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 20 Lighting Systems Lamps • A lamp generates heat and light as current flows through the filament • Filament vacuum sealed in glass envelope • Lamps are normally single filament or double filament Sealed-Beam Headlights • Air tight assembly • Contains filament, reflector, and lens • Type is high beam • Type is high and low beam Composite Headlights • Use a replaceable bulb • Improves aerodynamics, fuel economy, and vehicle styling HID Headlights • • • • • Also called xenon headlamps Use gas-discharge lamps Electronically controlled Use an electric arc instead of a filament Uses high-voltage to jump gap and about 80 volts to maintain Headlight Switches • Controls most exterior lighting • Instrument panel (IP) lights come on when switch is in park or headlight position • IP light brightness may be controlled by rheostat in headlight switch • The system can be power-side or ground-side controlled Dimmer Switches • Allows driver to switch between high- and lowbeams • Connected in series with headlight circuit • Typical dimmer switch Daytime Running Lights (DRLs) • Added safety feature • Headlights connected in series when the ignition switch is on and headlights are off • When headlights are turned on normal operation returns Automatic Light Systems • Light-sensitive, automatic, on-off control • Uses a photocell sensor/amplifier • Manual headlight switch operation overrides automatic setting • High-beam detection system turn high-beams on and off – Forward looking light sensor detects conditions Fog Lights • Designed to send a flat, wide beam under the fog • Mounted low and aimed low • Often fitted with yellow or amber lenses to reduce glare Courtesy Lights • Provides light inside the vehicle • Operated by doors, headlight switch, or separate switch • Often tied into keyless entry and/or alarm • Map lights usually independent of courtesy lights Rear Exterior Lights • Taillights • Turn signal and hazard lights • Brake lights • Center high-mounted stop light • Side marker lights • Reverse or back-up lights • License plate lights Turn, Stop, and Hazard Warning Lights • • • • Each system has a switch to control operation Turn signals only powered with key on Stop and hazard lights powered with key off Turn signal and hazard lights may be part of multifunction switch Flashers • Used by turn signal and hazard systems • Some styles use temperature sensitive bi-metallic strip • Many flashers are electronic • An inoperative turn signal bulb generally causes a different flashing rate Brake (Stop) Lights • Controlled by brake light switch normally mounted on brake pedal bracket • All late model vehicles have a center highmounted stop light (CHMSL) • Brake light switch input is also used for cruise control, ABS, and traction control systems Backup Lights • Operate when transmission is placed in reverse • May share fuse with turn signal system • Usually part of transmission range switch on automatic transmissions • Separate switch on manual transmissions Basic Lighting System Diagnosis • Bulbs are quickly checked with ohmmeter or powered test light • Inspect for corroded or loose wiring • Many exterior lights are exposed to climate and weather conditions that can damage wiring and sockets Bulb Replacement • • • • Make sure the replacement is the correct bulb Inspect the bulb socket Often removal of light assembly is necessary Do not remove lenses from light assemblies ... input is also used for cruise control, ABS, and traction control systems Backup Lights • Operate when transmission is placed in reverse • May share fuse with turn signal system • Usually part... and headlights are off • When headlights are turned on normal operation returns Automatic Light Systems • Light-sensitive, automatic, on-off control • Uses a photocell sensor/amplifier • Manual... available, a screen can be used to determine headlight accuracy Other Light Bulbs • Most designs prevent using incorrect bulb type • May be several types within the design • Bulbs have trade numbers