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Clean Diesel = Outstanding Fuel Economy

Clean diesel engines, like the Cummins B 6.7 and the anticipated Detroit™ DD5™, are more fuel-efficient and provide best-in-class fuel economy than diesel engines of the past. In fact, diesel remains the most fuel efficient engine (due to more BTU’s), providing nearly 50% better fuel economy than any other similar-sized gasoline, propane or compressed natural gas engines. Take a look for yourself in the chart below.  Diesel provides the best fuel economy in the industry followed closely by CNG and then by gasoline and propane, which both offer a 50% reduction in fuel economy compared to diesel.

Fuel Efficiency Fuel Economy
Propane (LPG) Propane offers 66% of the energy efficiency of diesel.  It burns at 91,333 BTUs per diesel gallon equivalent (DGE). Propane reduces fuel economy by nearly 50%  compared to diesel.
CNG CNG has excellent fuel efficiency, burning more efficiently than LPG but less efficiently than diesel.  CNG provides 91% of the energy efficiency of diesel.  It burns at 125,370 BTUs per diesel gallon equivalent (DGE). CNG typically shows a 1% to 5% reduction in fuel economy  compared to diesel.
Diesel Diesel remains the most fuel efficient fuel choice (due to more BTUs) vs. propane, compressed natural gas and gasoline.   Diesel burns at 138,490 BTUs per gallon. Diesel provides the best fuel economy.
Gasoline Gasoline engines are not as fuel efficient as other fuels. Gasoline burns at 112,114 BTUs/gallon. Gasoline reduces fuel economy by nearly 50%  compared to diesel.


Given the fact that fuel costs represent more than two-thirds of the typical school bus fleet’s annual operating expense, running a fleet on diesel vs. a less-efficient fuel source can have a tremendous positive impact on your budget.

In fact, with its overall low cost, efficiency, engine durability and resale value, diesel has a total cost of ownership that can be much lower than propane, gasoline and compressed natural gas. It delivers proven performance and reliability and is just as cleaning-burning (if not cleaner) than any other fuel types at the tailpipe.

How to Increase Your Fuel Economy

Fuel represents one of the highest operating costs for fleets, so tracking fuel consumption and taking action to optimize fuel efficiency is critical.

When it comes to maximizing fuel economy, nothing is more important than having a good driver behind the wheel. It’s critical to educate drivers on improving fuel economy through reducing highway speeds, avoiding hard braking or acceleration, shortening idle times and properly selecting gears.

Besides educating your drivers, ensure your school buses are in good operating condition, stick to preventative maintenance schedules and make sure your tires are inflated properly.

To learn more about the benefits of diesel or what you can do to run a more efficient fleet, contact your local dealer.

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