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June 2004 Hydrogen-Boost Newsletter


Air/Fuel Ratio Controller

 

          After working with the Auterra Dyno-Scan monitoring system I realized that without some sort of control over the ECU (engine control unit, on-board computer) I would never be able to get serious reduction in fuel use in the EFI (electronic fuel injection) vehicles on the market today.  Before I went on to develop technology that would further increase the combustion efficiency of today's vehicle I needed to develop a way to get the ECU to inject less fuel.  Then I could work on serious fuel delivery system modification.

 

          Researching in Internet was productive.  I found a device that had already been discontinued that was called the HKS Super AFR (air/fuel ratio regulator).  This device can reprogram a number of places on the fuel map of the ECU by adding or subtracting up to 50% of the original programs specified amount of fuel to be injected.  I thought this might be what I need so I ordered one.  The more I though about it the more I thought that this device was not really what I needed, especially for experimentation when I need to make adjustments while driving.  i searched for an electronics expert who could improve on the design of the device we were already using to add an adjustable amount of voltage to the oxygen sensor signal going to the ECU.

 

Air/Fuel Ratio Meter

 

          Another things I really needed was some sort of  device that could read out the air/fuel ratio the vehicle was operating at, especially when I was adjusting the amount of fuel being injected.  During my Internet research I ran across the Innovate Motorsports A/F Ratio Meter, which uses a wide-band "oxygen sensor" to determine the ratio.  Before ordering one I researched how the wide-band sensors worked, and purchased one to see if I could use a multimeter to read out the sensor voltage and translate that into fuel ratio.  There was no simple way to do that so I ordered a meter. 

 

Electronic Control Circuit

 

          While waiting for both of the above devices to be shipped I was tipped off to an idea that led me to develop a fairly simple circuit of my own that allowed me to take control over most ECUs and dial in whatever fuel ratio I wanted.  Of course without a meter to tell me what the ratio was, the circuit didn't tell me anything except that I could dial in a too-lean mixture.  I was anxious to get the Innovate A/F Ratio Meter so I could determine if the new circuit would control the ratio enough to make it worth while to develop the planned fuel delivery system modifications that I had been designing for over a year.

 

          When the A/F Ratio Meter finally arrived I removed the regular oxygen sensor and installed the wide-band sensor that ran the meter.  Of course this caused a trouble code to trip on the check engine light, but with the Dyno-Scan I could reset that anytime I wanted so I didn't care.  A further problem was that the lack of oxygen sensor voltage causes the ECU to think the engine is running too lean so it runs the long-term fuel trip up to the maximum allowed by the ECU.  On my car that was about 15% positive.  I remedied this problem by turning my EFIE voltage up to about 600 mv and disconnected the coolant temperature sensor.  I later found out that the sensor did not have to be disconnected to keep the ECU operating in open loop so I reconnected it. 

 

          Around this time I figured it was time to begin making modifications to the fuel delivery system.  The first thing I tried was an intake air heater.  I removed the air box and installed a proper size heater core between the air filter and the air box cover.  This allowed the intake air to be as hot as 150 degrees.  I expected this to vaporize more of the injected fuel allowing us to run with a little higher fuel ratio.  Of course the meter wasn't here yet so I couldn't tell if it did what I thought it would do.  I did notice that with the intake air heater the maximum available power was reduced because warm air is not as compact as cold air and the engine could not suck in quite as much air as before.  You horsepower chasers know that a cold air induction system can increase your maximum available power and a hot air induction system with reduce the maximum available power.  The air heater was left on for some later experiments, which I will discuss now.

 

          The next modification I pursued was a simple intake vaporization system.  I took a sea sponge and crammed it into my intake hose leading from the air filter to the throttle body.  The sponge was inserted right where the hose came off the main hose and fed the crankcase ventilation system.  I disconnected the crankcase vent hose and installed a short hose with a funnel attached.  I pour in an ounce of gasoline and drove.  By now I had the A/F Ratio Meter installed and could see the ratio at any time.  Before this last modification I typically drove at 17:1 to 18:1 ratio around town.  With the intake vaporizing sponge I was comfortable driving at 19:1 to 20:1 ratio with no bucking.  The excess vapor allowed me to dial down the injected fuel control.  This proved to me that we could run at ratios beyond what was available with our previous electronic control circuit that added voltage to the oxygen sensor (EFIE device from Eagle Research). 

 

          To date there is only one more slight modification to report.  Instead of stopping every five to ten minutes to pour gas into the intake, I installed a fuel injector to the hose that leads into the intake air main.  This injector is tied electrically to one of the cylinder injectors and has a manual shut off switch.  My first test of it was at night on the way to Bible study.  We were able to drive comfortably with a ratio of 20:1 for acceleration and hill climbing, and at 25:1 at cruise and descending hills.  What I did was set my electronic controller for a cruise ratio of 25:1 and whenever I came to a hill or got a slight buck trying to accelerate I would flip the switch on to the intake injector for 5 seconds or while I climbed the hill.  If the ratio went below 18:1 I shut the switch off no matter what driving conditions I had.  Earlier in the day I tried to leave the switch on while dialing in 25:1 ratio while driving around town but I found that the limits of my controller were reached and I would have to modify the electronics some to get down to 25:1 ratio with the extra injector.  I also found that some heavy fuel molecules dripped down to the bottom of the sponge and pooled in the intake hose.  When I braked this little bit of gas would flow to the air filter.  I remedied this problem by installing a drain below the sponge that took the drained fuel to the exhaust wrapped vaporizer described in the Hydrogen-Boost installation manual that we tested in Switzerland three years ago.

 

          All in all May was a very productive month.  Now I am waiting for my EGT gauges to come so I can test the effectiveness of my cool mist water injection system at keeping the exhaust temperature down so NOx emissions will not be produced, or whether we even need the water injection at the fuel ratios we are working with.

 

          By the way, I never did hook up the HKS Super AFR air/fuel ratio regulator.

 

Exhaust Gas Temperature, Lean Mixtures, and Burning Valves

 

Will operating my vehicle at a leaner mixture with Hydrogen-Boost, cause damage to my valves?

 

With Hydrogen-Boost seeking to run on the leanest air/fuel mixture that has acceptable torque and power, in pursuit of the best possible gas mileage, we have had repeated questions from misinformed customers concerning whether they would burn their valves by running the extra lean mixture. 

I am sure the misinformation comes from the aviation field.  Being an aviator until last year's near fatal experimental aircraft accident, I know that piston engine aircraft take off and climb at maximum power, and cruise at a leaner mixture, watching the EGT gauge to insure a safe temperature.  Of course we all assume that safe temperature means a temperature that doesn't burn the valves. 

This information gets us to assume that an electronic fuel injected engine runs at the rich mixture that is cool enough to protect the valves from burning.  Most also assume that if we lean out the mixture we will be in danger of burning the valves.  A too hot exhaust gas temperature also would indicate a too hot combustion temperature that happens to produce NOx, the oxides of nitrogen that are considered as toxic pollution. 

What most of us don't know is that during warm up and acceleration the EFI (electronic fuel injection) engine does indeed run with a rich mixture, but during cruise the engine control unit (ECU) runs in what is called closed loop operation, which targets a 14.7 to 1 air fuel ratio.  This ratio is called stoichiometric, meaning that there is a perfect mixture of air and fuel to insure complete combustion. This also happens to be the perfect mixture to get the highest temperature of combustion, and therefore the highest exhaust gas temperature (EGT).  Any leaner (more air) mixture will cause a cooler combustion, and any richer (more fuel) mixture will also cause a cooler combustion. 

The following quote was obtained from http://www.sdsefi.com/techegt.htm and is chemically accurate:

Some gauge manufacturers say you should tune to achieve maximum or peak EGT for maximum performance. This is incorrect. Peak EGT generally occurs at an AFR of around 14.7- 15.0 to 1 on gasoline. This is far too lean for maximum power and is dangerous under continuous WOT conditions. Many people think that the leaner you go, the higher the EGT gets. This is also incorrect. Peak EGT occurs at stoichiometry- about 15 to 1 for our purposes. If you go richer than 15 to 1, EGT will drop and if you go leaner than 15 to 1 EGT will ALSO drop. It is VERY important to know which side of peak EGT you are on before making adjustments. It is safe to say that peak power will occur at an EGT somewhat colder than peak EGT.

 

          As you can probably figure out by now, leaning the mixture from the target 14.7 to 1 will NOT cause a hotter exhaust nor will it cause you to burn your valves.  This is not to say that leaning the ECU's program under all conditions will cause a cooler exhaust.  There is one condition that could be hotter and that would be running at WOT (wide open throttle) at 14.7 to 1 instead of the programmed 13 to 1.  A continuous running at this condition might indeed burn your valves. 

But how often would a mileage conscientious driver equipped with Hydrogen-Boost want to run at WOT for extended periods of time at 14.7 to 1 mixture?  First of all a conscientious driver would be following the driving tips in the manual which discourages WOT driving all together, say nothing about an extended WOT operation.  Also if a Hydrogen-Boost system is adjusted properly, it will be running at a much higher (leaner) mixture than 14.7 to 1, even at full throttle. 

Being a research scientist, I don't like to take anyone's word for anything so I have ordered two EGT gauges, both of which can read the temperatures of two sensors.  I will verify all that has been written in this newsletter and will report the results in a later issue.

 

So to answer the original question:

Will operating my vehicle at a leaner mixture with Hydrogen-Boost, cause damage to my valves?  NO.

 

Verification:

 

            On June 11th I finally installed one of my EGT gauges.  The probe had a rather short lead so I ended up running with the EGT gauge on top of my hood, rubber banded to the windshield wiper.  I had to drill and tap a hole for the threaded probe, which worked out fine.   It was a little tight for space inside the engine compartment so I used a right angle portable drill and a socket and ratchet on the tap. 

          Once the probe was warmed up I cruised at a constant speed and throttle setting and dialed in a leaner fuel mixture while watching the gauge.  What is claimed above regarding EGT and fuel ratio was indeed verified.  At cruise the EGT was about 10 degrees cooler at 13:1 air/fuel ratio than it was at 14.7:1.  At 17:1 it was also 10 degrees cooler.  At 19:1 it was 20 degrees cooler, and at 21:1 it was 30 degrees cooler.  The temperature really had more to do with the throttle setting than anything else.  At high throttle settings the EGT was in the 900s, at high cruise in the 800s, at medium cruise in the 700s, at low cruise in the 600s, and at idle in the 500s.  With this large range of temperatures the small change due to fuel ratio was insignificant. 

          One thing that is notable is the fact that any set power output typically produced the same or similar temperatures, regardless of the fuel ratio.  Even though the higher fuel ratio caused a lower temperature at a set throttle position, to keep the same power it took a slightly more open throttle, which caused the temperature to rise back to the same reading as the lower ratio and throttle setting that produced the same power.  Of course this was not quite true with those full throttle, rich ratio conditions when the EGT is hot but not as hot as it would be at 14.7:1 fuel ratio. 

          The throttle setting determined more than just the EGT, it determined the amount of temperature drop that was caused by the increasing fuel ratio.  At idle there was only a 5-10 degree drop, but at higher throttle settings there was more than a 40 degrees of drop. 

          What does all this mean in relation to the question that started this discussion?  Will operating my vehicle at a leaner mixture with Hydrogen-Boost, cause damage to my valves?  To answer that question we would determine the condition that causes the highest EGT.  This would be at full throttle and 14.7:1 fuel ratio.  Neither a stock vehicle nor a Hydrogen-Boost system equipped vehicle would run at this condition.  The stock vehicle would run at 12 or 13 to 1, and a Hydrogen-Boost equipped vehicle would run at the same 12 or 13 to 1, for those using the old electronic control circuit, or 18 or 20 to 1, for those with the new electronic control circuit.  Of course any Hydrogen-Boost equipped vehicle would not likely be seen at full throttle for extended periods of time.  So to conclude, the EGT that causes valves to burn would never be encountered with a Hydrogen-Boost equipped vehicle.

         

EGT and NOx Emissions

 

          It is worthy to note here the effects of the Hydrogen-Boost System on exhaust emissions.  Of course we have already determined that running at a nice lean mixture drastically reduces hydrocarbon and carbon monoxide emissions.  This is due to the extra oxygen available during combustion.  The extra oxygen reacts with the carbon monoxide and the lingering hydrocarbons to form water vapor and carbon dioxide.  The other emission of concern to environmentalists is the oxides of nitrogen (NOx, meaning NO2 and NO3).  NOx is produced when combustion temperatures exceed 1200 degrees.  Exhaust gas recycling (EGR) systems are installed on some vehicles to prevent NOx production.  We have already established that the maximum exhaust gas temperature of a Hydrogen-Boost equipped vehicle is at least 40-50 degrees lower than the same vehicle not equipped with our system.  The logical conclusion would be that NOx emissions are not evident from a Hydrogen-Boost equipped vehicle.

 

Hydrogen-Boost Emissions Challenge

 

          I am willing to bet a complete installed Hydrogen-Boost system ($1000 value) that the emissions of a properly adjusted Hydrogen-Boost system in the exhaust pipe before the catalytic converter will be less than the emissions of a stock vehicle exhaust pipe after the catalytic converter.  This would mean, if proven by emissions tests, that the Hydrogen-Boost system would render the catalytic converter obsolete.  My challenge is to anyone who owns an emissions testing machine that tests CO, CO2, HC, and NOx.  You bring the tester to my shop along with your vehicle.  We test the emission from your tail pipe, installed the Hydrogen-Boost system on your vehicle, and test the emissions in front of the catalytic converter.  If the emissions are not better with Hydrogen-Boost you can have the system for free.  If my emissions are better than your stock emissions you can still have the Hydrogen-Boost system in exchange for your emissions testing machine.

           

 


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