15 Questions
What is an IC Engine?
An IC Engine is a machine that transforms the energy released from the combustion of fuel into mechanical energy.
What type of engines are commonly used in passenger cars, motorcycles, and small aircraft?
Spark Ignition (SI) Engines
Two-stroke engines have valves.
False
Match engine components with their proper sequence in the four-stroke cycle:
Intake = 1 Compression = 2 Power = 3 Exhaust = 4
In the four-stroke cycle engine, the piston completes _____ strokes to complete one cycle.
four
What happens to the fuel-air mixture in the compression stroke in a two-stroke cycle engine?
It is forced upwards into the cylinder through the transfer port
What is a disadvantage of two-stroke engines regarding their lubrication system?
They require a mix of oil with the gas to lubricate the crankshaft, connecting rod and cylinder walls
What is an advantage of two-stroke engines?
They have the potential for about twice the power in the same size
What happens to the burnt gases in the exhaust stroke of a two-stroke cycle engine?
They are expelled from the engine
What is a characteristic of two-stroke engines that leads to increased fuel consumption?
Some of the fresh charge escapes through the exhaust port
What is a disadvantage of two-stroke engines regarding their lifespan?
They don't live as long as four-stroke engines
What is a difference between two-stroke and four-stroke engines?
Two-stroke engines do not have valves, four-stroke engines do
What is an advantage of two-stroke engines regarding their construction?
They are lighter and cost less to manufacture
What is a characteristic of two-stroke engines regarding their idling speed?
They are unstable at idling speed
What is a characteristic of two-stroke engines regarding their torque?
They have low torque even at idling speed
Study Notes
Internal Combustion Engine
What is an IC Engine?
- An IC engine is a machine that transforms the energy released from the combustion of fuel into mechanical energy.
- The motion of the piston is converted into rotary motion by a crankshaft, which can be used to drive a wide range of machines and vehicles.
Working of IC Engine
- Intake stroke: The piston descends from the top dead center of the cylinder to the bottom, reducing the pressure inside the cylinder, and the fuel-air mixture is drawn into the engine cylinder through the open intake valve.
- Compression stroke: The intake and exhaust valves are closed, and the piston returns to the top dead center, compressing the mixture or air.
- Power stroke: The fuel-air mixture is ignited by a spark plug or a high-pressure injector, causing an explosion that forces the piston to move downward, generating mechanical energy.
- Exhaust stroke: The exhaust valve opens, and the piston moves upward, pushing the exhaust gases out of the engine through the open exhaust valve.
Engine Classifications
- Basic Design: Reciprocating engines (four-stroke and two-stroke engines) and rotary engines (Wankel and turbine engines)
- Types of Ignition: Spark Ignition (SI) and Compression Ignition (CI)
- Engine Cycle: Otto cycle and Diesel cycle
Spark Ignition (SI) Engines
- Use gasoline as the primary fuel
- Combustion process is initiated by an electric spark
- Commonly used in passenger cars, motorcycles, and small aircraft
Compression Ignition (CI) Engines
- Use diesel as the primary fuel
- Combustion process is initiated by the high temperature and pressure of the compressed air in the cylinder
- Commonly used in heavy-duty vehicles, marine, and stationary power applications
Differences between Diesel and Gasoline Engines
- Ignition: Diesel engines rely on compressing air and then injecting diesel, while gasoline engines use spark plugs
- Size and Power: Diesel engines are bigger and produce more power
- Fuel Consumption: Diesel engines use less fuel to generate the same amount of energy
Classification of IC Engines Based on Cycle Type
- Four-Stroke Cycle Engine: One power stroke over two engine revolutions
- Two-Stroke Cycle Engine: One power stroke over one revolution
- Dual Cycle: A combination of the Otto and Diesel cycles
Four-Stroke Cycle Engine
- Intake stroke: Fuel-air mixture is drawn into the cylinder
- Compression stroke: Mixture is compressed
- Power stroke: Spark plug ignites the mixture, causing a rapid expansion of gases
- Exhaust stroke: Burnt gases are expelled from the engine
Two-Stroke Cycle Engine
- Compression stroke: Fuel-air mixture is drawn into the crankcase
- Power stroke: Mixture is ignited, causing a rapid expansion of gases, and then burnt gases are expelled from the engine
Advantages and Disadvantages of 2 Stroke Engines
- Advantages: Lighter, cost less to manufacture, potential for about twice the power, and no valves
- Disadvantages: Shorter lifespan, require a mix of oil with gas, fuel consumption is higher, and unstable at idling speed
Internal Combustion Engine
What is an IC Engine?
- An IC engine is a machine that transforms the energy released from the combustion of fuel into mechanical energy.
- The motion of the piston is converted into rotary motion by a crankshaft, which can be used to drive a wide range of machines and vehicles.
Working of IC Engine
- Intake stroke: The piston descends from the top dead center of the cylinder to the bottom, reducing the pressure inside the cylinder, and the fuel-air mixture is drawn into the engine cylinder through the open intake valve.
- Compression stroke: The intake and exhaust valves are closed, and the piston returns to the top dead center, compressing the mixture or air.
- Power stroke: The fuel-air mixture is ignited by a spark plug or a high-pressure injector, causing an explosion that forces the piston to move downward, generating mechanical energy.
- Exhaust stroke: The exhaust valve opens, and the piston moves upward, pushing the exhaust gases out of the engine through the open exhaust valve.
Engine Classifications
- Basic Design: Reciprocating engines (four-stroke and two-stroke engines) and rotary engines (Wankel and turbine engines)
- Types of Ignition: Spark Ignition (SI) and Compression Ignition (CI)
- Engine Cycle: Otto cycle and Diesel cycle
Spark Ignition (SI) Engines
- Use gasoline as the primary fuel
- Combustion process is initiated by an electric spark
- Commonly used in passenger cars, motorcycles, and small aircraft
Compression Ignition (CI) Engines
- Use diesel as the primary fuel
- Combustion process is initiated by the high temperature and pressure of the compressed air in the cylinder
- Commonly used in heavy-duty vehicles, marine, and stationary power applications
Differences between Diesel and Gasoline Engines
- Ignition: Diesel engines rely on compressing air and then injecting diesel, while gasoline engines use spark plugs
- Size and Power: Diesel engines are bigger and produce more power
- Fuel Consumption: Diesel engines use less fuel to generate the same amount of energy
Classification of IC Engines Based on Cycle Type
- Four-Stroke Cycle Engine: One power stroke over two engine revolutions
- Two-Stroke Cycle Engine: One power stroke over one revolution
- Dual Cycle: A combination of the Otto and Diesel cycles
Four-Stroke Cycle Engine
- Intake stroke: Fuel-air mixture is drawn into the cylinder
- Compression stroke: Mixture is compressed
- Power stroke: Spark plug ignites the mixture, causing a rapid expansion of gases
- Exhaust stroke: Burnt gases are expelled from the engine
Two-Stroke Cycle Engine
- Compression stroke: Fuel-air mixture is drawn into the crankcase
- Power stroke: Mixture is ignited, causing a rapid expansion of gases, and then burnt gases are expelled from the engine
Advantages and Disadvantages of 2 Stroke Engines
- Advantages: Lighter, cost less to manufacture, potential for about twice the power, and no valves
- Disadvantages: Shorter lifespan, require a mix of oil with gas, fuel consumption is higher, and unstable at idling speed
Quiz about the principles of internal combustion engines, including engine classifications and their role in the development of automobiles.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
