Thread: 4BD1 with LPG?

Originally Posted by isuzurover

......... (but can I interest you in some homeopathic remedies or a fuel polarizer?)

No......

......but do you sell hiclones ?

Originally Posted by isuzurover

Your "real world" anecdotes are not conducted on dynamometers with accurate measurements of BSFC and emissions. The few tests that have been done on dynamometers are usually done by installers with a vested interest (i.e. a bias) and no accurate emissions testing equipment.
At best the anecdotes from users report $$$ and unreliable measures like visible smoke and colour of exhaust deposits. Many people on here insit on reporting fuel consumption in km per tank!

As I said. All scientific studies have found increased gaseous emissions and worse fuel economy - which does not mean increased $$$ per km over straight diesel as I have pointed out.

There is a large study about to be published by Australian researchers, however overseas studies have been producing equivalent results for years, e.g.:







The consensus from all the studies is reduced soot and NOx, however (unacceptably) increased CO and HC emissions, along with increased BSFC at low and part load conditions (where most engines operate most of the time).

Interestingly your tests talk about 40% substitution and increased hydrocarbons. All the results I have back from my customers indicates the direct replacement of litres of diesel with litres of LPG is optimised at around 20% replacement rates. At higher rates you get loads more power but the combined economy suffers considerably. It makes sense that the extra fuel appears as HC and CO at the tailpipe.

Originally Posted by isuzurover

CSIRO also did an extensive series of emissions tests on Australian vehicles (mostly petrol). Comments by one of the lead researchers after the tests were that most LPG systems fitted are poorly designed and optimised, resulting in significant increases in emissions (even for factory installed systems).

I wonder if those results also apply to sequential LPG vapour injection systems that closely follow petrol injection settings. Then GMH and Ford went to liquid injection in their latest LPG vehicles and you'd expect a bit of rigorous testing to have gone into these complex systems.

I was an LPG business rep for 23 years & we tried & tried ( & threw a lot of money at) getting the trucking industry on to LPG supplementing.
There were a few successes but overall, the vast majority of the heavy vehicle industry has not adopted it.
One trial I recall was a trucking company in Ballarat that ran a fleet of Semi's in to Ford at Broadmeadows. They ran 2 vehicles on Diesel/Gas & dropped the idea of rolling it out after mucking around with it for 6 months as the vehicles added 12 minutes per trip on average. They kept the gas going until the conversion paid off, but by then we had ceased dealing so I don't know how long it took.
Probably not relevant to this thread but one thing to note that I only recall one fire ( & I think that was CNG or LNG) and no instances of premature wear in truck engines with gas supplementation.
Full gas conversion is another matter altogether..

Originally Posted by bee utey

Interestingly your tests talk about 40% substitution and increased hydrocarbons. All the results I have back from my customers indicates the direct replacement of litres of diesel with litres of LPG is optimised at around 20% replacement rates. At higher rates you get loads more power but the combined economy suffers considerably. It makes sense that the extra fuel appears as HC and CO at the tailpipe.



I wonder if those results also apply to sequential LPG vapour injection systems that closely follow petrol injection settings. Then GMH and Ford went to liquid injection in their latest LPG vehicles and you'd expect a bit of rigorous testing to have gone into these complex systems.

litre for litre substitution would be an unbelievable improvement in bsfc and everyone would be doing it.

If you pm me your email i can send you the full papers. The paper that mentioned 40% tried a wide range. I have seen other papers on diesel+petrol injection where they went up to 85% substitution. Scientists like to research every option.

The Csiro work was done 2009/2010. So whatever was available new or sh then.

Thanks guys. Jeepers!

...Shall we move on, to a debate about solar Land Rovers now then? 🙃

Originally Posted by isuzurover

litre for litre substitution would be an unbelievable improvement in bsfc and everyone would be doing it.

Oh well, I'll have to assume my Land Rover diesel owning customers are all lying to me then when they calculate their consumption in their log books that 8 (litres diesel) plus 2 (litres LPG) equals 10 (litres diesel without LPG) per 100km. They'll be interested to know that it has been proved to be impossible by experts. The 10% running cost reduction due to the fuel price difference must therefore be imaginary too.

Originally Posted by isuzurover

If you pm me your email i can send you the full papers. The paper that mentioned 40% tried a wide range. I have seen other papers on diesel+petrol injection where they went up to 85% substitution. Scientists like to research every option.

Not necessary but thanks anyway. I've found similar reports online and am studying them now to see if there is any relevance to my work.

5.2. Effect of engine speed

Tuan and Truc examined in AVL 5402 single cylinder engine that at full load, higher LPG mass fraction can be reached at lower engine speeds due to knocking limit; however, the economic efficiency with dual fuel is better at higher engine speeds, as at these operating regimes the better diesel injection quality and better fuel evaporation can help to improve the combustion. Due to knocking limit the LPG mass fraction can reach 54% at engine speed lower or equal to 2000 rpm on full load curve as shown in Fig. 10. At higher engine speed, the LPG mass fraction can reach up to 40%. The total fuel consumption of dual fuel cases showed no improvement at 10% LPG mass fraction, but obvious improvement with 20%LPG (at 1400 rpm and higher), and with 30%LPG (at 1200 rpm and higher). These express that the economic efficiency with dual fuel is better at higher engine speeds as at these operating regimes the better injection quality and better fuel evaporation can help combustion improve [62].

my bolding

http://www.sciencedirect.com/science...10016815000162

Originally Posted by isuzurover

The Csiro work was done 2009/2010. So whatever was available new or sh then.

That should cover the earlier sequential vapour systems but not the liquid injection systems. Having dealt with a few factory Impco BRC sequential vapour systems I'm not surprised that the CSIRO testing found problems, their fine mixture control isn't as good as some other systems I've used.