1. Engine Dissection Project Your team is dissecting a 3.5 HP single cylinder, 4 cycle engine, made by Briggs and Stratton in Milwaukee, Wisconsin These engines are typically used in lawn mowers, snow blowers, go-carts, etc (ref. 2, Used by permission of Briggs and Statton, ©1992, all rights reserved)

2. Engine Dissection Project n Start engine. n Disassemble engine. n Review parts and functions – Ask questions! n Reassemble engine. n Re-start engine. n Write individual report on how engine works.

3. 4 Cycle Process Intake Stroke Intake valve opens, admitting fuel and air. Exhaust valve closed for most of stroke Compression Stroke Both valves closed, Fuel/air mixture is compressed by rising piston. Spark ignites mixture near end of stroke. Intake Manifold Spark Plug Cylinder Piston Connecting Rod Crank Power Stroke Fuel-air mixture burns, increasing temperature and pressure, expansion of combustion gases drives piston down. Both valves closed - exhaust valve opens near end of stroke 1 2 3 4 Exhaust Stroke Exhaust valve open, exhaust products are displaced from cylinder. Intake valve opens near end of stroke. Crankcase Exhaust Manifold Exhaust Valve Intake Valve

4. 1. Intake2. Compression 3. Power 4. Exhaust

5. Reciprocating to rotary motion The pistons & crankshaft Image from: http://www.eng.iastate.edu/explorer/topics/car/engine.htm

6. Piston, crankshaft, & fly wheel Image from: www.web-masters.com/ gms/crank_p.html

7. Piston Image from: www.rbracing-rsr.com/ 113orca.htm darryl.hudson.home.mindspring.com/ ww.eng.iastate.edu/explorer/topics/car/engine.htm

8. Crankshaft Image from : toyotaperformance.com/crankshaft_kits.htm

9. Several common types of car engine arrangement Image from : Automotive mechanics, 8 th ed. By William H. Crouse 4 cylinder in-line Flat-4 engine Flat-6 engine 6 cylinder in-line V-6 V-8

10. 4 cylinder 6 cylinder 8 cylinder Power strokes in 2 crankshaft rotations Why you need flywheel Image from : Automotive mechanics, 8 th ed. By William H. Crouse time Output torque time Output torque time

11. piston valve rocker valve lifter camshaft cam crankshaft push rod Valve Mechanisms: How you get the right timing Image from : Automotive mechanics, 8 th ed. By William H. Crouse Timing marks

12. Lubrication Image from : Automotive mechanics, 8 th ed. By William H. Crouse

13. Fuel Higher Pressure Outside Engine Venturi ChokeThrottle Venturi-type Carburetor The carburetor of our engine

14. How do engines work? How does the engine complete these Primary Functions? n Get started? n Suck in fuel? n Suck in air? n Mix air and fuel? n Compress the mixture? n Ignite the mixture (at the right time)? n Make the combusting gases do work? n Make the work available to somebody? n Exhaust the gases? n Shut off? Think about the parts and processes involved for each. Hint

15. How do engines work? How does the engine complete these Secondary Functions? n Stay lubricated? n Operate the valves at the right time? n Smooth out the power pulses? n Store the fuel? n Keep cool? n Make it easy to start? Think about the parts and processes involved for each. Hint

16. Some variations: Fuel Injection (electronic, multi-port) 50 psi typical Monitored Engine Operating Conditions: Manifold Pressure Engine Speed Air Temperature Coolant Temperature Acceleration COMPUTER TRIGGER INJECTOR DRIVE UNIT Pressure RegulatorFuel Filter Fuel Pump FUEL TANK Injectors

17. More variations: OHC( overhead camshaft): DOHC, SOHC…… Image from : Automotive mechanics, 8 th ed. By William H. Crouse Crankshaft Connecting rod Piston Camshaft Valve lifter Rocker Valve spring Valve

18. More variations: VTEC( Variable valve timing and lift electronic control)

19. 2 Stroke Process (for comparison) Compression (ports closed) Air Taken Into Crankcase Combustion (ports closed) Exhaust (intake port closed) Air compressed in crankcase Scavenging and Intake (ports open)

20. This presentation created by former ENGR 100 students Sam Henry, Thomas Munsey, Grayson Deitering, Daniel Munro Wankel Rotary Engine Smoother Engine is continuously moving in one direction rather than changing direction like in piston engines. Slower Main moving parts move slower which increase the reliability of the engine. Fewer Moving Parts The rotary engine consists of three main moving parts while a piston engine contains at least 40 moving parts. Challenges Passing the US Emissions tests. Manufacturing costs are higher. Consumes more fuel.