A short Course in Energy Conversion Session 5 Jim Rauf OLLI Fall 2019 1 Internal Combustion Engines Fire, Smoke and Noise • Piston engines • Otto Cycle-Spark Ignition • Diesel Cycle-Compression Ignition • Brayton Cycle engines • Gas Turbines • Jet engines • Rocket Engines • Liquid Fuel • Solid Fuel • Fire Arms OLLI Fall 2019 2 Internal Combustion Piston Engines • 1680 - Dutch physicist, Christian Huygens • 1862 - Alphonse Beau de Rochas, a French designed (but never built) an internal civil engineer, patented but did not build a combustion engine that was to be fueled four-stroke engine with gunpowder • 1864 - Austrian engineer, Siegfried Marcus, • 1807 - Francois Isaac de Rivaz of built a one-cylinder engine with a crude Switzerland invented an internal carburetor, and attached his engine to a combustion engine that used a mixture of cart for a rocky 500-foot drive hydrogen and oxygen for fuel • Several years later, Marcus designed a vehicle that briefly ran at 10 mph • 1858 - Belgian-born engineer, Jean Joseph Étienne Lenoir invented and patented • Some historians have considered it the forerunner of the modern automobile by (1860) a double-acting, electric spark- being the world's first gasoline-powered ignition internal combustion engine fueled vehicle by coal gas • In 1863, Lenoir attached an improved • 1866 - German engineers, Eugen Langen engine (using petroleum and a primitive and Nikolaus August Otto improved on carburetor) to a three-wheeled wagon that Lenoir's and de Rochas' designs and managed to complete an historic fifty-mile invented a more efficient gas engine road trip OLLI Fall 2019 3 Internal Combustion Piston Engines • 1876 - Nikolaus August Otto invented and later patented a successful four-stroke engine, known as the "Otto cycle" • 1885 - Gottlieb Daimler invented what is often recognized as the prototype of the modern gas engine • It had a vertical cylinder, and with gasoline injected through a carburetor (patented in 1887) 1886 Daimler Motor Carriage • Daimler first built a two-wheeled vehicle the "Reitwagen" (Riding Carriage) with this engine • A year later he built the world's first four-wheeled motor vehicle • 1886 - On January 29, Karl Benz received the first patent for a gas-fueled car 1886 Benz Patent Motor Car OLLI Fall 2019 4 Internal Combustion Piston Engines- Otto Cycle • Spark Ignition Engine (SI) Otto Cycle • In 1867, Nicolaus August Otto, a German engineer, developed the four-stroke "Otto" cycle • He patented it • The Otto Cycle has been widely used in transportation • Automobiles • Trucks • Boats • Aircraft http://www.animatedengines.com/otto.html • It uses gasoline for fuel • The fuel-air mixture is throttled and is ignited by electrically by a spark plug OLLI Fall 2019 5 Internal Combustion Piston Engines -Otto Cycle Ideal Otto Cycle Actual Otto Cycle OLLI Fall 2019 6 Internal Combustion Piston Engines- Otto Cycle • 1925-1926 lightweight, air-cooled radial • The R-4360 had a Displacement of engines were introduced 4,362.50 in³ • Revolutionized aviation by making bigger, • Initial models developed 3,000 HP final faster planes possible models delivered 4,300 hp using two large turbochargers in addition to the • The final development of the air cooled supercharger radial aircraft IC engine: • They weighed 3,482 to 3,870 lbs • Pratt &Whitney R-4360 a 28-cylinder four- row radial engine • Power/weight ratio of 1.11 hp/lb matched by very few engines • 18,697 were built between 1944 and 1955 • Applications included: • Boeing C-97 • Douglas C-124 • Fairchild C-119 • Boeing B-50 • Consolidated B-36 bombers • Boeing 377 Stratocruiser OLLI Fall 2019 7 Internal Combustion Piston Engines- Atkinson Cycle • Atkinson cycle is a modified Otto cycle engine in which the intake valve is held open longer than normal to allow a reverse flow of intake air into the intake manifold • The effective compression ratio is reduced but the expansion ratio is unchanged • The goal of the modern Atkinson cycle is to allow the pressure in the combustion chamber at the end of the power stroke to be equal to atmospheric pressure • All the available energy has been obtained from the combustion process • A number of hybrid automobiles used the Atkinson cycle OLLI Fall 2019 8 Internal Combustion Piston Engines- Atkinson Cycle • Atkinson cycle is a modified Otto cycle engine in which the intake valve is held open longer than normal to allow a reverse flow of intake air into the intake manifold • The effective compression ratio is reduced but the expansion ratio is unchanged • The goal of the modern Atkinson cycle is to allow the pressure in the combustion chamber at the end of the power stroke to be equal to atmospheric pressure • All the available energy has been obtained from the combustion process • The disadvantage versus the Otto cycle is reduced power density • A number of hybrid automobiles used the Atkinson cycle • A smaller portion of the compression stroke being devoted to compressing the intake air, an Atkinson cycle engine does not take in as much air as would a similarly designed and sized Otto cycle engine OLLI Fall 2019 9 Internal Combustion Piston Engines –Diesel Cycle • Compression Ignition Engine (CI) No spark plug Diesel Cycle • The Diesel Engine came about in 1892 by German engineer, Rudolph Diesel • Uses diesel fuel (kerosene) • Fuel injected into cylinder • Air not throttled • Fuel-air mixture is auto- ignited due to high temperature of fuel-air mixture • Generally lower speeds than Diesel engine SI engine • Higher efficiency than SI Diesel cycle is widely used in transportation engine and stationary applications • Trucks • Ships • Electric generation OLLI Fall 2019 10 Internal Combustion Piston Engines –Diesel Cycle Ideal Diesel Cycle Actual Diesel Cycle Modern passenger car diesel engines may have efficiency of up to 43% Engines in large trucks, and buses can have peak efficiencies around 45% Large two stroke ship diesel engines have achieved efficiency up to 55% OLLI Fall 2019 11 Internal Combustion Piston Engines SI and CI Engine Comparison Diesel cycle engines tend to have higher torque, lowe power and lower fuel consumption than Otto cycle engines OLLI Fall 2019 12 Internal Combustion Piston Engine Comparison • 1929 Duesenberg Model J • 265 hp • 420 cu in (0.63 hp/cu in) • Straight 8 cylinder • DOHC • 4 valves/cylinder • 5.7:1 CR • 2019 Chevrolet Corvette • 455 hp • 378 cu in 1.2 hp/cu in) • V 8 cylinder • OHV • 2 valves/cylinder • 11.5 : 1 CR OLLI Fall 2019 13 Internal Combustion Piston Engine Comparison 1908-1927 Model T 2019 Mustang Configuration I-4 I-4 Fuel delivery Carburetor Direct Injection Turbo charged Block and Head Cast Iron Aluminum Displacement 177 cu in 138 cu in Bore/Stroke 3.75/4.00 in 3.45/3.70 in Compression ratio 3.98:1 9.5:1 Valvetrain 2 valves/cylinder 4 valves/cylinder Cam in block DOHC Side valve(flat head) Twin variable cam timing Ignition Ditributor less-coil on plug Horsepower 20 HP @ 1500 RPM 310 HP @ 5500 RPM Torque 83 ft lb @900 RPM 350 ft lb @ 3000 RPM MPG 13-21 mpg 21-31 mpg Top speed 45 mph 145 mph OLLI Fall 2019 14 Two Stroke Internal Combustion Engine OLLI Fall 2019 15 Increasing the Power Output from Piston IC engines • Increase the compression ratio of the • Supercharger engine • Air pump driven mechanically from • CR=Volume of cylinder/volume of the engine by belts, chains or gears combustion chamber • Increase RPM of the engine • Power is work/time • Reduce pressure losses in the intake and exhaust paths • Larger valves • Soother flow passages • Reduced exhaust back pressure • Increase the mass of air in the cylinder – allows increased amount of fuel to be burned –more energy converted Centrifugal supercharger • Increase the displacement of the engine- larger pistons/longer stroke • Pump more air into cylinders • Supercharger • Turbocharger OLLI Fall 2019 16 Increasing the Power Output from Piston IC engines • Turbocharger is a centrifugal compressor driven by a small gas turbine that uses the piston engine to generate the hot gases to drive the turbine • Turbo chargers first used on airplane engines to increase power at high altitude ( air is less dense at altitude) • Turbocharger • Pumps air into cylinders • Driven by exhaust gases from engine • Uses some of the energy in the engine’s exhaust gases • No mechanical connection with engine OLLI Fall 2019 17 Internal Combustion Engines -Brayton Cycle • In 1872 George Brayton patented an internal combustion stationary engine known as Brayton's Ready Motor • The engine had one cylinder for compression, a receiver reservoir, and a separate power cylinder in which the products of combustion expanded for the power stroke. • The significant difference is that the two cylinders are arranged so that the fuel/air mixture burns progressively at constant pressure as it is transferred from the compressor cylinder and reservoir to the working cylinder • Constant pressure combustion • The constant pressure combustion gas turbine engine is referred to as the Brayton Cycle Engine OLLI Fall 2019 18 Internal Combustion Engines -Brayton Cycle • Brayton cycle is used to describe several configurations of gas turbine engines and jet engines • Stationary gas turbine engines-shaft power • Gas turbine engines used in transportation-shaft power • Turbojet engines-jet exhaust • Turbo fan jet engines-fan and jet exhaust OLLI Fall 2019 19 Gas Turbine Components • Inlet • Directs air into the compressor • Compressor • Increases pressure (and temperature) of the air • Combustor • Fuel injected into air leaving the compressor is burned