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Development of Sensor Concept to Regulate Fuel Supply During Priming of Water to Air Heater in Production

Tid: To 2021-04-15 kl 11.00 - 12.00

Plats: Online (Zoom): https://kth-se.zoom.us/j/69272070677

Respondent: Karl Hemlin

Opponent: Gustav Marstorp

Handledare: Robert Matilla

Examiner: Bo Wahlberg

Abstract: The Water To Air heater (WTA) is a component that heats the interior and the engine of the truck by heating coolant through a combustion of diesel fuel. It is vital that the Water To Air heater is primed with fuel prior to using it in order for it to start when desired. Priming of the heater is done in production, which is where the trucks are built. This is done to ensure that there is fuel available to heat the coolant. However, the current priming process has too many weaknesses, it is sensitive to component changes and there are a number of uncertainties present. The goal of this thesis is to investigate the priming process and try to improve the process so that it becomes more robust. The aim is to present an alternate method that could be used to minimize the number of uncertainties and the impact of these. 

Several methods of how to regulate the fuel supply were studied and evaluated according to a few criteria and limitations. The first method that was tested was to try and detect fuel through a simple type of Electrical Capacitance Tomography. However, initial measurements proved that it would not be possible to use this method in order to achieve the desired result. Instead, fuel was detected by creating a prototype consisting of a photoresistor and a laser pointer. Once it had been established that fuel could be detected through this prototype, a microcontroller was programmed to automatically be able to make measurements and handle the output from the photoresistor. 

The developed concept is a concept that, if implemented in production, would solve many of the problems that are present with the current priming process. Many of the uncertainties would either be eliminated completely, or decreased massively. However, there is some work that remains. In order to use the proposed solution as a stand-alone system that regulates the fuel supply, it is necessary that a stop signal is implemented. Additional tests need to be performed in order to decide how the final implementation is going to work. Finally, the prototype needs some improvements.