidation of desorbed fuel is assumed complete if the mean of burned gas and lubricating oil film temperatures is greater than 100 K. Below this value, the desorbed fuel is considered to contribute to hydrocarbon emissions. Comparison with engine test data corroborates the absorption/desorption hypothesis. The model indicates the equal importance of gas and liquid-phase conductance. 

Hydrocarbon Emissions from Spark-Ignition Engines

A new ultrasonic velocity thermometer is presented for the simultaneous measurement of transient exhaust gas velocity and temperature under motoring and firing conditions in an internal combustion engine. Included in the instrumentation are a crank angle (CA) selection unit, a high voltage impulse generating unit, and other accessories. The instrument is described, and its operating principle and calibration are discussed. Its performance is compared with that of the spark discharge velocity meter and the wire resistance thermometer, under dynamic conditions. Exhaust temperature and velocity measurements are plotted against CA; these experimental results are discussed, including some comparisons with theoretical results obtained using a finite difference theory of gas exchange processes in internal combustion engines.

P. A. Lakshminarayananan

Papers

An Ultrasonic Flowmeter for Measurement of Gas Velocity and Temperature in Intake and Exhaust of an Internal Combustion Engine