Document: LPG and CNG vs gasoline

[Genie47]

http://www.p2pays.org/ref/36/35452.pdf

 

It is a whopping 3.61MB document.

 

Very detailed study but involving American cars. Can't believe it that a SGI 3.1L V6 Lumina pushes out only 98BHP at 4500RPM and this is alaready a 10.6% loss from powered with gasoline. Either CNG is really lousy or American automotive technology is really bad. My 1.4L DOHC already pushes out 94 ponies at 4500RPM with petrol.

[Bugsbunny]

 

[Trex101]

Latest in liquid injection technology, 5% FC losses when compare with petrol. Extract from Ford forums au.

http://www.fordforums.com.au/showthread.ph...11217031&page=2

 

 

quote:

I am the Australian LPG Warehouse's Managing Engineer. The Liquid Injection system you are discussing above is made by Icom and developed for Australian vehicles and conditions by us. We have been doing extensive durability testing and development on the system (Called JTG) over the past year with great results.

 

We have been developing emission compliant kits for the most common vehicles first. On that list is BA/BF sedan, Territory 1&2, Holden 5.7lt sedan and Holden 6lt sedan.

 

We have given our first training session on the JTG liquid injection system to our first group of installers with positive feedback. As the demand for this system is huge, we have made a decision to only supply to the first 2 groups trained for the first 6 months. To be a certified installer of this product the installer must first attend the training and have the appropriate tooling as the technology is quite different to traditional systems.

 

Just to cover a few topics discussed above. The system has no requirement for any injection timing strategies. Full control of the system is via the factory engine management system. This is quite different to standard vapour injection systems as they need to manipulate the injection pulse with due to pressure, temperature, and flow issues. The JTG controller is only there to switch the pulse from the petrol to lpg injectors and control the LPG pump.

 

The system is quite similar to a petrol system. The cylinder has a pump integrated that pushes the LPG to the injectors common rail. This is then ran through a pressure regulator similar to a petrol regulator and fed back to the tank via a return line. The pressure is kept 3 bar over tank pressure.

 

The injectors deliver liquid LPG directly into the manifold via a small tube. This is installed much the same as vapour injection. A hole is drilled in the manifold as close to the petrol injector as possible and a nozzle is taped in. The difference is that the liquid is passed through a small inner hose that is inserted into the nozzle. An outer hose is then placed over the smaller hose and onto the outside of the nozzle.

 

The injector is made by Siemens specifically for the JTG system. The flow of this injector is matched to the flow of the petrol injector via a calibration tip inserted into the housing. This is all developed by us before the kit is sent out. We measure the flow of the petrol injector for each vehicle type and then select the appropriate calibrator and injector combination. This is then tested for power, drivability, economy and Emissions. Once we have a final match, this system is then sent to the emission lab for certification.

 

The end result is a complete kit with laser cut brackets, plug and play wiring and ready to bolt on and drive. We have seen huge fuel savings and power gain using this system. The fuel usage using JTG is within 5% of petrol unlike vapour injection which is only within 20%. This makes it a very viable option. As with all technology it is more expensive than its predecessor. However it will only be from $300 to $400 more per kit depending on the vehicle. This is well made up for in the 15% benefit over vapour injection economy.

The system can run as straight gas or duel fuel. The only issue with straight gas is that there is a delay of 3 seconds before start up. JTG requires a purge of the supply and return lines before start up. This is to remove any vapour from the lines. On duel fuel systems this is set for about 30 seconds. The system during this time will run on petrol while it circulates LPG. After this time it will then switch to LPG by itself. Straight gas vehicles have this purge time set at a minimum.

The system cannot be upgraded from traditional systems as mentioned above. The cylinder has an integrated pump and uses a return line (This pump however can be accessed). The fill line in the JTG system also has a filter. This is to stop any contaminants affecting the pump. The filter can be replaced and we set an interval of 50,000km.

Turbo

Edited April 17, 2008 by Trex101