Vehicle Diesel Engines: History and Overview

Diesel Engines, Direct Injection, CompressionUnless you live under a rock, I’m sure you’ve heard of Diesel Engines and know a little bit about them. However, do you know the controversial history of the invention of the Diesel Engine? Below I will reveal some interesting facts about the sordid history of diesel engines and a brief exploration of how they work (including how direct injection and compression increase power).



Diesel Engines: History

The European Industrial Revolution brought about a vast surge of creativity and improvement in the sciences. Scientists, physicists, and thermodynamics students invented machines that revolutionized manufacturing, transportation, and communication. In 1876, Nikolaus Otto invented and patented the gasoline engine. This invention used the four-stroke combustion principle, called the “Otto Cycle.”

It is the basic design for most modern car engines in use today. In the beginning, the gasoline engine wasn’t a very efficient mode of transportation. It competed with the steam engine, which was also relatively inefficient. Only about 10% of the fuel used in gasoline and steam engines translated to momentum, resulting in a lot of useless heat. Enter Rudolf Diesel. His Diesel Engine was one of several new inventions that changed the world.

Rudolf Diesel

A German mechanical engineer Rudolf Christian Karl Diesel, born in 1858, designed his namesake, the Diesel Engine. Rudolf graduated from the Royal Bavarian Polytechnic of Munich in 1880 with top honors. Early in his career, he gained valuable experience working with one of his professors, establishing a modern refrigeration and ice plant. During his lifetime, he patented numerous designs in many countries, including France, Germany, and the United States. His work on the Diesel Engine took place between 1893-1897. Rudolf’s first successful Diesel Engine was the Motor 250/400. He officially tested the engine in 1897, and it resides in the German Technical Museum in Munich.


German entrepreneur Emil Capitaine claimed that Rudolf Diesel didn’t invent a new engine but used existing designs to create the Diesel Engine. Capitaine filed a patent lawsuit against Diesel but lost the case due to unsupportable evidence. Otto Köhler was also a vocal critic of Diesel’s designs. Köhler published an essay seven years earlier than Diesel describing a similar engine but dismissed its effectiveness. In the end, Friedrich Sass (a German engineer, university professor, and historian) declared Rudolf Diesel’s engine design was his “very own work.” He also stated that any “Diesel myth” is a “falsification of history.”

Mysterious Death

On September 29, 1918, Rudolf Diesel disappeared from the GER steamer ship’ SS Dresden’ in Antwerp. He was traveling to a meeting at the Consolidated Diesel Manufacturing company in London. Rumors indicate that he intended to meet with agents of the British Royal Navy to discuss using diesel engines in British submarines. Documents show that Rudolf had dinner on board the ship and retired to his cabin around 10 pm. He requested a wake-up call for the following day at 6:15 am.

However, in the morning, his cabin was empty, and his bed undisturbed. A nightshirt was still laid out, and his watch was left near the bed. Ship employees later found Rudolf’s hat and overcoat under the after-deck railing. A Dutch pilot boat found a badly decomposed corpse in the water ten days later. Although they left the body in the sea, his son was able to identify Rudolf Diesel by his gathered personal effects. Theories regarding the cause of his death vary between suicide and murder. Authorities found few clues, and the cause of his death remains unsolved to this day.

Diesel Engines: How They Work

During Rudolf Diesel’s time, steam-powered engines were external combustion engines that burned fuel outside the engine’s cylinders. Diesel Engines were internal combustion engines that burned fuel inside the engine. This process made Diesel Engines much more efficient than the steam-powered engines used at that time. After Rudolf Diesel’s death, engineers made many improvements to his original design. Check out these classic examples of vehicles using various types of diesel engines.

Vehicle Four-Stroke Combustion Cycle

Diesel Engines designed for vehicles mostly use a four-stroke combustion cycle to produce power. The heat generated from compressed air ignites the fuel in a Diesel Engine.

  • Intake Stroke:Air enters the cylinders through the intake valve, and the pistons move down.
  • Compression Stroke:The pistons move up, compressing the air.
  • Combustion Stroke:Fuel is injected and ignited at a specific time, forcing the pistons down again.
  • Exhaust Stroke:The pistons move back toward the top, pushing out the exhaust created during the combustion stroke.


Diesel Engines utilize a compression-based injection system instead of a spark-based system used in gasoline combustion engines. In a compression-based system, the engine piston compresses the diesel fuel after its injected into the combustion chamber. This compressed gas creates high temperatures causing combustion, which transfers into the power that moves the vehicle.

Direct Injection

Modern Diesel Engines utilize one of the following direct injection systems:

Distributor Pump Direct Injection

Older diesel engines utilize a distributor-type injection pump regulated by the engine. It supplies fuel spurts through the injectors into the engine’s combustion chamber. This early type of direct injection system was usually limited to commercial vehicles, with a few exceptions, due to its noisy operation and higher (smellier) smoke emissions. One bonus is fuel usage can be 15-20% lower than indirect injection Diesel Engines.

Common Rail Direct Injection

For common rail direct injection, a pump stores fuel at high pressure (up to 26,000 psi) in a tube-like reservoir. This reservoir feeds computer-controlled injector valves containing a nozzle and plunger controlled by a solenoid or piezoelectric actuators.

Unit Direct Injection

This direct injection system combines the injector and pump into a single unit positioned over each cylinder. This method prevents pressure fluctuations and achieves more consistent injection.

Vehicle Diesel Engines Maintenance & Repair

As an owner of a vehicle with a Diesel Engine, you know it is important to perform routine maintenance and schedule service for repairs with a reliable auto shop. We take pride in providing quality service and reasonable prices at Wentworth Automotive in San Diego, CA. Visit our website to make a reservation, or call us at (858)541-1044 to discuss your Diesel Engine needs.