Fuel savings

At the 2011 GIE+EXPO, John Deere released the ZTrak PRO Z925 zero-turn mower with Electronic Fuel Injection (EFI), which can provide up to 25 percent fuel savings for landscapers. In a nutshell, the mower offers a closed-loop fuel injection system that monitors engine performance for maximum efficiency.

To learn more about what EFI means for contractors, we caught up with Jamie Palmer, product manager of John Deere Commercial Mowing.
 

How does EFI work?

As implemented on the Z925A EFI, it is essentially identical to an automotive application. The fuel is pressurized by a second, higher pressure fuel pump and metered into the cylinders by precisely controlled fuel injectors – this is a sequential system, meaning that the fuel is injected only when the engine is in its intake cycle. Older fuel injection technology sprayed fuel the whole time; this new system leads to greater efficiency; as much as 25 percent demonstrated fuel savings. Also, the 4-wire oxygen sensor (as fitted to modern automobiles) senses the amount of uncombined oxygen in the exhaust stream, and therefore the amount of excess fuel, if any, and adjusts the amount of fuel being fed to the engine multiple times per second.
 

How is the engine unique?

The fuel injection system replaces the carburetor. There are other minor changes needed to the fuel system, including a slightly different fuel tank.
 

Are there different maintenance requirements?

The Z925A EFI system doesn't require special maintenance. The built-in diagnostic systems can tell you if anything is wrong with the engine and what it is.

The author is editor and associate publisher at Lawn & Landscape. He can be reached at cbowen@gie.net.

Watch a video of the ZTrak PRO Z925 from the show floor at bit.ly/deereEFI.