There’s always a lot of noise about the future. We talk about new technology, innovations, and inventions almost daily. Sometimes, it’s nice to look at the past to see where things originated. Modern passenger vehicles with diesel engines have a fascinating origin story. Want to find out who invented the diesel engine, how compression creates power, and why glow plugs are essential? This blog series will address those questions and explore diesel repairs and maintenance tips for diesel cars, diesel trucks & SUVs, and finally, diesel commercial vehicles.


Officially, the credit for designing the first diesel engine goes to Rudolf Diesel. He received a German patent for his original design in 1892. After additional research, Rudolf revised his initial design and obtained another patent in 1893. He completed and tested his first official working diesel engine (the Motor 250/400) in 1897. 

The diesel engine design slowly evolved as engineers used it in a wide variety of applications. In 1903, France and Russia launched the first two diesel-powered ships for use in rivers and canals. In 1904, the French built the Z, the first diesel-powered submarine. Unfortunately, Rudolf Diesel died under mysterious circumstances from the ship SS Dresden on September 29, 1913. After his death, his engine design became the primary replacement for the steam piston engine. 

Throughout the 1910s and 1920s, stationary machines, ocean vessels, locomotives, tractors, commercial trucks, and submarines used diesel engines as their primary source of power. The 1930s saw passenger cars, airships, tanks, and passenger trains using diesel-powered engines. Today, many commercial trucks, buses, and passenger vehicles use diesel engines based on Rudolf Diesel’s original concept.


Diesel engines and gasoline engines are both internal combustion engines. Basically, the engines burn fuel to produce power. A gasoline-powered combustion engine requires a spark to ignite the fuel, but a diesel-powered engine does not. Simply put, the diesel engine is an internal combustion engine designed to use compression for the ignition instead of a spark. Once injected into the compressed air inside the combustion chamber, the diesel fuel ignites. Let’s break the process down:


Air heats up with compression. Therefore, the diesel engine draws air into the cylinders and then the pistons compress the air until it reaches about 700–900 Celsius (°C) or (1300–1650 Fahrenheit (°F).  Next, the fuel injection system injects a fine mist of diesel fuel into the combustion chamber. The atomized fuel promptly ignites on contact with the compressed/superheated air. 

This combustion creates more heat and air expansion in the cylinder, which causes the pistons to move up and down. A connecting rod transfers this action to a crankshaft that converts linear motion to rotary motion, thus creating power. 

Modern engineers equip most diesel engines with either a turbocharger or a supercharger to increase the air volume intake.  A good rule of thumb – the more air forced into the chamber, the greater the power output. 


Diesel engines generally operate by repeating the combustion cycle of four strokes. The piston moves up and down two times, driven by the crankshaft, which rotates twice during the cycle. The combustion cycle works like this:

  • INTAKE STROKE: Piston moves down – Cylinder fills with air  
  • COMPRESSION STROKE: Piston moves up – Compresses the air and mists fuel into the chamber
  • COMBUSTION STROKE: Fuel ignites – Pushes the piston down
  • EXHAUST STROKE: Exhaust releases – Pushes the piston up  


In a two-stroke diesel engine, the combustion cycle completes as the piston moves up and down one time. To create three steps in two strokes, the Intake and Exhaust strokes as well as the Compression and Combustion strokes are combined. Two-stroke diesel engines are usually smaller, lighter, and more efficient since they produce power with each rotation. Instead of once every two rotations, like in four-stroke diesel engines.


Diesel engines can be difficult to start in frigid weather or cold climates. The cold metal of the cylinder leaches out the heat built-up in the cylinder during the compression stroke. If the compressed air does not reach a high enough temperature, a diesel engine won’t start. Some diesel engines use glow plugs to alleviate this issue and aid ignition. 

Glow plugs are like small heaters inside the cylinder to help the compressed air reach sufficient temperatures to ignite the fuel. Other methods include resistive grid heaters in the intake manifold that heat the incoming air or electric resistive heaters to warm the engine block. The use of glow plugs (or the other methods) enables diesel engines to operate in any weather or climate.


There are several benefits to owning and operating a diesel vehicle. Let A&R Complete Auto Care be your diesel experts when it’s time for diesel repairs or maintenance. We have the expertise, equipment, and technology to diagnose any issue you may be experiencing with your diesel engine. We will fix it right the first time and get you back on the road.


Call A&R Complete Auto Care at (931) 552-0606 or visit us online to make an appointment for your diesel repairs or maintenance.


Part 2 in the Diesel Engines Series will look at diesel cars, how they work, how to care for them, and ways to enhance their performance and efficiency.


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