Car Heater Controller Design

It is a long history for automobile heater as the major equipment for car's warming from 1940s. As the modern science processes, its design and research method has a substantial improvement. Meanwhile, with the development and application of the neoteric electronic technology, its control technique is improved from original mechanical or semi-automatic control to intelligent embedded microprocessor control, which enhanced the reliability and stability of heater. In order to contrive the new style heater, the intelligent controller is designed based on the working principles of the heater.The controller uses Cypress's PSoC system-on-chip microprocessor as a control core. In addition to the digital processing functions the normal MCU possessed, the PSoC chip also integrates a number of analog blocks, related Analog Bus, Comparator Bus and Analog Buffers. The user can achieve the required specific functions and save the system resources via allocating the on-chip digital and analog blocks resources. Because of the realization of In-System Serial Programming and the usage of dynamic re-allocation function, the PSoC has powerful flexibility and integration capabilities, eliminates the burden of chip microcomputer system expansion, also improves the system reliability and stability.This paper gives a specific description on the hardware and software design of the controller. It introduces the structure of the system hardware and the principles of circuit, especially the fault detection circuit which increase the safety of heater. The modularization design in software advances its efficiency. Through using the different function separately to complete the startup,operation monitoring and fault diagnosis, the protection can be made timely to avoid the damage to the heater and controller when fault detected. As the working environment of controller is bad and subject to the outside interference, the anti-interference technology is adopted in the hardware circuit and software design. Such as the use of optically coupled isolator, the setup of the shielding ground, the digital filtering technology and traps in software as well.The ignition of heater is a very important process, in order to shorten the time required for ignition and to ensure the stable and reliable ignition, the ignition test is implemented, the two different ignition processes under petrol and diesel oil is concluded, in addition, the design of soft flow is optimized. In the premise of guaranteeing the heater power, to increase thermal efficiency of the heater combustion and improve the software parameter settings, the performance test is implemented which also provide the evidence to control the fans, fuel pumps and water pumps.