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An optical fibre sensor based intelligent system for monitoring and control of exhaust emissions from road vehicles (OPTO-EMI-SENSE)

Final Report Summary - OPTO-EMI-SENSE (An Optical Fibre Sensor Based Intelligent System for Monitoring and Control of Exhaust Emissions from Road Vehicles)

The project 'An Optical Fibre Sensor Based Intelligent System for Monitoring and Control of Exhaust Emissions from Road Vehicles' (OPTO-EMI-SENSE) addressed the problem of pollution of the environment by road vehicles as defined under the Thematic Priority 1.6.2 Sustainable Surface Transport relating to the Work Programme 'Integrating and strengthening the European Research Area'. The research activities of the consortium were based around state of the art developments in the area of optical fibre sensor and intelligent instrumentation technology to formulate a system for on line monitoring of exhaust emissions from road vehicles. The application of this technology to resolving the problems of atmospheric pollutants and their regional impacts is therefore highly appropriate to the issue identified in the thematic roadmap i.e. 'New technologies and concepts for all surface transport modes'.

The project's technical objectives were as follows:
- To set up laboratory based test facilities such that the sensor systems may be characterised in a precisely controlled and reproducible manner. Therefore, individual parameters such as optical absorption and scattering may be studied in isolation as well as collectively.
- To isolate and identify the optical signals arising from contaminants present in the complex mixtures of exhaust systems of a wide range of vehicles using advanced and novel optical fibre based spectroscopic interrogation techniques
- To develop novel optical fibre sensors which are miniature and robust in their construction and may be integrated in an optical network and fitted and/or retro-fitted to the exhaust systems of a wide range of vehicles
- To interface and fully integrate the novel sensor systems into the existing data network of the vehicle, thus providing the driver with clear and unambiguous in-car information on contaminant levels of exhaust emissions. This may take the form of alarm levels or analogue display as well as enabling emission minimisation through accessing the vehicle's engine control unit.

The work performed in the project has been to research the use of optical fibre sensors for the measurement of exhaust gas emissions and temperature in the exhaust system of road vehicles. The gases identified as being of interest under successive EC emission control standards (currently Euro IV) are as follows
Nitric Oxide (NO)
Nitrogen dioxide (NO2)
Carbon dioxide (CO2)
Carbon Monoxide (CO)
Sulphur Dioxide (SO2)
Hydrocarbons (Many, including Methane, Benzene, Toluene)
Water Vapour (Interfering Parameter)
The work performed to implement these sensors was initiated as sensor design in WP 1 (Temperature sensor) and WP 2 (Gas sensors) during the first 12 month period of the project. These designs were initially tested in University of Liverpool and system integration performed during the second 12 month period. The integrated systems were comprehensively tested on the demonstrator vehicle, the Fiat Croma in the testing centre of CRF during the final 12 month (extended to 18 month) period.

The fundamental approach used in the investigation was to use an open path gas cell as the gas sensor and either a fluorescence decay time or Bragg grating base temperature sensor.
The sensor systems were rigorously tested at the test laboratory of Liverpool University prior to locating at the test facilities of CRF in Turin. The data gathered and analysed at Liverpool provided vital information for development of the sensor systems to be mounted on the Fiat Croma. These were reported at the 24 Month stage and were detailed in the activity report of that period. This section comprises a synthesis of activities in the work packages relating to this phase of the work (WP3,WP4,WP5 and WP 6 (partially)) and the results from those activities.

The final demonstrator vehicle was selected primarily for being Euro IV compliant but also for being relatively easy to accommodate the projects sensors within the exhaust system.The vehicle selected was a Fiat Croma 1.9 MJT 16v 150 HP. The vehicle is Euro IV compliant and equipped with a catalysed Diesel Particulate Filter, necessary to avoid the accumulation of soot onto the downstream positioned optical fiber lens and the consequent signal alteration.
A portable multi gas analyser MIR9000 comprisinga multi component non dispersive IR analyser using Gas Filter Correlation Technique (GFC). GFC is a well established method to reduce the cross sensitivity to gases that cause interference in infrared measurements; therefore, using this analyser is possible to monitor simultaneously a numbers of different gaseous species with the following detection ranges:
CO2, 0-15%
CO, 0-5000 ppm
NO, 0-3000 ppm
NO2, 0-3000 ppm
THC, 0-2500 ppm
SO2, 0-100 ppm
O2, 0-21%
The above mentioned devices were located in the rear trunk of the car, together with a portable gas bottle of nitrogen, needed for the gas analyser calibration (Fig 5.1.2); the heated sampling line has been directly connected to the exhaust line just prior the muffler (downstream the aftertreatment devices) in order to monitor the gas composition as close as possible to the optical fibre sensors position.

Optical Fibre Based Sensor Systems for measuring the gas concentration and temperature in the exhaust systems of road vehicles have been developed and fully implemented at the test laboratories of the University of Liverpool and underneath the car at the rolling road test facilities of CRF. Considerable interaction between all partners of the consortium has resulted in a number of packaged sensor probes which has lead to a fully operational demonstrator system mounted underneath a Fiat Croma. Comparison with simultaneously recorded results using commercial instrumentation has showed excellent correspondence with the data recorded using the optical fibre sensors.