Why is Cummins developing their own new 15 liter spark ignited engine? Is Westport part of that development effort? It doesn't appear to be the case. If that is true and Westport has such a great patent portfolio, how is that portfolio being protected? Or just maybe the patent portfolio is easily circumvented. If my memory serves me correctly, the big price drop in early 2012 was due to the new engine announcement. So, the market apparently does not like the scenario.
Feel free to answer any part of the message.
The reason why the WPRT price dropped when Cummins announced that they were pressing ahead, on their own, with the development of a NG version of their ISX15 diesel engine was that the market feared that the Cummins-Westport joint-venture was unraveling. When both Cummins and Westport made it clear that that was not the case the stock fairly quickly recovered much of the lost ground, although it has since declined for other reasons.
Right now it is clear that the joint venture is solid and the main interest centers around the ISX12G engine, shipment of which began this month.
As for the 15 liter engines, whether Cummins with their ISX15G (as I imagine it will be called when it is ready) or Westport with their HPDI engine will be more successful only time will tell. Anyway, that battle is a year or two away right now.
the pump raise the pressure and the engine exhaust raise the pressure and temperature more
So if yo wanted to not have a pump you would have warm lng(cold but not as cold) but the tank would have to stronger than the cold lng as the pressure needed is higher to keep it a liquid
Wprt supplies the higher pressure tank and a pump so that you can use the lower temperature lng
So you need a pump to raise the pressure up for cng
No pump for high temperature lng
and a pump for low temperature lng
Stored pressure in lng is not the pressure delivered to the engine
When you warm it up with the exhaust you also raise the pressure
there is warm and cold lng ,both are cold
The higher temperature one does not need a pump as its pressure is higher
wprt supplies a tank and pump that can work on both
Some stations have warm(cold but not as cold) lng and some colder
I do think its perfectly clear if they use more diesel at low rpm
the 5% could be just the average
Ng engines could have more torque ,horse power at lower rpm
The horse power or torque is chosen to give the best use of the fuel at a rpm,best millage
Wprt has adjusted the transmissions ratio and added a gear to try to give more power at lower speeds
For some they are used to spark and are trained on it,so for some spark is their choice
Its my feeling that cummins thought they could do spark them selfs or did not want to give the same profit
For cummins it was not just the US ,it was Asia,for the Chinese its money 1st
So they want a product for both
They win either way.They have both products
Warm LNG, where are you getting this information? Do you have more information.
LNG is stored as a cryogenic liquid at -250F at just below atmospheric pressure, around 5 PSI. Insulated tanks are needed to keep heat out. The heat which does get in causes the LNG to boil off. It will stay at -260F as long as the energy going in is removed by the boil off.
The pressures of liquid stored above -260 would be too high. You may know something I don't and if you have more information I would like to read it. I know of no non-cryo storage of LNG.
What have you found?
Cummins is developing the 15L spark ignited engine because they know that truckers have to weigh the pros & cons of :
A.) Performance (horsepower & torque)
C.) Fuel costs
HPDI requires higher pressure than you get with CNG, so you need more expensive LNG, (or an add-on compressor like the one iGas is working on, but that adds significant cost). A 15L spark ignited engine would give them the option of using CNG if they don't need the range of LNG, but the 12L spark ignited engine doesn't meet their power requirements. So Westport passed on the 15L SI because they felt it filled too small a niche.
I don't think your reply about CNG pressures is correct. LNG is cryonic storage of liquid allowing more fuel to be held in the tank but, it must be vented to hold the low temperature as it is slowly boiled off. Liquid LNG is not injected into the combustion process. The fuel delivery in both systems will be CNG after it has left the tank. No way is -260F liquid nat gas going into the cylinders. The same power will be generated with LNG or CNG as only some much fuel can be added for the air in the intake. Plugs are only needed because Nat gas will not ignite under compression like diesel does. The Westport HPDI injector only used enough diesel to ignite the Nat. gas. This injector allows for the use of Nat. gas on current engines with out replacing cylinder heads which have no spark plugs or spark ignition system. The diesel involved in the HPDI injectors has nothing to do with power. This is great stuff because it allow Westport to convert million of existing engines to CNG or LNG.
A tank with -260F LNG has more fuel in it then a loaded 3000PSI CNG tank. The LNG is for longer range not because of any power issue.
If an expert can verify one way or the other that would help. There needs to be more technical discussion on this forum.
I think at one point David Demers said WPRT made the decision not to partner with Cummins on the 15L spark ignited engine because WPRT believed HPDI was the way to go on 15L and that the 15L spark ignited was not that big of an opportunity. He said did not want to invest the significant resources that woudl be required to go after 15L spark ignited with Cummins.
I may nto have all of that exactly right but it is close to what he said.
Biz has it right. Spark ignition is tolerable on flat lands but a heavy truck in hilly country will struggle - too little torque compared diesel. Only HPDI has the same torque range as diesel. The reason being that, gallon to gallon, LNG has only 57% of the energy density of diesel. Cummins wants to get a nat gas engine that is cheap. Suppose there is a market for that, but it will dwindle as HPDI costs come down and customers become frustrated with the lack of power.