Internal combustion engine
In 1876, German engineer Nicolaus Otto patented the compressed charge four-cycle engine. This invention marked a turning point in mechanical history. Before this moment, inventors like John Barber and Thomas Mead had created gas turbines and engines in the late 1700s. Robert Street built an internal combustion engine using liquid fuel in 1794. Nicéphore Niépce ran a prototype called the Pyréolophore on the Saône river in France during 1807. Napoleon Bonaparte granted a patent for that boat-powered device.
Rudolf Diesel developed the first compression ignition engine in 1892. Karl Benz began commercial production of motor vehicles with a three-wheeled design in 1886. George Brayton invented the first commercial liquid-fueled engine in 1872. These early machines relied on simple atmospheric pressure or basic compression to move pistons. The Great Seal Patent Office issued patent number 1655 to Eugenio Barsanti and Felice Matteucci in 1857. Their work obtained motive power from gas explosions across multiple European nations including Belgium and Piedmont between 1857 and 1859.
A four-stroke engine completes intake, compression, power, and exhaust strokes over two crankshaft revolutions. Top dead center marks where the piston sits nearest to valves while bottom dead center places it furthest away. During the compression stroke, both valves close as the piston moves upward reducing chamber volume. Pressure, temperature, and density increase within the cylinder according to ideal gas law approximations. Ignition begins just before reaching top dead center via spark plugs or fuel injection sprays.
Two-stroke engines finish all four processes in only one revolution. Scavenging occurs around seventy-five degrees before bottom dead center when exhaust ports open. Intake ports follow shortly after allowing fresh charge to displace burned gases. Loop scavenging systems create a gas current that sweeps the entire cylinder before reaching the exhaust port. Uniflow designs use separate intake and exhaust valves for better efficiency. SAE news published in the 2010s stated loop scavenging performs better under any circumstance compared to uniflow methods. The Wankel rotary engine operates with three power strokes per rotor revolution despite rotating once per shaft cycle.
Engine blocks typically consist of cast iron or aluminum materials offering wear resistance and low cost. Cylinder liners may be made from steel or coated with nikasil or alusil layers. Pistons slide continuously inside cylinders sealing high pressure combustion products. Aluminum pistons appear in smaller engines while cast iron or forged steel serves larger applications. The piston crown sits flat or concave at its top surface transferring force through an integral web structure to a gudgeon pin.
Connecting rods link pistons to offset crankshaft sections called crankpins. Big ends attach via detachable half-caps secured by removable bolts. Main bearings hold the crankshaft relative to the block allowing rotation. Bulkheads form half of every main bearing while caps complete the other half. A sump collects falling oil during normal operation cycling it back into the system. Water jackets circulate cooling fluid around cylinder passages in water-cooled designs. Air-cooled engines feature fins protruding away from blocks transferring heat directly to surrounding air.
Hydrocarbon fuels like gasoline, diesel fuel, and natural gas power most modern internal combustion engines. Biodiesel replaces petrodiesel using triglycerides derived from crops such as soybean oil. Ethanol and ETBE produced from bioethanol run spark ignition engines. Rudolf Diesel used peanut oil to operate his compression ignition engines as early as 1900. Hydrogen remains rarely used but can be obtained from fossil fuels or renewable energy sources.
Nitrous oxide adds extra gasoline for tactical aircraft and specially equipped cars enabling short bursts of added power. Compressed oxygen appears inside Japanese Type 93 torpedoes alongside compressed air. Liquid hydrogen possesses extremely low density requiring extensive insulation despite higher specific energy than gasoline. Woodgas comes from onboard wood gasifiers converting solid wood into usable fuel. Powdered magnesium injection cycles have seen experimental use alongside explosive materials. Most engines depend on atmospheric oxygen as an oxidizer eliminating storage needs within vehicles.
Reciprocating piston engines dominate land and water vehicle propulsion including automobiles motorcycles ships and locomotives. Rotary Wankel designs appear in some automobiles aircraft and unmanned aerial vehicles. Jet engines compress air through fan blades then mix it with JP fuel before igniting. Turbofan efficiency reaches forty-eight percent operating at high altitudes where aviation demands exist. Marine diesel engines like the Wärtsilä-Sulzer RTA96-C achieve thermal efficiencies exceeding fifty percent.
Combined cycle power plants utilize exhaust heat to boil superheated water steam running additional turbines. These systems reach efficiencies between fifty and sixty percent extracting more energy than combustion alone. Small two-stroke single cylinder gasoline engines power lawnmowers string trimmers chainsaws leaf blowers pressure washers radio controlled cars snowmobiles jet skis outboard motors mopeds and motorcycles. Large container ships rely on turbocharged two-stroke diesels producing brake powers around four point five megawatts or six thousand horsepower. The EMD SD90MAC class of locomotives exemplifies these massive reciprocating internal combustion engines.
Theoretical thermal efficiency cannot exceed Carnot cycle limits determined by lower and upper operating temperatures. Real world applications introduce complexities reducing overall performance below idealized calculations. Most engines retain average efficiency around eighteen to twenty percent despite turbocharger aids. Formula One engines have boosted thermal efficiency past fifty percent using latest technologies. Auto-ignition resistance measured as octane rating determines allowable peak cylinder temperature before spontaneous ignition occurs.
Brake specific fuel consumption measures mass flow rate divided by power produced for shaft engines. Thrust specific fuel consumption calculates propellant needed generating impulses measured in pound force-hour or grams per kilonewton-second for jet engines. Vehicle fuel economy appears as miles per gallon or liters per one hundred kilometers. Higher compression ratios increase engine efficiency but require advanced fuel technology and management systems. Charles Kettering developed lead additives allowing higher compression ratios until abandoned from automotive use during the 1970s due to poisoning concerns.
Incomplete combustion produces carbon dioxide water soot called particulate matter nitrogen oxides sulfur and uncombusted hydrocarbons. Inhaling particulate matter causes asthma lung cancer cardiovascular issues and premature death according to human and animal studies. Catalytic converters reduce exhaust emissions flowing through tailpipes after collecting gases from cylinders. Mufflers dampen noise generated by expanding combustion products exiting the system.
Regulatory standards limit air pollution consequences from reciprocating internal combustion engines. Two-stroke gasoline engines were banned for road vehicles within the United States due to excessive polluting exhaust gases. Off-road motorcycles remain often two-stroke but rarely achieve road legal status despite thousands of lawn maintenance units still operating. Modern diesel engines employ glowplugs pre-heating combustion chambers reducing no-start conditions in cold weather. Electronic engine control units adjust combustion processes increasing efficiency while lowering emission outputs across new engine designs.
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Common questions
When did Nicolaus Otto patent the four-cycle engine?
German engineer Nicolaus Otto patented the compressed charge four-cycle engine in 1876. This invention marked a turning point in mechanical history.
Who invented the first compression ignition engine and when was it developed?
Rudolf Diesel developed the first compression ignition engine in 1892. His work established the foundation for modern diesel technology used across various industries today.
What materials are typically used to construct engine blocks?
Engine blocks typically consist of cast iron or aluminum materials offering wear resistance and low cost. Cylinder liners may be made from steel or coated with nikasil or alusil layers.
How does Rudolf Diesel use peanut oil in his engines?
Rudolf Diesel used peanut oil to operate his compression ignition engines as early as 1900. This historical fact demonstrates the versatility of biofuels in early internal combustion applications.
Why were two-stroke gasoline engines banned for road vehicles in the United States?
Two-stroke gasoline engines were banned for road vehicles within the United States due to excessive polluting exhaust gases. Modern regulations prioritize emission reductions over older engine designs that fail to meet current standards.