roughrider power

Roughrider Power/GTI provides innovative Bi-Fuel solutions for a wide variety of diesel engine applications. Our technology is used in the power generation, marine, and oil and gas exploration/ production/ process industries.

Roughrider Power/GTI serves the global market via a worldwide network of authorized distributors and OEMs.

Bi-Fuel System

The GTI Bi-Fuel System from Altronic offers an affordable and efficient means of operating industrial diesel engines utilizing both diesel and natural gas (or other available gas) as fuel sources. This innovative, patented system, which requires no modification to the internal components of the engine, allows for operation on natural gas up to a maximum of 70%* of the fuel required to maintain the desired speed and load. Reduced exhaust emissions and fuel costs are just a few of the benefits of Bi-Fuel operation.

The GTI Bi-Fuel System operates by blending both diesel fuel and natural gas in the combustion chamber. This is achieved using a fumigated gas-charge design, whereby natural gas is pre-mixed with engine intake-air and delivered to the combustion chamber via the air-intake valve. The air-gas mixture is ignited when the diesel injector sprays a reduced quantity of diesel fuel into the chamber. This diesel "pilot" acts as the ignition source for the primary air-gas combustible mixture. Because the Bi-Fuel System utilizes the OEM air-intake and diesel injection systems, no internal engine modifications are required for installation.

*Subject to gas quality and other application conditions

¨ Converts industrial diesel engines to Bi-Fuel operation by substituting up to 70% natural gas for diesel fuel

¨ Save on operating fuel costs by using natural gas with return to 100% diesel operation at any time

¨ Allows the use of available or interruptible gas supplies

¨ No modification to internal engine components is required

¨ Cleaner burning natural gas reduces exhaust emissions

¨ Reduces requirements for on-site fuel storage

¨ Unique, patented design ensures no loss of power or efficiency

¨ Low cost and easy to install

Major Bi-Fuel System Components and Sub-Systems

AIR-FUEL MIXER

The Air-Fuel Mixer of the patented GTI Bi-Fuel System, located downstream of the gas power valve, incorporates a fixed venturi design.This innovative mixer is installed such that all of the incoming air flows through the mixer. For engines with multiple air intake systems,one mixer is at each of the intakes. The GTI Bi-Fuel System uses mixing devices that do not incorporate any type of air throttle plate in their design. After exiting the mixing device, the air-gas mixture enters the engine air-intake manifold, and distributes the charge to each cylinder via the normal air distribution scheme of the engine.

GAS POWER VALVE

The gas power valve, located downstream of the gas pressure regulator, is a needle-type valve and is one of the adjustable components to the GTI Bi-Fuel System. This device is set during the tune-in phase of the engine conversion and sets the maximum gas flow rate to the engine.Once set, this valve remains in a fixed position regardless of engine load.Note: For added flexibility on engines that operate over a wide spectrum of load levels, an optional, automatically actuated gas trim valve is substituted for the gas power valve.

GAS TRAIN

Conditioning and regulating the natural gas prior to admission into the engine is a critical part of the GTI Bi-Fuel System. The system “gas train ” includes a 20-micron fuel filter, a manual shutoff valve, an electrically operated solenoid valve actuated in the event of an emergency or for system shutdown, and a zero-pressure, demand-type gas pressure regulator. This latter component reduces the inlet gas pressure (1–5 psi) to roughly atmospheric pressure. With a negative outlet pressure, the design allows the system to use a “demand ” control scheme whereby engine intake airflow determines the gas flow of the engine. As engine load changes, corresponding changes in intake air volume automatically draw additional fuel into the mixer.

Text Box: CONTROL PANEL The Control Panels are based on proven Altronic controllers and provide state-of-the-art engine control and safety shutdown monitoring. The system is designed specifically for GTI Bi-Fuel applications and is straight-forward and easy to operate. The panel monitors a number of pressure and temperature points and returns the engine to 100% diesel operation should any parameter deviate from its normal range. In addition, an hourmeter function tracks the operating hours when in Bi-Fuel mode.Alarms are annunciated in English-language messages (other languages can be programmed), and the controller maintains an alarm log of the last 100 events.

Text Box: FAQ’s What does "Bi-Fuel" mean? In simple terms, Bi-Fuel can be defined as the simultaneous combustion of two fuels. In the case of GTI's Bi-Fuel System, natural gas is utilized in conjunction with diesel fuel to operate the engine. After conversion, the engine is able to operate on either 100% diesel fuel, or alternately, on a mixture of diesel fuel and natural gas (or other methane based fuels). At no time is the engine able to operate on natural gas exclusively. Will my engine have to be modified to operate on GTI Bi-Fuel? No. GTI's conversion technology has been designed to allow for in-field retrofit of diesel engines without the need to change or modify the design of the engine. GTI's conversion hardware is mounted externally on the engine and does not require modification of the engine or alteration of any critical engine parameter. Will the system affect my engine warranty? Most OEM engine warranty programs do not prohibit the use of aftermarket parts or Technologies. In brief, the policy of OEM's is that they neither recommend nor endorse aftermarket technologies; however, the use of these products does not automatically void the validity of the engine warranty. If the cause is unrelated to Bi-Fuel, the OEM's have historically honored the warranty and repaired the engine. Additionally, all GTI Bi-Fuel components that fail within the warranty period will be covered under the GTI warranty policy. Why can't the engine use 100% natural gas? Because of the very high ignition temperature of natural gas (approximately 1300 degrees Fahrenheit), sufficient heat is not generated during the diesel compression stroke to ignite 100% natural gas. As such, dedicated gas engines employ spark plugs and an ignition system to facilitate combustion of the air-natural gas mixture. In contrast, during Bi-Fuel operation, a reduced quantity of diesel fuel acts as the ignition source for the air-gas mixture; this process is often referred to as pilot ignition. Will my engine lose power after conversion to Bi-Fuel? Under normal circumstances, engines converted to GTI Bi-Fuel do not suffer any horsepower losses while operating in Bi-Fuel mode. Because the system maintains OEM compression ratio values and does not incorporate an air-throttling device, peak horsepower and efficiency levels of the converted engine remain on par with 100% diesel operation. In some circumstances, the engine may be de-rated in Bi-Fuel mode due to shortcomings in gas supply composition and/or quality. Will my engine run hotter on Bi-Fuel? GTI's Bi-Fuel technology has been designed to maintain OEM specifications for all engine temperatures including engine coolant temperature, oil temperature, exhaust gas temperature and intake air temperature. The Bi-Fuel System replaces diesel fuel normally consumed by the engine with an equivalent quantity of natural gas, relative to the heat value of each fuel. As such, engine air-fuel ratios during Bi-Fuel operation remain largely an "equivalent gallon" of natural gas is consumed resulting in similar engine fuel efficiencies. Note: 1 gallon #2 diesel = 140 scf natural gas based on #2 diesel hhv. What about efficiency? As explained above, GTI's Bi-Fuel System replaces diesel fuel with an equivalent quantity of natural gas. This process results in the same net fuel burn vs. load as would be experienced during 100% diesel operation. For each gallon of diesel fuel displaced during Bi-Fuel operation, there is a corresponding consumption of approximately 140 cubic feet of pipeline quality natural gas (based on 129,000 btu/gallon # 2 diesel & 930 btu/scf natural gas). Thus, for each gallon of diesel fuel displaced during Bi-Fuel operation, an "equivalent gallon" of natural gas is consumed resulting in similar engine fuel efficiencies. Note: 1 d of natural gas = I liter # 2 diesel. What effect will GTI's System have on the durability of my engine? Generally speaking, operation in Bi-Fuel mode has no negative effects on engine wear rates and durability. As explained above, because engine thermal loads are equivalent to 100% diesel operation, no excess wear of combustion chamber components (pistons, rings, valves, injectors, etc.) occurs. In addition, many users of Bi-Fuel have reported positive benefits relative to engine wear including extended oil change intervals and extended time between overhauls. This is primarily the result of the cleaner burning characteristics of natural gas compared to diesel fuel. What are the economic benefits to operating on Bi-Fuel? Fuel cost savings resulting from operation in Bi-Fuel mode will vary according to the respective cost of each of the fuels. If there is a significant cost differential between the cost of diesel fuel (per gallon, liter, etc.) and the equivalent quantity of natural gas (heat value basis) in favor of the natural gas, significant fuel cost savings would result. The closer the fuels are in price, the lower the fuel cost savings will be during Bi-Fuel mode. In addition to fuel cost savings, engine maintenance savings (as explained above) may also contribute to the economic benefit of Bi-Fuel operation.

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The GTI Bi-Fuel System provides gas to the engine using a technique known as fumigation. In a process similar to that utilized by carburetors found in spark engine applications, the system supplies gas to the engine using the original air intake system. In the typical configuration, the gas is introduced at a location upstream of the turbocharger and downstream of the engine air cleaner. The gas is introduced at approximately atmospheric pressure using a proprietary air-fuel mixing device that allows for a high level of fuel atomization with the smallest possible air restriction.

After exiting the mixer, the fuel-air charge is compressed in the turbo and then distributed to each cylinder by the engine air-intake manifold. The intake valves deliver the mixture to individual cylinders at the proper moment according to the normal valve timing of the engine. Upon entering the combustion chamber, the air-gas mix is compressed during the compression stroke and ignited when the diesel injector is activated.

Because a majority of the fuel and air is already pre-mixed prior to activation of the injector, the combustion differs slightly from the normal "stratified charge" process of the diesel engine. During bi-fuel operation, the combustion is slightly accelerated and the pressure rise in the cylinder is slightly "steeper" than normal diesel combustion.

Peak cylinder pressures reached during bi-fuel operation, however, are within normal limits. Although natural gas has a lower energy density than diesel fuel, the lean-burn/excess air operation of the diesel engine combined with the compression provided by the turbocharger, allow the system to supply adequate quantities of natural gas to the combustion chamber, therefore assuring that the equivalent power can be realized.

All OEM engine specifications for injection timing, valve timing, compression ratio, etc., remain unchanged after installation of the Bi-Fuel System, and no engine modifications are required.

The included control system monitors various engine parameters (depending on engine size and application) such as manifold air pressure (boost pressure), exhaust gas temperature, intake manifold air temperature, inlet air restriction, supply gas pressure and engine vibration. This data allows the system (see inset) to determine when to activate or deactivate bi-fuel operation depending on load level, ambient conditions, knock limits, low or high gas pressure or a detected malfunction in the engine. The automatic default mode is always to 100% diesel operation.