What is the fundamental definition of an internal combustion engine (ICE)?

An internal combustion engine (ICE) is a type of heat engine where the combustion of a fuel occurs within a combustion chamber that is an integral part of the working fluid's flow circuit. The expansion of high-temperature and high-pressure gases produced by this combustion directly applies force to engine components, converting chemical energy into kinetic energy.

How does an internal combustion engine convert chemical energy into mechanical motion?

In an ICE, the combustion of fuel within a chamber creates high-temperature and high-pressure gases. The expansion of these gases exerts force on moving parts, such as pistons in a piston engine or turbine blades in a gas turbine. This force moves the components over a distance, transforming the chemical energy stored in the fuel into kinetic energy that powers the attached machinery.

When were the first commercially successful internal combustion engines invented, and who designed the first modern ICE?

The first commercially successful internal combustion engines were developed in the mid-19th century. The first modern internal combustion engine, known as the Otto engine, was designed in 1876 by German engineer Nicolaus Otto.

What are the two main categories of internal combustion engines based on their combustion process?

Internal combustion engines are primarily categorized by their combustion process: those with intermittent combustion, such as the familiar two-stroke and four-stroke piston engines and the Wankel rotary engine, and those with continuous combustion, which include gas turbines, jet engines, and most rocket engines.

What are the most common applications for internal combustion engines?

While ICEs are used in many stationary applications, they are most commonly found in mobile applications. They serve as the primary power source for vehicles like cars, aircraft, and boats, and are also used in various other forms of transportation and machinery.

What types of fuels typically power internal combustion engines?

Internal combustion engines are typically powered by hydrocarbon-based fuels, including natural gas, gasoline, diesel fuel, and ethanol. Renewable fuels like biodiesel and bioethanol can also be used, and historically, inventors like Rudolf Diesel experimented with vegetable oils.

Who were some of the early pioneers in the development of internal combustion engines, and what were their contributions?

Several individuals contributed to early ICE development: John Barber developed the gas turbine in 1791. Thomas Mead patented a gas engine in 1794. Robert Street patented an ICE that used liquid fuel in 1794. John Stevens built the first American ICE in 1798. Nicéphore and Claude Niépce created the Pyréolophore engine in 1807, and François Isaac de Rivaz invented a hydrogen-based ICE in 1807, later fitting it to a vehicle.

What is the distinction between an 'engine' and a 'motor' in traditional terminology?

Historically, the word 'engine' referred to any piece of machinery, a sense still seen in terms like 'siege engine.' A 'motor' is specifically a machine that produces mechanical power. While electric motors are not typically called engines, combustion engines are often referred to as 'motors.' An 'electric engine' usually refers to an electric locomotive.

How are reciprocating internal combustion engines classified by the number of strokes?

Reciprocating internal combustion engines are classified by the number of strokes a piston makes to complete a power cycle. These include two-stroke engines (like the Clerk and Day cycles), four-stroke engines (following the Otto cycle), and six-stroke engines.

What are the two primary methods of ignition used in internal combustion engines?

Internal combustion engines primarily use either spark ignition (SI), where a spark plug ignites the fuel-air mixture, or compression ignition (CI), where the heat generated by compressing the air ignites the injected fuel, as seen in diesel engines.

What are the thermodynamic cycles commonly associated with reciprocating engines, particularly in hybrid vehicles?

Besides the standard Otto and Diesel cycles, reciprocating engines can utilize other thermodynamic cycles, such as the Atkinson cycle and the Miller cycle. These are sometimes found in hybrid vehicles and are noted for their potential fuel efficiency benefits.

What is the basic structure of a reciprocating internal combustion engine?

A reciprocating ICE typically consists of an engine block containing cylinders, pistons that slide within the cylinders, a cylinder head sealing the cylinders, a crankshaft converting linear piston motion to rotation, and a crankcase housing the crankshaft. Cooling passages (water jacket) or fins are also part of the block.

What are the key components within a cylinder head?

The cylinder head seals the top of the cylinder and houses essential components for the combustion process. These include intake and exhaust ports, the associated valves (typically poppet valves), and either a spark plug (for SI engines) or a fuel injector (for CI engines).

Describe the four strokes of a four-stroke internal combustion engine.

A four-stroke engine completes its cycle in four distinct piston movements: 1. **Intake:** The piston moves down, drawing the fuel-air mixture (or air) into the cylinder. 2. **Compression:** The piston moves up, compressing the mixture. 3. **Power:** Ignition occurs, forcing the piston down. 4. **Exhaust:** The piston moves up again, expelling the burnt gases. This cycle requires two full rotations of the crankshaft.

How does a two-stroke engine differ from a four-stroke engine in its cycle?

A two-stroke engine completes its power cycle in just two piston strokes (one crankshaft revolution), combining intake and compression into one stroke, and power and exhaust into the other. This is achieved through port timing controlled by the piston's movement, rather than dedicated valves for each phase like in a four-stroke engine.

What are the main disadvantages of crankcase-scavenged two-stroke engines?

Crankcase-scavenged two-stroke engines often suffer from lower efficiency and higher emissions compared to four-stroke engines. This is partly due to their 'total-loss' lubrication system where oil is burned with fuel, conflicting requirements for efficient scavenging (preventing fresh charge from escaping with exhaust), and the difficulty in completely expelling exhaust gases.

What is the purpose of lubrication in an internal combustion engine?

Lubrication is crucial in ICEs to reduce wear and friction between moving parts, minimize noise, and help dissipate heat. Key components requiring lubrication include the surfaces between pistons and cylinders, crankshaft bearings, connecting rod bearings, and valve gear.

What are the two main types of lubrication systems used in ICEs?

The two primary lubrication systems are splash lubrication, where the crankshaft splashes oil onto components (common in small four-stroke engines), and forced (or pressurized) lubrication. Forced systems use an oil pump to deliver oil through galleries and passages to critical parts, returning it to a reservoir, typically the sump (wet sump) or a separate tank (dry sump).

What are some common cylinder configurations found in reciprocating engines?

Common cylinder configurations include inline (straight) engines, V engines, and flat (boxer) engines. Less common but also used are radial configurations (especially in older aircraft engines), and more unusual designs like W, H, and X configurations.

What is the Brayton cycle, and where is it primarily used?

The Brayton cycle describes the operation of gas turbines and jet engines. It involves continuous combustion where air is compressed, mixed with fuel, combusted, and then expanded through a turbine. Unlike the Otto cycle's constant-volume combustion, the Brayton cycle features constant-pressure combustion.

How does a Wankel engine differ from a conventional piston engine?

A Wankel engine is a type of rotary engine that uses a triangular rotor instead of pistons. This rotor orbits within a specially shaped housing, performing the four phases of the Otto cycle (intake, compression, power, exhaust) in different locations simultaneously. This design eliminates reciprocating parts, leading to a smoother operation and a higher power-to-weight ratio.

What is forced induction in the context of ICEs?

Forced induction is a process that increases an engine's power and efficiency by delivering compressed air to the intake. This is typically achieved using a supercharger (driven by the engine's shaft) or a turbocharger (driven by exhaust gases), which forces more air into the cylinders, allowing for more fuel to be burned.

What are the most common fuels used in modern internal combustion engines?

The most common fuels for modern ICEs are derived from fossil fuels, primarily hydrocarbons like gasoline (petrol) and diesel fuel. Liquefied petroleum gas (LPG) and natural gas are also frequently used.

What is the role of cooling systems in internal combustion engines?

Cooling systems are essential to remove excess heat generated during combustion. This prevents engine failure caused by overheating, which can lead to material stress, warping, and the breakdown of lubrication. Common cooling methods include air cooling and liquid (water) cooling.

How were early ICE vehicles started before the invention of the electric starter?

Before the development of the electric starter by Charles Kettering, early ICE vehicles were typically started using a hand crank or by turning the engine's flywheel. This manual starting method was common until the widespread adoption of electric starters in automobiles.

What are the main measures used to evaluate engine performance?

Engine performance is measured by several key metrics, including energy efficiency, fuel or propellant consumption (e.g., brake specific fuel consumption or thrust specific fuel consumption), power-to-weight ratio, thrust-to-weight ratio, torque curves, and compression or overall pressure ratios.

What is meant by 'parasitic loss' in an internal combustion engine?

Parasitic loss refers to the energy consumed by components within the engine or drivetrain that are necessary for its operation but do not directly contribute to output power. Examples include the oil pump, water pump, piston rings, valve springs, and drivetrain components like transmissions and differentials.

What are the primary air pollutants emitted by internal combustion engines?

Internal combustion engines, particularly those using fossil fuels, emit several key air pollutants due to incomplete combustion. These include carbon dioxide (CO2), a greenhouse gas; particulate matter (soot); nitrogen oxides (NOx); sulfur dioxide (SO2); and carbon monoxide (CO). Other hazardous compounds like benzene can also be produced.

How do nitrogen oxides (NOx) contribute to air pollution?

Nitrogen oxides (NOx) are formed when atmospheric nitrogen reacts with oxygen at high temperatures during combustion. While NOx itself is harmful, it also reacts with volatile organic compounds (VOCs) in the presence of sunlight to form ground-level ozone, a major component of smog that is detrimental to human health and the environment.

What is the significance of carbon dioxide (CO2) emissions from ICEs?

Carbon dioxide (CO2) emissions from the combustion of fossil fuels in ICEs are a major contributor to human-induced climate change. While improving fuel efficiency can reduce CO2 output per distance traveled, the fundamental process of burning carbon-based fuels inherently produces CO2.

What are some methods used to control air pollution from ICEs?

Pollution control measures include exhaust gas recirculation (EGR) to reduce NOx, and catalytic converters which chemically convert harmful exhaust gases like CO, uncombusted hydrocarbons, and NOx into less harmful substances like CO2, water vapor, and nitrogen. Diesel engines may also use diesel particulate filters (DPFs) to capture soot.

What is the role of a catalytic converter in an ICE's exhaust system?

A catalytic converter is a device in the exhaust system that uses catalysts to convert toxic pollutants from engine combustion into less harmful gases. It typically transforms carbon monoxide (CO) into carbon dioxide (CO2), uncombusted hydrocarbons into CO2 and water vapor, and nitrogen oxides (NOx) into nitrogen (N2) and oxygen (O2).

What is the relationship between engine efficiency and CO2 emissions?

Improving an engine's fuel efficiency generally leads to reduced CO2 emissions, as less fuel is burned to produce the same amount of work. However, since most common fuels are carbon-based, any combustion will produce CO2, meaning efficiency improvements reduce, but do not eliminate, these emissions.

What is the purpose of a 'power band' in engine operation?

The 'power band' refers to the range of engine speeds (RPM) where an engine operates most efficiently and produces its optimal power output. Engines are often designed with specific power bands suited to their intended application, such as high RPM for sports cars or lower RPM for heavy-duty trucks.

How is fuel efficiency measured for different types of engines?

For shaft engines (like those in cars or boats), fuel efficiency is often measured by Brake Specific Fuel Consumption (BSFC), which relates fuel consumption rate to power output. For jet engines, Thrust Specific Fuel Consumption (TSFC) is used, measuring propellant needed per unit of thrust.

What are the primary sources of noise pollution from internal combustion engines?

Internal combustion engines contribute significantly to noise pollution through various sources, including the engine's mechanical operation, exhaust noise, and intake noise. Traffic from automobiles and trucks on roads, as well as aircraft engines and rocket launches, are major contributors to environmental noise.

What is 'idling' in the context of ICE operation, and why is it a concern?

Idling occurs when an engine is running but not actively driving a vehicle or machinery, such as when a car is stopped at a traffic light. During idling, the engine continues to consume fuel and emit pollutants, contributing to both fuel waste and air pollution, which is why systems like stop-start technology aim to reduce it.

How is the mass of carbon dioxide produced from burning diesel fuel calculated?

The mass of CO2 produced from burning diesel can be estimated by considering diesel's approximate carbon-to-hydrogen ratio and molar masses. A common calculation involves multiplying the fuel's density (approx. 0.838 kg/L) by its carbon fraction (approx. 12/14) and the ratio of CO2's molar mass (44 g/mol) to carbon's (12 g/mol), yielding roughly 2.63 kg of CO2 per liter of diesel.

What is the difference between a supercharger and a turbocharger in terms of how they operate?

Both superchargers and turbochargers provide forced induction by compressing intake air. However, a supercharger is mechanically driven directly by the engine's crankshaft, while a turbocharger uses a turbine powered by the engine's exhaust gases to drive the compressor, generally resulting in lower parasitic loss.

What are some examples of parasitic loads within an engine's drivetrain?

Parasitic loads in the drivetrain include components like bearings, piston rings, valve springs, oil pumps, transmissions, driveshafts, and differentials. These parts consume engine power through friction and mechanical resistance, reducing the amount of power delivered to the wheels.

How can parasitic loads be reduced to improve engine efficiency?

Parasitic loads can be reduced through careful design choices and modifications. Examples include using dry sump lubrication instead of wet sump, replacing engine-driven fans with electric fans, or using more efficient components throughout the drivetrain to minimize friction and power consumption.

What is the significance of the 'Otto cycle' in gasoline engines?

The Otto cycle is the thermodynamic cycle that most gasoline (spark-ignition) engines follow. It consists of intake, compression, power (combustion), and exhaust strokes, with ignition occurring near the end of the compression stroke, making it fundamental to how these engines operate.

What is the 'Diesel cycle' and how does it differ from the Otto cycle?

The Diesel cycle is characteristic of diesel engines and involves compression ignition. Unlike the Otto cycle where combustion occurs at constant volume, in the Diesel cycle, fuel is injected directly into the cylinder during the compression stroke, leading to combustion that occurs at approximately constant pressure as the piston moves.

What are the main components of a turbofan jet engine?

A turbofan jet engine consists of several key sections: a fan at the front, followed by a compressor, a combustor where fuel is burned, a turbine that drives the compressor, a mixer (for bypass air), and a nozzle to expel exhaust gases and generate thrust.

What is the primary function of a gas turbine?

A gas turbine is a rotary engine that compresses air, mixes it with fuel, and combusts the mixture to spin a turbine. This turbine powers the compressor and also provides useful work output, typically through a rotating shaft, making it suitable for power generation and propulsion.

What is the main advantage of a Wankel engine's design compared to piston engines?

The Wankel engine's primary advantage lies in its rotary design, which eliminates the reciprocating motion of pistons. This results in smoother operation, fewer vibrations, a more compact size, and a higher power-to-weight ratio compared to conventional piston engines.

What role do hydrogen and biofuels play as potential fuels for ICEs?

Hydrogen and biofuels like ethanol and biodiesel are explored as alternatives to fossil fuels for ICEs. Hydrogen offers zero-emission combustion (producing only water), while biofuels can reduce reliance on fossil fuels and potentially lower net carbon emissions, though challenges remain in production and infrastructure.

What is the significance of 'uniflow scavenging' in certain engine designs?

Uniflow scavenging is a process used in some two-stroke engines, particularly blower-scavenged diesel engines, where the intake and exhaust ports or valves are positioned at opposite ends of the cylinder. This design allows for more efficient expulsion of exhaust gases and intake of fresh charge, contributing to higher thermal efficiencies, especially in large marine diesel engines.

Internal Combustion Engine Wiki: The Engine's Heartbeat: An ICE Deep Dive

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History

Early Innovations

The development of the internal combustion engine spans centuries, with contributions from numerous inventors. Early milestones include John Barber's 1791 gas turbine and Robert Street's 1794 engine utilizing liquid fuel. Jean Joseph Etienne Lenoir patented the first commercially successful gas-fired ICE in 1860. Nicolaus Otto, working with Gottlieb Daimler and Wilhelm Maybach, patented the compressed charge, four-cycle engine in 1876, a foundational design.

Liquid Fuel and Vehicles

Karl Benz patented a reliable two-stroke gasoline engine in 1879 and began the first commercial production of motor vehicles with ICEs in 1886. Rudolf Diesel developed the compression ignition engine in 1892, initially experimenting with vegetable oils. The 20th century saw rapid advancements, including Robert Goddard's 1926 liquid-fueled rocket and the 1939 Heinkel He 178, the world's first jet aircraft.

Evolution of Cycles

Early ICEs often lacked compression, leading to inefficiency. Otto's cycle became dominant, but variations like the Atkinson and Miller cycles emerged for improved fuel efficiency, particularly in hybrid vehicles. Continuous combustion engines, such as gas turbines and jet engines, represent another major class, utilizing different thermodynamic principles.

Etymology

Engine vs. Motor

The term "engine" historically referred to any machinery, while "motor" specifically denotes a machine producing power. Traditionally, electric motors are not called engines, but combustion engines are often referred to as "motors." An "electric engine" typically means an electric locomotive. In marine contexts, engines installed in the hull are "engines," while those mounted externally are "motors."

Applications

Land and Sea Transport

Reciprocating piston engines are the primary power source for most land and water vehicles, including automobiles, motorcycles, ships, and locomotives. Rotary engines like the Wankel are used in some cars, aircraft, and motorcycles. These are collectively known as internal-combustion-engine vehicles (ICEVs).

Aviation and Power Generation

High power-to-weight ratios make ICEs suitable for aircraft, often using reciprocating engines or jet/turboshaft engines (a type of turbine). Gas turbines are crucial for power generation, driving large electric generators in power plants, often in combined-cycle configurations for higher efficiency.

Small Machinery

Smaller engines, typically two-stroke gasoline types, power lawnmowers, chainsaws, leaf blowers, pressure washers, and other light machinery. They are valued for their simplicity and power-to-weight ratio, though often less efficient and more polluting than larger counterparts.

Classification

By Cycle and Ignition

Engines are classified by their operating cycle (e.g., two-stroke, four-stroke, six-stroke) and ignition type. Spark Ignition (SI) engines use a spark plug, while Compression Ignition (CI) engines (diesel) rely on the heat generated during compression. Specialized cycles like Atkinson and Miller are used for enhanced fuel efficiency.

Reciprocating vs. Rotary

The most common type is the reciprocating piston engine. Rotary engines, like the Wankel, use a rotor instead of pistons, offering a different mechanical design and often a higher power-to-weight ratio. Continuous combustion engines, such as gas turbines and jet engines, operate differently by maintaining a constant combustion process.

Continuous Combustion

Gas turbines and jet engines operate on continuous combustion principles. They compress air, mix it with fuel in a combustor, and use the expanding hot gases to drive a turbine or generate thrust. These are distinct from the intermittent combustion found in piston engines.

Reciprocating Engines

Core Structure

The foundation is the engine block, typically cast iron or aluminum, housing cylinders. Pistons move within cylinders, connected via connecting rods to a crankshaft, converting linear motion to rotation. The cylinder head seals the cylinders and contains valves (intake/exhaust) and ignition/fuel systems (spark plug or injector). Lubrication systems (splash or forced) and cooling systems (air or liquid) are essential.

Four-Stroke Cycle

The dominant cycle involves four piston strokes per two crankshaft revolutions: Intake (drawing in air/fuel), Compression (increasing pressure/temperature), Power (combustion forcing the piston down), and Exhaust (expelling burnt gases). Ignition timing is critical and advances with engine speed.

Intake: Piston moves down, intake valve opens, drawing in the charge.
Compression: Both valves close, piston moves up, compressing the charge. Ignition occurs near Top Dead Center (TDC).
Power: Combustion gases expand, pushing the piston down, generating power.
Exhaust: Exhaust valve opens, piston moves up, expelling gases.

Two-Stroke Cycle

Completes the power cycle in two strokes (one crankshaft revolution). It combines intake/exhaust with compression/power strokes using ports in the cylinder wall, often managed by the piston's movement. Crankcase-scavenged two-strokes are mechanically simpler but less efficient and more polluting due to oil burning and charge loss.

Operation: Combines intake, compression, power, and exhaust phases into two strokes. Uses ports instead of valves in some designs. Crankcase acts as a pump. Lubrication is typically mixed with fuel (petrol-oil).

Challenges: Lower thermal efficiency, higher emissions (unburnt fuel, oil), potential for charge loss during scavenging.

Advantages: Simpler construction, higher power-to-weight ratio.

Combustion Turbines

Jet Engines

Jet engines (turbojets, turbofans, turboprops) use continuous combustion. Air is compressed, mixed with fuel, ignited, and expelled through a nozzle or turbine to create thrust. Modern turbofans achieve high efficiencies (up to 48%). Key components include the fan, compressor, combustor, turbine, mixer, and nozzle.

Gas Turbines

Similar to jet engines but optimized to drive a shaft, producing mechanical power. They consist of a compressor, combustion chamber, and turbine. About two-thirds of the work drives the compressor, with the remaining one-third available as output. Combined cycle plants achieve efficiencies exceeding 60%.

Brayton Cycle

Gas turbines operate on the Brayton cycle, characterized by continuous combustion at constant pressure. This contrasts with the Otto cycle's constant volume combustion. The cycle involves compression, combustion, and expansion stages.

Wankel Engines

Rotary Design

The Wankel engine, or rotary engine, replaces pistons with a triangular rotor inside an epitrochoid-shaped housing. It follows the Otto cycle phases (intake, compression, power, exhaust) occurring simultaneously in different locations around the rotor. The rotor orbits the eccentric shaft, resulting in three power pulses per rotor revolution, but only one per eccentric shaft revolution.

Advantages

Wankel engines offer a higher power-to-weight ratio and smoother operation compared to piston engines due to the absence of reciprocating parts. They have been notably used in Mazda vehicles (RX-7, RX-8) and are also found in unmanned aerial vehicles where size and weight are critical.

Forced Induction

Increasing Air Density

Forced induction uses a compressor (driven by a supercharger or exhaust-powered turbocharger) to increase the pressure and density of intake air. This allows more fuel to be burned, significantly boosting engine power and efficiency, especially crucial for aviation engines operating at high altitudes.

Superchargers vs. Turbochargers

Superchargers are mechanically driven by the engine's crankshaft, providing boost directly related to engine speed. Turbochargers use exhaust gases to spin a turbine, which drives the compressor, offering efficiency benefits but potentially introducing lag.

Fuels and Oxidizers

Common Fuels

Most modern ICEs use hydrocarbon fuels derived from fossil fuels, including gasoline (petrol), diesel fuel, natural gas, and LPG (propane). These fuels store significant chemical energy released through combustion with an oxidizer, typically atmospheric oxygen.

Alternative Fuels

Biofuels like ethanol and biodiesel, along with hydrogen, wood gas, and biogas, can also power ICEs, often requiring engine modifications. Hydrogen offers zero carbon emissions during combustion but faces storage challenges. The choice of fuel impacts efficiency, emissions, and engine design.

Oxidizers

While atmospheric air is the most common oxidizer, special applications use compressed air, pure oxygen (liquid or gaseous), nitrous oxide, or hydrogen peroxide. Rockets, for instance, often utilize liquid oxygen as a powerful oxidizer.

Cooling Systems

Preventing Overheating

Cooling is vital to prevent engine failure from excessive heat. Common methods include air cooling (using fins) and liquid cooling (circulating coolant through passages, often called a water jacket). Many engines also employ oil coolers. In some high-performance applications, fuel itself can be used as a coolant.

Starting Mechanisms

Ignition and Rotation

ICEs require initial rotation to start their cycles. This is achieved through various methods: hand cranks (early automobiles), electric starters (most modern vehicles), kick starters (motorcycles), pull-rope mechanisms (small engines), or compressed air starters (large diesel engines).

Ignition Systems

Spark Ignition (SI) engines rely on spark plugs energized by magnetos or battery-based systems (like capacitor discharge ignition - CDI). Compression Ignition (CI) engines rely solely on the heat from high compression, sometimes aided by glow plugs for cold starts.

Performance Measures

Efficiency and Power

Engine performance is measured by energy efficiency (converting fuel energy to work), fuel consumption (e.g., Brake Specific Fuel Consumption - BSFC), power-to-weight ratio, and torque/thrust characteristics. Theoretical efficiencies are limited by thermodynamic cycles (like Carnot), while practical efficiencies are affected by friction, heat loss, and operating conditions.

Fuel Economy

Vehicle fuel economy is measured in miles per gallon (MPG) or liters per 100 kilometers (L/100km). While modern engines incorporate efficiency aids, average thermal efficiency is often around 18-20%, though high-performance and specialized engines can exceed 50%.

Pollution Impact

Air Pollutants

Incomplete combustion releases pollutants like particulate matter (PM), nitrogen oxides (NOx), carbon monoxide (CO), unburnt hydrocarbons, and sulfur dioxide (SO2) if sulfur is present in the fuel. NOx contributes to ground-level ozone formation, while SO2 contributes to acid rain.

Climate Change

The combustion of fossil fuels releases carbon dioxide (CO2), a primary greenhouse gas contributing to climate change. Reducing CO2 emissions involves improving engine efficiency and transitioning to sustainable fuels or alternative powertrains like electric motors.

Noise Pollution

ICEs are significant contributors to noise pollution through exhaust noise, mechanical operation, and intake noise. Aircraft and rocket engines generate particularly intense noise levels.

Idling Emissions

Engines consume fuel and emit pollutants even when idling. Stop-start systems are implemented in many vehicles to reduce idling time and associated emissions.

CO2 Formation

Calculating Emissions

The mass of CO2 produced per liter of fuel can be estimated based on the fuel's carbon content and the stoichiometry of combustion. For diesel (approx. 86% carbon by weight), burning 1 liter produces roughly 2.63 kg of CO2. This calculation highlights the significant carbon footprint of fossil fuel combustion.

Combustion Chemistry

Complete combustion of hydrocarbons yields CO2 and water. Incomplete combustion, due to insufficient oxygen or flame quenching, produces CO, unburnt hydrocarbons, and soot. Increasing air supply reduces incomplete combustion but can increase NOx formation.

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The Engine's Heartbeat

💡 Dive in with Flashcard Learning! 💡

History 📜

💡 Early Innovations

🚗 Liquid Fuel and Vehicles

⚙️ Evolution of Cycles

Etymology 🏷️

🤔 Engine vs. Motor

Applications 🚀

🌍 Land and Sea Transport

✈️ Aviation and Power Generation

🛠️ Small Machinery

Classification 🗂️

🔄 By Cycle and Ignition

⚙️ Reciprocating vs. Rotary

🔥 Continuous Combustion

Reciprocating Engines ⚙️

🔩 Core Structure

💨 Four-Stroke Cycle

⚡ Two-Stroke Cycle

Combustion Turbines 🌪️

✈️ Jet Engines

⚡ Gas Turbines

📊 Brayton Cycle

Wankel Engines 🔄

⚙️ Rotary Design

🚗 Advantages

Forced Induction 💨

⬆️ Increasing Air Density

🚗 Superchargers vs. Turbochargers

Fuels and Oxidizers ⛽

⛽ Common Fuels

🌿 Alternative Fuels

💨 Oxidizers

Cooling Systems ❄️

🌡️ Preventing Overheating

Starting Mechanisms ⚡

🔑 Ignition and Rotation

💡 Ignition Systems

Performance Measures 📊

📈 Efficiency and Power

⛽ Fuel Economy

Pollution Impact 🏭

💨 Air Pollutants

🌍 Climate Change

🔊 Noise Pollution

🚦 Idling Emissions

CO2 Formation 💨

⚖️ Calculating Emissions

🔬 Combustion Chemistry

Teacher's Corner 🧑‍🏫

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Disclaimer ⚠️

📜 Important Notice

Dive in with Flashcard Learning!

History

Early Innovations

Liquid Fuel and Vehicles

Evolution of Cycles

Etymology

Engine vs. Motor

Applications

Land and Sea Transport

Aviation and Power Generation

Small Machinery

Classification

By Cycle and Ignition

Reciprocating vs. Rotary

Continuous Combustion

Reciprocating Engines

Core Structure

Four-Stroke Cycle

Two-Stroke Cycle

Combustion Turbines

Jet Engines

Gas Turbines

Brayton Cycle

Wankel Engines

Rotary Design

Advantages

Forced Induction

Increasing Air Density

Superchargers vs. Turbochargers

Fuels and Oxidizers

Common Fuels

Alternative Fuels

Oxidizers

Cooling Systems

Preventing Overheating

Starting Mechanisms

Ignition and Rotation

Ignition Systems

Performance Measures

Efficiency and Power

Fuel Economy

Pollution Impact

Air Pollutants

Climate Change

Noise Pollution

Idling Emissions

CO2 Formation

Calculating Emissions

Combustion Chemistry

Teacher's Corner

True or False?

Test Your Knowledge!

Gamer's Corner

Discover other topics to study!

References

Feedback & Support

Disclaimer

Important Notice