Fuel Injection...it’s not just for hot rods anymore
Twenty to thirty years ago, a revolution swept through the automobile world like a hurricane—and now it’s making its impact on the green industry. Driven by rising gas prices in the 1970s and ’80s and tougher clean-air standards, changes were desperately needed under the hoods of American cars. Detroit engineers agreed on one thing—carburetors couldn’t cut it. They weren’t flexible or versatile enough. The days when any mechanic with a good ear and a screwdriver could tune an engine were ending . . . enter Electronic Fuel Injection (EFI).
Commercial mowers are now going through a high-tech changeover that echos what happened in the automobile industry a couple of decades ago. Specifically, we’re talking about the increased use of EFI engines in mowers.
For 2014, you’ll see more commercial mowers with EFI engines than ever before. Are these hightech mowers right for you, or is EFI just another over-hyped buzzword?
Climb aboard and ride along as we give you an overview of EFI engines. And get ready for a little tech talk that will make the newest trends and hardware easy to understand.
How EFI Works
Mowers powered by EFI engines promise more horsepower, better fuel economy, lower emissions and integration with other on-board electronics. That’s a ton of benefits. It’s like replacing your typewriter with a computer; you can still produce documents but do a lot more as well.
“Contractors are responding to the cost savings and the fuel efficiency,” said Rob Little, director of marketing at Toro. “EFI is a continuing trend throughout the industry.”
Engineers estimate that electronic fuel injection can reduce fuel costs by as much as 25 to 30 percent. Tim Cromley of Walker Manufacturing in Ft. Collins, Colorado, says that 40 percent of their sales are EFI-powered mowers, a huge chunk of overall business. And it’s only going to grow.
Except for NASCAR racers, every non-electric automobile today uses EFI—and has for years. This technology replaces the familiar carburetor with one fuel injector per cylinder. But what the heck is electronic fuel injection and how can it give you such big fuel savings?
Pioneered by Mercedes-Benz, the early mechanical fuel injection systems for cars began in the 1950s and ’60s. These systems were more like hybrids of carburetors and fuel injectors. They were complicated and leaky and there was no computer control. Chevrolet’s Corvette also used an early, mechanical fuel injection system; it worked, but had problems.
Next came the union of fuel injection and computers. At first, there was only one fuel injector and it delivered gas for the whole engine.
That was called singlepoint injection. It was an improvement, but still not ready for the tougher clean air rules. Then we progressed to true EFI, sometimes called sequential or multipoint fuel injection. Let’s dig a little deeper to see how it operates.
A fuel injector is an electronic valve that sprays a fine mist of fuel at each cylinder, in a precise amount that matches engine demand, gives clean combustion and maximum power. The fuel coming into the injector is usually under pressure, so the spray is dense and fast. There’s a computer upstream of the injector measuring air intake volume, temperature, air density and throttle position. As these readings change, the computer recalculates instantly and varies the length of time that the injector sprays.
Because of the different sensors and the precision timing of the injector, you have an exact amount of fuel dispensed under all conditions. Unlike the carburetor, which does the same thing whether it’s a hot or cold day and whether you are mowing grass in Miami, Florida, or Colorado Springs, Colorado, the fuel injector is always changing and adapting. You might call it a “smart” system.
“We think that the big winner in the long run is going to be EFI, which is what we’ve thought for 15 years. Just looking at the current state of automobiles, and the alternate fuel ideas—well, we’re not seeing a whole lot of propane cars,” said Cromley. “We saw a big change in the delivery of fuels in the automotive industries in the ’80s and ’90s, and we believe that this is where our industry is now. And that’s where we’re putting our future. We’ve produced more than 20,000 machines that have EFI engines in them, so you could say we’ve paid our dues.”
Service and maintenance
Mike Simmon of Grasshopper Mowers in Mound Ridge, Kansas, mentioned another benefit of EFI: service. Unlike a carbureted engine, an engine with EFI can tell you where it hurts.
“We’ve got Kohler Command PRO engines in our new models, like the 327 EFI and 727T EFI,” Simmon told us. “They have plug-in diagnostics that are a secondgeneration system that’s much improved over just a few years ago.”
For contractors who work in the commercial area, an EFI engine is the perfect addition to their lawn mower fleet. If there’s a problem with the engine, there is less downtime and faster repairs.
The dealer can take that machine, plug in the little box next to the engine and the system will spit out diagnostic codes about what’s wrong with the engine. It helps the technician narrow down the areas where the problem is occurring. And that means quicker service time. “For commercial contractors, lost time is lost money,” said Simmon.
At some point, larger fleet operators will probably want to get diagnostic computers or software of their own rather than depend on dealers for service.
Every EFI engine has an Engine Control Unit (ECU). This is a small, dedicated computer chip that gets input from various sensors, controls engine warm-up and idle, and determines how much fuel the injectors spray. It also logs some data for use in service calls. The ECU uses ‘mapping’ to calculate the amount of fuel delivered to the engine. It’s like looking up information, but very fast. These mapping values have been determined by extensive testing and real-world trials. They are pre-set by the factory and should not be altered. But since most manufacturers make it nearly impossible to crack their internal codes, it’s not easy to make changes in the systems.
Exmark has taken the capabilities of EFI to a higher level with the RED system (it’s not an acronym). “This system gives our Kohler engines a built-in capability to sense operating environments, and the ability to get the best fuel/air mixture into the combustion chambers,” said Daryn Walters, director of marketing for Exmark Manufacturing in Beatrice, Nebraska.
“RED is a controller that mounts next to the engine. It enables us to alter the performance of that engine in certain operating environments. So, EFI by itself gives some fuel savings, but RED offers even greater savings,” said Walters. “We’re going to continue to invest in that onboard computer capability, and we feel that this will really get the notice of others in the industry. When you’re burning less fuel, you’re saving a lot of money.”
Greg Scharf, owner of Greg’s Lawn and Landscaping in Cedar Rapids, Iowa, has been in the landscape business for 30 years. He puts between 60 and 65 mowers in the field every working day in season. He has had mixed experience using EFI engines in his commercial equipment.
When we asked if a properly working EFI mower was a benefit to the commercial contractor, Scharf said, “Absolutely. When you burn half the amount of fuel, darn right it’s helpful. We burn a lot of fuel in a year.”
“Well, we’ve got some EFIs—I guess it’s DFIs—in our Kawasakis,” Scharf told us. Kawasaki uses the term Digital Fuel Injection (DFI) for their engines. It means the same thing: fuel injection under computer control. “And those, knock on wood, those are just flawless. We’ve had those for a number of years,” he said. “I think we started buying those on our Scag Turf Tigers, probably about seven or eight years ago.
I wouldn’t buy anything other than those machines. When you compare those DFIs to similar-sized carburetor engines, they run about 30 percent less fuel.”
Industry-wide, it would be surprising if the transition to EFI engines goes off without a hitch. While there’s nothing radical or experimental about electronic fuel injection today, putting it on a given engine and making it work under the difficult conditions faced by landscape workers is something else.
Although we have noted a few difficulties with some EFI engines in the field, any new technology will require some break-in time. Given that EFI dominates the automotive industry—and that’s unquestioned today— it’s a good bet that, with certain exceptions, you’ll see this technology spread throughout the commercial mower field over the next few years.
Accordingly, not every EFI mower engine has worked out so well. “We bought three brand new mowers with Kohler engines on them earlier this season and, when they’re running, they burn about half the fuel of a similarly-sized engine,” Scharf said. “However, keeping them running has been an absolute nightmare. My dealer convinced me to try these EFI engines, but we’re having problems with the regulators (which are like charging units). We can’t keep regulators in them. Those mowers should have over 400 hours on them by now, and each one of them is under 200.”
Since pump gas has the highest energy density of any popular fuel—by far—EFI engines help extend the life of gasoline as a fuel by giving you lower fuel costs. But gas is still expensive, has emissions problems and is tied to touchy international politics. This is where alternative fuels come in.
On a slightly different note, Joe Kujawa of Kujawa Enterprises Inc. in Oak Creek, Wisconsin, said, “We do not have EFI engines on our equipment. The mowers we use were not equipped with EFI engines, and in talking with other contractors, we heard that EFI engines were not very water-friendly. The computers and electronic controls seem to be sensitive to water and dampness. And, secondly, perhaps more importantly, if the battery dies and you need to jump it and you forget or fail to disengage the computer, you can fry the electronics—and that’s not covered under warranty. At the time we looked at it that was one of the concerns we had, and we didn’t want to risk that,” said Kujawa.
Briggs & Stratton has taken a slightly different approach and does not currently produce an EFI engine. In their newest line of Vanguard engines, Briggs has opted for bulletproof reliability and increased torque, citing the need for mowers to operate under the most difficult conditions over many years of service.
Their latest engines offer increased displacement for more horsepower to meet the demands of new, larger zero turn radius mowers with wide cutting decks and power-hungry accessories. Vanguard engines will be available as single-cylinder models or V-Twins, ranging from 13 hp to 36 hp.
“Briggs & Stratton is known for helping people cut grass; it’s in our DNA,” said Dan Roche, marketing manager with Briggs & Stratton Commercial Power. “We have logged tens of thousands of hours testing to ensure we’ve perfected the design, materials and assembly processes.”
We’re defining alternative fuels as everything other than gasoline. Due to the increasing popularity of alternate fuels and some misconceptions about them, we’ll be featuring an article about them with a complete rundown on each one in our next issue.
It looks like the industry is headed solidly in the direction of fuel efficiency. While some issues remain, as with the auto industry, the manufacturers of these EFI engines will be working hard to get them resolved.
One thing is for sure: contractors cut a lot of turf every year. As the cost of fuel continues to rise, anything that allows them to save money on this necessity will be welcome. Fuel savings of 25 to 40 percent will have a big impact on your bottom line…and there’s nothing wrong with that.