To see and hear the two Caterpillar 988Fs loading the crusher at Fred Weber's North Stone Quarry in Maryland Heights, Mo., one might think they are just like any other large wheel loaders working on any other quarry or construction job site in the Midwest. They look, sound and run like any well-maintained 988Fs would as they move quickly between the piles and the plant, but these are different; they're significantly more fuel efficient.

Equipped with the Combustion Catalyst System manufactured by Emissions Technology, these wheel loaders use about 30-percent less fuel than a machine without the system.

According to Moss, the Combustion Catalyst System also promotes cleaner exhaust and cleaner engines in addition to increased fuel efficiency.

"The exhaust is cleaner because you get a more complete burn," Moss said. "That's what provides the fuel savings and it also means cleaner engines. It does such a good job cleaning up the exhaust that we have installed the units on every piece of equipment we have in our underground facilities. Our operators in those facilities notice the difference when it gets low on solution because they can start to see and smell the exhaust."

Fred Weber, Inc. installed its first Combustion Catalyst System in 2003 on one of the 988s at the quarry and recently had the opportunity to see its engine cleaning results.

"The local distributor, Mobile Equipment Sales & Service, put the first system on at their expense to prove what it would do for us," Moss said. "The machine already had more than 6,000 hours on it and after the initial period of about 400 hours that it takes for a used engine to get the full benefit, we were saving more than 30 percent on our fuel.

"We monitored our fuel usage off and on for the next year and it continued to provide that same savings. By the end of last year we had run the engine about 7,000 hours with the unit on it."

Over the winter, when the machine was in the shop for service, Moss' technicians went ahead and pulled the engine for an overhaul.

"When we tore it apart, we were amazed at how clean the inside of the engine was after about 14,000 hours," he said.

"We see some engines with just 2,000 hours that have lots of carbon buildup but there weren't any carbon deposits in this engine and the machining was still in the cylinders. We were even able to reuse the pistons because they had virtually no wear."

Moss said the company currently has the Combustion Catalyst System on several pieces of equipment and they plan to put it on the larger equipment they acquire in the future.

"One of my goals is to try to get it on at least 50 more machines this year," he said, noting that he intends to put them on gen sets and 340 horsepower or larger engines where the savings will be greatest.

"The system works best on generators and larger machines, anything that runs at a fairly constant rpm," he said. "On the generators we've had it on, our fuel savings has been in the high 30-percent range. We save about 30 percent on large equipment and just less than 20 percent on rigid-frame haul trucks. We haven't had anything less than 12-percent savings and the majority has been more than 20 percent."

The Combustion Catalyst System consists of a bottle of catalyst solution, a pump and a digital hour meter packaged in a plastic case a little larger than a children's lunchbox. It is installed upstream of the turbo and whenever the machine runs the pump draws air into the bottle, creating an aerosol catalyst that is both pumped and sucked into the combustion chamber with the air. The air and catalyst mix with the fuel to create a highly combustible material that produces a cleaner, more complete burn.

The initial cost of one unit is about $1,000 and one is needed for each turbo. After installation, which Emissions Technology says takes just over 30 minutes, the catalyst solution bottle has to be replaced every 400 hours at a cost of 50 to 60 cents per hour. According to the manufacturer, the system's benefits include extended engine life; increased power and fuel economy; lower exhaust temperatures; and reductions in diesel particulate matter (40 percent to 70 percent), hydrocarbons (30 percent to 50 percent) and carbon monoxide (10 percent to 40 percent).

"We have to prove the products we sell," said Fred Alvis of Mobile Equipment Sales & Service in St. Louis, the authorized Combustion Catalyst System dealer for Missouri, Kansas and part of Illinois.

"If a contractor knows how many gallons of fuel a piece of equipment is using per hour," said Alvis, "I'll install the system and let them evaluate it, usually for about 400 hours. If it's not an asset, we'll take it off and they won't owe me anything."