Diesel Tundra or Tacoma? Could this Patent from Toyota Suggest a High Compression Gas OR Diesel Engine?

Can Toyota reinvent the combustion engine?

2022 toyota tundra diesel hd new engine

This patent may be for a high compression gas or diesel engine

Initially filed on December 2019, U.S. patent (US20200208601) was made public on July 2nd, 2020. The patent indicates that Toyota is developing an engine that uses high compression for enhanced performance and reduced emissions. We don’t know if it’s a gas or diesel engine.

I’ll try to avoid going through the minutia of how high compression work. It’s easiest to say that more power is exacted by the engine with minimum use of fuel. More force is exerted on the piston, which is higher on the compression stroke than normal. This creates additional push on the expansion stroke, creating more power without burning additional fuel.

toyota compression engine patent diesel tundra tacoma

This technology is not new, diesels have used it for years and gas engines now use it often. In addition to the extra power (which means less fuel usage for power, thus less consumption) the system burns very clean.


In the patent, one of the notations states that the process they are creating will mitigate smoke. We believe that is a reference to exhaust gases. Now, that’s what caught our attention. This is where it could mean a diesel engine, which is intriguing.

First of all, Toyota already builds high compression gas engines. The Dynamic Force Engines used in a variety of four-cylinder vehicles. It has a proven track record for power and efficiency. They, along with Mazda and other automakers, have proven the benefits of high compression over the long run.

Toyota Dynamic Force Engine

Is this a diesel engine?

Having a high compression diesel engine that can burn off excess “smoke” would be a boon to any vehicle. Imagine, not having to use DEF to convert NOx to nitrogen and water? There have been some systems in the past that used a variety of other methods (including ultra high heat) to combat NOx – but this could be a game changer.

Right now, nearly every 1/2 ton truck sold in the United States has a six-cylinder diesel variant. Not counting Nissan, the rest build a version of a 3.0-liter diesel that tends to be much more efficient than the gas equivalent. There are some drawbacks, including DEF, additional weight and pricing issues. By building a lighter, more efficient diesel engine, some of those issues can be addressed. A diesel that doesn’t need additional (costly) plumbing for its exhaust system.

This is all based on conjecture, but it is intriguing to think about the possible applications of such a power-plant. What do you think? Would you buy a diesel Toyota Tundra, or even a diesel Toyota Tacoma?

Easily amused by anything with four wheels, Nathan Adlen reviews vehicles from the cheapest to the most prestigious. Wrecking yards, dealer lots, garages, racetracks, professional automotive testing and automotive journalism - Nathan has experienced a wide range of the automotive spectrum. Brought up in the California car culture and educated in theater, childhood education, film, journalism and history, Nathan now lives with his family in Denver, CO. His words, good humor and video are enjoyed worldwide.