POWERTRAIN SYSTEM: CNG & LNG ENGINES

arge U.S. reserves and the ability to use existing engine technology make attractive. In fact, natural Natural gas charges gas price projections are significantly lower than historical averages as more information becomes available on mas- Lsive shale gas reserves. into the future Engine and fuel availability continue to by Curt Bennink expand. “We are in the stage of investment in Explore natural gas options when designing new vehicles. both infrastructure build-out and product devel- opment,” says Paul Blomerus, Senior Director, High Horsepower Corporate Development, Westport Innovations Inc., Vancouver, BC, Canada. “Where those two meet is a perfect storm of new products to meet demand and available cheap fuel. Then we will see an inflec- tion point.” In the push to transition from petroleum-based vehicles to an affordable domestic alternative, natural gas is quickly gaining favor. Any vehi- cle traditionally powered by gasoline or die- sel can be converted to natural gas. Although natural gas does produce greenhouse gases, it is much cleaner than either gasoline or diesel. It is an odorless, nontoxic, gaseous mixture of hydrocarbons—predominantly methane (CH4) and it possesses the lowest carbon con- tent of any hydrocarbon fuel. A side benefit is that (CNG) fuel sys-

CNG refueling of refuse trucks in Livermore, CA. NGVAmericA

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tems are completely sealed, so there are no evaporative emissions. But the economic business case remains strong. “There are so many different angles and they are all predicated on economics,” says Richard Kolodziej, President of Natural Gas Vehicles for America (NGVAmerica). “The more fuel you burn, the greater the potential savings.” There is also customer familiarity. Natural gas Cryogenic LNG refueling. already accounts for a quarter of the energy used Westport InnovatIons in the U.S. But a couple of hurdles need to be overcome. First is development of the distribu- enough stations you can go after other fleets, tion channel. “There are two million miles of the ones that don’t return to a depot every night. natural gas pipeline delivering gas to almost After these natural gas fueling communities (the every city and town,” says Kolodziej. “You have Refueling an LNG storage tank on a Class 8 heavy-duty truck. hubs) develop, the next step is to place fueling sta- to get it from the underground pipeline to the Westport InnovatIons tions along the interstate highways that connect vehicle, so fueling stations need to be built.” them (the spokes). Through this hub-and-spoke There are about 1,100 CNG fueling sta- the country, with most stations popping up approach, a national CNG fueling network is tions around the country with 20 to in heavily populated areas. “The four counties being created.” 25 new stations coming online around L.A., for example, have 100 stations,” says Fuel availability is critical to the speed of every month. But they are Kolodziej. Salt Lake City has quite a few stations growth. “A number of options can be employed Vertical LNG storage tanks. Westport InnovatIons not equally distrib- and growth is now occurring in Oklahoma City, in key market segments, from on-site delivery in uted around Tulsa and other key cities. “The industry’s strat- the case of (LNG) for key egy has been to go after return-to-home fleets machines, or strategic fueling locations nation- through this business value stream.” first, where one public station can serve sev- wide in the case of rail,” says Scott Fiveland, GAS The other hurdle is the availability of the eral fleets in an industrial park. Once there are New Technology Manager, Caterpillar Inc., engines. Finding the perfect size engine for Peoria, IL. “The successful deployment of LNG many applications can be difficult. There are

Westport high-pressure direct injection solutions will require the economics through the gaps in the natural gas engine range – including (HPDI) injector for heavy-duty engines. value stream from fuel to infrastructure to fuel a critical gap between 9 and 15 liters. Numerous Westport InnovatIons use. We expect the economics to look attractive companies use the 9-liter natural gas engine on

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a Class 8 truck. “That only works if you are working on flat ter- Actually, engine manufacturing capacity isn’t as much of an rain. Even there you are working that engine pretty hard,” says issue. “Our business model has always been to leverage existing Kolodziej. manufacturing capacity wherever possible,” says Blomerus. “We He explains, “That is why the 12-liter Cummins Westport engine will utilize engine manufacturers or existing supply chains. We that is supposed to come out in April is exciting for so many really don’t see supply or capacity as an issue. If anything, as the people. In many cases the 8.9-liter is too small and the 15-liter is share of gas increases the capacity will switch from supporting too big.” A 12-liter natural gas engine hits a sweet spot for many diesel fuel to supporting gas fuel.” in the Class 8 truck market. Currently there is a 9-liter engine from Cummins Westport Engine types and use Inc., Vancouver, BC, Canada, and the 15-liter Westport HD engine. Three types of engine technologies are currently employed for More choices will be coming in the future that will help further natural gas engines used on mobile equipment – spark ignited, Fueling an LNG powered refuse truck. fill in the gaps. dual fuel and high pressure direct injection (HPDI). The technol- NGVAmericA

Economics drive natural gas vehicles

“Natural gas supply has skyrocketed because of the shale gas,” “Fuel selection is driven by economics and availability, among other Who Says Gears Can’t Be Fun? Gears for today’s off-highway applications must operate smoothly, says Richard Kolodziej, President of Natural Gas Vehicles for America factors,” says Scott Fiveland, GAS New Technology Manager, Caterpillar quietly and around the clock in the harshest environments – and reliability is paramount. Forest City Gear helps design, develop and (NGVAmerica). “Demand is growing, but slowly. That puts huge downward Inc. “Since natural gas offers savings to customers, due to lower fuel manufacture the highest quality gears for some of the leading OEMs. pressure on price.” The price at the time of this writing was under $4/ operating costs, Caterpillar expects natural gas growth to explode. The Let’s have some fun together. million BTUs. “When natural gas is $5.60/million BTUs, that translates economic savings, depending on the natural gas to diesel fuel delta, Visit: www.forestcitygear.com. to .70 cents a gallon gasoline equivalent (GGE) in the field. You have to can translate to more than a 50% savings to the customer in operating 11715 Main Street move it and you have to compress it.” But even if this adds $1.50/million fuel costs.” Roscoe, IL 61073 815-623-2168 BTUs to the cost, the consumer price is around $2.00 per GGE. “There Demand is being driven by high fuel use customers, including railroads are eight gallons equivalent in a million BTUs. There are seven gallons and mine truck operators. “A locomotive will consume 300,000 gallons diesel equivalent in a million BTUs.” per year,” explains Paul Blomerus, Senior Director, High Horsepower This pricing makes natural gas attractive. “In duty cycles that use a Corporate Development, Westport Innovations Inc. The biggest mine lot of fuel, there are customers that can pay back their vehicle in a year trucks can more than double that. The economic motive is extreme. The [or] a year and a half,” notes Kolodziej. In addition, natural gas exhibits business is growing where the volume is large (Class 8 or smaller truck- many positive attributes. “It is cleaner burning so the engine oil stays ing) or where the fuel burns are large. The middle will fill in and it will cleaner longer.” There is less carbon buildup in the engine. benefit from the new engine technologies developed.”

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How an LNG station operates. GraphIc by chart IndustrIes

engine has a flatter torque curve which gives that nice low-end response.” Westport uses spark ignition on light-duty (1- to 5-liter) and Cummins Westport cur- rently uses SI on medium-duty (5.9- to 9-liter) engines. Many light-duty engines used on pas- senger cars and light-duty trucks are configured for bi-fuel operation. In medium-duty vehicles natural gas can also be cost effective with a ogy deployed depends on the application. “But spark-ignited engine. [for] the largest and most demanding engines An upside of the spark-ignited engine is that where efficiency and power response are core it is much quieter than a diesel compression- requirements, the HPDI is more suitable,” says ignition engine. The downside of a spark-ignited Blomerus. natural gas engine is it typically provides 85 Natural gas needs an ignition source to make it to 90% of the power of a diesel and 80% of the work. It will not ignite by compression alone like torque of a diesel. diesel fuel. This ignition source is usually a spark But the spark ignited engines also have emis- plug in a spark-ignited engine or a small mixture sions benefits. “On the Cummins Westport of diesel in a compression-ignited engine. But engines you don’t have a particulate filter and you do lose a little torque and cooling require- you don’t need urea to control the NOx,” says ments are increased. Kolodziej. Instead the engine relies on a three- Think of a spark-ignited engine more like a way catalyst. gasoline engine. “It has a more peak-shaped But many industries need effi- torque curve,” explains Blomerus. “You need to ciency. Dual-fuel and HPDI technology provide rev it up to get the power whereas a diesel cycle the solution. In a diesel/CNG dual-fuel engine the diesel acts as an ignitor to get the explosion Westport HD 15-liter engine and LNG fuel system with HPDI going. These engines can be run on diesel or a technology diagram. combination of diesel and gas. The engines are Westport InnovatIons

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started as a pure diesel engine and as the inlet ing 50% diesel. But it is an attractive solution air temperature rises natural gas is injected into since the engine can run on 100% diesel when the cylinder from an additional intake valve. As natural gas is not available. “A dual-fuel engine the natural gas is injected, the amount of diesel has all of the same emissions reduction technolo- being injected is reduced. The average substitu- gies because there are certain conditions where tion in medium- and heavy-duty truck applica- a dual-fuel engine is going to be running 100% tions is often 50%. on diesel,” says Blomerus. This requires the engine to be certified as both Caterpillar offers a unique dual-fuel technol- a diesel and a gas engine and it lengthens the ogy with its dynamic gas blending technology, payback period since the engine is still consum- which has already penetrated the petroleum drilling market. “We are going to be moving that technology into mobile machinery,” says Stationary natural gas engines Fiveland. It continuously optimizes gas substi- offer customized solution tution up to 70% while maintaining diesel per-

Caterpillar has a unique solution for drillers, formance levels. Caterpillar Dynamic Gas Blending. This technol- “The advantages of the technology are it ret- ogy continuously adjusts to changes in incoming rofits to the engine,” explains Fiveland. “This can retrofit to any of the large Cat engines as fuel quality and pressure, allowing your engines A Westport HPDI engine. long as you continue to meet the emissions to run on a wide variety of fuels, from associ- Westport innovations ated gas to gasified LNG, all while consistently standards.” The technology uses existing Cat maintaining your diesel power and transient per- gas engine hardware along with no change to formance. It lowers fuel costs with up to 70% core diesel engine components. “With dynamic fuel. Low methane numbers (MN 30) contain detects gas presence, gas quality and gas pres- replacement of diesel with gas. gas blending you are putting gas in at a low pres- higher-order hydrocarbons while fuels that con- sure to optimize fuel savings while maintaining Designed for compatibility with existing sure. Then you are injecting the diesel fuel in a tain mostly methane and ethane may exceed performance. Like any solution it has advantages land drilling rig controls and production multi- very conventional way.” MNs of 80.” in certain markets and segments. “We are going generator set control systems, the gas blending Unlike gasoline or diesel fuel, there can be Dynamic Gas Blending utilizes sophisticated to continue to look at the customer payback. kit provides robust transient response and an variability in its composition. “Very simply, the control software that accommodates fuel quality Dynamic gas blending is going to be applied integrated gas induction control which maintains quantity of methane, ethane, propane, butane, changes. “So if you go to a lower methane num- where it makes sense to the customer.” stable generator output. It is easily integrated etc. may vary with geographic location and sea- ber fuel the engine picks that up and dynami- With HPDI technology, gas is introduced at with drilling and production generators in the son,” says Fiveland. The methane number (MN) cally adjusts the amount of gas or the amount high pressure directly into the oil and gas industry. is an index that quantifies the reactivity of the of diesel fuel,” says Fiveland. It automatically chamber. These engines run on 90 to 95% nat-

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“A number of options can be employed in key market segments, from on-site delivery in the case of liquefied natural gas (LNG) for key machines, or strategic fueling locations nationwide in the case of rail.” — Scott Fiveland, GAS New Technology Manager, Caterpillar Inc.

ural gas. A small amount of diesel is still needed As publicly announced, Caterpillar is partner- as this technology utilizes diesel pilot injection. ing with Westport to develop the HPDI technol- “An HPDI engine uses a small amount of diesel as ogy for both rail and mobile off-highway mar- an ignition source,” says Blomerus. “Typically it kets. This engine solution is expected to provide is such a small amount that you can still get the the customer unsurpassed value with a substi- benefit of the clean burning gas, allowing you tution rate at the 95% level. The application of to reduce the cost and complexity of the emis- Caterpillar various dual-fuel options (DGB and sions reduction equipment.” Again, this could HPDI) will be driven by the customer value they be critical to industries such as railroads where provide in a given market segment/application. new emissions requirements for diesel locomo- BTIC Westport cryogenic liquefied natural gas (LNG) storage tanks with integrated LNG pumps. tives that take effect in 2015 will increase the Natural gas storage Westport InnovatIons initial cost. considerations “Direct injection is directly comparable to die- Natural gas can be stored as a compressed gas sel engine performance,” says Blomerus. If an or a liquefied gas for use on mobile vehicles. The and pressure required by the engine, [typically The storage volume required per unit of energy application requires low-end torque and respon- main difference is that CNG is stored as a gas at 110 to 150 psi],” explains Blomerus. “The custom- is larger for both fuels. “LNG requires a volume of siveness, then a diesel cycle with direct-injection 2,900 to 3,600 psi pressure while LNG is stored as er will pick an appropriate tank solution. There about 1.7 times that of diesel to store an equiva- gas technology is the best solution. a liquid at a very low temperature. The natural are advantages and disadvantages to all of the lent amount of energy,” says Fiveland. “CNG sys- Fiveland agrees, “Power density is defined gas storage tanks and more complex fuel deliv- filling technologies.” One safety advantage for all tems, depending upon the degree of pressuriza- appropriately as power/engine displacement. ery systems will add cost to the initial purchase natural gas vehicles is the gas is lighter than air tion (usually 3,600 psi), require upwards of four Engines burning on natural gas can match price of the vehicle. and disperses quickly into the atmosphere when times relative to diesel and 2.5 times relative to equivalent continuous or variable speed die- But natural gas engines don’t care whether gas spilled. It is also worth noting that natural gas LNG. In key industries, LNG fuel systems will sel power requirements, within the same is being supplied by a CNG or LNG tank. “The gas has a narrow flammability range which makes be designed to continue to meet key customer engine envelope.” that it receives is regulated to the temperature it a relatively safe fuel. requirements while not sacrificing payload, etc.”

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“Up until now it has been more CNG than LNG, but that is changing very rapidly,” says Blomerus. Many recent announcements tout additional capacity being added for LNG. “CNG is very popu- “That is why the 12-liter Cummins Westport engine that is supposed to come out in April lar on return to base vehicles.” This is because is exciting...In many cases the 8.9-liter is too small and the 15-liter is too big.” trickle compression filling is a very efficient way — Richard Kolodziej, President of NGVAmerica to fill up a CNG tank. You plug in the compres- sor and you fill up the tank overnight when the electricity is cheap. “On an over-the-road haul truck the LNG is going to be a better choice for vehicles that come back to a common depot and atmospheric pressure. At this temperature fuel – better range, faster filling.” they are not used overnight.” LNG occupies one six hundredth the volume Caterpillar works with customers to match But LNG has two big advantages. “One is that of natural gas at atmospheric temperature and fuel system storage requirements with customer you can put more fuel on board than you can pressure. It is stored in double-walled vacuum needs and executes the appropriate packaging on with CNG with the same weight and the same insulated stainless steel tanks. There is -200 F an application basis. “CNG does have some ener- space,” says Kolodziej. “If you have a weight prob- liquid in a thermos on the side of the vehicle. To gy density storage challenges, but in some cases lem, then LNG is more effective. If you cannot use this fuel it is vaporized in a heat exchanger where CNG is directly available at a cheap cost, it put enough cylinders in the back of the tractor or and gets to the engine at about 110 to 150 psi. can be utilized,” says Fiveland. “In this case, the on the side rails of the tractor, then LNG is more When the engine is not running the LNG fuel appropriate storage technology and cycle times, attractive. If you want to get 500 or 600 miles in the tank will slowly return to the gaseous form derived via customer needs, will be designed into of range you are going to have to go with LNG.” as the fuel warms, increasing pressure inside LNG fueling at the Port of Long Beach. the products to maximize the customer value.” The second big advantage for LNG is that it is the tank. LNG inside the tank is stored up to NGVAmericA A CNG vehicle usually gets less range than a not compressed. The heat of compression makes 230 psi. If the vehicle is used on a regular basis, conventional gasoline engine. Gas mileage for a it difficult to rapidly fill a CNG tank to capacity. pressure inside the LNG tanks will be managed CNG vehicle is similar to a gasoline engine, how- There are also challenges with rapid fill on “If you pull up to a pump and try to put in 100 by the system. However, if the vehicle is parked ever, CNG tanks are quite bulky so integrating CNG. “If you want to get more gas into it quickly to 120 gallons of CNG equivalent, you only get for an extended period of time the pressure in the them into the vehicle can be a challenge. This you need a big store of it at a high pressure,” says about 70% of the capacity,” says Kolodziej. “It tank may increase to a point to cause the tank to compressed gas travels through a series of highly Blomerus. “It takes energy and if you compress will read full, but an hour later the pressure will vent gaseous fuel and reduce tank pressure. For pressurized stainless steel lines until it reaches gas it produces heat, so that is a challenge.” drop as the heat dissipates. You don’t have that this reason, LNG should not typically be used on the regulator where the pressure is reduced to This heat of compression can be overcome by problem with LNG.” vehicles that are parked for weeks at a time. ● around 115 psi to match the amount needed by using a time fill. “You plug it in and then you LNG tanks store natural gas in a liquefied state. the fuel injection system. leave,” notes Kolodziej. “It is for fleets that have Natural gas is liquefied by cooling to -260 F at

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