INTRODUCTION TO I.C.ESession 1 Course Introduction Taught by Chris Coles Teacher Introduction Health & Safety, Risk Assessments Ground Rules Class Introductions Ice Breaker VARK Questionnaire
Aim Build Basic Knowledge of Internal Combustion Engines (I.C.E)
INTRODUCTION TO I.C.ESession 4 Engine Components Taught by Chris Coles
Module Objectives Present the: • Piston and Combustion Chamber. • Engine Arrangements and Cylinder Configuration. • Con-rod and Crankshaft. • Intake and exhaust valves. • Cam-shaft and configuration SOHC, DOHC. • Auxiliary Gearing or Belt Drives. Demonstrate and discuss the interaction of components of an I.C.E.
Combustion Chamber • Cylindrical in shape known as a Cylinder. • Pressurised Chamber. • Made for Combustion. • Directs Explosive Force to Piston.
Piston Head • Fits inside Combustion Chamber. • Explosive force acts on the Piston Head. • Produces LINEAR movement. • Friction creates heat. • Oil cooling by Scraper Rings.
Cylinder Configuration • Straight (also known as Inline engines). • Single Bank of Cylinders.
Cylinder Configuration • V Type (V6, V8, V12) • Two Banks of Cylinders < 180º
Cylinder Configuration • O Type (Opposed Cylinders) • Two Banks of Cylinders = 180º
Cylinder Configuration • W Type (W12) • Three Banks of Cylinders 90º
Cylinder Configuration • Straight • V • O
Cylinder Configuration • Other less popular variations: X – 4 Banks of Cylinders (1 Crankshaft). H – 4 Banks of Cylinders (2 Crankshaft). U – 2 Banks of Cylinders (2 Crankshaft). • Deltic – 3 Banks (Triangular Shape). • Star – 5 or more banks.
Movement • LINEAR movement (Piston). • ROTATIONAL movement (Wheel).
Crank Shaft • Pistons connect to the Crankshaft. • Explosive force of combustion pushes the Piston downwards (LINEAR). • Offset pins transfer linear force to rotational force.
Crank Shaft • A 2nd Explosion on a different offset pin will push that pin down. • Causing the Crankshaft to turn, and the 1st piston to rise back up the Cylinder.
Con Rod • Piston Head connects to the Con Rod by Gudgeon Pin. • Con Rod connects to Crankshaft in a bearing. • White metal bearing is 2x ‘U shapes’ tightened by bolts.
Con Rod • Piston Head to the Con Rod by Gudgeon Pin. Con Rod connects to Crankshaft. • Transmits force from Piston to Crank.
Intake Valves • When OPEN provide the cylinder with a fresh charge of air for compression. • When CLOSED creates a pressurised chamber for compression.
Exhaust Valves • When OPEN purges exhaust gas from the cylinder to the exhaust system. • When CLOSED creates a pressurised chamber for compression.
Valves What prevents the valves from staying open and always ensures they are closed?
Valves Stem & Spring A Spring ensures the valve remains: CLOSED until something pushes down on the Stem Top.
Cam Shaft • A Cam Shaft is a single shaft with egg shaped Cams fitted. • The Cams apply pressure at different intervals to different valves. • So Cylinder 1 may be on an exhaust stroke whilst Cylinder 2 may be on a intake stroke.
SOHC Cam Shaft A Single Overhead Camshaft (SOHC). on a Straight 4 Cylinder Engine.
DOHC Cam Shaft A Double Overhead Camshaft (DOHC). may be used on a V Type Engine or may just operate different Valves.
Incorrect Cam Timing • If the valves do not operate at the correct time, the chamber will not be pressurised. • The spark would not ignite the gas if there was no pressurised fuel/air mix. • Without an explosion, the Piston will not be forced downwards. • The Crankshaft has no linear movement to convert to rotation.
Water and Fuel Pumps A water pump cools the engine block due to the incredibly hot temperatures of the cylinder combustion chambers and valves. How is the water pump powered/driven?
Belt Drives • A non-slipping mechanical belt driven by the Crankshaft. • Made of durable rubber. • Known in cars as Timing Belts. • Speed increased by increasing engine speed; therefore more power created, more heat is generated, so more coolant cools the engine block.
Auxiliary Gears • Same purpose as a timing belt but replaces a belt with grooved teeth gears. • Often found in larger engines due to cost. • No requirement for timing belt change when purchasing a 2nd hand car.
Cam Shaft • When the piston is at Top Dead Centre (highest point) • If either valve was open, a collision with the piston could bend the valves. • Therefore the valves must be timed with the piston. How is this achieved?
Timing Belt • Belt Drive • Timing Belt • Cam Belt • Auxiliary Gears Can drive the following auxiliaries: • CamShaft (SOHC) or both CamShafts (DOHC) • Water Pump • Oil Pump and Fuel Pump
Flywheel • A rotating mechanical device weight. • Resists sudden changes in speed by storing rotational movement (kinetic energy). • A car going down a hill; will slowly speed up as the fly wheel prevents the engine over speeding. The fuel is then decreased. • Same principle applies going up hill, the flywheel weight will still turn the engine until the driver has caught up (until the flywheel stored energy runs out)
Atomised Fuel Injector SUCK, SQUEEZE, BANG, BLOW! Intake Stroke, Compression Stroke, Combustion Power Stroke, Exhaust Stroke. • The Fuel Spray Head injects fuel at the compression stroke. • Fuel mixes with the high pressure compressed air. • The fuel/air mix is then ignited by a spark.
Spark Plugs • A Spark Plug creates a spark (arcing across 2 contacts) for a combustion explosion • Will operate only at the point where all air is fully compressed and fuel is mixed. • Require very high voltages 25,000 – 60,000volts. • The current is very small. (static shocks are 1,000 – 23,000).
Combustion / Power • The spark ignites the fuel injected which has mixed with the compressed air in the pressure tight cylinder. • The explosion generated causes force on the Piston Head downwards creating linear movement. • This rotates the Crankshaft and the exhaust valve opens. As the Crankshaft rotates the piston will rise back up purging the exhaust gases.
Any Questions? Build Basic Knowledge of Internal Combustion Engines (I.C.E) Session 4 – Basic Components of an Engine
Summary Objectives Covered: • Piston and Combustion Chamber. • Engine Arrangements and Cylinder Configuration. • Con-rod and Crankshaft. • Intake and exhaust valves. • Cam-shaft and configuration SOHC, DOHC. • Auxiliary Gearing or Belt Drives. • Interaction of all Components. Module Learning Objective: “Students understand the basic components of a modern engine and there interaction”.