The following is an excerpt from an article appearing in the September 2013 issue of OEM Off-Highway magazine, a Green Industry Pros sister publication.
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 for Exmark. “For a landscape contractor, that is a really high priority considering how directly fuel costs impact their profitability.” The solutions that find their way onto the next generation of mowing equipment accomplish reduced fuel consumption and increased productivity together, not one or the other.
EFI and propane improve performance
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 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.
“We worked with Kohler and the Propane Education and Research Council (PERC) 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.
On-board intelligence amplifies fuel savings
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.
“Because the E-Gov system is more responsive than a spring and wind-based governor system, the engine doesn’t have the rpm droop you can get if you’re cutting a patch of heavy, wet grass,” says Swanson. “Engine droop is significant on the mechanical governor system we’ve used in the past in the industry. With the electronic governor, it doesn’t mean you have zero droop, but it’s close to zero. As opposed to a binary system that looks for feedback after a condition has changed, the electronic version senses condition changes and can supply feedback immediately allowing the engine to adjust accordingly.”
The RED technology is essentially an engine management system that interacts with the electronic governor technology and allows Exmark to define the performance modes of the engine. A contractor can work in Max, Efficient or Low modes depending on the conditions. “I would say approximately 80% of the time the contractor should be running in Efficient mode which allows the engine to run at its peak performance while maximizing fuel efficiency. If they encounter overgrown or heavy cutting conditions, for example, the operator can switch to Max mode,” says Swanson.
In the long term, Exmark can see a fully automated system allowing the machine to run in its most efficient mode dependent on conditions without any operator engagement, but transitioning an operator from full mechanical control to zero control is too significant of a mindset and operational shift for Exmark. As an interim solution, the RED platform system features a physical rocker switch with three mode selection. “We’re phasing it in to ensure our customers end up with the performance we want and they need,” Swanson states.