Thread: 4BD1 with LPG?

If you can justify the cost you get better economy, cleaner, cooler running engine & an increase in power. Contact the 4BD1 gurus st KLR South Windsor.

We've got it on a 120 😀

Interesting you say cooler running ...So it doesn't run too hot at the cylinders for an old engine? Not detrimental to the lifespan of 4BD1?

I've done a few over the last few years, both NA and turbo, all of them are still happily running. With LPG displacing diesel (ie you back off the diesel when LPG is added) you get slightly lower EGT's, if you use the LPG to add power you raise the temps but hey, it's an Isuzu heavy duty truck motor and can handle it just fine.

The scientific tests that have been done by independent researchers shows that overall bsfc fuel economy gets worse. It is just the lower price of lpg that may make it economical. Many emissions also are worse.

Originally Posted by isuzurover

The scientific tests that have been done by independent researchers shows that overall bsfc fuel economy gets worse. It is just the lower price of lpg that may make it economical. Many emissions also are worse.

References & Links please isuzurover -

Clearly, real world experience would indicate that what you have stated is incorrect, however it would be interesting to review your info.

Lowdown??
Read away


http://www.aulro.com/afvb/isuzu-land...isuzu-lpg.html

Originally Posted by 87County

References & Links please isuzurover -

Clearly, real world experience would indicate that what you have stated is incorrect, however it would be interesting to review your info.

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 test results showed that the smoke and Nitrogen oxide (NOx) emissions decrease, while carbon monoxide (CO) and hydrocarbon (HC) emissions increase at all mixtures of LPG and diesel fuel. Brake specific fuel consumption (bsfc) decreases by 3.5-15% with 40% LPG while the load increases. Exhaust gas temperatures at the mixture fuel were lower than that of diesel fuel in general. It was concluded that LPG can be used with diesel fuel as a mixture up to 40-60% of LPG, provided that CO and HC emissions can be lowered.

Source:
EFFECTS OF LPG PERCENTAGE TO PERFORMANCE AND EXHAUST EMISSIONS IN A DUAL FUEL ENGINE

Aktas, A (Aktas, Abdurrazzak)[ 1 ] ; Dogan, O (Dogan, Oguzhan)[ 1 ]

JFEAGU 25(1), 171-178
Published: MAR 2010

...HC, CO emissions and 'bsfc' are higher for part load gas diesel engine operations.

source:
Effect of engine parameters and type of gaseous fuel on the performance of dual-fuel gas diesel engines-A critical review

Sahoo, BB (Sahoo, B. B.)[ 2 ] ; Sahoo, N (Sahoo, N.)[ 1 ] ; Saha, UK (Saha, U. K.)[ 1 ]

RENEWABLE & SUSTAINABLE ENERGY REVIEWS

13(6-7),1151-1184

DOI: 10.1016/j.rser.2008.08.003

Published: AUG-SEP 2009

The results show that, over a wide range of operating conditions (engine speed, load), the dual fuel engine clearly shows the benefits of reduced NOx emissions. However, under low loads, the results indicate high CO and HC emissions and a higher BSFC when compared to those of the corresponding diesel engine.

Performance Analysis of a Dual Fuel Engine Using LPG and Diesel with EGR System

By:Kumaraswamy, A (Kumaraswamy, A.)[ 1 ] ; Prasad, BD (Prasad, B. Durga)

DOI: 10.1016/j.proeng.2012.06.326

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).


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'm in the don't bother camp, and are simply basing my judgement on my experience with my last vehicle being a gu patrol with the td42t.

With the LPG it had barely noticeable more power, ran higher egt, used about 2L/100 less diesel but used 4L/100 gas so $/100k was no saving.

Was a pain filling up as some servos have the LPG bowser separate, the extra LPG tank is heavy and can be in the way, adds another unnecessary system to look after and I generally regretted fitting it. The only good thing about it was that it made me sell it and get my Isuzu 130

Just my experience.

Cheers,
Andrew.