shaax.blogg.se

For the assessment presented here, a global warming potential for methane of 25 is used, in accordance with the most recent recommendation from the Intergovernmental Panel on Climate Change ( 7). These are primarily in the form of CO 2 and CH 4 for HPDI, the tailpipe CO 2 includes the contributions from both diesel and natural gas combustion. Tailpipe emissions represent the vast majority of the emissons of GHGs from an HPDI natural gas engine. Saunders, in Internal Combustion Engines: Performance, Fuel Economy and Emissions: IMechE, London, 27–28 November 2013, 2013 3.5 Tank-to-Wheel Life Cycle Assessment The ignition system, such as spark ignition, glow plug ignition or pilot fuel ignition, adds extra cost to a gas engine. Fourth, a DI gas engine also needs an additional ignition device, which is not necessary in a diesel engine.

Third, a gas injector is more difficult to seal than a diesel injector, and tends to cost more, though the cost difference could be reduced if the production volume of gas injectors becomes comparable to that of diesel injectors. Second, the fuel pump/compressor, which either compresses gaseous fuel or pumps liquid LNG, tends to cost more to build than a diesel pump. A LNG tank is subjected to only a few bars of internal pressure, but has to use expensive material to withstand the cryogenic temperature, and requires sufficient insulation to preserve the low temperature of LNG for an extended period of time, making it more expensive than a diesel tank, or a CNG tank, of the same capacity.

Both the costs of materials and the cost of manufacturing are higher than those of a diesel tank. A CNG tank has to withstand over 200 bars of internal pressure.

First, fuel tanks, either for CNG or for LNG, are more expensive than those for diesel. Zhang, in Advanced Direct Injection Combustion Engine Technologies and Development: Gasoline and Gas Engines, 2010 8.4.4 Cost of fuel systemsįuel systems for DI natural gas engines tend to be more expensive than those for diesel engines.