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Post by eisdielenbiker on Feb 10, 2012 18:22:55 GMT
Hi, being only an owner of a Rover P5B all year round and that of an old Mercedes on LPG for the summer season I enjoy providing my beloved with more recent cars. They mostly have to pay themselves ;-) At the latest in March our new Opel/Vauxhall Zafira will be delivered:  You will wonder about the strange underbody structures. It is a Compressed Natural Gas powered vehicle. Actually my wife , mostly, and me are driving a 2001 Vectra on Liquid Petrol Gas. If you once enjoy paying half of the bill at the station you just wont like to reverse to ordinarily taxed gas. The Zafira's exhaust is ending under the rear nearside (continental) door. In winter the fumes are impressive like a steam engine I was told. That is for CH4 (methan gas) containing relatively a lot more Hydrogene than standard fuel. Standard fuel includes a lot more Carbon atoms relatively. Therefore it is also very environmental friendly in measures of Carbon Dioxide emission. And CNG can be obtained from rotten organics, organic CNG is very common in Switzerland. Does anybody drive on CNG or LPG cars too ? A conversion for the rover would not allow low historic taxes in Germany, except the gas conversion was contemporary e.g. in the 1970s or early 1980s. Had they been done in England at the time ? Here one would need a printed document to prove that. Otherwise tax due would be excessive for the 3.5 litres displacement. Regards Mark |
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Post by johnwp5bcoupe on Feb 10, 2012 19:54:39 GMT
Our daily driver is LPG Mark its a Honda HRV and if I have another car I would convert that as well  How does the filling up procedure work as it is compressed gas? |
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Post by eisdielenbiker on Feb 11, 2012 6:26:37 GMT
Filling procedure works at 200 bar pressure. The filling nozzle looks like the one of petrol at first glance. Of course it seals by an integrated o-ring in the adapting stud at the car when it is locked upon connection. The procedure itself is temperature compensated. I.e. in cold weather you succeed filling a 21 kilogrammes tank with 24 kilogrammes and vice versa in hot weather. The technology itself has evolved a lot over the last few years of CNG. This is due to the new car philosophy of CNG. That also means you nearly always start immediately on CNG, if it not colder than -15 degrees. LPG is ideal for conversion an CNG is ideal for new cars at least in continental Europe. In the UK there are not many more than 1 station according to the databases.
Mark
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Post by colnerov on Feb 11, 2012 10:58:13 GMT
Hi, it has always been the same with 'new' fuels, Getting hold of
the stuff. It was the same with petrol, only available from chemists.
Colin
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Post by Warwick on Feb 14, 2012 3:12:54 GMT
Hi Mark,
I've had dual fuel cars running mainly on LPG since the early '80s. Company cars. Holden Commodores or Ford Falcons. But then the company was a gas company and one of the largest LPG suppliers here.
These days I've got the Range Rover on dual fuel but intend to remove the petrol tank and injection system completely and run gas only. That is also the plan for the P5B. The Rover V8 really loves LPG. All the black oil sludge disappears from inside the engine and the oil is still clear on the dipstick at oil change time.
Do you have compressor systems in Germany for refuelling a CNG car at home overnight from the town gas supply? It's a slow filling process.
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Post by eisdielenbiker on Feb 14, 2012 7:49:28 GMT
Hi Warwick,
oh yes I remember you were driving on LPG. I dont have or plan a home filling station. There is no gas line here on my new premises. If I had one that station would be very expensive due to technical regulations in respect to safety issues. In effect you would pay a higher price per KG than at a public filling station. The CNG-equivalent of 1.5 litres (= 1 KG) of petrol costs nearly one GBP. For LPG a home station would definitley pay off, as the pressure involved is so much lower. A few people do have these.
Recently I have read that in Australia public buses are on CNG too.
Mark
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Post by mcgill on Feb 17, 2012 16:53:49 GMT
ive been running lpg for 15 years in a v8,then converted the coupe.Yes there is a drop in power,or should i say lasier,but i dont boot around like a Dick head,its not like when the roads where empty,then you had 3 litre capris for that  .... |
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Post by Warwick on Feb 18, 2012 7:30:56 GMT
Recently I have read that in Australia public buses are on CNG too. Mark Not many that I know of Mark. Mostly diesels. There are some operators of short routes that tried it but I'm not sure it's that widespread. They were experimenting with CNG buses in a fleet near where I worked 25 years ago. One of the big dairy companies here runs part of its diesel milk tanker fleet on LNG. That gives very good savings and good range, but is technically more difficult and costly to set up. You need your own filling station. |
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Post by eisdielenbiker on Feb 18, 2012 9:45:49 GMT
Hi Warwick,
that LNG is absolutely new and exciting, isn't it ? They have been building LNG terminals and tank ships for a few years in Norway e.g. That would be a future substitute for oil tank ships as gas will possibly last a lot of decades longer than oil. Do you have a link or more information on LNG in Australia ?
Isn't CNG the same when pressurized at 200 bar ? But the filling procedure would run in liquified form. I am not really sure if on CNG it wouldn't be the same.
MArk
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Post by eisdielenbiker on Feb 18, 2012 9:51:16 GMT
ive been running lpg for 15 years in a v8,then converted the coupe.Yes there is a drop in power,or should i say lasier,but i dont boot around like a thingy head,its not like when the roads where empty,then you had 3 litre capris for that .... I do not quite understand? You reinstalled the original smooth 6-pot-engine on petrol again ? Of course there are options to even gain power over petrol mode. But they are costly, Australians seem to have elaborated injection devices for that purpose. In the end it is a matter of cost. You wont end up saving anything if you just do 2000 miles a year or even 4000 like me... Mark |
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Post by Warwick on Feb 20, 2012 4:01:27 GMT
Hi Warwick, that LNG is absolutely new and exciting, isn't it ? They have been building LNG terminals and tank ships for a few years in Norway e.g. That would be a future substitute for oil tank ships as gas will possibly last a lot of decades longer than oil. Do you have a link or more information on LNG in Australia ? Isn't CNG the same when pressurized at 200 bar ? But the filling procedure would run in liquified form. I am not really sure if on CNG it wouldn't be the same. Mark Hi Mark, Natural gas is basically methane, which is a permanent gas. It doesn't liquefy when compressed like LPG (propane), butane, or CO2 do. As you compress natural gas into a cylinder, the more you put in the higher the pressure goes, just like compressed air. The major atmospheric gases, nitrogen and oxygen, are permanent gases too. Therefore the limiting factor for natural gas (methane) storage is pressure. How strong you can make the cylinder and how heavy that cylinder will be. Make it stronger and it gets heavier. The stronger it is the higher the pressure that you can achieve, the more gas you have crammed in, and so the greater the distance you can get between refuelling stops. LPG on the other hand liquefies once it reaches a certain pressure. This varies with temperature and at 25 deg.C it's about 10 Bar. As you pump in more gas, once the pressure reaches 10 Bar, the gas just liquefies and the pressure doesn't increase. In liquid form the gas takes up a fraction of the space, so you can get more fuel into the same size cylinder. The other advantage is that the relatively low storage pressure means a relatively thin-walled, lightweight cylinder. Compare the weight and construction of an LPG cylinder with that of an oxygen cylinder. The oxygen cylinder needs to be at around 140 Bar and still it contains much less gas than a similar size LPG cylinder at 10 Bar. Therefore, in order to get better range from a natural gas "fuel tank", you need the gas to be in liquid form. As this can't be done to methane by compression, it must be done by refrigeration. Methane is one of the cryogenic gases. It becomes a liquid if cooled to around -160 deg.C. I say "around" because it depends on the pressure. Liquid nitrogen in a bucket is -196 deg.C but is warmer if it is under pressure in a cylinder. If you liquefy natural gas this way, the cylinder pressure only needs to be about 25 kPa. But to keep it at -160, you need a cylinder (or fuel tank) with very good insulation. Vacuum insulation. A big high tech Thermos flask. These are special pieces of equipment and take up a fair bit of space as they must be cylindrical and the volume to surface area ratio needs to be as large as is practicable. This is easier to do on a large truck than a car. The other disadvantages are the need for cyrogenic storage vessels at the refuelling station, and the fact that if you don't use it it eventually leaks away. Because no insulation is perfect, heat slowly leaks into the vacuum insulated tank and as it does the liquid warms and boils off to become gas again. This increases the pressure in the cylinder so it must be vented to waste to prevent the cylinder being over pressurized. LPG is maintained as a liquid by pressure in the refuelling system, so when you fill your car tank it is being pumped in as a liquid. Similarly with cryogenic liquids which are kept refrigerated and under pressure during the transfer from the bulk storage vessel to the fuel tank. If you're interested, I can e-mail you some stuff I wrote for a training course years ago - once I find it. |
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Post by eisdielenbiker on Feb 20, 2012 7:10:44 GMT
Warwick, I see you are an expert. Thank you for learning some exciting facts...although I should have known from university basic courses. As time passes by...
Mark
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Post by Warwick on Feb 21, 2012 3:32:56 GMT
Warwick, I see you are an expert. Thank you for learning some exciting facts...although I should have known from university basic courses. As time passes by... Mark Cryogenics, yes. LNG, very much less so. I worked in cryogenics for most of my working life, beginning in the early '70s when it was pioneering stuff outside of the space industry. I left it 12 years ago and only occasionally get a chance to dabble in it these days. |
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