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Diesel
Dynamometer Testing Analysis
In the past few days I have had
more time to analyze in depth the dynamometer testing results from Purdue University that is reported on in
our May 2007 newsletter. Review
that report at
http://www.hydrogen-boost.com/May%202007.html
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Initially when I examined the
charts below, supplied to me by the Purdue University
team, I focused mostly on the black torque curves and was impressed with
the increase in torque with Hydrogen Boost across most of the operating
range of the engine, especially with the Vegetable oil as fuel
tests.
This week I had more time to
examine the blue dotted curves corresponding to the fuel used per
horsepower hour, which is basically the inverse of the work done per
gallon used that I reported on in the May 2007 newsletter mentioned
above. So these blue dotted lines
indicate fuel used per unit of work performed. Since we want to use less fuel to do
the same amount of work, the lower the lines are on the chart the better.
Close examination of these curves on the Petroleum Diesel chart
shows that as the RPM increase (as you move from left to the right of the
chart) these lb/hphr curves first go up
slightly then gradually go down steadily.
When looking at the Chart labeled Diesel Fuel With Hydrogen we see
that to the far left the curves are actually higher than on the Petroleum
Diesel chart, but as you move to the right (increase RPM and throttle
setting) the curves drop quickly so that after 1100 RPM the curves are
usually below those of the Petroleum Diesel Chart. The further to the right you go on the
chart for Diesel Fuel with Hydrogen (increasing RPM and throttle setting)
the lower the curves go.
More importantly when you compare the curves on both charts you
will find that the further you go to the right (higher RPM and throttle
setting) the greater the difference between them (the greater the
benefits of the hydrogen). This
only makes sense because the more fuel there is in the combustion chamber
the more the benefits that can be achieved by making it combust better (the
purpose of the hydrogen). However,
since more fuel is combusting better and releasing its energy, I would
expect a higher exhaust gas temperature, and hence a higher possibility
of NOx emissions, especially during these
higher RPM and throttle settings.
Hydrocarbons and Carbon Monoxide emissions should be lower
however. I am expecting future Dynomometer emissions test to bare this out but I
expect the emissions to still meet EPA standards.
Conclusions:
What does this mean to those who are mostly concerned with fuel
economy? Is Hydrogen Boost a
benefit or not? My answer to that
is that it depends on the operating condition of the engine. Obviously at idle and below 1100 RPM
our fuel used per unit of work done were actually higher with Hydrogen
Boost than without. But for the
vast majority of the operating range of the engine the effects of
Hydrogen Boost were to reduce the fuel used to accomplish the same
work.
So, what if we apply this to driving a diesel car or diesel
pickup, or even a diesel tractor trailer pulling an empty trailer, or no
trailer at all? Will we get better
mileage with hydrogen Boost? The
answer as usual is, “It depends.”
If your normal driving is just
putt-putting around at near idle and never getting into high throttle
settings, then you might actually reduce your mileage with Hydrogen
Boost. But if you normal driving
it above 1100 RPM and at medium to heavy throttle settings I would expect
a reduction in fuel used and an increase in fuel mileage. If your vehicle is pulling heavy loads
or going at high speed and high wind resistance, I would expect an
outstanding improvement in mileage with Hydrogen Boost.
Now that I look back on our testing history with Hydrogen Boost,
with gasoline vehicles as well as diesel vehicles, I can say that this is
consistent with what we already know.
I have typically seen a greater % increase in mileage at 70 mph on
a vehicle with Hydrogen Boost that at 45 mph. And the two customers who surprised me
early in our presentation of Hydrogen Boost systems for diesel vehicles,
showing 20% and 25% increases in mileage were indeed correct, while I
doubted their results. Both were
testing with diesel pickup trucks hauling heavy loads at high
speeds. These are the conditions
under which Hydrogen Boost can really perform amazing achievements.
As a result of the analysis of these results we are recommending
a small change in our installation instructions and may add a few
components to our wiring kit. The
addition of a couple more relays and a couple large resisters and a set
of throttle position micro-switches would allow us to produce hydrogen at
3 or 4 rates so we only produce the hydrogen needed at any particular
engine operation condition. Later
on we may add to our welded hydrogen generators a capability to safely
accumulate the hydrogen under some pressure and a way to meter the
delivery of that hydrogen to match the need during different engine
operating conditions.
Another In Depth Analysis
Going back to the tables of raw data for the
petroleum diesel tests with and without Hydrogen Boost, we once again
take each data point and divide the torque by the fuel consumption to get
the work done per gallon of fuel.
Below we put those results side by side in a table form so you can
easily compare the diesel alone results with the hydrogen assist results
for each data point individually.
Notice that the benefits of the hydrogen are
really evident at high throttle settings, especially full throttle at
less than 2300 RPM. I have been told
that accelerating a tractor trailer down the road and powering up hills,
the RPM is usually kept 1300 and 1900 which happens to be the range where
Hydrogen Boost gave a 17-31% increase in work done per gallon of fuel
used at full throttle. I am also told
that cruising RPM is usually kept between 1100 and 1500 which in a range
where Hydrogen Boost gave a 1-27% increase at 50% throttle. So if we can shut off the Hydrogen
boost at idle and low throttle, low RPM conditions we could expect to see
even better improvements than the 15% overall average for the operating
envelope of the engine. Our plan
is to make a change to our wiring kit to include a vacuum switch or
throttle position switch that will turn on the hydrogen generator only at
cruise and acceleration condition.
This should enable us to expect a 20% increase in mileage on
tractor trailers if they are driven whenever they are running, and not
sitting all night idling.
Possible
Savings With Hydrogen Boost
In the
charts below notice that hydrogen production is not free. It takes energy to produce the hydrogen
and this energy does not always get compensated for with improved
combustion and efficiency. The key
is to produce only the hydrogen you need to ignite the combustion mixture
at the ultra lean mixture we produce with our electronic control circuit
or the normal fuel mixture in a diesel engine. If excess hydrogen is produced the
improved mileage will be lower than what is possible at optimum hydrogen
production.
In the charts below the light
blue shaded area represents the possible savings with Hydrogen
Boost. The yellow shaded areas
represent the possible NEGATIVE savings with Hydrogen Boost. Notice that at idle there is always a
negative savings and at low cruise the savings may be negative or
slightly positive. As stated in
recent newsletter and documents the Hydrogen Boost benefits are
especially prevalent when high power and torque are being produced (when
lots of fuel is being combusted).
This really shows that Hydrogen Boost can be most valuable with
vehicles that are heavily loaded or underpowered.
The
conditions where Hydrogen Boost may improve mileage the least is when the
driver is already implementing driving tips like slow acceleration and
cruising at low speeds and throttle settings. It may be possible that the cost of the
hydrogen production could be higher than the benefits of that hydrogen to
the miniscule amounts of fuel that are being combusted while using these efficient
driving techniques. This is
exaggerated when the operator sets his hydrogen production too high for
the engine he is operating.
Our
Model 20 is designed to produce enough hydrogen for even the largest
gasoline engines including those of 8 liters displacement. So those who are installing and
operating on a one liter Geo Metro engine may be only preventing improved
mileage when producing hydrogen at 20 amps.
Recent
changes in installation instructions provide for installation of a
throttle position switch or intake manifold vacuum switch that would only
turn the hydrogen generator on during acceleration and high cruise
throttle settings. This will avoid
most of the negative savings operations.
Adjusting the vacuum switch to optimum setting should practically
eliminate the negative savings zones.
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