Dual Fuel System - How It Works
The natural gas is mixed with air at precise quantities to substitute the reduced diesel energy. The injected diesel fuel provides the necessary ignition source for the air-gas |
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mixture which then combusts at a similar speed and pressure compared to 100% diesel operation. Although the
injected diesel fuel acts as |
an ignition source for the air-gas mixture, it is also provides a small portion of the total energy needed for combustion, based on the substitution rate required at different speeds and loads.
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| Dual Fuel System - Speed Governor |
| The Dual Fuel System replaces the original mechanical governor with a electronic |
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governor for engine speed. The system then becomes a drive-by-wire system.
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Dual Fuel System - Engine Performance
Conversion to DFS results in the same performance levels as OEM Diesels in terms of engine power, stability, torque and response, with the advantages of reduced fuel costs and lower emissions. |
Dual Fuel System - Diesel Substitution
Vehicle duty cycle is the most important variable for determining |
| substitution rates. In general, moderate to heavy engine loading (over the road conditions) will typically yield gas substitutions between 70-85% (assuming high quality natural gas). Lower average engine loads |
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| (stop and go high traffic conditions) will typically limit natural gas substitution rates to between 65-70% |
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Dual Fuel System - Engine Oil
No changes is engine lube oil specifications are required for Dual Fuel Operation. Natural gas burns with minimum particulate residues
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so that the engine oil is less contaminated with Dual Fuel operation. This leads to longer average intervals between lube oil and oil filter changes and extended periods between engine overhauls.
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| Dual Fuel System - Engine Operating Temperatures |
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Operating engine temperatures in Dual Fuel mode are similar to 100% diesel performance.
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Engine exhaust gas temperature, coolant temperature, oil temperature and manifold air temperature levels remain within the limits set by the engine manufacturer.
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Dual Fuel System - Engine Efficiency
The engine power is 100% maintained. In addition the DFS maintains a net fuel efficiency (specific fuel
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consumption) equivalent to 100% diesel operation.
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Dual Fuel System - Emissions
Dual Fuel operation will typically reduce production of nitrogen oxides, sulfur oxides,
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| reactive hydrocarbons, carbon dioxide and particulates. Exhaust opacity levels (visual emissions) are also typically reduced. For emissions sensitive |
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| application, 2-way oxidation catalysts are recommended. |
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