Design and External Monitoring System Development of Car Exhaust Gases in Rwanda
Since the beginning of the 21st century, many countries and institutions worldwide have focused on importance of the environmental protection. Typical example is Rwanda, where the control for vehicle exhaust gases emissions is a mandatory practice. This dissertation had an objective of designing an external system for automatic monitoring of vehicle emission. This research was an applied research where desk study was applied for collecting secondary data. Study design was also applied for research design of the system. In the design of this system; the combination of four MQ series of gas sensors, namely MQ5, MQ6, MQ7 and MQ135gas sensor were used to determine the vehicle exhaust content of hydrocarbons (HC), carbon monoxide (CO), carbon dioxide (CO2) and Nitrogen oxides (NOx). The system test sample was conducted to eight vehicles petrol and diesel type. This system constantly rechecks the car exhaust gas on the road under any driving condition. It is therefore very efficient since it extends the car serviceability by alerting the driver, or user to carry out the required maintenance on time. The current work has been accomplished using MQ gas sensors, but these are not the only existing sensors. Therefore, the interested researchers are advised to make a very deep research on the vehicle exhaust gas monitoring using different type of gas sensors to achieve much better results. This system also was limited to the detection of CH4 among hydrocarbons. We therefore recommend the interested researchers to find means of detecting the total hydrocarbons in the exhaust gas. They may also work on the Particulate matters monitoring for diesel engine because these also are very harmful exhaust gas components. After conducting these tests, it is rational to conclude that the target has been reached since the designed emission monitoring system shows acceptable results. Even though sampled vehicles for the experiment were equipped with emission reducing systems, namely electronic fuel injection, electronic ignition and catalytic converter; there are some redundant toxic quantities. These are still harmful to humans in particular, and to the environment in general.
Keywords: Automobile Vehicles, Environment Pollution, MQ Sensors, Vehicle emission control, Exhaust gas.