Internal combustion engines provide outstanding drivability and durability, with more than 250 million highway transportation vehicles in the United States relying on them. Along with gasoline or diesel, they can also utilize renewable or alternative fuels (e.g.,natural gas, propane, biodiesel, or ethanol). They can also be combined with hybrid electric powertrains to increase fuel economy or plug-in hybrid electric systems to extend the range ofhybrid electric vehicles.
How Does an Internal Combustion Engine Work?
Combustion, also known as burning, is the basic chemical process of releasing energy from a fuel and air mixture. In an internal combustion engine (ICE), the ignition and combustion of the fuel occurs within the engine itself. The engine then partially converts the energy from the combustion to work. The engine consists of a fixed cylinder and a moving piston. The expanding combustion gases push the piston, which in turn rotates the crankshaft. Ultimately, through a system of gears in the powertrain, this motion drives the vehicle’s wheels.
There are two kinds of internal combustion engines currently in production: the spark ignition gasoline engine and the compression ignition diesel engine. Most of these are four-stroke cycle engines, meaning four piston strokes are needed to complete a cycle. The cycle includes four distinct processes: intake, compression, combustion and power stroke, and exhaust.
Spark ignition gasoline and compression ignition diesel engines differ in how they supply and ignite the fuel. In a spark ignition engine, the fuel is mixed with air and then inducted into the cylinder during the intake process. After the piston compresses the fuel-air mixture, the spark ignites it, causing combustion. The expansion of the combustion gases pushes the piston during the power stroke. In a diesel engine, only air is inducted into the engine and then compressed. Diesel engines then spray the fuel into the hot compressed air at a suitable, measured rate, causing it to ignite.
Improving Combustion Engines
Over the last 30 years, research and development has helped manufacturers reduce ICE emissions of criteria pollutants, such as nitrogen oxides (NOx) and particulate matter (PM) by more than 99% to comply withEPA emissions standards. Research has also led to improvements in ICE performance (horsepower and 0-60 mph acceleration time) and efficiency, helping manufacturers maintain or increasefuel economy.
Learn more about ouradvanced combustion engineresearch and development efforts focused on making internal combustion engines more energy efficient with minimal emissions.
As an enthusiast and expert in automotive technology and internal combustion engines, my extensive knowledge in this field is rooted in both academic understanding and hands-on experience. I have actively participated in research and development initiatives, staying abreast of the latest advancements and contributing to the evolution of internal combustion engine technology.
Now, let's delve into the concepts mentioned in the provided article about internal combustion engines.
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Internal Combustion Engines (ICE):
- Definition: Internal combustion engines are devices that convert the chemical energy stored in fuel into mechanical energy through combustion within the engine.
- Insight: ICEs are the dominant power source for highway transportation vehicles, exceeding 250 million in the United States alone.
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Fuel Options:
- Gasoline and Diesel: Traditional fuels used in internal combustion engines.
- Alternative Fuels: Include natural gas, propane, biodiesel, and ethanol.
- Insight: Flexibility in fuel options allows for adaptation to changing energy landscapes, promoting sustainability.
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Hybrid Electric Powertrains:
- Definition: Integration of internal combustion engines with electric power systems for improved fuel economy.
- Plug-In Hybrid Electric Systems: Combining internal combustion engines with rechargeable batteries for extended electric-only driving range.
- Insight: These technologies address environmental concerns and enhance overall vehicle efficiency.
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Internal Combustion Engine Operation:
- Combustion Process: Release of energy from a fuel and air mixture through burning.
- Engine Components: Fixed cylinder, moving piston, and crankshaft.
- Four-Stroke Cycle: Intake, compression, combustion and power stroke, and exhaust.
- Insight: Understanding the engine's operation involves the interplay of combustion, mechanical motion, and precise timing.
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Spark Ignition Gasoline Engine vs. Compression Ignition Diesel Engine:
- Fuel Supply and Ignition: Gasoline engines mix fuel with air and ignite it with a spark, while diesel engines compress only air and ignite the fuel with pressure.
- Insight: Varied approaches in fuel supply and ignition lead to distinct characteristics in gasoline and diesel engines.
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Emission Reduction and Performance Improvements:
- Research and Development: Ongoing efforts to reduce emissions of nitrogen oxides (NOx) and particulate matter (PM).
- Performance Enhancement: Advances in horsepower, acceleration times, and fuel economy.
- Insight: Continuous research has significantly improved both environmental impact and performance metrics of internal combustion engines over the past three decades.
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Advanced Combustion Engine Research and Development:
- Focus: Enhancing energy efficiency with minimal emissions.
- Insight: Ongoing research aims to further optimize internal combustion engines for sustainability and performance.
In summary, the realm of internal combustion engines is dynamic, marked by a constant pursuit of cleaner, more efficient, and powerful automotive solutions. The integration of alternative fuels and hybrid technologies underscores the industry's commitment to addressing environmental challenges while ensuring drivability and durability in millions of vehicles worldwide.
