An extended Zeldovich mechanism, which models the kinetics of nitric oxide formation, is included in a multizone combustion model. The combustion model is subsequently integrated into a well-developed emptying and filling engine code to predict the transient nitric oxide emissions in the exhaust of a diesel engine. The predicted nitric oxide emissions, in terms of ppm level, have been validated satisfactorily with the experimental results obtained from a computer-controlled dynamic engine test bed on which a fully instrumented, turbocharged, direct injection (DI) diesel engine and a fast response regenerative d.c. dynamometer are mounted. The experimental results used in the comparison were reconstructed from the nitric oxide emission signals obtained by a conventional, slow response, chemiluminescence analyser.

Measurement of particulate mass concentration in the exhaust of automotive engines by means of the filter sampling method prescribed by the USA's Environmental Protection Agency (EPA) is tedious, costly, time consuming and labour intensive. This paper presents a new approach, which is capable of measuring real-time particulate mass emissions in the exhaust of a diesel engine by using a tapered-element oscillating microbalance (TEOM) and a fast-response flame ionization detector (FID). The measuring principle rests on the fact that, by operating the TEOM at 50 °C, water interference is minimized, albeit at the expense of reducing the hydrocarbon content condensed on the particles. This is corrected by a method that consists of a measurement of hydrocarbon gas concentration, used with an empirical correction factor to recover what the filter sampling method would produce. The time resolution for the measurement using this new method is limited by the sampling window of the TEOM which is 0.42 s, though the response of the FID offers a time resolution of milliseconds. Results show that the mass concentration of particulate matter measured by TEOM and FID is well correlated to that based on the conventional EPA filter sampling method. Keywords: particulate mass concentration, tapered-element oscillating microbalance, flame ionization detector, diesel exhaust particulate measurement, correlation to EPA (USA) standard

This paper describes an innovative carbon-atom-balance-based method for diesel particulate measurement using a single non-dispersive infrared CO2 sensor. The diesel particulate sampler (DPS) uses two integrated steps of operation, i.e. collection and analysis of diesel particulate. In the collection operation, the diesel exhaust is channelled through a heated sampling line to a quartz filter where soot particulates, unburned hydrocarbons, water vapour, etc are trapped. Upon completion of particulate collection, the DPS system is isolated from the surroundings. This is followed by an analysis of the diesel-particulate sample by either one of two analysis modes, namely, the regular and ramp modes. In the regular mode, the quartz filter is heated at a constant temperature for a defined dwelling period. Multiple sessions of heating at constant temperatures with individual dwelling periods are allowed for each analysis. In the ramp mode, the temperature controller is programmed to achieve a specified heating rate. The lowest possible rate is 2 °C min-1. Some preliminary results, in terms of mass concentrations of particulates, were obtained from engine emission sampling using this DPS system.