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Next Generation Mowers Go Green

Posted on 27th Mar 2011 @ 1:32 PM

Mowing has come a long way from the poor guy who had to use a scythe to smite the tall grass. And although President Woodrow Wilson thought it a great idea to use sheep to mow the White House lawn, most people are not as enthusiastic about having animals grazing in their front yard. 

The way things used to be . . .

An English engineer named Edwin Budding invented the first mechanical push mower in 1827. In 1870, Elwood McGuire of Richmond, Indiana, designed a push mower that was lighter, easier to push and had fewer moving parts than the old versions. Almost overnight, every ambitious teenage boy in the country began mowing their neighbor’s lawns for money, and an entirely new commercial industry was born. Mowing one or two lawns a day on the weekends wasn’t going to be nearly as profitable as mowing several lawns every day of the week. In order to accomplish this successfully, “man-power” muscle was soon replaced by gas-powered engines.

Motorized mowers first appeared in the United States in the late 1890s and were powered by lightweight gas engines or small steam powered units. These machines worked quite well but they had one major drawback: they were very difficult to turn. For certain jobs, walking behind a mower is standard; however, changes have been made since the early models of push mowers. As the engineers developed new technology, self propelled mowers appeared. This state of-the-art machine still works today; in fact, you can buy an attachment—a sulky—to stand on and have this self-propelled walk   behind mower pull you.

Nearly 80 years later, the zero turn mowers (ZTM) entered the scene and revolutionized the entire lawn mower market. Zero-turns have . . and now . . . what does the future hold? 

The demand for eco-friendly equipment and products is ushering in a new wave of power sources which are beginning to replace gasoline engines and gained in popularity among professional landscape contractors. All of these improvements in the design of the modern mowers were developed with one thought in mind: to ensure that your crew members will stay fit and healthy. Mowers that are more efficient and easy to operate will result in less stress on your workforce, more productivity for your company and an increase in your bottom line.

While creating a beautiful landscape will always be the number-one selling point for landscape contractors, sensitivity to environmental issues has become just as important in servicing your customers’ needs . With increased awareness of carbon emissions and pollution restrictions, legislation is on the rise. The demand for ecofriendly equipment and products is ushering in a new wave of power sources that are beginning to replace gasoline engines.

Thanks to the advances in technology over the last several years, lawn mower engines have become more fuel efficient and eco-friendly. This new technology meets the requirements of the industry by providing a broad choice of alternatives for both efficiency and environmentally-friendly performance.

Up until the early part of the 21st century, the three industry standard engines were gasoline, diesel and propane. Of the three, the most common was gasoline. However, gasoline engines are the least fuel efficient of the three. More importantly, gasoline engines have been reported to be a major contributor to global warming and air pollution because of their exhaust fumes.

The diesel is the engine workhorse. It is built to sustain heavy loads. Diesel engines have routinely produced a higher fuel-efficient performance than gasoline, and had very low maintenance characteristics. Diesel mowers have suffered a bad rap over the years due to their slow ignition and acceleration, especially during cold seasons. They were also very noisy and emitted tons of smelly carbon dioxide into the air.

However, with the innovation of clean technology, long-time mower manufacturers Grasshopper and John Deere have found a way to use ‘clean’ diesel engines, so performance has gone up and emission problems have decreased.

“A variety of factors point to clean diesel as the practical alternative fuel,” says Ray Garvey, Grasshopper communications coordinator. “Diesel has long made sense from power, productivity and fuel consumption perspectives. Recently, the near elimination of impurities in diesel fuel combined with improved e n g i n e technolog i e s h a s m a d e ‘ c l e a n ’ d i e s e l a reality. Saving 700 gallons of fuel over 1000 hours with diesel while reducing costs and emissions addresses the most fundamental needs of a growing number of clients who are motivated by a practical and cost-effective approach to carbon reduction and greater productivity.”

Propane-powered engines are considered to be the ‘purest’ among the other engine types, because they emit less toxic emissions. Compared to a diesel engine, the propane engine increases burning efficiency by 15 to 20%. Propane engines also generate 10 to 20% of torque at the reduction of fuel costs. Propane fuel is also less expensive than either gas or diesel fuel. According to the Energy Information Administration (EIA), recent fuel prices—while fairly close in cost—when compared to performance and efficiency, can vary widely. Gasoline prices rose 98% in one year compared to 50% for diesel and only 22.6% for propane.

While conversion kits have been around for awhile, propane-dedicated mowers are just beginning to emerge onto environmentally-sensitive landscapes across the country. Many manufacturers are now offering a propane-powered commercial mower that will run for up to 10 hours on two tanks of propane.

“The low polluting propane-powered mower is better for the environment,” says Bill Shea, vice president of commercial sales for the Briggs & Stratton Yard Power Products Group. “Propane also produces 30% less smog-forming emissions when compared to gasoline and diesel.”

The ‘new kid on the block’ for lawn mower fuel alternatives is compressed natural gas (CNG).  

Compressed natural gas unit

cngm2.bmpintroduced a liquid propane mower three years ago. This mower was marketed to ease emissions concerns, then they took the eco-friendly trend one step further by introducing CNG. CNG is made by compressing natural gas, mainly composed of methane, to less than 1% of its volume at standard atmospheric pressure.

Although CNG produces a small amount of greenhouse gases during combustion, it is a more environmentally-clean alternative to gasoline, diesel or propane. It also is much safer than other fuels in case of a spill, because natural gas disperses quickly when released.

Another growing trend in ecofriendly fuels is biodiesel. Biodiesel is an alternative fuel made from new or used vegetable oil. The oil can originate from many plant sources, such as corn, soybeans, rapeseed, palm oil, and coconut oil. The main reaction used to produce biodiesel involves mixing oil, alcohol and a catalyst (usually lye) in approximate ratios of 80%, 20%, and 0.35% respectively. Essentially, it is taking a triglyceride (vegetable oil) and making it into a methyl/ethyl ester (biodiesel).

Electric mowers have zero emissions, no engine noise and low maintenance.

The Toro Company tested everything from soybean oils to French Fries grease as fuels, before they introduced a biodiesel-powered lawn mower a few years ago. “Toro has branded the equipment “Biodiesel Ready,” meaning they can run on 20% vegetable oil and 80% petroleum diesel, a blend known as B20,” said Steve Wood, Toro’s chief engineer. “These engines are very attractive to municipalities which are enacting environmentally-sensitive legislation.

Liquids and gas fuels won’t  be the only source of power in the future. Although not yet as popular as the traditional fuels, manufacturers are looking into an all-electric zero-turn lawn mower. Electric mowers have zero emissions, no engine noise and are low maintenance. Hustler by Excel has introduced a battery-powered zero-turn mower; however, it is limited by the short operating time (about one hour).

The downside is that the current batteries have a short use time before they have to be recharged. Industry experts predict that the technology will get better as time passes, allowing for more use-time between battery charges. Another problem is that, being a new technology, electric mowers are more expensive than other engines. But like computers or flat screen televisions, prices will begin to go down as battery manufacturers develop longer lasting, more versatile products.

Unlike hybrid automobiles, which run on gas and electricity, a hybrid lawn mower combines a DC battery with AC electric power. In some models, the operator can switch between DC or AC power in order to run the motor on either line voltage or battery. During times of battery run-out it can work on the cables, where it has the dual function of putting the equipment to work and automatically charges the battery.

Remote-controlled wireless mowers are the greatest human energysaving products on the market today. The unit is controlled by the operator, much like a toy airplane or truck. The commercial-grade units can handle very steep hills, rough terrains that might be too risky or uncomfortable for humans to go. While not meant as a replacement for the more traditional mowers, they do have a place in the commercial field. The little round units can mow on slopes in place of a bunch of men with weed eaters.

An electric lawn mower that utilizes solar power as an energy source may be the wave of the future. But for some manufacturers, the future is closer than you can imagine. Husqvarna introduced an automatic electric solarpowered hybrid robotic lawn mower in 2008. The residential model will mow for around 40 minutes, and then charge for 40 minutes in its charging station. By using the solar panels on a sunny day, the device will be able to stay out cutting for up to 50% longer. The unit isn’t quite “ready for prime time” for the commercial indust r y, but the technology is well on its way.

lawnbott-lb1200.jpgRobotic mowers have a long way to go before they’re a commercial staple. For one thing, they are rather slow moving. Some robotic mowers are narrower than others, so they take a longer time to cut a whole yard. This is problematic, since your business depends on quantity as well as quality, and no matter how exact a mechanical “man” is, manufacturers have yet to invent one that will completely replace a real human being.

Lasers may sound like something from Star Wars, but they serve a very valuable purpose right here on earth. Laser-guided mowers, although still in early development, hold much promise for the industry. Electric eyes or wires need to be installed around the property to be mowed. The mower can be programmed to mow the turf in what ever pattern is desired. The pattern can be changed according to the job. When the crew person arrives at the jobsite, he/she can take the mower off the trailer or truck, start it up and place it on the lawn. As the mower reaches the end of the lawn, it will break the beam of the electric eye, or come close to the wire, then make a turn as programmed.

“Sensors actually ‘sense’ when the mower is over grass to cut,” says Steve Jones of Probotics. “The Lawnbott robot mower doesn’t need wires because it senses obstacles and reverses direction when moving over walkways, curbs, patios and mulched areas.”

While the lawn is being mowed, the worker can be cleaning out the beds, checking on the sprinklers, or pruning the bushes.  

While the turf is being cut, the crew person is free to perform other maintenance tasks, basically working in two places at once. While the lawn is being mowed, the worker can be cleaning out the beds, checking on the sprinklers, or pruning the bushes. When the mower has finished its job, the crew person would be finished with his as well, then put the mower back on the trailer and move on to the next job. When this becomes reality, one-person crews could become the norm.

As you can see, lawn movers have come quite a long way since the early days of pushing rotating blades by hand. The future will be whatever the market demands and the imagination can create.