Thread: Isuzu Emissions.

That 300Tdi is terrible. I had expected that it would be similar to the 4BD1. It must be sick.

When is it visible xxx mg/m3?

Originally Posted by slug_burner

That 300Tdi is terrible. I had expected that it would be similar to the 4BD1. It must be sick.

When is it visible xxx mg/m3?

Yes the 300Tdi was a shock, however it was obviously smoky. Interestingly though it still returns excellent economy <9L/100km including some stop-start driving (measured over several months).

The definition of visible is vague. From how far away andin what sort of light conditions???

>100 mg/m3 would definitely be regarded as visible in all conditions. Even as low as 20-50 mg/m3 is (just) visible when you are standing right next to the exhaust.

Fuel quality also affects particulates - probably the main reason why sulphur has been reduced in diesel fuel.

Originally Posted by Bush65

Fuel quality also affects particulates - probably the main reason why sulphur has been reduced in diesel fuel.

John - agree with your PM - particulates are indeed affected by atomisation (injector pressure etc), and by injection timing, state of tune, etc, etc, etc... The results above are nothing more than a bit of fun, and they don't represent anything meaningful, without knowing the full engine settings and telemetry at the time. I was interested to see though that the 4BD1 seems to combust about as cleanly when cold as hot (idle soot levels).

You would also need to use a dyno to do the tests if you want representative results. Which we don't have yet.

Sulphur has some influence on particulate formation (you do get some nice sulphur crystals in filters - especially when measuring at coal fired power stations), however more on SOx formation, which is the main reason sulphur was removed from fuel. We have measured low levels of H2S and SOx in the exhaust gases from the above diesels.

On the topic of particulates - I saw an interesting papeer at a recent conference by some greek researchers. They stated that the EURO test standards for light vehicles use an accelaration rate which is too low. They found that all diesels tested fail emissions standards when tested at higher acceleration rates.

Interestingly, they also found that between Euro 1-5, the number-based emissions rates have not changed, significantly. What has changed is elemental carbon levels have reduced over time (diesel soot is categorised as being composed of elemental carbon (EC) and organic carbon (OC)). Vehicle emissions testing measures total particulates (EC+OC+..), but occupational standard are EC only.

What this implies is that higher injection pressures from Euro I-V, combined with higher combustion temperatures, allow smaller droplets to be produced, with more of the OC combusted to produce EC+CO2, however still the same number of EC particles.

Studies are finding that health effects (from soot and other particles) are related to particle surface area rather than mass. So Euro V standards and beyond will include a particle number limit as well as mass-based emission limit.

Btw - the Measurements above were taken with a TSI DustTrak DRX. Which is not the best method for soot measurement, as it measures a scattered light signal for each particle (related to refractive index and size), then converts it to a mass based on assumed particle density. It is also unable to detect particles in the smaller part of the size fraction. Despite all of the above, it has generally been found to be +/- 10% of the actual values.
We will be doing more accurate measurements soon using an SMPS, which can count and size all soot particles down to 4 nm (as well as giving the full size spectrum), plus a low pressure cascade impactor (NanoMOUDI).

Another interesting anecdote. HV emissions are measured in g/kWh, light vehicles in g/km. So a 4BD1 engine in a landie wagon (if subject to emissions standard) would be assessed based on g/km, whereas in a truck it would be g/kWh.

Have you tested an LPG fumigated engine?

Would be interested to know a comparison, as the people I know with fumigated diesels all have grey exhaust pipes instead of the black sooty ones I'm used to with moderately worn diesels.

Originally Posted by Lotz-A-Landies

Have you tested an LPG fumigated engine?

Would be interested to know a comparison, as the people I know with fumigated diesels all have grey exhaust pipes instead of the black sooty ones I'm used to with moderately worn diesels.

No. Don't know anyone who owns one, and AFAIK there is usually no fumigation at idle or under no-load conditions, so it would be hard to test. However if someone in Perth has one, it would be interesting to see what the emissions are like.