Some question regarding the volvo B10BLE
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For the one with Natural gas powered engine, does the bus have an exhaust?
I cant seem to find any. Is it just because of the complete combustion and thats why there is no exhaust pipe? Thanks
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If I'm not wrong the final product of the combustion is water...Originally posted by geforcefx:For the one with Natural gas powered engine, does the bus have an exhaust?
I cant seem to find any. Is it just because of the complete combustion and thats why there is no exhaust pipe? Thanks -
No, there is still CO2, NO2, particulate matter, etc emission, just that it is reduced.Originally posted by off_service:If I'm not wrong the final product of the combustion is water...
It is the Fuel Cell buses that produce only water. -
oh i see, i agree too. For complete combustion, the carbon will burn to CO2 while the hydrogen will always burn to water.
So that means the exhaust pipe is very well hidden? -
Hydrogen (H2) burns and combines with Oxygen (O) to form water (H2O) . All hydrocarbons aka methane (main component of natural gas), ethane and fossil fuels burns to form Carbon dioxide and water in a complete combustion. Carbon monoxide forms when incomplete combustion happens.Originally posted by geforcefx:while the hydrogen will always burn to water.
Btw i rmbr CNG engines doesnt produce an emission that diesel engines produces. Think its sulphur dioxide or Nitrogen Oxide (NOx) if im not wrong. -
Yep, I tried to take notice of the exhaust pipe today. If you look at the nearside, you'll see 2 grilles at the bottom near the back. Look under the first grille (the one nearer to the front of bus), and you'll see a bit of the catalytic converter.Originally posted by geforcefx:So that means the exhaust pipe is very well hidden? -
Natural gas engines produce similar engine-out emissions as diesel engines, only at different quantities (i.e. generally lower). No engine can function without some form of INTAKE and EXHAUST. A dedicated natural gas engine has an extensively modified intake system in order to allow for the delivery of the fuel outside of the combustion chambers (i.e. usually via single point injection like the Volvos). A gas engine also requires a butterfly (throttle) valve in the intake system in order to control airflow (and therefore fuel flow, which affects power) whereas a diesel engine relies entirely on fuel flow to control power output (i.e. they are throttle-less). On the exhaust side of things, a catalytic converter is installed in the exhaust manifold to lower emissions of carbon monoxide and hydrocarbons (two-way oxydising catalytic converter). Without a catalytic converter, the Volvo DH10A/B/C gas engines would not meet even Euro 1 due to extremely high levels of methane in the exhaust stream. The latest Volvo G9A gas engine features, aside from a more efficient combustion system, a three-way catalytic converter that also reduces emissions of nitrogen oxides (NOx) in addition to carbon monoxide and hydrocarbons to levels well below Euro 5.
Regards,
Dave -
PM10 forms a major part of the black "smoke" that comes out of the exhaust in diesel engines.
And since CNG engines greatly reduces the amount of PM10 emission (partly due to more complete combustion and cleaner fuel), therefore when the exhaust is emitted from the exhaust pipe of a B10BLE, you dont get as much black soot / smoke coming out of a engine unlike diesel counterparts such as a Dennis Lance.
If u dont know whats PM10, check out http://en.wikipedia.org/wiki/Particulate -
Dennis Lances dont produce that much PM10 (in terms of visibility) tho. LO3x produces the most IMO. However, SG diesel vehicles cant compete with US V8s. Look at some Youtube's videos about old V8 trucks. The amount of PM10 is horrifying!Originally posted by XiaoTaro:PM10 forms a major part of the black "smoke" that comes out of the exhaust in diesel engines.
And since CNG engines greatly reduces the amount of PM10 emission (partly due to more complete combustion and cleaner fuel), therefore when the exhaust is emitted from the exhaust pipe of a B10BLE, you dont get as much black soot / smoke coming out of a engine unlike diesel counterparts such as a Dennis Lance.
If u dont know whats PM10, check out http://en.wikipedia.org/wiki/Particulate
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U mean the Volvo DH10A/B/C isn't fuel efficient? As far as i know, methane forms most of Natural Gas ( in this case CNG), up to 75%.Originally posted by Powered_By_CNG:Without a catalytic converter, the Volvo DH10A/B/C gas engines would not meet even Euro 1 due to extremely high levels of methane in the exhaust stream.
Regards,
Dave
Ai.....I still dont know how the CNG engines operates. Could anyone here enlighten me?
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Sorry, I made a slight mistake in my original post. I meant that the GH10A/B/C require catalytic converters to meet Euro 2/3/4. Diesel engines also require catalytic converters for Euro 1 or stricter requirements.Originally posted by Scania N113CRB luver:U mean the Volvo DH10A/B/C isn't fuel efficient? As far as i know, methane forms most of Natural Gas ( in this case CNG), up to 75%.
Ai.....I still dont know how the CNG engines operates. Could anyone here enlighten me?
Regarding CNG engines, here's a brief description on how they work.
1. Natural gas fuel is stored at high pressure (up to 200 bar) in cylinders usually mounted on the roof of a bus.
2. Gas is delivered to the engine bay from the cylinders via a high pressure gas line.
3. Prior to entering the intake stream, the gas is filtered for impurities and then depressurized to a set working pressure, typically anywhere from zero pressure to 10 bar. This is done in one or more pressure regulators, heated with coolant from the radiator. The pressure regulator(s) may have one or more stages.
4. The gas is then mixed with incoming air. This can be done at a gas mixer (elementry carburettor) or via gas injectors.
5. Airflow is controlled by a butterfly valve in the intake stream and in case of a turbocharged engine, a wastegate in the exhauast stream.
6. When the air/fuel mixture reaches the engine, it is ignited by spark plugs that are connected to the engine's ignition control system.
Regards,
Dave