Automotive-5.pdf

AUTOMOTIVE Engine Classification Objectives Explain the four stroke cycle engine. Discuss the cylinder arrangement. Identify and explain the function of each engine parts. Internal combustion engine needs Engines fuel, ignition and compression in order to run. Four-Stroke Gasoline E...

AUTOMOTIVE Engine Classification Objectives Explain the four stroke cycle engine. Discuss the cylinder arrangement. Identify and explain the function of each engine parts. Internal combustion engine needs Engines fuel, ignition and compression in order to run. Four-Stroke Gasoline Engine Two-Stroke Gasoline Engines Diesel Engine Engine Parts Cylinder Block Cylinder Block Cylinder block or Cylinder are main part of an engine. It is a part in which combustion of fuel takes place. All other parts like piston, connecting rod, crankshaft , water jacket etc. are bolted on it. Configuration/Arrangement Inline Engines: The cylinders are arranged in a line, in a single bank. V Engines: The cylinders are arranged in two banks, set at an angle to one another. Flat Engines: The cylinders are arranged in two banks on opposite sides of the engine Cam Shaft: The shaft that has intake and Exhaust cams for operating the valves. Cam Lobe: Changes rotary motion into reciprocating motion. Camshaft location is one way to classify engines. Overhead cam, SOHC, DOHC Double Overhead Cam Valves: Minimum Two Valves per Cylinder Exhaust Valve lets the exhaust gases escape the combustion Chamber. (Diameter is smaller then Intake valve) Intake Valve lets the air or air fuel mixture to enter the combustion chamber. (Diameter is larger than the exhaust valve) Valve Springs: Keeps the valves Closed. Valve Lifters: Rides the cam lobe and helps in opening the valves. Different arrangement of valve and camshaft.  Spark Plug It provides the means of ignition when the gasoline engine’s piston is at the end of compression stroke, close to Top Dead Center(TDC) The difference between a "hot" and a "cold" spark plug is that the ceramic tip is longer on the hotter plug. Piston A movable part fitted into a cylinder, which can receive and transmit power. Through connecting rod, forces the crank shaft to rotate. Cylinder head Part that covers and encloses the Cylinder. It contains cooling fins or water jackets and the valves. Some engines contains the cam shaft in the cylinder head. Connecting (conn.) Rod Attaches piston (wrist-pin) to the crank shaft (conn. rod caps). Crank Shaft Converts up and down motion into circular motion. Transmits the power to transmission. Piston Rings Four stroke: Three rings Top two are compression rings (sealing the compression pressure in the cylinder) and the third is an oil ring (scrapes excessive oil from the cylinder walls) Two Stroke: Two Rings Both the rings are Compression rings. Blow-by from Piston Rings Engine blow-by will cause oil burning in the combustion chamber, producing blue(grey) smoke. Flywheel Attached to the crankshaft Reduces vibration Cools the engine (air cooled) Used during initial start-up Transfers power from engine to Drivetrain Helps glide through strokes  Manifold: It is bolted on the cylinder head one each for intake and exhaust. Its function is to evenly distribute air-fuel mixture for intake & collects the exhaust gases from all cylinders. Gaskets: It is used to seal the cylinder head and cylinder so no pressure is allowed to escape. It is placed between the cylinder block and cylinder head. Engine Bearing: Bearings are used to support the moving parts. The purpose of bearings is to reduce friction. Engine Bearing: The crankshaft is supported by bearing. In engine two types of bearing are used sliding bearing and rolling bearing. Firing Order Four cylinder engines are 1-3-4-2 and 1-2-4-3 Six cylinder 1-5-3-6-2-4 or 1-4-2-6-3-5 All modern six cylinder- 1-5-3-6-2-4 Firing Order The firing order is the sequence of power delivery of each cylinder in a multi-cylinder reciprocating engine. This is achieved by sparking of the spark plugs in a gasoline engine in the correct order, or by the sequence of fuel injection in a Diesel engine.