Types of engines, and how they work

Chris Horton
December 15, 2021 0 Comment

An engine is a machine that converts energy into work. An engine is a perfect tool to help you move. However, not all engines work the same and there are many types of engines.

The most obvious way to distinguish them is by the type of power they use.

  • Thermo engines
    • Internal combustion engines (IC engines)
    • External combustion engines (EC engines)
    • Reaction engines
  • Electric engines
  • Engines for physical applications

Thermo engines

These engines, in the broadest sense possible, require heat to turn into motion. These engines can either be combustive, which burns stuff, or non-combustive depending on how they generate heat. They can be used to produce work by either direct combustion of propellant, or by the transformation of fluids. Many thermal engines have some overlap with chemical drive systems. There are two types of these engines: non-airbreathing (which takes oxygen from the air) and airbreathing (which uses oxidizers such as oxygen from an atmosphere).

Internal combustion engines

Today, internal combustion engines (IC engines) are quite common. These engines power vehicles, such as cars, lawnmowers, helicopters, and so forth. An IC engine with 109,000 HP can power a ship capable of moving 20,000 containers. IC engines are powered by fuel that is burned in a special area of the system, called a combustion chamber. The combustion process produces reaction products (exhaust), which have a greater volume than the combined reactants (fuel and oxygenize). This is what provides motion in IC engines. Heat is a byproduct of combustion. It represents a waste part of fuel’s energy storage since it doesn’t provide any physical work.

IC engines can be distinguished by the number of cycles of each piston that makes it complete rotation. Four-stroke engines are the most common, and they break down combustion reactions in four steps.

  1. Induction or injection into the combustion chamber of a fuel-air mixture (the carburate).
  2. Mix compression
  3. Compression or spark plug ignition — fuel goes boom.
  4. Emissions from the exhaust

A 4-stroke piston can be pushed down or up for each step. The only step in which work is generated is ignition. All other steps rely on energy from outside sources such as the other pistons, an electrical starter, manual cranking, or the crankshaft’s inherent inertia to move. This is why you need to pull the cord on your lawnmower and why your car requires a functioning battery to start running.

The type of fuel used, several cylinders, total displacement, internal volume (internal volume) of cylinders, distribution of cylinders (inline or radial), are all factors that can be used to distinguish IC engines. Power and power-to-weight output are also important. Check out for more information – https://enginert.com/honda-amaze

External combustion engines

External combustion engines (EC engines) keep the fuel and exhaust products separate — they burn fuel inside one chamber and heat working fluid within the engine via a heat exchanger, or the engine’s walls. This category includes the steam engine, the granddaddy-o in the Industrial Revolution.

EC engines work in some ways similar to their IC counterparts. They both need heat, which can be obtained by burning things. However, there are some differences.

Fluids used in EC engines undergo thermal dilation-contraction and/or a shift of phase. However, their chemical composition is not altered. Fluids can be either liquid (the Organic Rankine engine), gaseous (the Stirling engine), or phase change. IC engines almost always use a mixture of liquid fuel and air that combusts, changing their chemical composition. The engines can either use the same fluid continuously (closed-cycle engine) or exhaust it after each use (IC engines).

Surprisingly the first steam engines to see industrial use generated work by creating pressure rather than pressure. These were known as ‘atmospheric engines’ and were heavy-weighted machines that were very fuel-inefficient. As steam engines evolved, they took on the characteristics and form we now expect from them. They were more efficient with the introduction of the piston system by reciprocating steam engines and compound engine systems that re-used fluid in cylinders at decreasing pressures to generate more ‘oomph.

Steam engines are no longer in widespread use. They’re bulky, heavy, and have a lower fuel efficiency than IC engines. Also, they can’t alter output as fast. They are great if you don’t mind their size and weight and require a steady supply of work. EC is used as steam turbine engines in naval operations and power plants.

Because they use the same principles as EC engines, but do not derive their power from combustion, nuclear power applications are called noncombustive and external thermal engines.

Reaction engines

Reaction engines are also known as Jet engines. They generate thrust by releasing reactionary mass. Newton’s Third Law is the basic principle behind reactionary engines. It states that if you push enough force through the engine’s back end, it will propel the front end forward. Jet engines are very adept at this.

We refer to the things we call a “jet” engine as they are attached to a Boeing passenger aircraft. These engines fall under the turbine-powered category. Although they are considered easier and more reliable because they have fewer moving parts (up to zero), Ramjet engines are still airbreathing engines. They fall under the ram-powered category. The main difference is that turbojets draw in air and compress it into the combustion chamber while ramjets depend on speed. They function almost identically beyond that.

Turbojets use air to draw in the engine chamber and compress it using a rotating turbine. By going very fast, Ramjets can draw and compress air. It is mixed with high-power fuel, ignited, and then withdrawn from the engine. You can concentrate air and oxygen, mix it with lots of fuel, and then detonate it. This will create exhaust and thermal expansion and a reactionary product with a large volume relative to the air that was drawn in. All this mass of gases can only pass through the engine’s backend, and it does so with great force. It powers the turbine by drawing in more air and then sustaining the reaction. To add insult to injury, there is a propelling tip at the back of the engine.

This hardware makes it possible for all gas to move through a smaller area than it originally came in, accelerating it further into ‘a jet of matter. The plane accelerates forward when the exhaust leaves the engine at amazing speeds — up to three times that of sound.

Non-airbreathing Jet engines or Rocket Engines function exactly like jet engines but without the front piece. They don’t require external material to sustain combustion. They can be used in space as they contain all the oxygen they require, which is why they are packed in the fuel. They are one of few engines that can consistently use solid fuels.

You can have heat engines that are either huge or small. What if you only have a socket and need to power your stuff. In that case, you will need:

Electric engines

The clean gang, oh yes! There are three types: electrostatic, piezoelectric, and magnetic.

Like the battery, the magnetic one is the most widely used. To generate work, it relies on the interaction of a magnetic field with an electrical flow. It works in the reverse of what a dynamo does to generate electricity. You can generate some electrical power by hand cranking an electric-magnetic motor.

A magnet and a conductor are required to create a magnetic engine. An electrical current applied to the winding creates a magnetic field that interacts with the magnet to produce rotation. These two components must be kept separate. Therefore, electrical motors have two main parts: The stator (which is the engine’s outermost part that remains immobile) and the rotor which spins within it. An air gap separates the two. The conductor wraps around the rotor while the magnets are usually embedded in the stator. However, the two can be interchangeable. A commutator is also available for magnetic motors to control the electrical flow and modulate the induced magnetic field while the rotor spins to maintain its rotation.

Piezoelectric drives can be described as engines that harness the property of some materials to generate ultrasonic vibrations when they are subjected to electricity to create work. Like-charges are used to repel each other and create rotation in an electrostatic engine. They aren’t as popular as magnetic drives because they use more expensive materials and require higher voltages to operate.

The classic electrical engine converts up to 90% of the energy into work, making it one of the most efficient engines available.

Ion drives

Ion engines are a combination of electric and jet engines. This type of drive accelerates ions (plasma), using an electric charge to generate propulsion. They won’t work if there aren’t enough ions around the craft.

They also have very low power output. They only use electricity and small particles of gas for fuel. This makes them ideal for spaceships. Ion drives have been successfully used in Deep Space 1 and Dawn. The technology is best suited to small satellites and craft as the electron trail created by these drives can negatively impact their overall performance.

EM/Cannae drives

EM/Cannae engines use electromagnetic radiation contained within a microwave cavity to create trust. This engine is probably the most unusual of all engines. Because it is a non-reactionary drive, it does not produce thrust and produces no discharge. This makes it a unique engine.

Although there was much debate about whether or not this engine works, NASA tests have proven it to be functionally sound. The engine will soon receive an upgrade. It is the most suitable drive for space exploration because it only uses electrical power to generate thrust.

But it’s all in the future. Let’s look back at the beginning. Let’s have a look at:

Engines for physical applications

These engines use stored mechanical energy for their function. Clockwork enginespneumatic and hydraulic engines all serve as physical drives.

They aren’t very efficient. They are not able to draw on large amounts of energy. For example, clockwork engines store elastic energy in springs and must be wound every day. Hydraulic and pneumatic types of engines must carry heavy tubes filled with compressed fluids, which don’t last long. The Plongeur was the first mechanically-powered submarine constructed in France between 1863 and 1860. It had a reciprocating engine that was supplied by 23 12.5 bar tanks. These engines took up 153 cubic meters / 5,403 cube feet of space and only powered the craft for five nautical miles (9 km/5.6 mi) at 4 km.

Physical drives were still the most common. This type of engine is used in catapults and trebuchets as well as battering rams. The same goes for the man- or beast-powered cranes, which were in use long before any other type of engine.

This is not a comprehensive list of all engines that man has created. Not to mention the fact that biology has also produced drives — which are amongst the most efficient we have ever seen. You can be sure that your engine is running out of fuel if you’ve read this far. Relax, take a deep breath, and when you see an engine again, make sure you are familiar with the basics.