ME240/107S: Product Dissection ME240/107S: Engine Dissection You are dissecting a 3.5 HP single cylinder, 4 cycle engine, made by Briggs & Stratton in Milwaukee, WI 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)

ME240/107S: Product Dissection Lecture 3 n Material Considerations n Why Internal Combustion? n Engine Labeling Diagram

ME240/107S: Product Dissection Session 2: Engine Block and Drivetrain n What materials are used in the camshaft? How are the cams fastened to the shaft? n What material is used for the crankshaft? n What manufacturing processes were used for the crankshaft, camshaft, connecting rod, wrist pin, and piston? n What type of lubrication system does your engine have and how does it work? Which components receive lubrication?

ME240/107S: Product Dissection Crankshaft n Originally steel forged; however, large stiff crankshafts with relatively low stresses allowed cast iron to be substituted as a means to reduce cost n How is crankshaft supported?

ME240/107S: Product Dissection Piston Assembly n Piston: aluminum, cast steel or cast iron n Wrist pin: machined steel n Connecting rod: forged-steel or cast iron

ME240/107S: Product Dissection Cylinder Head and Crankcase n Crankcase and cylinder block are usually cast iron; however, some have been assembled from welded steel plate n Crankcase and cylinder are usually integral for greater rigidity n How is cylinder head made? Cylinder block Crank case

ME240/107S: Product Dissection Cylinders n How are cylinders fabricated? n Gray cast iron with cylinder bores machined to meet tolerance n Why must a new engine be “broken in”? n Cast iron forms a hard glazed surface when subject to sliding friction n When first assembled, slow speeds and light loads should be used to facilitate forming this protective coating to give long engine life

ME240/107S: Product Dissection Camshaft and Cams n Camshaft and cams are usually made from steel n In your Briggs & Stratton engine, how is camshaft made? How are cams fastened? What does the little metal flapper do?

ME240/107S: Product Dissection Valves n Intake valve: a chromium-nickel alloy n Exhaust valve: a silicon-chrome alloy since it operates at higher temperatures (about 1200 o F)

ME240/107S: Product Dissection Engine Temperature Profiles n What two purposes does engine lubrication serve? n minimize friction n dissipate heat

ME240/107S: Product Dissection How does your engine lubrication system work? n An oil pan seals the engine block, providing a reservoir for lubricating oil for most drivetrain components n How is oil pan fabricated? Oil gallery (for piston) Oil gallery Oil pan Dip stick

ME240/107S: Product Dissection Automotive Fuel Needs x1.1x2.2x2.5 After combustion and friction losses are considered, only about 1/6 of energy available in gasoline is actually used

ME240/107S: Product Dissection Minimizing Losses

ME240/107S: Product Dissection Streamlining to Reduce Air Drag

ME240/107S: Product Dissection Why Internal Combustion? n IC engines were thought to have a bleak future when first invented “You can’t get people to sit over an explosion” “The automobile industry will surely burgeon…but this motor will not be a factor.” -Col. Albert A. Pope, largest automobile manufacturer at the turn of the century

ME240/107S: Product Dissection Why Internal Combustion? n Each group will be assigned either a steam, electric, or internal combustion engine. n Within your group, discuss the pros/cons of your particular type of engine based on what you know and read in “Why IC?” article n At the end of your discussion, be prepared to share your results with the class

ME240/107S: Product Dissection History of IC Engines 1860 Lenoir’s engine (a converted steam engine) combusted natural gas in a double acting piston, using electric ignition

ME240/107S: Product Dissection Stanley Steamer

ME240/107S: Product Dissection History - continued n 1876 Nikolaus Otto patented the 4 cycle engine; it used gaseous fuel n 1882 Gottlieb Daimler, an engineer for Daimler, left to work on his own engine. His 1889 twin cylinder V was the first engine to be produced in quantities. It used liquid fuel and Venturi type carburetor, engine was named “Mercedes” after the daughter of his major distributor n 1893 Rudolf Diesel built successful IC engine which was 26% efficient (double the efficiency of any other engine of its time)

ME240/107S: Product Dissection Complementary Technologies for IC Engine-powered Automobiles n Pneumatic tires (1888, Dunlop) n Cheap liquid fuels (Oil industry born in PA 1859) n Venturi effect carburetor (1892, Willi Maybach) n Variable mechanical transmission (primitive type by Levassor, 1891) n Electric starter (1912 by Kettering of Cadillac)  The real end to electric cars?

ME240/107S: Product Dissection Parts of an IC Engine CROSS SECTION OF OVERHEAD VALVE FOUR CYCLE SI ENGINE Name as many parts as you can Your name:_________________