1. CCAS 3381 AUTOMOTIVE SKILL I ENGINE SUBSYSTEMS

2. OBJECTIVES To understand the operational principles and basic mechanisms of engine sub-systems Lecture – 1 hour 15 mins Workshop – 45 mins

3. LUBRICATION SYSTEM (1) Makes sure every moving part in the engine gets oil so that it moves easily especially: –Pistons (so they can slide easily in their cylinders) –Any bearings that allow things to rotate freely Oil is sucked out of the oil pan by oil pump, run through oil filter to remove any grit & squirted under high pressure onto bearings & the cylinder walls before trickling down into the sump

4. LUBRICATION SYSTEM (2) Piston rings - provide a sliding seal between the outer edge of the piston and the inner edge of the cylinder –Prevent the fuel/air mixture and exhaust in the combustion chamber from leaking into the sump –Keep oil in the sump from leaking into the combustion area, where it would be burned and lost Cars that "burn oil" have to top up engine oil every 1,000 miles are burning it because the rings no longer seal things properly (stinky bluish/whitish smoke)

5. LUBRICATION SYSTEM (3) Whitish engine oil due to leaked gasket – coolant mixed with engine oil

6. LUBRICATION SYSTEM (4) SAE 10W-30, SAE 20W-50 (mineral) SAE 0W-30 (synthetic)

7. FUEL & EXHAUST SYSTEM (1) Pumps petrol from the tank and mixes it with air so that the proper air/fuel (A/F) mixture flows into the cylinders by either: –carburetion, –port fuel injection –direct fuel injection 10 mg of gasoline per combustion stroke is needed during each cycle Carburetor mixes just the right amount of gasoline with air (not too lean/too rich)

8. FUEL & EXHAUST SYSTEM (2)

9. FUEL & EXHAUST SYSTEM (3)

10. Valves - intake & exhaust valves open at the proper time to let in A/F & to let out exhaust (both valves are closed during compression and combustion so that the combustion chamber is sealed) Exhaust system - includes exhaust pipe, muffler to reduce noise & a catalytic converter

11. COOLING SYSTEM (1) IC engines waste 70% of the chemical energy in petrol as heat Engine cooling system must remove this heat to prevent overheating Engine runs best at a fairly high temperature (93 o C)

12. COOLING SYSTEM (2) In cold engine, components wear out faster, & is less efficient & emits more pollution Cooling system allows engine to heat up as quickly as possible & then keep it at a constant temperature

13. COOLING SYSTEM (3) Liquid Cooling –circulates a fluid through pipes and passageways in the engine, absorbs heat, cooling the engine –The fluid leaves the engine, passes the radiator which transfers the heat from the fluid to the air blowing Water pump (driven by belt connected to crankshaft) sends the fluid into the engine block Thermostat opened – water goes to radiator & thermostat closed – fluid back to pump & engine Auto cars have separate circuit for cooling transmission fluid built into the radiator

14. COOLING SYSTEM (4) Radiator cap increases the boiling point of your coolant by about 25 o C Cooling fan controlled to maintain engine constant temperature (FWD - electric fan controlled by thermostatic switch or ECU) Water - most effective fluids for holding heat, (most cars use mixture of water and ethylene glycol (C2H6O2) also known as antifreeze

15. COOLING SYSTEM (5)

16. IGNITION SYSTEM (1) Ignition oil - generates high voltages to create a spark (current flows from battery through primary winding suddenly disrupted by breaker points to 100,000 V

17. IGNITION SYSTEM (2) Distributor - distribute the high voltage from the coil to correct cylinder Spark timing - critical to an engine performance –Spark advance (high speeds) & spark retard (idling & low speeds)

18. IGNITION SYSTEM (3) Spark plug - spark plug supplies spark that ignites the A/F –forces electricity to arc across a gap –must have insulation –Must withstand extreme heat & pressure (plug tip burns deposits) –must happen at just the right moment for things to work properly. Distributor-less ignitions have a coil for each spark plug, located directly on the spark plug itself – no spark cables & no distributors

19. THE END IQ + EQ + SQ = TQ*