1.
The average temperature of the burned gases in the combustion chamber is ___________.
Correct Answer
A. 3600 degrees F
Explanation
The correct answer is 3600 degrees F. This indicates that the average temperature of the burned gases in the combustion chamber is extremely high. Combustion chambers are designed to reach high temperatures in order to efficiently burn fuel and generate energy. A temperature of 3600 degrees F suggests that the combustion process is operating at a high level, allowing for effective energy production.
2.
The heat of combustion is carried away in three ways. One third is removed by the cooling system and one third by the exhaust system. That which remains is used to produce_____.
Correct Answer
B. Engine power
Explanation
The heat of combustion is carried away in three ways: one third is removed by the cooling system, one third by the exhaust system, and the remaining heat is used to produce engine power. This means that the heat energy generated during combustion is utilized to generate power for the engine, allowing it to perform work and propel the vehicle forward.
3.
Why is the temperature of the inside cylinder wall relatively cool compared to the combustion temperature?
Correct Answer
A. A boundary layer of stagnant gas acts as an insulator
Explanation
The temperature of the inside cylinder wall is relatively cool compared to the combustion temperature because there is a boundary layer of stagnant gas that acts as an insulator. This boundary layer prevents the heat from the combustion process from directly transferring to the cylinder wall, thus keeping it relatively cool.
4.
What are two ways to prevent overheating of air-cooled engines?
Correct Answer
A. Keep the engine clean, and properly lubricated
Explanation
Keeping the engine clean and properly lubricated are two effective ways to prevent overheating of air-cooled engines. A clean engine ensures that there is no accumulation of dirt or debris that could obstruct the airflow and cause the engine to overheat. Proper lubrication, on the other hand, helps reduce friction and heat generated within the engine, ensuring its smooth operation and preventing overheating. Regular maintenance, including cleaning and lubrication, is crucial in maintaining the optimal performance and preventing overheating in air-cooled engines.
5.
When used fpr engine cooling, water is about ____________ times as effective as air.
Correct Answer
C. Four
Explanation
Water is about four times as effective as air when used for engine cooling. This means that water is able to absorb and dissipate heat more efficiently compared to air. As a result, using water for engine cooling can help maintain lower temperatures and prevent overheating, which is crucial for the proper functioning and longevity of the engine.
6.
Cylinders or water-cooled engines are surrounded by ______________.
Correct Answer
C. A water jacket
Explanation
Cylinders or water-cooled engines require a way to regulate their temperature to prevent overheating. A water jacket is a common method used for this purpose. It is a surrounding structure that contains coolant, usually water, which circulates around the cylinders or engine to absorb and dissipate heat. This helps in maintaining the optimal temperature for the engine's operation and prevents any damage that may occur due to excessive heat.
7.
The _______________ water flow system in out-board engines utilizes the tips of the propeller to circulate water.
Correct Answer
B. Pressure-vacuum
Explanation
The pressure-vacuum water flow system in out-board engines utilizes the tips of the propeller to circulate water. This system works by creating a pressure difference between the front and back of the propeller, which causes water to be drawn in through the front and expelled out through the back. This circulation helps to cool the engine and prevent overheating.
8.
A heat sensitive device that maintains a constant engine operating temperature in is the _________________.
Correct Answer
C. Thermostat
Explanation
A thermostat is a heat sensitive device that is responsible for maintaining a constant engine operating temperature. It does this by regulating the flow of coolant through the engine. When the engine temperature rises above a certain point, the thermostat opens, allowing coolant to flow and cool the engine. Once the temperature drops to the desired level, the thermostat closes, restricting the coolant flow. This continuous cycle helps to ensure that the engine operates at an optimal temperature, preventing overheating and potential damage to the engine.
9.
In cold weather, a(n) ___________________ should be added to water-cooled engines.
Correct Answer
B. Antifreeze
Explanation
In cold weather, adding antifreeze to water-cooled engines is necessary. Antifreeze is a solution that prevents the water in the engine's cooling system from freezing, which could cause damage to the engine. By adding antifreeze, the engine is protected from freezing temperatures and can continue to function properly.
10.
What cooling system defects can cause hot spots?
Correct Answer
A. Clogged cooling fins
Explanation
Clogged cooling fins can cause hot spots in a cooling system. When the cooling fins are clogged, airflow is restricted and the heat transfer from the system is compromised. This can result in certain areas of the system not being properly cooled, leading to hot spots. Hot spots can cause overheating and potential damage to the system if not addressed. Therefore, it is important to regularly clean and maintain the cooling fins to ensure proper cooling efficiency.
11.
What two fluids are used to cool engines?
Correct Answer
A. Water and oil
Explanation
Water and oil are used to cool engines because they have different properties that make them effective for this purpose. Water has a high specific heat capacity, meaning it can absorb and transfer large amounts of heat without a significant rise in temperature. This makes it ideal for absorbing heat from the engine and carrying it away. Oil, on the other hand, has lubricating properties that help reduce friction and heat generated by moving engine parts. Therefore, a combination of water and oil is commonly used in engine cooling systems to ensure efficient heat transfer and lubrication.