A new 12-liter, spark-ignited natural gas engine should be a natural fit for tank truck fleets when it becomes commercially available in 2013
Jul 1, 2012 12:00 PM, By Rick Weber
CUMMINS has produced over 13,000 ISL G nine-liter engines since its introduction in 2007 — used predominantly in transit and refuse applications — but the 12-liter ISX 12 G will be a game-changer when it hits the natural-gas market next year.
“The nine-liter engine has been a great success but it has its limitations,” said Charles Ker, industry relations manager for Cummins Westport. “We won't put it into an application that hauls more than 80,000 pounds. It's really designed for 65,000-lb gross weights.”
Target markets are regional haul truck/tractors in vocational and refuse. The engine has a peak rating of 400 hp and 1,450 ft-lbs, is EPA/CARB-certified at or below EPA10 emission levels, and is a dedicated natural gas engine that will operate on CNG or LNG and is capable of using up to 100% biomethane.
Ker said that the title of the session — “CNG/LNG: Fueling the Future” — was a bit of a misnomer because “there are trucks on the road today that are fueled with natural gas.” Ker was one of three speakers to address the latest developments in natural gas as a commercial vehicle fuel during the National Tank Truck Carriers 64
He said Cummins Westport Inc, a 50-50 joint venture between Cummins and Westport Innovations Inc, has been around since 2001 and has delivered over 34,000 engines around the world, 90% of them in North America.
He said the ISL G uses an 8.9-liter stoichiometric-cooled EGR engine with ratings from 250 hp to 320 hp to get to low emissions (0.20 g/bhp-hr Nox, g/bhp-hr PM) and has a three-way catalyst aftertreatment that is maintenance-free.
“Customers have seen diesel-like performance, reliability, durability,” he said. “It has the same rated speed and similar torque curve, over 30% more torque at idle versus the previous engine, and improved fuel economy.”
“The three-way catalyst aftertreatment is similar to the catalyst on gasoline passenger cars. It's packaged as a muffler, with a vertical or horizontal mount, weighs 100 pounds, and is a passive device. It's maintenance-free, reliable, with no regeneration events and no DEF or SCR required. It's 100% natural gas, and customers like that. “The ISL G is under 2010 Nox and PM requirements. We believe we can get even lower. We have customers asking us to do that who are looking at zero-emissions technologies. They want another option, so stay tuned — we're going to give them that option.”
As far as technology, here's what is the same as diesel: major engine components (block, crankshaft, main bearing, piston rods, EGR), 500-hour maintenance interval, parts and service, and compatibility with Cummins diagnostic tools.
What's different: It uses spark ignition (SI) technology versus compression, has an intake manifold versus common rail injection, a three-way catalyst versus particulate filter and SCR, two-valve versus four-valve, a specific oil that meets Cummins specification CES 20074, and is 20db quieter at idle.
Ker said natural-gas fueled trucks emit up to 20% less greenhouse gas emissions.
“As natural gas fuel economy improves, CO2 emissions are reduced,” he said. “CH4 emissions, adjusted to consider GHG impact, are less than 10% of total GHG emissions. Well to wheel analysis with the GHGenius modeling tool predicts up to 20% GHG emissions for natural gas versus diesel. Using landfill gas or anaerobic gas as a biomethane fuel increases the GHG difference to 90%. Cummins Westport approves the use of biomethane that meets fuel specifications.
“The whole gist of this natural gas experience for the past 10 years has been to make it as comfortable, seamless, and hassle-free as possible. This is an important part of that.”
He said one of the best testimonials came from Michael O'Connell, senior director of fleet capability for Frito Lay, in a New York Times article on April 17: “The payback for the extra cost of the natural gas trucks is a year and a half, so it's a little bit of a no-brainer.”
Natural gas market
Robert Carrick, sales manager of natural gas for Freightliner Trucks, said Frito Lay has up to 75 NG trucks, Saddle Creek Transportation (Lakeland, FL) has 40 and is looking at 40 more now that it has installed its own fuel station, Swift Transportation has 25, and Sysco Corp has 80 in Waldon, CA, where it has an LNG station that the state helped finance 10 years ago.
“If you have an application that uses natural gas and a fuel station, there is no reason not to buy natural gas,” he said. “Fuel costs are lower, there is less price volatility than diesel fuel, and payback is quicker. Even without federal or state incentives, it's a year and a half to recoup the investment cost. After that, between $15,000 and $30,000 a year goes into your pocket.
“There's dependable spark-ignition engine technology and simple aftertreatment, with no DPF, no regenerations, and no SCR required. Next year, greenhouse gas emissions become important. There's domestic fuel and energy security with natural gas. And it builds American jobs. Anybody who has been in Pennsylvania at the Marcellus Shale and doesn't see the economic comeback that's being driven by drilling and the manufacturing of all components has to be blind. It's everywhere. If we didn't have this, unemployment would be above 9%.”
He said Freightliner parent company Daimler Trucks North America has delivered over 1,350 NG vehicles to a variety of segments: LNG and CNG port tractors; LNG and CNG food-delivery tractors; CNG regional-haul tractors; CNG refuse trucks; CNG sewer trucks; CNG gas utility trucks; and CNG municipal government trucks.
He said Freightliner had 277 natural-gas fueled trucks on order in April, with quotes out on 650 more.
CNG fuel tanks are factory-installed 60- and 75-gallon tanks that add 25 inches back of cab and 1000 lbs more than diesel vehicles that have the same amount of fuel in them, he said. LNG fuel tanks are: 119 gallons/64 DGE: 204-061; or 150 gallons/84 DGE: 204-092.
“It equals 84 gallons of diesel equivalent, so you have a range of 400 miles,” he said.
He said the biggest issue is the number of existing or planned filling stations. “We're listening to fuel suppliers saying, ‘We're going for five years,’” he said, “and ‘We're going for five years’ doesn't put fuel in trucks.”
It's also difficult to estimate the resale value of NG trucks.“Tell us what the price of diesel fuel is going to be in five years and we can give you a pretty good estimate of what the value of the trucks will be,” he said.
- How safe is natural gas?
“It's a very safe fuel. This is a heavily regulated industry. We install 20-year tanks that are virtually indestructible. You cannot hurt these tanks. They have been tested by drop/crash, bonfire, dynamite, pistol/rifle. Natural gas is as safe, or safer, than diesel and gasoline.”
- Maintenance costs.
“The costs are very similar to diesel units. You have to adjust PM costs to a 15,000-mile schedule, so that might be twice the rate of PMs you are doing today. Just calculate that into the equation. A daily fuel filter drain is required, which takes about 30 seconds. For a sparkplug change, it's $450 at 45,000 miles, so add a penny per mile. Deduct all costs for aftertreatment maintenance and repair. Keep in mind the cost of repairs for a diesel engine if you blow the tip of an injector. That $450 spark plug replacement pales by comparison.”
- Dealer/customer shop requirements.
“There are NFPA 30A requirements for working on the vehicles. The local fire marshal is key. Consult him early in the project. Get the NFPA requirements. Basically, with newer shops that were built in the last 10 years and have proper air flow, you don't have to do much if you're doing CNG. For LNG, you will need methane detection, heater relocation, exhaust fans, and explosion-proof lighting.
- The Natural Gas Act.
“It has been dead for 17 months. However, with the provisions the Senate put in, there are now payback provisions. The general feeling in Washington is that the Natural Gas Act will be back, and will be a $32,000 tax credit for vehicle purchase and up to a $100,000 credit for fueling infrastructure.”
Jim Mulvenna, general manager for the dairy and bulk foodgrade division for Ruan Transportation, said Fair Oaks Farms, “one the most recognized dairies in the world,” selected Ruan Transportation Management Systems to haul milk and manage its CNG fleet in Fair Oaks, Indiana. It's the first project of this size using renewable CNG for a fleet with an 80,000-pound hauling capacity and a range of almost 650 miles.
Ruan began hauling Fair Oaks milk on CNG-powered trucks in August 2011.
“We had a few bugs — I'm not going to sugarcoat it,” he said. “Primarily, the problems included overheating on engines. We had a nine-liter application hauling 80,000 pounds up and down hills. The engine is rated for 65 mph at 60,000 pounds, so we have problems. There were a few manufacturing mistakes on these trucks — certain cooling hoses weren't connected — but we had that taken care of.
“With compressed natural gas fuel tanks, we had a larger-than-expected failure rate, but technology is improving. Our problems were caused by damage from rocks kicked up on farm roads. When you look at it from an objective point of view, these fuel tanks are volatile if they were to explode. So with any chip or bruise on them, you definitely want to take them out of service. You don't want drivers driving around with a potential explosive device strapped to a truck.”
The fleet, operated by Ruan, includes 110 professional drivers, 42 tractors powered by renewable CNG, and 75 6,400-gallon milk tankers.
“We try to average 800 miles a day per truck in this fleet of 42 trucks,” he said. “Everything runs back empty, so our fuel economy varies. Average is 5.5 mpg empty and 4.5 loaded, so the combined average is just over 5 mpg.
“We're using renewable natural gas made during treatment of manure. We believe in this technology. Digesters make methane gas that you can scrub and put back into a CNG pipeline. Non-fuel-quality methane can be used at the dairy to run generators and the electricity can be sold back to the grid. It makes nitrous water, a good source of fertilizer. And it also makes a fibrous material that will ultimately replace peat moss in the US. The goal is to put 16,000 digesters into play in the next 10 years.”
Summing up his experience, he said: “The bottom line is we had teething pains with it. I'm not going to say these trucks are more than prototypes going down the road, but it is an emerging technology. As far as our application is concerned, there will be options in the future for larger loads and longer-haul fleets. We believe in the technology. We believe it's good for the environment and good from a security standpoint for America, and economically for America.”
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