Basic Engine Operation & Construction Purpose of an engine - To create power for a specific use! Use for What? Purpose of an Piston type engine - To create power for a specific use and convert reciprocating power to rotary power How do you create Power? Easy !! A Potato Gun !!! How does it work!! Converting reciprocating power to rotary power is done with three basic parts It’s just like riding a bike ! What are other uses for straight line power ? Rotary Power is more usefull !

External Combustion or Internal Combustion Combustion: the act or process of burning, creating pressure for a specific use! External Combustion: Pressure/Power created outside of the engine Ie: Steam Engines Web Link Internal Combustion: Pressure/Power created inside of the engine Ie: Four Stroke Cycle Engines Web Link

Creating Internal Combustion Vacuum – Low Pressure Area, air moves “High to Low”

Creating Internal Combustion Compressing the A/F mixture makes it more volatile! Why? Compression Creates Energy Heat An super active A/F mixture Compress the A/F to much add ! Pre-Ignition!

Creating Internal Combustion Ignition starts the burning of the A/F mixture Power – burning A/F mixture Combustion Completed

Creating Internal Combustion Remove the burnt A/F Mixture via pressure Start Over! How? Done!

Welcome to the Four Stroke Cycle Intake Compression Power Exhaust Animated 4 Stroke

Basic Engine Terminology

The Four Stroke Cycle Intake - Intake valve opens, piston travels from TDC to BDC, creating a vacuum, drawing in air/fuel mixture into the combustion camber. Intake valve closes. Compression - Both valves closed, piston travels from BDC to TDC compressing the air/fuel mixture. A volatile mixture, and heat are created. Power - air/fuel mixture is ignited and begins to burn, and expands. the pressure forces the piston down from TDC to BDC causing the crankshaft to turn. Exhaust - exhaust valve opens, piston moves from BDC to TDC forcing out the burnt gases remaining from the created power. Exhaust valve closes CYCLE REPEATS

Engine Classification Number of Cylinders: . Cylinder Arrangements: Valve Train types: Fuel Types: Cooling System: Ignition Types:

Number of Cylinders & Cylinder Arrangements Inline: V-Type Opposed 2, 4, 6 2, 4,6, 8, 10,12, 16 1, 2, 3, 4, 5, 6, 8 Animation Link Cylinder Numbering Firing Order: the order in which each cylinder begins its power stroke

Other Piston Cylinder Arrangements Radial W12 Radial Animation

Engine Classification Number of Cylinders: . Cylinder Arrangements: Valve Train types: Fuel Types: Cooling System: Ignition Types:

Valve Train Types L Head T Head F Head I Head

How valves Open and Close Briggs & Stratton L Head Design Mechanically with A Cam Lobe Valve Timing with gear ratio’s Camshaft Crankshaft Camshaft Crankshaft 1 : 1 1 : 2

How valves Open and Close T Head F Head I Head Animated I Head

How valves Open and Close Overhead Camshaft DOHC Double Over Head Cam

Engine Classification Number of Cylinders: . Cylinder Arrangements: Valve Train types: Fuel Types: Cooling System: Ignition Types:

Fuel Types Advantages Disadvantages Gasoline Propane Natural Gas - different octane levels - availability - highest polluting Gasoline cost low polluting power loss 10% availability Propane power loss 20% availability - carrying danger - cost, cheapest - very low polluting Natural Gas high octane - Very low polluting high cost - poor fuel economy Alcohol cost, better fuel economy lots power/torque - long lasting high polluting engine cost - noise / low RPM Diesel

Engine Classification Number of Cylinders: . Cylinder Arrangements: Valve Train types: Fuel Types: Cooling System: Ignition Types:

Cooling System / Ignition Type Air Cooled Spark Liquid Cooled Compression

Other Engine Types Diesel Engine Diesel Fuel oil – by product from the crude oil refining process. - rated by cetane number, difficult to ignite Compression Air Only Creating Heat Power Hot Air Ignites Injected Diesel Exhaust Burnt A/F Pushed Out Intake Air Only

Other Engine Types Diesel Engine Diesel Injectors must: Enter correct amount of fuel Be at the right time Control the rate of fuel Start and stop abruptly Advantages - cost, better fuel economy - lots power/torque - long lasting Disadvantages slow acceleration low RPM - engine cost fuel system repairs noise

Other Engine Types Two Stroke Cycle Basic operating principles - similar to a 4 stroke, operating principles of Intake, Compression, Power and Exhaust. - the above principles are completed in two strokes instead of four, stages are combined How do you combined 4 strokes into 2 ? Exhaust Intake Compression Power

Other Engine Types Two Stroke Cycle Intake - intake port is cleared by the piston - Air/Fuel mixture is pushed into the combustion chamber. Compression only occurs for aprox. 1/2 of the piston movement up Compression

Other Engine Types Two Stroke Cycle Power - only occurs for aprox. the first 1/2 of the piston moving down. Exhaust - exhaust port is cleared by the piston. exhaust to escapes from the pressure of the power stroke Exhaust CYCLE REPEATS Animated 2 stroke

Other Engine Types Two Stroke Cycle Other Operating Principles How is the A/F pushed into the combustion camber? A/F mixture is drawn into the crankcase as the piston is moving up during the power stage by a vacuum in the crankcase, drawing in the air/fuel/oil mixture Animated 2 stroke As the moves down on the power stage, pressure is created in the crankcase, therefore forcing the A/F mixture into the combustion camber

Other Engine Types Two Stroke Cycle Advantages Disadvantages less moving parts, no valves - runs at any angle high revving fast acceleration Disadvantages - high wear rate - low torque - lubrication needs to be mixed or injected - high in pollutants

Other Engine Types Two Stroke Diesel Similar operating principle of the two stoke gasoline engine. However: the crankcase is not used to create pressure! Air is forced by a blower!

Other Engine Types Two Stroke Diesel Advantages Disadvantages - better fuel economy - lots power/torque - long lasting - less moving parts higher revving faster acceleration Disadvantages - engine cost - fuel system repairs - noise

Other Engine Types Rotary Combustion Turbine / Jet engines Not a reciprocating motor - motion of operation is already in rotary motion Turbine / Jet engines WANKEL ENGINES Bingo! A Wankel! Imagine a spinning triangular block inside a can! The cambers on each side do not change volume. However! If the triangle is turning of centre, the camber change volume as it rotates.

Other operating principles Other Engine Types Rotary Combustion Basic Operating Principles – Stages Stage 1 - rotor clears intake port, chamber increases in size, creating a vacuum drawing in A/F mixture Other operating principles - three chambers acting at the same time doing different stages - some motors wth two rotors therefore six power thrust for one revolution - power to crankshaft done with gears on an eccentric - 3 to 1 ratio of rotor to crankshaft rotation Stage 2 - rotor continues to rotate, intake port closed off, chamber begins to compress A/F mixture Stage 3 - A/F mixture ignited by spark plug, burning creating power against rotor continuing rotary motion Stage 4 - turning rotor uncovers exhaust port, forcing out exhaust gases as chamber is decreasing STAGES REPEAT Wankel Animation

Other Engine Types Rotary Combustion Advantages Disadvantages - fewer moving parts - less power loss to friction - 1/2 size / hp of piston engine - almost vibration less - quite running - great acceleration - constant torque - high RPM obtained Disadvantages rapid wear of appex seals repair costs - poor fuel economy - high in air pollutants