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Vehicle emissions are one of a number of environmental problems in urban areas which have received much public attention for nearly twenty years [1] and are still now very topical. In particular, public opinion in Europe is opposed to the visible smoke, ‘black’ from diesel engines and ‘blue’ from oil burning petrol and diesel engines. This paper describes the use of 90 degree backscatter measurements to determine and measure ‘black’ and ‘blue’ smoke effects in an in-service environment, i.e. no dynamometer or loaded cycle testing. The measurements are compared to opacity measurements and the advantages and disadvantages discussed. White smoke effects will not be addressed in this paper.

This paper reviews solid-state gas sensing techniques that could be developed to supersede the NDIR bench and the electrochemical cell that are presently used in the majority of aftermarket emission analysers. Techniques considered include acoustic wave devices, chemfets, chemi-resistors and optical devices. Technical performance, e.g. sensitivity, selectivity, stability and speed of response, are assessed and compared. Manufacturability, cost, interfacing and processing requirements are also examined. The capability for inclusion in a hand-held analyser unit is the key consideration. Techniques that meet the review criteria are identified and recommendations are made as to requirements for further research and development.

This paper describes a novel “drive-on” RPM measurement system intended for use on Heavy Goods Vehicles (HGVs). The system transducer is a piezoelectric element placed under a drive wheel of the vehicle under test. The sensor responds to engine and suspension system vibrations and derives the RPM value from the vibration signature. This paper presents experimental data from the novel system and provides analysis and comment upon the results.

This paper describes the application of an Active Thermal Imaging technique (ATI), whereby a temperature gradient is produced by the operation of the braking system in use, to determine thermal brake imbalance. Results obtained from passenger vehicles and heavy goods vehicles (trucks) are detailed, showing how side-to-side thermal imbalance can be quickly and quantitatively recorded at the roadside.

Modern automotive engine design is making the measurement of engine speed increasingly difficult, due to problems with access for the sensors and, hence, forms the motivation for this investigation. Some manufacturers provide a dedicated pin/socket for engine speed, but this is clearly vehicle specific and may not always be accessible. A novel method is described for the measurement of the speed of a reciprocating internal combustion engine, based on the analysis of the vibration of the engine block using an accelerometer. The Power Spectral Density (PSD) derived from the accelerometer signal contains a dominant peak of which engine speed is a multiple, and it is possible to track this peak over the engine speed range. Whilst initially developed for diesel engine application, the range of application has been extended to petrol engines, and hence the device can be truly described as a universal tachometer.