• Question: whats an engine, can you describe in detail?

    Asked by anon-74521 on 11 May 2020.
    • Photo: Charles Sparey

      Charles Sparey answered on 11 May 2020:

      At its heart, an engine is a device that converts energy from one form to another to do useful work, that is, it converts energy into a kinetic form to enable it to move something by exerting forces or rotational torque. When people talk about engines, they normally mean heat engines which convert heat, typically generated by burning a fuel like oil or coal in a chemical reaction, into mechanical motion. This would include internal combustion engines used in most vehicles as well as steam engines used in power plants and some locomotives. Electrical ‘engines’ that convert electricity into motion are normally referred to as motors. There are also pneumatic and hydraulic engines that convert the forces exerted by compressed air and other working fluids into motion as well.

    • Photo: Ross Hall

      Ross Hall answered on 11 May 2020:

      An Engine is a machine with moving parts that converts power into motion.
      Typically a fuel with chemical energy is burnt creating thermal energy which is then converted to Kinetic energy (Movement).

      There are many different types of engine so it would be difficult to go into detail for all of them.If your interested in engines have a look at Reciprocating engines (car engines) or Gas turbines (aeroplane engines) to understand the differences.

      https://www.youtube.com/watch?v=zA_19bHxEYg Reciprocating Engine

      https://www.youtube.com/watch?v=zcWkEKNvqCA Gas Turbine

      I hope this helps.

    • Photo: Ed Chester

      Ed Chester answered on 11 May 2020:

      An engine is a machine that converts an energy source into some kind of motion. Most engines create spinning motion (rotation) which is then used to work – for example, to turn wheels on a vehicle, drive a pump for water, air or another fluid, and so on. The energy source is usually a fuel, but could also be electrical energy. The link between the fuel and the mechanical work of the engine is heat – burning a fossil fuel like coal or petrol, or less directly in using heat from burning fuel to boil water to produce steam in a steam engine.

    • Photo: Nicola Grahamslaw

      Nicola Grahamslaw answered on 11 May 2020:

      Most engineering jobs actually don’t have anything at all to do with engines! It’s a total coincidence that the two words sound similar – the word “engineering” comes from the same Latin word as “ingenuity” so engineering is much more about general problem-solving than about engines.
      As for the engine part, well it depends on what kind of engine. Generally the way an engine works is by heating up air, usually by burning fuel, which makes it want to expand and that air can then do work. In some engines the expanding air is used to push something (like a piston), in some engines it it used to make a fan turn around (by pushing the blades). The turning motion can then be turned into whatever motion is needed using gears. In some other engines the air is pushed out of the back as a jet to create propulsion.

    • Photo: Martin McKie

      Martin McKie answered on 11 May 2020:

      Engine:

      Purpose is to create energy that can be used to propel the vehicle forward.

      There are different sections within the Engine

      Air in – The engine needs air or oxygen to mix with the fuel to burn and create the energy. There is an air filter which filters out particles from outside the engine. If the engine is Naturally Aspirated it means it doesn’t have a turbo charger or supercharger. Basically a Turbo charger or supercharger pulls in air and forces it into the engine which is known as forced induction.

      Fuel in – You put petrol in the petrol tank and there is a pump which takes the fuel from the tank and pulls it through into injectors and this sprays it into the cylinders were it mixes with the air.

      Spark Plugs – You need a spark to ignite that air and fuel mix. So you have a spark plug usually one per cylinder but can be more.

      Then you have the ingredients of the fire triangle which you have likely learnt at school Fuel (Petrol) / Air (Oxygen) / Ignition (Spark Plug) this creates an explosion in the cylinder which pushes the piston down on a crank as it returns it pushes the waste gases out via an exhaust value and then usually into the exhaust system and out of the car. This process is known as the four stroke engine.

      The easiest way to remember the four stroke process is to remember the following saying Suck, Squeeze, Bang, Blow.

      Suck in the air
      Squeeze – the air and fuel mix (compress it)
      Bang – Spark from the spark plug ignites the fuel mixture
      Blow – The waste gas is pushed out through the exhaust system.

      There’s obviously a lot of heat generated during this process. So around the cylinders and in the cylinder head there are water channels / cavities. these circulate water around the engine taking heat away from the cylinders. A water pump, pumps the water around the engine. The hot water goes to a radiator and the cold air whilst your driving along hits the radiator cooling the hot water which is re-circulated back into the cylinders to take the heat into the water and back into the radiator. Have a look into heat transfer for more information.

      Please see the video below which visually shows the four stroke process and engine components involved.

      If you need anymore information, please contact me.

    • Photo: anon

      anon answered on 11 May 2020:

      A mechanical engine is a machine, that has moving parts, which can convert some form of power source into physical motion.
      For instance, I work with big diesel engines that convert diesel fuel (which is a liquid that is made from crude oil) into a rotational form of power, which primarily rotates wheels around to move big trucks.
      The diesel liquid is made of long hydrogen-carbon chains, if you are not sure about this chemistry then it isn’t too important, just think of it as a liquid made of many chains with each link in these chains containing lots of energy. Now to use this contained energy you must beak the chain’s links, and the way we do that is to make it explode.
      The explosion of the links happens because we add some extra energy to the chains by way of squeezing it all together, more energy than the links can withstand, and then we add an extra ingredient (oxygen) to allow the explosion to occur.
      The actual conversion of this explosive energy/power to rotational movement happens because the explosion happens in a sealed tube with a piston at one end, a piston is like a plug that can slide up and down but still stops anything going past it, and the piston gets pushed away very fast by the explosion. We attach the piston to a rod so that when the piston moves away it makes the rod (known as a crankshaft) spin, and (although it is a bit more complex than this) basically the spinning rod makes the wheels spin too.
      Most engines have multiple pistons/cylinders firing at different times to make sure the engine keeps the rod spinning. This is why you might have heard of people talking about engines called “V8”, the 8 is just the number of pistons/cylinders that engine has and the V is because they are arranged in a V shape.

      I’ve tried to break this down as simply as possible, feel free to message me if you do not understand something or if you want a bit more detail.

    • Photo: David Linsell

      David Linsell answered on 11 May 2020:

      Other contributors have given good descriptions of the common reciprocating engines: petrol (spark ignition reciprocating engine) and diesel (compression ignition reciprocating engine). They all agree that an engine is a device that converts energy from one form into another. The first form of energy is some form of fuel and the final form of energy is some form of motion. There are other engines we can include under this general heading.

      Steam engines – convert fuel (coal, oil, wood) into heat, then use the heat to convert water into steam (a gas), then use the expansion of the steam (gas) to achieve movement of a piston, then a connecting rod and crank to produce rotary motion.

      Steam turbines – convert fuel (coal, oil, wood) into heat, then use the heat to convert water into high temperature and high pressure steam (a gas), then use the expansion of the steam (gas) in a turbine to achieve rotary movement of a shaft.

      Gas turbines – convert fuel (usually oil or Natural Gas) into a high temperature and high pressure gas, then use the expansion of the gas in a turbine to achieve rotary movement of a shaft.

    • Photo: Helen Taylor

      Helen Taylor answered on 11 May 2020:

      An engine is a machine that does work. Car and plane engines work on the “Suck, Squeeze, Bang, Blow” principle.

    • Photo: Frances Askill-Kirk

      Frances Askill-Kirk answered on 12 May 2020:

      Hi!

      I work in the automotive industry and although I work on electric vehicles that do not have a traditional engine bay I will revert back to the much loved but not so environmentally friendly V8 engine.

      If you are interested in engineering – this youtube channel ‘Engineering Explained’ is fantastic! It breaks down complex systems into a really easy to understand video! I love watching them!!

      Here’s their video on the V8 engine!

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