Review Exam #4 Engine Air Fuel Components Expenses
Stroke The distance swept by a piston as it goes from BDC to TDC or from TDC to BDC.
Throw is one half (1/2) the Stroke Throw vs Stroke Throw is one half (1/2) the Stroke
Intake Compression Power Exhaust Four Strokes Intake Compression Power Exhaust
Basic Engine Components Engine Block Crankshaft Pistons Connecting Rods Camshaft(s) Intake and Exhaust Valves
Configuration The design of the engine block which describes how the cylinders are arranged
Engine Size / Displacement The combined swept volume of all of the cylinders Displacement = 𝝅 ( 𝒃𝒐𝒓𝒆 𝟐 ) 𝟐 x stroke x (# of cylinders) Example: Bore (D) = 4 in Stroke = 3 in # of cylinders = 8 Displacement = .7854 x 42 x 3 x 8 = 301.6 in3
Ignition / Spark Test Set Gap to .030 inches Ensure spark tester is clipped to a good ground on engine block or cylinder head
Compression Test At least three to four pulls of starter cord Hand tighten into spark plug hole
Cylinder Compression Leaks Four common locations: Intake Valve Exhaust Valve Cylinder Head Gasket Piston Rings
Combustion Byproducts CH4 + 2O2 CO2 + 2H2O + Heat + + CO + HC + NOX = Good = Not so Good
Air Intake Must go through an Air Filter before entering the intake manifold. Filters particles.
Seals Prevents leaks Under compression Gaskets Seals Prevents leaks Under compression
Flywheel Stores Energy by using inertia/momentum to offset the three non-power producing strokes of the four stroke engine. A larger/heavier flywheel takes more energy to get it rotating up to speed, but it will store more energy and allow for a smoother ride than a lighter flywheel.
Diameters Outside Inside
Vernier Caliper Toggle between inches, fraction of inches, and mm Zeroize Depth Measurement
Crankshaft Types Cast - pouring liquid metal into a mold, which contains a hollow cavity of the desired shape, and then allowing it to cool and solidify. Forged - manufacturing process involving the shaping of metal using localized compressive forces. Given the same type of steel (e.g. 4340, 1020, etc) forging will be stronger than casting. Billet has the capability of being stronger than a forged crankshaft.
Crankshaft Measurements Connecting Rod Journals are same as Crankpin Journals
Driven Gear Teeth / Drive Gear Teeth Gear Ratios Driven Gear Teeth / Drive Gear Teeth Example is 75/25 or 3:1 In a four stroke engine, the crankshaft turns twice for every one turn of the camshaft
Valve Tip Stem Margin Face / Seat
Air Induction Components Air Filter Cleans the air of particles being drawn into the engine. A dirty air filter can reduce engine performance. Mass Airflow Sensor (MAF) Measures the mass of the air entering the engine. Chapter 11 © 2013 Rolling Hills Publishing www.AutoUpkeep.com
Air Induction Components Throttle Body Has the throttle (butterfly) valve Intake Manifold Air flows and finally mixes with gas as it dumps into combustion chamber Chapter 11 © 2013 Rolling Hills Publishing www.AutoUpkeep.com
© 2013 Rolling Hills Publishing www.AutoUpkeep.com Fuel System Purpose: Store (Tank) – Transport (Pump and Lines) – Mix (with air by Injectors or carburetor) Ideal gasoline mixture (Stoichiometric) – 14.7 : 1 air to fuel ratio. Carburetors mixed air/fuel before fuel injection Three Generations of Electronic Fuel Injection: Throttle Body Injection (TBI) Port Fuel Injection (PFI) Gasoline Direct Injection (GDI) Chapter 11 © 2013 Rolling Hills Publishing www.AutoUpkeep.com
Fuel System Components Tank Pump Lines Filter Injectors
Gasoline Properties Octane Resistance to detonation (knocking) Common 87, 89, 91-93 The higher the octane rating the more the fuel resists knocking.
© 2013 Rolling Hills Publishing www.AutoUpkeep.com Flex-Fuel and E85 E85 vehicles can burn a blended fuel that contains 85% ethanol and 15% gasoline. Ethanol is a grain alcohol made from renewable resources, commonly corn. “Flex Fuel” means the car can burn any percentage mixture of ethanol and gasoline Chapter 18 © 2013 Rolling Hills Publishing www.AutoUpkeep.com
Engine Tools Spring Compressor Compression Tester
© 2013 Rolling Hills Publishing www.AutoUpkeep.com Parts and Labor Mitchell Prodemand Estimate Guide Chapter 3 © 2013 Rolling Hills Publishing www.AutoUpkeep.com
© 2013 Rolling Hills Publishing www.AutoUpkeep.com Expenses include… Loan Payments Insurance Fuel Expenses Annual License and Registration Routine Maintenance Unexpected Repairs Chapter 3 © 2013 Rolling Hills Publishing www.AutoUpkeep.com
© 2013 Rolling Hills Publishing www.AutoUpkeep.com Insurance Deductible The amount you pay before the insurance applies. You can decrease your insurance costs if you increase your deductible. Only applies to collision and comprehensive (not Liability) Chapter 3 © 2013 Rolling Hills Publishing www.AutoUpkeep.com
© 2013 Rolling Hills Publishing www.AutoUpkeep.com Insurance Liability Insurance The minimum policy required by law. Covers claims to others that you cause. Chapter 3 © 2013 Rolling Hills Publishing www.AutoUpkeep.com
© 2013 Rolling Hills Publishing www.AutoUpkeep.com Insurance Collision and Comprehensive Covers the cost to repair your vehicle if you were at fault. Collision – auto accidents. Comprehensive – natural disasters, vandalism, theft, fire, animal collisions. Chapter 3 © 2013 Rolling Hills Publishing www.AutoUpkeep.com
© 2013 Rolling Hills Publishing www.AutoUpkeep.com Fuel Expenses Fuel economy varies greatly depending on the vehicle and it impacts your monthly costs. Chapter 3 © 2013 Rolling Hills Publishing www.AutoUpkeep.com
License and Registration Sales tax Title fees License plate tags Pay at DMV (Dept of Motor Vehicle) Chapter 3 © 2013 Rolling Hills Publishing www.AutoUpkeep.com