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Diesel Progress Article Features Vanguard Engines
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IN THE VANGUARD ON SOLVING FUELISH PROBLEMS
by Mike Brezonick
There is a scientific doctrine suggesting that the simplest solution for any problem is invariably the correct one. In the commercial world, the corollary to that might be that the simplest solution to a persistent challenge is likely to be the right one for a market or a customer.
So when Briggs & Stratton Commercial Power spent more than a year huddling with customers and other users of small commercial gasoline engines, it found that a great many of the most frequent engine problems were related — in one way or another — to fuel getting into the engine oil. And those problems occurred because the average user frequently didn’t bother to use the fuel shutoff system that is part of most industrial gasoline engines these days.
So how do you get users to do something they already ought to be doing, but too frequently aren’t?
For Briggs & Stratton, the answer turned out to be one of the most basic of simple machines — a single lever.
But by incorporating both engine shutdown and fuel shutoff functions into that one bright red lever, Briggs &
Stratton came up with something that addresses just about all of the fuel related issues its customers raised.
And that integrated system, which the company has christened TransportGuard, is one of the key features of a new line of Vanguard single cylinder products the company is launching in early 2010.
The new air-cooled Vanguard engines encompass four models rated 5.5, 6.5, 8 and 10 hp (see related chart). They target a broad range of equipment applications in construction, industrial, turf care and power generation industries, and are the result of nearly three years of development in one of the most significant engine projects in the company’s long history.
“Our approach to product development is to stay connected to the customer,” said Dan Roche, marketing manager with Briggs & Stratton Commercial Power. “Our work in the field helped define the design criteria for these new Vanguard engines.
“We started our discovery process for these engines in June of 2006, and one of the things we found in talking to customers and people in the field is that on the surface, a lot of needs appeared to be met with current products. But when we drilled deeper, we found there were significant issues that needed to be addressed.”
Key among those were the issues generated by fuel in lube oil, which happened most frequently while the machines were being taken to and from job sites.
In as little as 30 minutes, the normal vibration of towing a piece of equipment or transporting it in the back of a truck, could result in as much as 5 oz. of fuel ending up in the engine cylinder, which then drains down the cylinder walls into the crankcase.
The effects of oil dilution are varied, Briggs & Stratton said. They include reduced oil viscosity, which can result in increased wear and shorted engine life. Fuel in oil can also lead to varnishing of internal engine surfaces, fouled spark plugs and even soaked filters, which reduces efficiency. A worst-case scenario can result in hydraulic lock — too much of the oil/fuel mixture ending up in the cylinder, immobilizing or locking up the piston — making the engine nearly impossible to start and stressing engine components such as rods, crankshaft and crankcases to the breaking point.
The patent-pending TransportGuard system eliminates the problem, as the fuel flow to the engine is shut off when the engine is shut down. “With TransportGuard, you can’t forget to shut off the fuel,” said Roche. “It happens automatically when you shut down the engine and when the engine isn’t running, there is no fuel going to it.
“It may not seem like much, but when we showed this to customers, especially those in the rental business, they got very excited because they encounter a lot of these problems in their equipment.”
Yet TransportGuard is just one aspect of the development of the new engines, according to Pete Hotz, vice president, engine product development at Briggs & Stratton. “I’ve been at Briggs & Stratton 25 years and I can say this is the most comprehensive engine program I’ve ever been involved in,” Hotz said. “We did a lot of testing when we launched the first Vanguard engines and when we launched our Big Blocks, but I don’t think we ever approached the level of testing or the use of statistical and engineering tools we used in developing these engines.”
The engines incorporate many similar features to the company’s existing Vanguard engine, such as aluminum blocks with cast-iron cylinder sleeves, splash lubrication systems and Briggs & Stratton’s Magnetron ignition system. The cylinder blocks have been redesigned to incorporate deeper ribbing that is designed to enhance the engines’ structural rigidity and cooling capacity.
Internally, a new combustion chamber has a refined configuration with improved air and fuel passages that improve performance and reduce emissions, Briggs & Stratton said. A precision mating system between the head and block, combined with a Briggs & Stratton Motorsports derived Fire-Ring head gasket is designed for more complete sealing integrity. Below, a heavy-duty forged crankshaft has front and rear ball bearings intended to provide better load distribution and longer service life.
Externally, Briggs & Stratton said the new Vanguard engines also include some significant enhancements, most of which are intended to improve durability and reliability and provide easier servicing. A new high-mount, canister-style air cleaner offers 22% more surface area than competitive units, Briggs & Stratton said, and is water repellant. The filer is protected by a metal cage, and it also incorporates a new triple-seal design that is engineered to be a more effective barrier to debris and dust.
A newly designed metal fuel tank is mounted directly to the engine block. This reduces vibration and evaporative emissions, the company said, and maximizes durability.
The engines include a new commercial- style carburetor with more fuel passages engineered to provide smoother operation over a wider speed range, and the fuel system incorporates a more efficient sediment filter bowl with a drain valve for easier draining.
The recoil system has a larger ignition coil, which Briggs & Stratton said develops adequate spark energy for starting at lower speeds, resulting in better startability. The rewind is fully skirted to keep out dirt and, combined with the specially designed engine shroud, helps direct more airflow — 15% more than competitive engines, Briggs & Stratton said — across the hottest areas of the engine.
All of the engines also feature the company’s new Vanguard oil sensor system that is designed to automatically shut down the engine in low oil conditions, but won’t trigger a premature shutdown in temporary high angle or high vibration conditions, the company said.
Briggs & Stratton validated the design of the new engines through the most extensive testing program the company has ever undertaken, Hotz said. “We tested 350 engines over the course of three years,” he said. “We had approximately 120,000 hours in testing and had 60,000 man hours devoted to this project, with all of the engineers and technicians.
“We also did a lot of application testing. The development team ran 60 equipment tests, in various types of equipment. Probably the toughest application you can have for an engine is a tamper. As part of the qualification plan, we built a tamper track at our plant in Milwaukee and ran over 1200 hours of qualification testing with different engines.
“We also did a lot of competitive testing. To make sure we were competitive, we had to really know what the market wanted and what customers expected, so we looked at a lot of other engines along with our own. We came away from those tests very confident about what our engines can do.”
Briggs & Stratton has begun building the new Vanguard engines at two sites. The 5.5 and 6.5 hp engines will be built at the company’s 280,000 sq.ft. Chongqing, China, engine plant.
“Briggs has been in China a lot longer than most companies,” Hotz said, noting the initial joint venture formed in 1986. That venture was revised in 1995, leaving Briggs & Stratton with 95% of the equity, with the remainder held by a Chinese partner. Following that, the company began to produce 205 and 250 cc horizontal and later, 160 cc vertical shaft engines, mostly for the European markets.
The 8 and 10 hp models will be built at the company’s Auburn, Ala., facilities. “A lot of the focus of these engines will be on the generator market,” said Hotz.
“Briggs has a global production philosophy that basically tries to produce engines as closely as possible to their markets. Some of the biggest markets for the 205 cc engines are in the emerging countries — China and Southeast Asia are all focused on 160 to 250 cc engines.
“In the U.S., we have more hurricanes and ice storms that raise demand for portable generators. Auburn, Ala., is pretty much in the center of where you’d be using a lot of those.
“We have plants all around the world, and wherever we build we have the same quality and production standards. Wherever they come from, the engines are ready to meet the needs of the global market.” dp
REPRINTED FROM JANUARY 2010 DIESEL PROGRESS North American Edition
Copyright Diesel & Gas Turbine Publications Printed in U.S.A.
