How Much Do You Know About Car Engines?


By: J. Reinoehl

6 Min Quiz

Image: kali9/E+/Getty Images

About This Quiz

Car engines need gasoline, just like you need food. It's science! In this quiz, however, we’re going to take things to the extreme and test your knowledge about engine facts that the average person doesn't know. Are you ready to be challenged yet? Good, you should be! 

The internal combustion engine is one of the great marvels of the modern world. As with any remarkable innovation or invention, it has a multi-faceted history, and the facts really do boggle the mind. When you’re done with this quiz, you’re going to listen to the hum of that engine in that car of yours with a whole new level of awe and respect.

And, let’s be honest, truly knowing the facts about what lies under the hood is important. For instance, did you know that the principle behind any reciprocating internal combustion engine is to put a tiny amount of high-energy fuel in a small space and ignite it, thus releasing an incredible amount of energy in the form of expanding gas? The energy that is released from an engine is enough to propel a potato 500 feet. (Don't' try that at home, though; that potato might just hurt someone. Just saying.)

Are you aware that the four-stroke combustion engine is also known as the _____ cycle? Named after Nikolaus _____, who invented it in 1867? You’re salivating now, aren’t you? Let’s get started on the quiz!

What is "firing order" when it comes to an engine?

The firing order of an internal combustion engine gives the correct order each cylinder is sparked to ignite the fuel. It is used to reduce power lost through vibration and other engine shifting.


An internal combustion engine would be good for what?

A diesel engine ignites the fluid inside the engine (the "internal" element of the "internal combustion engine." Coal power plants, trains and submarines are all heating air or water outside of the engine to drive the pistons.


What is the purpose of afterburners on jet engines?

Afterburners are generally equipped on military aircraft to increase thrust during combat situations, takeoff and supersonic flight. They work by introducing additional fuel into the pipe after the turbines. Afterburners are only meant to be operated for short periods of time because they consume large amounts of fuel.


Another name for a gas turbine engine is...?

A jet engine is also known as a gas turbine engine. As gas is burned, it creates an air flow that spins turbines to create thrust.


What happens during the power phase of the four-stroke internal combustion engine cycle?

During the power phase in a four-stroke internal combustion engine, the piston moves downward after the gas in the chamber has been ignited. The explosion creates the power that drives the piston through the rest of the cycle.


What is one definition of an engine?

An engine can be defined as a machine that converts energy, such as heat energy, into mechanical motion. The concept of an engine was first proposed in the 17th century.


What is the primary disadvantage of two-stroke internal combustion engines?

The main disadvantage that two-stroke engines have is that they burn the oil mixed in with their fuel, which increases pollution. On the plus side, they are simpler, lighter and more efficient than four-stroke engines, making them the right choice for tools such as garden equipment.


Robert Stirling invented what kind of external combustion engine?

Robert Stirling invented the Stirling engine in 1816. It was an external combustion engine that used air instead of steam to move its pistons. The Stirling engine was safer (although prone to higher failure rates) and more efficient than steam engines of that era.


A radial engine would be best used in which type of vehicle?

The first successful rotary engine was designed in 1908, and its use in airplane design was apparent. The design of the rotary engine aids in spinning propeller blades.


What is one element an external combustion engine might use to move the piston?

External combustion engines use a working fluid, such as steam, to move the piston. The heat source is outside of the engine (thus, external combustion).


One type of pistonless internal combustion engine is called what?

The center of the Wankel engine (or rotor) rotates around a stationary gear inside the housing. The rotor is continuously moving in the same direction and driving the stationary gear forward. Mazda has made use of the Wankel engine in some of its cars.


Which type of engine uses fuel and an oxidizer to make up the propellant?

Rocket engines are internal combustion engines that work by expelling a gas that is the result of high-pressure combustion of propellants. The propellants must contain a fuel and the oxidizer (or grain) for that fuel.


A two-stroke engine would not usually be used for which of the following?

Although highly efficient, two-stroke engines burn a lot of oil. In addition to paying for gas, you would need to purchase about a half-gallon of two-stroke oil for every tank of fuel. Because of the oil being burned, they are no friend to the environment. Two-stroke engines HAVE been used to power small cars, however.


Who is credited with inventing the first steam-powered submarine?

Robert Fulton, best known for his work on steamboat technology, was fascinated with steam engines and used one to power the first successful submarine, called the Nautilus, in the late 18th century. He went on to develop steam-powered torpedoes for Britain.


What was the Stanley Steamer?

The Stanley Motor Carriage Company produced steam vehicles in the early 20th century. It was founded by twins Francis E. and Freelan O. Stanley. Francis died in 1918 in an automobile accident while trying to avoid two farm wagons and the company was then sold.


Which of the following is NOT an electric motor?

The steam engine operates on combustion using a fuel source located externally from the engine, not electricity. All the others use small electric motors to convert electricity into mechanical power.


Which one is NOT an internal combustion engine?

Cold gas thrusters operate like a balloon with the air being released. They provide low performance but these cheap, simple engines can be useful for making minor adjustments to a spacecraft's course.


Generally, engines that run only on electricity are called what?

By definition, "engine" and "motor" both are used as machines that power other devices. However, "motor" is generally used when the power comes from electricity instead of combustion.


A fan, compressors, combustion chamber, turbine and nozzle are parts of which type of engine?

Although all internal combustion engines contain combustion chambers, turbines are unique to the turbojet. Jet engines pass air or water in the opposite direction of the desired motion using Newton's third law of motion ("For every action, there is an equal and opposite reaction").


Which of the following is not a major type of electric motor?

Magnetic motors are used the most. Electrostatic motors operate based on electrical charge attraction and repulsion, and piezoelectric motors are based on the principals of electric charge that accumulate in certain materials and vibration frequencies. HAWT (Horizontal Axis Wind Turbine) is a wind turbine, not an electric motor.


What is the difference between the Rankine cycle and the Otto cycle?

The Otto cycle is used to ideally describe a situation where the working gas remains a gas constantly, such as in spark-ignition systems. The Rankine cycle is the ideal in situations where the working fluid changes between gas and liquid states, such as in steam engines.


What is a disadvantage of a Wankel engine?

Although running the engine at a constant speed overcomes some of the fuel consumption issues, under normal operating conditions it consumes more fuel than what should be ideal. Linked to its poor fuel economy is also poor emission quality. This type of engine does have a superior power-to-weight ratio than a piston engine, however.


Hybrid cars use gas engines for what?

The gas engine in a hybrid car not only recharges the batteries but also improves acceleration, kicks in for higher speeds and can propel the vehicle if the electric motor is discharged. The electric motor operates alone during lower speeds and in slow acceleration.


Rotary and radial engines are both used in older propeller airplanes, but what is the difference between the two?

A rotary engine rotates around a central fixed shaft. It is for this reason Wankel engines are also called rotary engines, even though this term traditionally was applied to engines that spin, or rotate, with an airplane propeller.


Which of the following is not a current hybrid engine combination?

Although biomass is used to generate electricity, as of yet there are no biomass-electric hybrids vehicles in mass production. Turbines, petroleum and diesel are all used in currently produced hybrid engine systems.


Which of the following are types of two-stroke engines?

Although different oil delivery systems can cause variation between two-stroke engines, the main differences are based upon the gas inlet systems. Piston-controlled is the standard engine that uses the piston to control the intake.


What was the naphtha engine developed to power?

After several boiler accidents on steamboats, laws were enacted that required an engineer to be present on all steamboats. The naphtha engine, although equally dangerous, was developed so the owners of personal watercraft could get around this law.


What kind of fuel generally powers a two-stroke engine?

Because two-stroke engines are a simpler design, the oil must be mixed in with the fuel to lubricate the parts. The power-to-weight ratio in a two-stroke engine is often much higher, and these engines are usually easier to service. Two-stroke engines tend to be less efficient but lighter.


Which type of internal combustion engine is also called a "star" engine?

The radial configuration is generally five pistons radiating out from a central point (the crankshaft). When viewed from the front, it resembles a star of sorts, and that is how it got its name.


An external combustion engine would be best used for powering what?

External combustion engines use heat to power the piston, but the fire does not have direct contact with the piston. Steam engines are one example of this type of engine.


What is the purpose of a nozzle on a rocket engine?

Nozzles on rocket engines allow the hot gasses to escape but accelerate the speed of the exhaust. Half of a rocket's thrust comes from the pressure created by the nozzle.


What was the name of the first passenger car that used an external combustion engine?

The Puffing Devil was invented by Richard Trevithick in 1801. The first one was left unattended and running by its operators, and it self-destructed. By 1803, Trevithick had improved his design, but the London Steam Carriage never became popular.


What shape is the rotor on a Wankel engine?

The Reuleaux triangle is based on an equilateral triangle with bulging sides that create a constant curve. The Wankel engine uses sides that are slightly flatter than an official Reuleaux triangle.


Which of the following two-stroke engines is generally cooled by water instead of by air?

Outboard motors are used for propelling boats through water. They use the water pumped in from the water pump impeller, located beneath the water line, to cool them instead of air.


Which of the following is NOT an internal combustion engine type?

All of these except the Stirling are types of internal combustion engines. Stirling engines use a cyclic expansion and compression of gas. Diesel engines do not use spark plugs. Rocket engines are specialized jet engines. Radial engines are used to rotate the propellers in airplanes.


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