NO nd HC ppm
2500
2250
2000
1750
1500
1250
1000
750
500
250
1500
2000
2500
3000
Engine speed (rpm)
NO x concentration with gasoline
NO x concentration with CNG
HC concentration with gasoline
HC concentration with CNG
a
(
)
x
3500
4000
4500
5000
5500
238
Alternative Fuels for Transportation
Figure 8.4
NO x and HC concentration versus engine speed at WOT. (From Aslam, M. U., Masjuki, H. H .,
Kalam, M. A., Abdesselam, H., Mahlia, T. M. I., and Amalina. M. A., Fuel, 85, 717–24, 2006.
Reprinted with permission from Elsevier Publications.)
8.6.2 Natural gas in Ci e ngines
Dual fuel NG engines are based upon diesel technology. Diesel engines can
be converted as dual-fuel engines, in that diesel is injected through the injectors and NG is carbureted along with fresh intake air and enters into the
engine through the intake manifold. These engines also can operate on 100%
diesel fuel. When the engine runs at idle, it tends to operate on 100% diesel. As the vehicle begins to move to full load performance, an increasing
amount of NG replaces the diesel fuel to 80% or more. Dual-fuel NG replaces
80–90% diesel that reduces about 25% CO 2 .
Dual-fuel engines are throttle controlled using a fumigation system that
adds NG to the engine as higher speed is required. The computer controlled
dual-fuel engine ensures that the optimal ratio of NG and diesel fuel is delivered to the engine depending upon load and performance requirements
(www.unece.org).
The Dual-Fuel™ ECU can be interfaced with Original Equipment
Manufacturers’ (OEMs) ECU. This enables the Dual-Fuel™ ECU to control
the engine ECU, ensuring optimum conditions for dual-fuel combustion.
It has been reported that a contemporary integrated system will deliver
at least 70% overall gas substitution with CO 2 savings of 26 tonnes yearly.
Clean Air Power’s integrated C12 product is already c ertified to Euro 4
standards (http://www.cleanairpower.com/duelt echnology.php).
Natural gas is injected into the combustion chamber shortly before the
end of the compression stroke, a diesel pilot that precedes the NG injection
provides the ignition source. Varying the fuel composition has a significant
2500
2250
2000
1750
1500
1250
1000
750
500
250
1500
2000
2500
3000
Engine speed (rpm)
NO x concentration with gasoline
NO x concentration with CNG
HC concentration with gasoline
HC concentration with CNG
a
(
)
x
3500
4000
4500
5000
5500
238
Alternative Fuels for Transportation
Figure 8.4
NO x and HC concentration versus engine speed at WOT. (From Aslam, M. U., Masjuki, H. H .,
Kalam, M. A., Abdesselam, H., Mahlia, T. M. I., and Amalina. M. A., Fuel, 85, 717–24, 2006.
Reprinted with permission from Elsevier Publications.)
8.6.2 Natural gas in Ci e ngines
Dual fuel NG engines are based upon diesel technology. Diesel engines can
be converted as dual-fuel engines, in that diesel is injected through the injectors and NG is carbureted along with fresh intake air and enters into the
engine through the intake manifold. These engines also can operate on 100%
diesel fuel. When the engine runs at idle, it tends to operate on 100% diesel. As the vehicle begins to move to full load performance, an increasing
amount of NG replaces the diesel fuel to 80% or more. Dual-fuel NG replaces
80–90% diesel that reduces about 25% CO 2 .
Dual-fuel engines are throttle controlled using a fumigation system that
adds NG to the engine as higher speed is required. The computer controlled
dual-fuel engine ensures that the optimal ratio of NG and diesel fuel is delivered to the engine depending upon load and performance requirements
(www.unece.org).
The Dual-Fuel™ ECU can be interfaced with Original Equipment
Manufacturers’ (OEMs) ECU. This enables the Dual-Fuel™ ECU to control
the engine ECU, ensuring optimum conditions for dual-fuel combustion.
It has been reported that a contemporary integrated system will deliver
at least 70% overall gas substitution with CO 2 savings of 26 tonnes yearly.
Clean Air Power’s integrated C12 product is already c ertified to Euro 4
standards (http://www.cleanairpower.com/duelt echnology.php).
Natural gas is injected into the combustion chamber shortly before the
end of the compression stroke, a diesel pilot that precedes the NG injection
provides the ignition source. Varying the fuel composition has a significant