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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 25 Engine Performance Systems Engine Performance Systems • Responsible for how the engine runs • Complete combustion requires: – – – – Correct amount of air Correct amount of fuel Mixed in a sealed container Shocked with the correct amount of heat Purpose of the Ignition System • Generate enough heat to ignite mixture • Maintain the spark long enough for total combustion of the fuel • Must deliver the spark to each cylinder to allow combustion to begin at the correct time Firing Order • To supply spark at the correct time, each cylinder fires in a specific order every 720 degrees Fuel Systems • Typical fuel supply system includes: – Fuel tank, lines, filter, and a pump • A pressure regulator maintains system pressure • The pressure generates the spraying force to inject the fuel Fuel Injection - TBI Fuel Injection - CPI Fuel Injection - PFI Fuel Injection - GDI Troubleshooting OBD II Systems • • • • • • • Interview the customer Check the MIL Connect scan tool Check DTCs and freeze frames Check service history and information Record data and clear DTCs Visual inspection Troubleshooting OBD II (cont’d) • • • • • • Check DTCs and monitors Basic inspection DTC chart Check for intermittent problems Perform repairs Repair verification Intermittent Faults • • • • • • • May not set DTC or light the MIL Check history DTCs Evaluate symptoms and conditions Identify circuit or system that may be at fault Follow intermittent procedures in manual Visual inspection Test circuit wiring Serial Data • PIDs are codes used to request data from PCM • Scan tools request and receive serial data • Scan tool PID requests information from a device on the network • Many PIDs are standard but not all are supported by all manufacturers Diagnosing OBD I Systems • Limited self-diagnostic capability • Hard faults (on-demand) occur at time of self-test • Intermittent faults not present at self-test can store a DTC for a number of key cycles • Several different methods to access DTCs • Perform a thorough visual inspection .. .Engine Performance Systems • Responsible for how the engine runs • Complete combustion requires: – – – – Correct amount of... Emission Control Systems • Reduce pollutants and environmentally damaging substances • Smog irritates eyes, nose, and throat • Formed when HC and NOx are exposed to sunlight Engine Control Systems •... On-Board Diagnostic Systems • OBD I – Phased in 1988 – Most used flash codes – DTC represented open, shorted, high resistance, or outside normal range faults – Monitored a few systems and had limited