July 2006
Emissions Analysis With Hydrogen Boost
I
hooked up our 5 gas emissions analyzer and computer to an inverter plugged
into the cigarette lighter of my Saturn SL1. With the Hydrogen Boost system shut off I had my wife
drive around town as I recorded the readings on the readout of the
analyzer, which was on the computer.
The following is what I found:
At idle for extended
periods of time the ECU of the vehicle was quite good at optimizing the
fuel ratio to take advantage of the catalytic converter, bringing the
emissions down to fairly low levels.
CO at
times could actually get down close to zero.
HC at
times could get down fairly low.
NOx
took a while but eventually got down below 50.
During
acceleration the emissions would climb considerably and during
deceleration they would climb even more. Then once again if the throttle was set steady the ECU
would work out an optimum fuel ratio to minimize the emission once
again. The problem is that any
change in throttle setting would send the emissions readings into a
gyration. For a steady cruise
on a flat road this would work fairly well in keeping emissions down. But changing throttle settings are a
reality of vehicle operation and most throttles are not steady for more
than a few seconds, even while using cruise control.
With the stock vehicle operating
normally I noticed that the emissions readings on the readout were as
follows:
CO at
times would climb to 7.82%
HC at
times would climb to 400 PPM
NOx
at times would climb to 800 PPM
The
reason for these bad readings is that whenever the throttle setting is
changed there is an immediate change in fuel ratio which does not meet
the criteria of the perfect burn that the emissions control system is
designed to handle. Whenever
the fuel ratio is too rich the CO and HC are elevated, and when the
fuel ratio is too lean the NOx is elevated. And since the throttle setting is almost always changing,
the fuel ratio is always wrong for the design and the emissions are
higher than they could be.
There
are a couple things that can be done to improve this situation. One is to increase the speed at which
the ECU changes the amount of fuel being injected, and the other we
will discuss later. Enhancing
the adjustment speed of the ECU will not completely take care of the gyrations
because they are caused by fuel already injected and sitting in the
intake manifold during deceleration.
Present
day electronic fuel injection systems are a vast improvement over
carburetor and early fuel injection systems. But much could still be done to make the combustion more
efficient and reduce the emissions further.
Let us address the
efficiency issue first. Liquid
fuel doesn’t burn until it is first vaporized. Heating of the fuel can vastly
improve the rate at which the fuel will vaporize and thus hasten when
it will combust. This is why
the Hydrogen Boost system has a fuel heater.
Another thing that could be
done to improve efficiency is to ignite the air/fuel mix quicker so the
advanced timing can be reduced to a minimum so the combustion and compression
are not fighting against each other during the initial part of the
combustion, which is actually done during the later part of the
compression stroke. This is one
purpose of the added hydrogen (Brown’s gas) to the combustion chamber
with the Hydrogen Boost system.
The third thing that can be
done is to lean the target air/fuel mixture to the mixture that gives
us the greatest power per stroke (greatest torque). This is the purpose of the Hydrogen
Boost system’s electronic control circuit. At the moment the circuit is relatively crude and in need
of more sophistication in optimizing the fuel ratio. We would certainly like to
accomplish that goal in the future.
Of course a couple things
could be done to improve the efficiency of the vehicle that have
nothing to do with combustion but are indeed incorporated into the
Hydrogen Boost system. One is
to make the inside of the engine more slippery so there is less
friction and drag. We have done
this with the addition of the XCEL PLUS permanent engine treatment and
XCEL PLUS upper cylinder lubrication treatment. And the last thing we could do is to
get the vehicle to roll down the highway with less drag. We have done this by increasing the
tire pressure beyond the vehicle manufacturer’s recommended pressure
but within the tire manufacturer’s safety limits. We have addressed this in our
February 2002 newsletter.
How do each of these affect
the emissions of the vehicle?
Let me address that question.
First heating the fuel, this could increase evaporative
emissions if you had a leaky fuel system, but that would only be for
defective vehicles. Certainly
combustion of vaporized fuel can only cause less CO and HC emissions
because the fuel can burn more completely while it is still in the
combustion chamber.
The addition of hydrogen in
the combustion mix also gets more of the fuel to combust while it is
still in the combustion chamber so that is also good.
Leaning the fuel ratio
slightly will decrease CO and HC emissions because it insures enough oxygen
to combust all the fuel to completion but it can increase NOx
production because the presence of excess oxygen in the combustion
chamber during hot combustion allows the nitrogen in the air to combine
with the excess oxygen and form NO2 and NO3. This is not a good thing but it can be minimized in two
ways. Firstly, most engines
have a system to do this called the EGR, or exhaust gas recycling
system. The other way is to
decrease the temperature of the combustion so the needed energy to
combine the nitrogen and the oxygen is not present. This may be a task that might
actually reduce our engine’s efficiency because we really would like to
operate at the highest exhaust gas temperature to get the highest torque. The methods we could use to reduce
the exhaust temperature is to further lean the air/fuel mixture or to
trade some of that excess heat for increased pressure by adding some
water mist into our air/fuel mix.
This would capture the energy of the excess heat and turn it
into torque. I have not tested
this option at this writing because the idea just came to me as I was
writing this report. I have
tested the addition of water mist in relation to fuel economy with the
Hydrogen Boost system and found no benefit, but I haven’t tested the
possible benefits of reduction in NOx emissions by adding water mist
because at the time of testing I didn’t own an emissions gas
tester. I have tested further
leaning the mixture and am reporting on that here.
When testing the emissions
with the Hydrogen Boost system turned on and operating I recorded the
following:
CO emissions were always as
low as the scale would go, basically zero.
HC emissions were always as
low as the scale would go, basically zero.
NOx emissions would depend
on power output and our electronic control circuit adjustment setting.
The first two above make
perfect sense because with excess oxygen there is plenty of oxygen to
combine with the CO and HC to make CO2 and H2O. NOx emission would be elevated with
any air/fuel ratio between stock and 20:1. At around 20:1 fuel ratio the combustion temperature is
low enough to keep the NOx emissions to a minimum but the available
torque/power of the engine is less than what I like. I prefer to run with a fuel ratio
between 16:1 and 18:1 but at these settings the NOx emission are not so
good.
Following are the readings
of NOx I recorded versus air/fuel ratio settings:
A/F 15:1 NOx 200–1800 PPM
A/F 16:1 NOx 200-1800 PPM
A/F 17:1 NOx 200-1300 PPM
A/F 18:1 NOx 150-900 PPM
A/F 19:1 NOx 120-400 PPM
A/F 20:1 NOx 100-250 PPM
Remember we are comparing
with stock vehicle NOx emissions of 50-800 PPM.
Below is a rough sketch of
a graph of estimated emissions versus air/fuel ratio for the typical
engine, based on the tests that we have run with the Saturn SL1. Note that the normal ECU operation
emission is likely to have a combination of emissions with higher total
emissions than the lean burn operation of Hydrogen Boost. The only exhaust emission that is
likely to be higher with Hydrogen Boost is NOx emissions during heavy
throttle operation. Since
Hydrogen Boost drivers are more likely to be interested in better
mileage they are not likely to be using heavy throttle setting very
often.
Conclusion: Compared to stock vehicle operation
the hydrogen Boost system can virtually eliminate all CO and HC
emissions while possibly elevating NOx emissions, except at an air/fuel
ratio that borders on loosing available power/torque. But, since the optimum air/fuel
ratio that gives comparable NOx emissions as a stock vehicle is
coincidentally the best fuel ratio for best indicated mileage (A/F
18:1), the present Hydrogen Boost system can drastically reduce total
emissions when adjusted for best mileage. Further testing will be done with more water mist or
vapor injection in an attempt to further reduce the NOx emissions. A slight modification to the present
design of our hydrogen generator may be all that is required. This would likely not increase the
cost of the Complete Hydrogen Boost system.
Emissions Challenge
A
week later, after discovering an easy modification to the hydrogen generator
that increased the gas production by about 30%, I took the Hydrogen Boost
Emissions Challenge. The
challenge was intended to be an offer to a technician that owned a five
gas analyzer and wanted a Hydrogen boost system. The challenge was for us to install
a Hydrogen Boost system on a technician’s vehicle and achieve better
emissions without a catalytic converter than the stock vehicle emissions
with a catalytic converter. I
had no takers on the challenge and now have my own five gas analyzer so
I decided to take the challenge myself.
I drilled a hole in the exhaust
pipe in a convenient place in front of the catalytic converter and
inserted the emissions tester probe and secured it to the bottom of the
vehicle. Then with the Hydrogen
Boost system turned on I took an extended drive, testing all driving
conditions and throttle settings.
The result was no surprise to anyone who knows about a catalytic
converter and has read the above article.
Let
me explain the workings of the catalytic converter. The purpose of the converter is to
insure that all CO and HC emissions in the exhaust pipe are encouraged
to react with oxygen in the exhaust, and at the same time rob any
oxygen from any NOx in the exhaust to supply it to the CO and HC. At the perfect stoichiometric fuel
ratio the converter does the job quite well, but as we have seen above,
the stock vehicle never has the perfect ratio because it is always changing.
Now
let’s get back to the emissions in the Hydrogen Boost equipped
vehicle. If there are no CO and
HC emissions in the exhaust pipe there is no place to force the oxygen
in the NOx to go, so reducing NOx is not done by the catalytic converter. If there is no CO and HC in the
exhaust and the converter can’t reduce the NOx without them, there is
no need for the catalytic converter, and the emissions would basically
be the same in front of the converter as they would be at the tail
pipe. I knew this before I did
the test but I had to follow through to prove it. Plus I couldn’t win the challenge
and give myself the tester without following the challenge rules.
Now I
can say that the emissions were not always perfect in front of the
catalytic converter, because there was the rare occasion that excess
fuel vapors from the tank would increase the fuel ratio from our ultra
lean setting. You might think
that this should show increased CO or HC in the exhaust pipe in front
of the catalytic converter, but that is not the case. Actually there was increased NOx at
these times, which proves to me that the hydrogen generator and
ignition system were doing a proper job of igniting the air/fuel mixture
and there was still plenty of oxygen to burn the fuel. The increased NOx was very short
lived and on very rare occasion, like when accelerating after sitting
at a traffic light for long periods at idle, which no self-respecting
good mileage driver would do.
Another
rare occasion of increased emissions is when the engine would skip or
buck, because of poor ignition.
This could be caused by a too lean mixture that the system is
barely igniting and occasionally not igniting. This show me that it would be nice
to have some more hydrogen in the mix.
This has spurred me to investigate ways to increase our hydrogen
production and I have already found one easy modification to increase
the gas production of our latest production model generators by about
30%. If you have purchased our
system between January 2006 and July 2006 you can email me at hydrogen.boost@verizon.net
for the modification instructions. The modification takes about 5 minutes if you have the hydrogen
generator in your hand or have easy access to the top of it.
Related information: The reduced emissions are closely
related to the increased mileage benefits of the lean-burn ability of
the Hydrogen Boost system. See www.hydrogen-boost.com/complete.html
for more details.
Click
here to ORDER
NOW
Home Savings
Test Results Technical Information Newsletter Order Contact
|