The goal of any manufacturer is to produce a piece of equipment that passes along productivity and profitability to its customers. “A major trend in our industry is finding ways to advance the amount of productivity per gallon of fuel,” says John Swanson, Product Manager, Exmark Mfg. Co. Inc. (company information, 11078696), Beatrice, NE. “For a landscape contractor, that is a really high priority considering how directly fuel costs impact their profitability.”
EFI and propane
As a frequent new technology development and launch partner with engine manufacturers, Exmark is able to get in on the front end of implementation and gain exclusivity and market share gains prior to a technology’s public launch. The company recently worked with Kohler Engines (company information, 10055682), Kohler, WI, to develop a closed-loop electronic fuel injection (EFI) propane engine system, the PCV740 Kohler EFI. “Our industry was a little resistant to convert to fuel injectors,” says Swanson, “but now that the technology is proven and more reliable, we’ve seen an industry transition to acceptance. I can see carbureted engine systems eventually being phased out completely,” he predicts.
“We worked with Kohler and the Propane Education and Research Council (PERC, association information, 10286979) to develop the PCV740 found exclusively on Exmark’s Lazer Z Propane zero-turn riding mower for the 2013 model year. In 2014, the engine will become more widely available to other manufacturers,” explains Swanson.
Kohler EFI engines integrate an oxygen sensor that analyzes the air/fuel mixture in the unit’s exhaust. If the oxygen level strays from the ideal mixture, the sensor triggers adjustments to the amount of fuel injected into the system. Kohler’s EFI technology then “closes the loop” between the air/fuel intake and the exhaust output to provide a constant stream of critical feedback, which helps deliver optimal fuel efficiency and a variety of other benefits, including easy starting, improved power and increased life span.
“With the closed-loop propane system, Exmark is seeing the Lazer Z Propane mower burn 40 to 50% less fuel, and the performance exceeds what we had on the old system,” Swanson says. “That’s helping to lower the amount of greenhouse gas (GHG) emissions dramatically as well.” Customers in the lawn care industry are now coming to understand that with an up-front investment in a mower with advanced EFI technology, they can get a long-term payback with fuel efficiency.
Using propane fuel is not without trade-offs for the manufacturer. There is a cost and weight penalty due to the amount of fuel needing to be hauled on-board the mower (or other vehicle) as well as the increased storage needs for the gaseous fuel. To combat the added weight issues, Exmark has worked to lower the overall package weight by going to a one-tank propane system as opposed to the two-tank solutions typically found in the industry. Instead of two 33.5-pound tanks mounted off the side, Exmark uses one 43.5-pound tank that is centrally mounted over the engine, reducing the overall weight and enhancing mower handling due to the balanced tank location.
“If there is ever a way we can reduce weight without impacting durability, it’s a win-win. But we won’t sacrifice the durability,” Swanson says.
Beyond the electronics and sensors included in the fuel injection system, Exmark implemented last year its RED on-board intelligence platform which is capable of improving fuel savings even further. Instead of a spring-based mechanical governor system, the RED platform features an electronic governor on the engine that was originally developed for generator and welder machines. The electronic governor offered by Exmark, E-Gov, helps to maintain a constant yet slightly reduced engine rpm which reduces fuel consumption while maintaining blade tip speed for improved and consistent cut quality.