Hydrogen
06-23-2008, 12:28 AM
#16
Registered User
The change in the numbers are off. A gas engine has its best efficiency at max torque. For a v8 thats about 4000 rpm. Check the Brake Specific Fuel Consumption, BSFC, to gauge VE. Check any gasser dyno sheet. A gasser will start off lower raise and then drop. So at 2500 rpm about 0.8VE and then raise to about 0.85 to 0.9VE at max torque and then drop 0.05 point from max. I am being very liberal with the numbers. Modern computer FI engines have very tight and high BSFC numbers.
Diesels have direct injection. This means that the fuel is injected after the intake closes. To supply fuel in the form of a gas prior to the intake valve is just plain silly. We have multiple injection events now. So the gas, if it could be produced in sufficient volume, would be by by at the first injection event. There is no physical way around this. So in theory you could get a cleaner burning 1st event. Tell me what percentage of the fuel is injected in the 1st event? Is the 1st event the main power event? The answer to these two questions will give you an idea as to the potential advantage, once fully developed, to modern diesels. Get a system that could supply enough volume and inject it into the chamber directly and a greater potential exists. Until then you are limited to the potential benefits of the 1st injection event ONLY.
The Hydrogen topic has been around since the 50's. It's is always good for entertainment though.
Damon
06-23-2008, 05:04 AM
#17
Hello,
The change in the numbers are off. A gas engine has its best efficiency at max torque. For a v8 thats about 4000 rpm. Check the Brake Specific Fuel Consumption, BSFC, to gauge VE. Check any gasser dyno sheet. A gasser will start off lower raise and then drop. So at 2500 rpm about 0.8VE and then raise to about 0.85 to 0.9VE at max torque and then drop 0.05 point from max. I am being very liberal with the numbers. Modern computer FI engines have very tight and high BSFC numbers.
Diesels have direct injection. This means that the fuel is injected after the intake closes. To supply fuel in the form of a gas prior to the intake valve is just plain silly. We have multiple injection events now. So the gas, if it could be produced in sufficient volume, would be by by at the first injection event. There is no physical way around this. So in theory you could get a cleaner burning 1st event. Tell me what percentage of the fuel is injected in the 1st event? Is the 1st event the main power event? The answer to these two questions will give you an idea as to the potential advantage, once fully developed, to modern diesels. Get a system that could supply enough volume and inject it into the chamber directly and a greater potential exists. Until then you are limited to the potential benefits of the 1st injection event ONLY.
The Hydrogen topic has been around since the 50's. It's is always good for entertainment though.
Damon
The change in the numbers are off. A gas engine has its best efficiency at max torque. For a v8 thats about 4000 rpm. Check the Brake Specific Fuel Consumption, BSFC, to gauge VE. Check any gasser dyno sheet. A gasser will start off lower raise and then drop. So at 2500 rpm about 0.8VE and then raise to about 0.85 to 0.9VE at max torque and then drop 0.05 point from max. I am being very liberal with the numbers. Modern computer FI engines have very tight and high BSFC numbers.
Diesels have direct injection. This means that the fuel is injected after the intake closes. To supply fuel in the form of a gas prior to the intake valve is just plain silly. We have multiple injection events now. So the gas, if it could be produced in sufficient volume, would be by by at the first injection event. There is no physical way around this. So in theory you could get a cleaner burning 1st event. Tell me what percentage of the fuel is injected in the 1st event? Is the 1st event the main power event? The answer to these two questions will give you an idea as to the potential advantage, once fully developed, to modern diesels. Get a system that could supply enough volume and inject it into the chamber directly and a greater potential exists. Until then you are limited to the potential benefits of the 1st injection event ONLY.
The Hydrogen topic has been around since the 50's. It's is always good for entertainment though.
Damon
06-23-2008, 07:23 PM
#18
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Engine efficiency and volumetric efficiency are two different subjects. Volumetric efficiency refers to the engines ability to move the charge in and out of the cylinder. I'm using a formula to calculate CFM of air not engine efficiency. http://www.installuniversity.com/ins...n_9.012000.htm And if you want more numbers http://www.epi-eng.com/piston_engine...efficiency.htm
Now back to my point. These units make HHO, 1/3 of what they produce is oxygen. When you add that to the amount of air we are moving they come up short of the 4% to 7% hydrogen for the total air flow. These small canisters can not possibly generate enough hydrogen gas to help with the combustion event in our trucks. The new trucks with the multiple injection event will have another problem. No matter how much hydrogen you are able to inject, all of it will be consumed by the first injection event leaving the main event unassisted.
For the rest of us the gas assisted combustion does work when done right. It does not matter if the gas is hydrogen, natural gas, or propane. The deciding factor for most of us will be, does it make economic sense. With the way these little canisters are being used (and the way most are being sold on the net) is in my opinion beating a dead horse. We need to come up with new materials, catalyst, electronics or a new process to get this off the ground.
Now back to my point. These units make HHO, 1/3 of what they produce is oxygen. When you add that to the amount of air we are moving they come up short of the 4% to 7% hydrogen for the total air flow. These small canisters can not possibly generate enough hydrogen gas to help with the combustion event in our trucks. The new trucks with the multiple injection event will have another problem. No matter how much hydrogen you are able to inject, all of it will be consumed by the first injection event leaving the main event unassisted.
For the rest of us the gas assisted combustion does work when done right. It does not matter if the gas is hydrogen, natural gas, or propane. The deciding factor for most of us will be, does it make economic sense. With the way these little canisters are being used (and the way most are being sold on the net) is in my opinion beating a dead horse. We need to come up with new materials, catalyst, electronics or a new process to get this off the ground.
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