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The fuel-efficient future of zero-turn mowers


June 10, 2013
By Mike Jiggens

By Mark Meyers
Marketing manager, Dixie Chopper
http://www.dixiechopper.com

More than ever, commercial cutters are concerned about the fuel efficiency of their zero-turn mowers. And it only makes sense…of all the ways to cut costs, reducing your fuel consumption is a no-brainer. Not only can you save a lot of money, but you can also help the environment by lowering emissions.

As a result, many of the latest technological advancements in zero-turn mowers have revolved around fuel efficiency and sustainability. The developments you’ve seen so far are only the tip of the iceberg, though, as you can expect to see new offerings in fuel efficiency in the years to come. To provide an idea of what zero-turn mower manufacturers have in store, here’s a rundown of the latest technologies that have been keeping research and development departments busy.

Electronic fuel injection

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One of the most natural transitions to fuel efficiency has been the development of electronic fuel injected (EFI) engines for mowers. Although it took a while for outdoor power equipment to move beyond traditional carbureted engines, vertical-shaft EFI engines have become cost-effective enough that many zero-turn mower manufacturers now offer EFI models.

Since their invention, EFI engines have been refined to be highly reliable. In addition to trouble-free operation, commercial cutters also benefit by not having to adjust their operations to accommodate another fuel type. They can continue purchasing and storing regular gasoline to power all of their equipment, just as they always have.
Because the technology is so well developed, there aren’t many disadvantages to EFI mowers. However, fuel injection doesn’t reduce emissions as significantly as other alternative fuel options. Additionally, EFI models do have a higher up-front cost than traditional carbureted mowers. Generally, this cost increase may be around 10 per cent but, after calculating fuel savings of approximately 25 per cent, the purchase price becomes a non-factor.

Diesel

Another fuel-efficient option is diesel, which has actually been used in mowers for quite a few years. Back in 1999, Dixie Chopper even installed a 50-horsepower, turbo-charged diesel engine on one of its mowers. Since then, the most recent demand for diesel mowers has been spurred by the popularity of organic fuels, such as vegetable oil and recycled fry oil.

One of the biggest advantages to diesel is that it produces high torque, which, as commercial cutters know, is a key performance factor in zero-turn mowers. Also, the fuel savings help cover the higher up-front cost of diesel mowers.

Currently, the use of diesel engines in zero-turn mowers is greatly affected by EPA emission standards. Engine manufacturers have invested a lot of money to meet the latest requirements, so the cost (and complexity) of diesel engines has risen dramatically. Consequently, not all mower manufacturers offer diesel models at this time. Instead, they have focused on the development of other alternative-fuel options, rather than passing on the higher cost of diesel engines to consumers.

Propane

Propane is one of the alternatives that many manufacturers are focusing on, and it is gradually gaining momentum as a fuel source among commercial cutters. In addition to purchasing new zero-turn mowers equipped with propane engines, some people are converting the gas-powered engines on their existing mowers to run on propane.

Although engines consume slightly more propane than they do gasoline, propane cuts emissions by up to 96 per cent, and the cost of refueling is still much cheaper. Propane has no evaporative emissions and, unlike gasoline, it doesn’t turn stale. Also, propane-powered mowers are easy to run. Similar to EFI models, operators don’t have to hassle with a choke.

In spite of the benefits, there are a few misperceptions about propane—one being safety. For instance, some people think that mishandling a propane tank may cause an explosion, but that’s only a myth. In fact, it can be argued that propane is actually one of the safest fuel choices available. Its flammability range is much narrower than gasoline and diesel, and propane fuel tanks are 20 times more puncture resistant than gasoline or diesel tanks.

Furthermore, many commercial cutters worry about performance and refueling. To alleviate these concerns, propane has been used successfully as a fuel for more than 80 years, and it offers comparable horsepower and torque to gasoline. Refueling is also simple, clean and fast, thanks to sealed, threaded connections. Propane is readily available at many gas stations and hardware stores, but the biggest disadvantage is the need to carry spare propane cylinders, which cost extra and take up more space.

Compressed natural gas

Compressed natural gas (CNG) is also a proven technology that has been around for quite some time, but the development of CNG as an alternative fuel for mowers didn’t happen until recent years. In fact, Dixie Chopper was one of the first manufacturers to introduce a CNG-powered zero-turn mower with the release of its Eco-Eagle model in 2010. (In comparison, its first propane model was launched in 2006.)

Similar to propane, commercial cutters can convert their existing gas-powered engines to run on CNG, rather than buying new. The other advantages are also comparable. CNG is an abundant natural resource that is cheaper than gasoline and burns much cleaner. It is also safer, since CNG is lighter than air and disperses quickly into the atmosphere in the event of a release.

The adoption of CNG has been slightly slower, though. The main deterrent is the lack of infrastructure for refueling, as CNG stations are currently few and far between. For this reason CNG models are more popular among homeowners who are able to conveniently refill the tanks from their own residential supply lines.

Electric

The next alternative fuel option eliminates emissions and fuel costs altogether. For years, manufacturers have been working behind the scenes to develop electric-powered prototypes, but there have been two main hurdles to overcome: (1) the length of time a mower can operate on one charge, and (2) the amount of time needed to recharge the battery.

Although electric motor and battery technology has seen significant improvements over the years, it is still not highly practical for zero-turn mowers. One of the biggest issues is that zero-turn mowers demand a constant high level of torque when cutting grass (unlike cars, which only use high torque when accelerating). Coincidentally, torque consumes a lot of battery power, so a full charge can be drained very quickly while mowing. This downfall is especially deterrent to commercial cutters who mow 10 hours per day, six days a week. They simply do not have the time between jobs to recharge their mowers, nor do they want the extra cost or hassle of carrying extra batteries. Therefore, there are not currently any production units of electric-powered zero-turn mowers designed for commercial cutters.

Hydrogen

Believe it or not, hydrogen is another fuel on the minds of some zero-turn mower manufacturers. This option is farther on the horizon than any of the others, but, if the automobile industry is able to make breakthroughs in this technology, it’s possible that we could see mowers follow suit in the future.

In order for hydrogen to become feasible, engine manufacturers must first overcome some significant hurdles in the cost, availability and storage of this fuel. If these issues are ever resolved, it would allow mower manufacturers to develop products for a fuel source that produces zero harmful emissions.

Whether it’s propane, CNG or any other alternative fuel, the more people who adopt it, the more feasible it becomes. If, for instance, demand causes engine manufacturers to make more propane engines, then the cost to produce them will go down. And, as more people fill up on propane, stores will begin offering better propane refueling services. In turn, this would cause even more people to purchase propane mowers, and the trend would have a snowball effect.

Ultimately, consumers will be the ones who decide which alternative fuel options thrive and which ones fade away. But, until a direction is picked, zero-turn mower manufacturers will continue leading the path to sustainability in the best way they know how: by developing better mowers that use less fuel.


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