Instructions
Read each section carefully and answer the questions to the best of your ability. This worksheet will help you understand the basic parts and functions of a car engine.
Part 1: Match the Terms
Match the engine part or concept in Column A with its correct definition in Column B. Write the letter of the correct definition in the space provided.
| Column A | Column B |
|---|---|
| 1. ___ Piston | A. A rotating shaft that converts the up-and-down motion of the pistons into rotational motion to turn the wheels. |
| 2. ___ Cylinder | B. The process of rapidly burning the fuel and air mixture, which creates the force to move the piston. |
| 3. ___ Spark Plug | C. A can-shaped component that moves up and down inside the cylinder. |
| 4. ___ Crankshaft | D. A device that delivers a high-voltage electric spark to ignite the fuel-air mixture. |
| 5. ___ Combustion | E. The hollow tube or chamber where the piston moves. |
Part 2: The Four-Stroke Cycle
An internal combustion engine works in a four-step cycle. Read the descriptions below and identify which stroke is being described. Choose from the following: Intake, Compression, Power, or Exhaust.
- The piston moves down, and the intake valve opens, drawing a mixture of fuel and air into the cylinder.
Stroke: ______________________________ - The spark plug ignites the compressed mixture, causing a small explosion that forces the piston down with great force.
Stroke: ______________________________ - The piston moves up, squeezing the fuel-air mixture into a much smaller space, which increases its potential energy.
Stroke: ______________________________ - The piston moves up again, pushing the used, burnt gases out of the cylinder through the open exhaust valve.
Stroke: ______________________________
Part 3: Fill in the Blanks
Complete the paragraph below using the words from the word bank. Each word is used only once.
A car engine creates motion by converting the chemical energy stored in _________________ into mechanical energy. This process happens inside hollow tubes called _________________. Within these tubes, movable parts called _________________ travel up and down. A mixture of air and fuel is ignited by a spark, causing a small _________________ that pushes the piston down with force. This downward motion turns the _________________, which is a rotating shaft that eventually transfers power to the car's wheels. This process generates a lot of _________________, which is why engines need a cooling system to operate at a safe temperature. The entire purpose of the engine is to create usable _________________ to move the vehicle.
Part 4: Short Answer Question
Based on what you have learned, answer the following question in 1-2 complete sentences.
What is the main difference between the "Power" stroke and the other three strokes (Intake, Compression, Exhaust)?
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Answer Key
Part 1: Match the Terms
- C. A can-shaped component that moves up and down inside the cylinder.
- E. The hollow tube or chamber where the piston moves.
- D. A device that delivers a high-voltage electric spark to ignite the fuel-air mixture.
- A. A rotating shaft that converts the up-and-down motion of the pistons into rotational motion to turn the wheels.
- B. The process of rapidly burning the fuel and air mixture, which creates the force to move the piston.
Part 2: The Four-Stroke Cycle
- Stroke: Intake
- Stroke: Power
- Stroke: Compression
- Stroke: Exhaust
Part 3: Fill in the Blanks
A car engine creates motion by converting the chemical energy stored in fuel into mechanical energy. This process happens inside hollow tubes called cylinders. Within these tubes, movable parts called pistons travel up and down. A mixture of air and fuel is ignited by a spark, causing a small explosion that pushes the piston down with force. This downward motion turns the crankshaft, which is a rotating shaft that eventually transfers power to the car's wheels. This process generates a lot of heat, which is why engines need a cooling system to operate at a safe temperature. The entire purpose of the engine is to create usable energy to move the vehicle.
Part 4: Short Answer Question
Example Answer: The main difference is that the Power stroke is the only one that actively creates force and pushes the piston down to turn the crankshaft. The other three strokes are preparatory or clean-up steps that use the engine's momentum but do not generate new power.