A cooling fan speed controller for energy efficient temperature control of a race car engine

Abstract

From small remote controllers to large vehicles, batteries are found almost in every portable device. Batteries have taken a lot of various shapes and sizes since the invention of the first battery by Alessandro Volta in 1799. They nowadays come in lithium cells, pencil batteries or lead-acid packages among other various forms. However since from they were invented, batteries have always caused some problems with regards to applicability as they lose their charge over time. Moreover the larger the current being drawn, the faster is the discharging process. Hence throughout time, the current required by a battery-powered electronic circuit was always minimised in order to reduce the size of the battery. This concept is quite vital when it comes to automotive applications. Minimising the current required will result in a less energy to weight ratio and hence a lighter battery for a lighter vehicle. Current can be reduced in several ways. One particular method is by developing a variable fan speed controller. Previous designers used to adopt an on-off controller system. Such a control scheme will switch on the fan when the temperature exceeds a specific value and switch the fan off again when the temperature is below a specified threshold. Although it is simple and easy to implement, it is not the most efficient method. Hence the variable fan speed controller, which monitors the engine and the cooling liquid temperature and adjusts the speed accordingly. The objectives of this dissertation are to: 1. Design and build an efficient DC-DC converter to vary the speed of the fan 2. Design and build all temperature measurement circuitry 3. Develop all the control algorithms to regulate the temperature and speed accordingly by generating and applying PWM signals to the DC-DC converter All the aforementioned controllers were modelled and simulated with MATLABR and Simulink application packages. These were then implemented on an Atmel ATmega328P microcontroller.