Jim Mulrooney

Monitoring of carbon dioxide exhaust emissions using mid-infrared spectroscopy

An optical fibre sensor for monitoring carbon dioxide emissions from modern road vehicles and operating in the mid-infrared spectral region is reported. The wavelength range of operation is centred at 4.23??m and has required a novel implementation of this sensor using low cost and robust components. The sensor is shown to be capable of detecting CO2 to a minimum level of 350?ppm, to be stable over several hours of continuous operation and insensitive to the presence of other species present in the exhaust.

Simulation and measurement of carbon dioxide exhaust emissions using an optical-fibre-based mid-infrared point sensor

A novel optical-fibre-based sensor for measurement of CO2 gas emission concentrations in exhaust systems of a motor vehicle is reported. The sensing principle is based on open-path direct absorption spectroscopy in the mid-infrared range. The sensor system comprises of low cost and compact mid-infrared components, which make it suitable for insertion into the exhaust system of automotive vehicles. The sensor utilizes a calcium fluoride CaF2 narrow band pass (NBP) filter for detection of CO2 gas without cross-sensitivity to other gases present in the exhaust system. Furthermore, it can be integrated into the mechanical and electronic interface systems of existing vehicles without any problems.

Vibration-insensitive temperature sensing system based on fluorescence decay and using a digital processing approach

A fluorescence-based temperature sensor system using a digital signal processing approach has been developed and evaluated in operation on a working automotive engine. The signal processing approach, using the least-squares method, makes the system relatively insensitive to intensity variations in the probe and thus provides more precise measurements when compared to a previous system designed using analogue phase-locked detection. Experiments carried out to determine the emission temperatures of a running car engine have demonstrated the effectiveness of the sensor system in monitoring exhaust temperatures up to 250 °C, and potentially higher.

Optical fibre sensors for the monitoring of harmful emissions from land transport vehicles

In order to meet increasingly stringent emission control laws it is necessary to develop a sensor that can accurately monitor the level of pollutants entering the atmosphere from land transport vehicles. These pollutants are generally a mixture of hot gases and particulates. An optical fibre sensor is particularly well suited to this task. Due to its small size and weight it is minimally invasive making it suitable for insertion into the vehicles exhaust system. Optical fibres are immune from poisoning by the analyte gases, although they do require shielding from airborne particulates. As they do not transmit electricity they are also highly safe and furthermore they are immune from electromagnetic interference. To detect the presence of the gases it is proposed to use an optical absorption technique. The majority of gases of industrial and environmental importance have their fundamental absorption line in the mid-infrared region of the electromagnetic spectrum, with weaker overtones in the near infrared. Due to the greater availability of components, optimised for communications, most optical fibre gas sensing has taken place in the near-infrared region of the spectrum. In this paper mid-infrared optical fibre gas sensing techniques are investigated and the results of the investigation are presented. Due to the inhomogeneous state of the gas flow it is necessary to measure temperature especially just upstream of the after-treatment section where this can rise to as high as 650oC with large temporal gradients. Measurements of temperature of hot gases from a full size test engine using an optical fibre probe based on fluorescence decay time measurements are also presented.

Online monitoring of exhaust emissions using mid-infrared spectroscopy

Existing automotive sensors do not quantify the levels of pollutants entering the atmosphere; instead they merely indicate that pollution is occurring. However to meet European legislation on emission control, it is necessary to quantify the levels of each type of pollutant leaving the exhaust of a vehicle. This paper discusses the development of an optical sensor suitable for the detection of gas emissions from a motor vehicle based on mid-infrared spectroscopy. Initial tests to detect carbon dioxide using low-cost mid-infrared components are described and a detection system, which could be fitted to an automobile, is outlined.

Detection of carbon dioxide emissions from a land transport vehicle using a mid-infrared optical fiber based sensor

An optical fibre based exhaust gas sensor has been developed from low-cost mid-infrared components which is capable of detecting carbon dioxide (CO2) emissions from both diesel and petrol engines. The optical fibre sensor is not cross sensitive to other gaseous species in the exhaust such as water vapour (H2O), carbon monoxide (CO), oxides of nitrogen (NOx) or oxides of sulphur (SOx). Initial tests of this sensor on a modern diesel engine are outlined in this paper.

Mid-Infrared Optical Fibre Sensor Based Detection of Exhaust Gas Emissions

In order to satisfy increasingly stringent automotive emission control laws, it is necessary to develop sensors that are capable of quantifying exactly the pollutants entering the atmosphere. The development of a mid-infrared optical fibre based sensor suitable for the detection of automotive emissions is discussed in this paper. Mid-infrared spectroscopy is deemed suitable for the task as the fundamental absorption lines of the majority of the pollutant exhaust gases are in the mid-infrared region of the spectrum. This paper focuses on the monitoring of carbon dioxide gas as it has significant absorption in the mid-infrared.

In-situ monitoring of Carbon Dioxide Emissions from a Diesel Automobile using a Mid-Infrared Optical Fibre Based Point Sensor

This paper describes an optical fibre based system suitable for monitoring the presence of carbon dioxide in the exhaust system of a motor vehicle. Conventional automotive pollution sensors fail to meet monitoring requirements as specified by the European Commission for various reasons. The sensor was designed using low cost and compact mid-infrared components, which make it suitable for insertion into a vehicle. The response of the sensor to carbon dioxide supplied from a cylinder in the laboratory is presented. In addition results taken in-situ in an exhaust of a Fiat Croma diesel engine are presented.

On board measurement of carbon dioxide exhaust car emissions using a mid-infrared optical based fibre

This paper describes the investigation of an optical sensor system for the online measurement of carbon dioxide emissions in the exhaust system of a motor vehicle. Current anti-pollution technology installed in motor vehicles fail to meet monitoring requirements as specified by the European Commission. A robust sensor design and construction have made it suitable for installation on the exhaust of a motor vehicle. Results are presented for the sensor output when calibrated to carbon dioxide supplied from a cylinder at the Centro Ricerche Fiat (CRF) research laboratory initially and in-situ in the exhaust of a Fiat Croma (diesel engine) during full scale tests on a roller test bench also at CRF.

Monitoring of harmful gaseous emissions from land transport vehicles using a mid-infrared optical fibre sensor

This paper discusses the development of an optical fibre sensor suitable for the detection of gas emissions from motor vehicles based on mid-infrared spectroscopy. Initial measurements are presented for carbon dioxide emissions from a petrol engine using low-cost mid-infrared components, and a practical detection system, which could be fitted to a vehicle, is outlined.