1. 1 Four Stroke Engines How does a canon work?

2. 2 Engine Operation Gasoline & diesel engines convert chemical energy into mechanical energy

3. 3 1 st stroke: Intake stroke Gasoline and diesel engines have to go through 4 strokes to create power to move the car  the intake valve opens  the piston moves down

4. 4 Intake Stroke Continued…  As the piston moves down the cylinder…  a mixture of gas and air enters the cylinder  this mixture is 15 parts air to 1 part gas (15:1 air – fuel ratio)  the air & fuel is mixed & delivered by the fuel system – either a carburetor or fuel injection system

5. 5 2 nd Stroke: Compression Stroke  Intake valve closes  Piston moves up the cylinder  When the piston reaches the top of the cylinder, the air & fuel has been squeezed to 150psi

6. 6 3 rd Stroke: Power Stroke  a spark created by the ignition system, jumps the gap at the spark plug & ignites the air/fuel mixture  This causes the burning gases to expand and drive the piston down the cylinder

7. 7 4 th Stroke: Exhaust Stroke Once the piston reaches the bottom of the cylinder from the power stroke…  The exhaust valve opens  The piston moves up  The burnt gases are pushed out of the cylinder

8. 8 Then what happens? After the exhaust stroke, the piston begins moving down on another intake stroke, continually repeating the 4 strokes

9. 9 Interesting Facts the burning air-fuel mixture can reach ≈1200°C or more the burning air-fuel mixture can reach ≈1200°C or more the crankshaft spins ≈750 times per minute at idle the crankshaft spins ≈750 times per minute at idle it spins ≈3000 times per minute at freeway speeds it spins ≈3000 times per minute at freeway speeds this equals 50 times per second! this equals 50 times per second! the force on the piston during the power stroke is ≈1700kgs the force on the piston during the power stroke is ≈1700kgs a well maintained engine can last 300,000 km or more! a well maintained engine can last 300,000 km or more! the design of a 4 stroke engine hasn’t changed very much over the last 100 years the design of a 4 stroke engine hasn’t changed very much over the last 100 years