Before you go out and start pumping gasoline into one of your tanks on your rig, know that this application is meant for light load, small diesel engines and is an experiment in low temperature operations.  A study funded by the joint University of Michigan/General Motors Collaborative Research Laboratory in Engine Systems was conducted by researchers from Shanghai Jiao Tong University in the use of “dieseline” for low temperature combustion (LTC).

The study was aimed at the low-emissions, high-efficiency operational range of an LTC engine for many applications and a paper on the work appeared in the journal Energy & Fuels earlier this month.

The idea was to lower both NOx and particulate matter (PM) emissions using both LTC and by delaying the fire enough to overcome the challenge of pre-mixing for efficient results.  Many methods, such as high pressure fuel injection using large amounts of exhaust gas recirculation (EGR), have drawbacks such as reduced oxygen content in the cylinder.  This reduces efficiency.

The research was based on the theory that by using a low-cetane fuel with a higher-volatility rate.  Dieseline (mixing diesel with gasoline) has been tested before with mixed results, but this team believed that the ratios were too high.

By lowering the mixture to 80:20 (80 parts diesel, 20 parts gasoline (93 octane), by volume), the researchers hoped to increase the ignition delay enough to cause higher vaporization of the PM and NOx emissions, reducing those coming out the stack.

They reduced the engines compression ratio from 19:1 to 15:1, added the fuel mix, and tested.  They found that the longer ignition delay achieved by adding the gasoline (which is not as susceptible to autoignition) caused the mixture to burn more thoroughly, extending smokeless combustion in the chamber and lowering both NOx and PM.

Very interesting stuff, though the applications for this are pretty limited.  The groundwork here, however, could lead to more efficient diesel (and biodiesel and similar) engines in the future.  Who knows?  Just as ULSD was introduced a few years ago and became the standard, so too could a dieseline mixture of some kind.

Related posts:

1. Gasoline vs Diesel
2. Meet the Glider, a Big Rig That Uses 40% Less Diesel Fuel