Question 1

The gasoline engine is also known as a spark ignition engine.

Accepted Answer

The gasoline engine uses a spark to ignite the fuel and air mixture, hence it is known as a spark ignition engine.

Question 2

In four stroke engine operation, gasoline will not burn unless it is mixed with the correct amount of air.

Accepted Answer

In a four stroke engine, gasoline will not combust unless it is properly mixed with air in the correct ratio. This is essential for combustion to occur and for the engine to operate efficiently.

Question 3

What is the purpose of the harmonic balancer?

Accepted Answer

The purpose is to dampen torsional vibrations that could result in a broken crankshaft.

Question 4

What cylinder arrangement is popular with designers when an engine has more than four cylinders?

Accepted Answer

V-type cylinder arrangement is popular with designers when an engine has more than four cylinders because it offers a good balance between performance, size, and weight, while also allowing for easy access to components for maintenance and repair.

Question 5

How many degrees is a complete cycle on a four stroke engine?

Accepted Answer

A complete cycle on a four-stroke engine requires two revolutions of the crankshaft, which equals 720 degrees.

Question 6

Technician A says that the I-head engine is widely used in automobiles because it can breathe better than earlier engine designs. Technician B says that increased valve lift is possible with an I-head engine. Which technician is correct?

Accepted Answer

Technician A is correct because the I-head engine design has separate intake and exhaust valves and can breathe better than earlier engine designs.
Technician B is also correct because the I-head engine design allows for increased valve lift compared to other engine designs.

Question 7

Describe the major differences in the diesel and gasoline engines.

Accepted Answer

The answer of Describe the major differences in the diesel...

Question 8

Two technicians are discussing "blowby." Technician A says that "blowby" is gases escaping past the valves. Technician B says that "blowby" is gases escaping past the rings. Which technician is correct?

Accepted Answer

Blowby refers to gases that escape past the piston rings and into the crankcase. This can lead to decreased engine performance and increased oil consumption. Technician B is correct that blowby is caused by gases escaping past the rings.

Question 9

Most of today's cars are powered by _____-cycle engines.

Accepted Answer

The vast majority of cars today are powered by four-stroke engines, also known as Otto cycle engines after their inventor, Nikolaus Otto. Therefore, the correct choice is B) Otto.

Question 10

The I-head engine has the valves in the block.

Accepted Answer

The I-head engine, also known as an overhead valve (OHV) engine, has the valves in the cylinder head, not the block.

Question 11

What proportion of gross horsepower is consumed by all of the accessories on a modern engine?

Accepted Answer

On a modern engine, accessories such as the alternator, power steering pump, air conditioning compressor, and water pump can consume up to 25% of the gross horsepower. Therefore, the best choice would be B) 25%.

Question 12

Two technicians are discussing the power stroke. Technician A says that on a V8 engine, a power stroke occurs every 90 degrees. Technician B says that on an inline six-cylinder engine, the power stroke occurs every 120 degrees. Which technician is correct?

Accepted Answer

In a V8 engine, the crankshaft completes two revolutions (720 degrees) to complete a four-stroke cycle for all eight cylinders, resulting in a power stroke every 90 degrees (720/8). In an inline six-cylinder engine, the same two revolutions (720 degrees) are divided by six cylinders, leading to a power stroke every 120 degrees (720/6). Therefore, both technicians are correct.

Question 13

Which of the following is NOT an Otto-cycle engine?

Accepted Answer

A radial engine is not an Otto-cycle engine. It is a type of internal combustion engine where the cylinders are arranged in a circular pattern around the crankshaft. The other options (B, C, and D) are all types of Otto-cycle engines, which use four strokes (intake, compression, combustion, and exhaust) to convert fuel into mechanical energy.

Question 14

What is the difference between a short block and a long block?

Accepted Answer

The answer of What is the difference between a short...

Question 15

Briefly explain how the ignition works in a diesel engine.

Accepted Answer

The answer of Briefly explain how the ignition works in...

Question 16

The ideal air-fuel mixture for a gasoline engine is _____.

Accepted Answer

The ideal air-fuel mixture for a gasoline engine is 14.7:1, also known as the stoichiometric ratio. At this ratio, there is just enough oxygen in the air to completely burn all of the fuel, resulting in the most efficient combustion and lowest emissions. The other ratios listed may be used in certain engine applications, but 14.7:1 is considered the ideal for most gasoline engines.

Question 17

A two stroke engine has a power stroke every other crankshaft revolution.

Accepted Answer

A two-stroke engine has a power stroke every crankshaft revolution, unlike a four-stroke engine which has a power stroke every other crankshaft revolution.

Question 18

Technician A says that most automotive gasoline engines have four strokes per cycle. Technician B says that the crankshaft makes four revolutions during the four-stroke cycle. Which technician is correct?

Accepted Answer

Technician A is correct because most automotive gasoline engines operate on a four-stroke cycle: intake, compression, power, and exhaust. The crankshaft actually makes only two revolutions during this cycle, not four as Technician B suggests.

Question 19

The camshaft controls the rate at which the engine breathes.

Accepted Answer

The camshaft controls the opening and closing of the engine's valves, which ultimately determines the amount of air and fuel that enters the engine. This affects the engine's breathing, or intake and exhaust process.

Question 20

What cylinder number is the closest to the front of the engine on almost all V-type engines?

Accepted Answer

Cylinder number 1 is typically the closest to the front of the engine on almost all V-type engines.

Quiz 1: Engine Operation