We’re developing an ultra-lean combustion strategy for gasoline engines using Turbulent Jet Ignition (TJI). TJI is a technology that greatly enhances the ignition process, improving fuel efficiency and reducing emissions.
The technology enables the combustion to progress in a stable manner when the fuel-air mixture has been diluted with additional air or exhaust gas.
It works by premixing a small quantity of air and fuel in a pre-chamber – a small cavity that is separate from the main combustion chamber. This mixture is then ignited, generating turbulent jets of hot radicals which enter the main combustion chamber, providing a wider distribution of ignition sources than a traditional spark plug.
We have developed considerable understanding of this promising combustion mode, focusing on two distinct approaches: Active and Passive.
A spark plug and secondary fuel injector are positioned inside the pre-chamber. This injector introduces a small quantity of fuel, which is then ignited by the spark plug to create the turbulent jet of radicals that ignite the main charge in the combustion chamber.
No secondary injector is required as this approach relies upon the piston design and injection strategy to guide a small quantity of air and fuel into the pre-chamber to be ignited by the spark plug.
While the two approaches leverage different hardware, both yield greater efficiency and reduced emissions.
This technology has been successfully tested by several technology providers, and Aramco is currently integrating TJI into an advanced gasoline vehicle, which will be showcased in 2020. If vehicle integrations prove successful, we hope to see it commercialized in the near future.