Design & Development Of Vehicle Heater Fault Diagnosis Instrument

Vehicle heater has been developing rapidly these years. It is now widely used in large-scale passenger cars, trucks, military vehicles, tanks and high-class cars. It can be a very good solution to the cold-start problem and the issue of room heating of vehicle in the cold season and cold regions. Once the heater fails, will it bring a lot of problems, and greatly affect the driving comfort and security. Due to the complexity of its installation on the chassis of the vehicle, in the event of problems, check out the demolition and some electrical malfunction in a circuit switched only in the middle of the emergence of separate checks may not be able to quickly and accurately identify the cause of the malfunction.Therefore, it is necessary for timely detection and heater fault diagnosis to make it always work in a good technical state. This instrument can not only check the heater without the disintegration, get safe, rapid and accurate diagnosis of faults and show the main operating parameters, but also be able to remember all kinds of fault information and make the follow-up maintenance expediently.This paper introduces the working principles of the vehicle heater fault diagnosis instrument, which is designed to use PSoC (programmable system on chip) as CPU and LCD & EEPROM as output units. This instrument can realize the real time display of the heater's working state and fault information, analyze all kinds of parameters off line and give repair suggestions. Take use of the user modules of UART, SPI, I2C to finish the diagnosis, display and data storage tasks. PSoC hardware and software design features greatly simplify the system complexity of R & D and improve the stability and reliability.This paper gives a specific description on the hardware and software design of the automobile heater fault diagnosis instrument. It introduces the structure of the system hardware and the principles of circuit, especially a detailed description of the various parts of the working principle and circuit implementation. In particular, a real-time clock RX8025 with independent power supply circuits is designed to strengthen the real-time monitoring performance. The modularization design in software advances its efficiency. Through using the different function separately to complete the serial communication started, the monitoring display, time display and adjustment, fault diagnosis, memory and so on. This instrument can make a diagnosis accurately and fault information can be recorded with occurred time. The anti-interference technology is adopted in the hardware circuit and software design. Such as the use of the setup of the shielding ground and the digital filtering technology and traps in software.