Diesel Generators: Two Centuries in Development

What is a Diesel Generator? 

Diesel generators, otherwise known as diesel gensets, are a part of modern day life. We are so well acquainted with diesel generators today, it’s easy to take the important function they serve and the role they play in our lives for granted. Diesel generators have become ubiquitous – they can be found throughout our communities, serving in the home, on the farm, in our work places, our schools, hospitals and sometimes as support for community power grids. The practical application of diesel generators in modern life is nearly limitless, yet we rarely stop to consider how they work their magic, or how they came to exist as a staple of the modern age – and that’s something we at Generator Power would like to change.

How a Diesel Generator Works

The short answer is that a diesel generator is the pairing of two marvelous inventions, the diesel internal combustion engine and the electric generator (known today as the alternator). The combustion in the engine provides mechanical energy, also known as kinetic energy, and the alternator converts that energy into electric power. You see this action at work every day in your personal vehicle, though diesel engines and generators function a bit differently from petrol engines.

A petrol engine compresses both air and fuel simultaneously with its pistons, and uses an accompanying device like a spark plug to achieve ignition and combustion. A diesel generator or engine only compresses air. Diesel fuel is injected at the end of the air compression process, which causes the fuel to self ignite. This self ignition removes the need for an auxiliary ignition device (like a spark plug in a petrol engine) and it stabilizes the engine knock in diesel generators and engines, something a petrol engine isn’t capable of. 

History of the Diesel Generator

The diesel generator as we know it today owes its existence to an innumerable number of great minds, however, the invention of the diesel generator is most often attributed to the combined life’s work of two men: Michael Faraday and Rudolph Diesel.

Michael Faraday

Michael Faraday was born in 1791 in Surrey, England. His family had few financial means, and the bulk of his education came from unconventional means. At age 14, he became the apprentice to a local bookseller, where he developed his interest in science and electricity in particular. As he grew older, he attended lectures at the Royal Institution and the Royal Society, and through those connections he managed to attain an assistant’s position at the Royal Institution in 1813.

There, he continued his work in chemistry and electricity. His breakthrough moment arrived when he discovered mutual induction, the interaction of magnetic fields on electrical force. That discovery lead to the creation of the ‘Faraday Disk’ in 1831, which operated by attaching two pieces of wire to a sliding contact, which was placed on a copper disk. The disk was then spun through the poles of a magnet, which generated continuous electric current as the disk rotated perpetually. 

The ‘Faraday Disk’ is the ancestor to today’s modern alternators, and is the invention for which Michael Faraday remains most remembered.

Rudolph Diesel

In the early 1800’s, the steam engine was high technology, utilized in trains and industry for power generation. Steam engines, however, only converted about 10% of the heat energy they produced into mechanical or kinetic energy. In the early 1890’s, Rudolph Diesel, a refrigeration engineer, set out to create a more efficient motor.

Diesel’s first design was nearly the death of him. As a refrigeration engineer, Diesel had become very familiar with the properties of ammonia, which he tried to use in a steam engine he designed himself. After his ammonia vapor engine exploded, putting him in the hospital for months, he set out in a different direction.

In 1892 he began work on his diesel engine, which originally called for coal dust as a fuel source. After experimentation and the realization that a great deal of the crude oil used to refine kerosene resulted in left over petroleum bi-product, he developed his liquid diesel fuel. His first successful engine resulted in an efficiency rating of 26.2%, an incredible leap beyond what the steam engine was capable of. He continued his work, experimenting with different fuels and designs – one of which used peanut oil and achieved a full 75% efficiency!

How a Diesel Generator Works

The short answer is that a diesel generator is the pairing of two marvelous inventions, the diesel internal combustion engine and the electric generator (known today as the alternator). The combustion in the engine provides mechanical energy, also known as kinetic energy, and the alternator converts that energy into electric power. You see this action at work every day in your personal vehicle, though diesel engines and generators function a bit differently from petrol engines.

A petrol engine compresses both air and fuel simultaneously with its pistons, and uses an accompanying device like a spark plug to achieve ignition and combustion. A diesel generator or engine only compresses air. Diesel fuel is injected at the end of the air compression process, which causes the fuel to self ignite. This self ignition removes the need for an auxiliary ignition device (like a spark plug in a petrol engine) and it stabilizes the engine knock in diesel generators and engines, something a petrol engine isn’t capable of. 

History of the Diesel Generator

The diesel generator as we know it today owes its existence to an innumerable number of great minds, however, the invention of the diesel generator is most often attributed to the combined life’s work of two men: Michael Faraday and Rudolph Diesel.

Michael Faraday

Michael Faraday was born in 1791 in Surrey, England. His family had few financial means, and the bulk of his education came from unconventional means. At age 14, he became the apprentice to a local bookseller, where he developed his interest in science and electricity in particular. As he grew older, he attended lectures at the Royal Institution and the Royal Society, and through those connections he managed to attain an assistant’s position at the Royal Institution in 1813.

There, he continued his work in chemistry and electricity. His breakthrough moment arrived when he discovered mutual induction, the interaction of magnetic fields on electrical force. That discovery lead to the creation of the ‘Faraday Disk’ in 1831, which operated by attaching two pieces of wire to a sliding contact, which was placed on a copper disk. The disk was then spun through the poles of a magnet, which generated continuous electric current as the disk rotated perpetually. 

The ‘Faraday Disk’ is the ancestor to today’s modern alternators, and is the invention for which Michael Faraday remains most remembered.

Rudolph Diesel

In the early 1800’s, the steam engine was high technology, utilized in trains and industry for power generation. Steam engines, however, only converted about 10% of the heat energy they produced into mechanical or kinetic energy. In the early 1890’s, Rudolph Diesel, a refrigeration engineer, set out to create a more efficient motor.

Diesel’s first design was nearly the death of him. As a refrigeration engineer, Diesel had become very familiar with the properties of ammonia, which he tried to use in a steam engine he designed himself. After his ammonia vapor engine exploded, putting him in the hospital for months, he set out in a different direction.

In 1892 he began work on his diesel engine, which originally called for coal dust as a fuel source. After experimentation and the realization that a great deal of the crude oil used to refine kerosene resulted in left over petroleum bi-product, he developed his liquid diesel fuel. His first successful engine resulted in an efficiency rating of 26.2%, an incredible leap beyond what the steam engine was capable of. He continued his work, experimenting with different fuels and designs – one of which used peanut oil and achieved a full 75% efficiency!