Tài liệu học tập cơ bản khái quát về động cơ và các bộ phận trên ô tô phiên bản tiếng anh. Tài liệu này nhằm giúp chúng ta tiếp cận được cấu tạo chức năng của các bộ phận của xe. Với tài liệu này giúp các bạn sinh viên ngành cơ khí ô tô tiếp cận được những kiến thức cơ bản về ô tô và đồng thời nâng cao kiến thức tiếng anh. Bộ tài liệu này được soạn thảo bởi trường đào tạo và huấn luyện nghề ở Canada.
Chapter 22 Basics of Electronics and Computer Systems Capacitors • • • • • • Stores and releases electrical energy Can smooth current fluctuations Store and release high voltage Can block DC voltage Can release all stored energy in an instant Used as noise filters Capacitors (cont’d) • Each terminal is connected to a plate • Voltage applies equally to each plate but with opposite charge • Once charged, has same voltage as source Semiconductors • • • • • • Can be a conductor or an insulator No moving parts Often used as a switching device Common uses are diodes and transistors Do not loose/gain electrons like conductors Share outer electrons with each other P-Type Semiconductor Hole Flow • Holes in P-type semiconductors (positive) attract electrons • Although electrons are not freed, the atom can rearrange to fill a hole in another atom • Electrons move to the positive side of the structure and holes move to the negative Diodes • Commonly used: – – – – LEDs Zener diodes Clamping diodes Photo diodes • Only allow current flow in one direction • AC in generator is rectified by diodes LEDs • Emit light as current passes through them • Light color depends on material used to make the LED Transistors • Used as a switching device • Are made up of three sections: – The Emitter • Path to ground is through the emitter – The Collector • With emitter makes the control circuit – The Base • Controls part of circuit or where circuit is switched Integrated Circuits • One diode or transistor is limited in what tasks can be done • Many semiconductors combined can perform complex functions • Integrated circuits are combinations of diodes, transistors, and other electronic components High Speed CANs • • • • • Engine management Antilock brake systems Transmission control Tire pressure monitoring system Vehicle stability control Network Gateways • Allow for data exchange between different buses • Interacts with each bus according to the bus’ protocol • The BCM is a common gateway module • Each CAN bus uses a different voltage Protecting Electronic Systems • • • • • • Avoid jump starting Do not connect/disconnect with key on Never touch electrical contacts Be aware of electrostatic discharge warnings Touch ground to discharge static electricity Use static-proof work mats inside vehicles Protecting Electronic Systems (cont’d) • Use grounding wrist straps • Never allow grease, lubricants, or solvents to touch sensors or connectors • Do not damage connectors or terminals when removing components • Identify correct terminals for testing Testing Electronic Circuits and Components • Lab scope can be used for voltage, pulse and duty cycle • AC voltages using a DMM – Most meters display average, some show RMS • Checking diodes – Many DMMs can check diodes – Voltage drop typically 500 – 600 mV • A one farad capacitor can store one coulomb at one volt • One coulomb = 6.25 billion billion (6.25 x 1018 ) electrons • One amp equals one coulomb per second • A one farad capacitor can store one amperesecond of electrons at one volt ... combinations of diodes, transistors, and other electronic components Computer Basics • Once mechanically controlled systems now computer controlled • Electronic systems made up of sensors, actuators, and. .. actuator • Drivers usually supply a ground circuit Duty Cycle versus Pulse Width • Duty cycle is a measurement of the amount of time something is on compared to the time of one cycle and is measured... stored in the computer? ??s memory • Output – Is a command given by the computer to operate an output device Inputs • All inputs have same basic function – detect a mechanical condition and change