Water Injection
07-05-2008, 10:28 AM
#1
Member
Thread Starter
Join Date: 05-18-07
Location: Bloomington, IL
Posts: 288
Likes: 0
Received 0 Likes
on
0 Posts
Water Injection
Water Injection has the potential to improve overall mileage however there is currently little information on NA applications. It appears, logically, that water injection in a 2.4L NA VVT engine controlled by a E-67 ECU will NOT see a great improvement in HP but that there MAY be an improvement in MPG as a result of the ECU leaning the injectors during increased throttle position resulting in increased output of the MAF sensor which will drive a progressive controller for the injection pump.
With the costs of a water injection system running in the $600 range, and gasoline (91 octane) at $4.50 a gallon, its a question of life cycle costs vs expense reduction (being able to use 89 octane gas) to recover the initial investment. IF the cost per gallon differential is 25 cents, one would have to buy 2400 gallons of gas just to recover the investment. Over three years, 2400 gallons is about 800 gallons a year and at 25 MPG average one would have to be driving more than 20,000 per year for three years!
While I would LIKE to try water injection on MY 2007 2.4L NA SS, the math does NOT provide any incentive.
With the costs of a water injection system running in the $600 range, and gasoline (91 octane) at $4.50 a gallon, its a question of life cycle costs vs expense reduction (being able to use 89 octane gas) to recover the initial investment. IF the cost per gallon differential is 25 cents, one would have to buy 2400 gallons of gas just to recover the investment. Over three years, 2400 gallons is about 800 gallons a year and at 25 MPG average one would have to be driving more than 20,000 per year for three years!
While I would LIKE to try water injection on MY 2007 2.4L NA SS, the math does NOT provide any incentive.
07-07-2008, 06:34 PM
#4
New Member
Join Date: 05-28-05
Location: Atlanta
Posts: 10
Likes: 0
Received 0 Likes
on
0 Posts
Water Injection has the potential to improve overall mileage however there is currently little information on NA applications. It appears, logically, that water injection in a 2.4L NA VVT engine controlled by a E-67 ECU will NOT see a great improvement in HP but that there MAY be an improvement in MPG as a result of the ECU leaning the injectors during increased throttle position resulting in increased output of the MAF sensor which will drive a progressive controller for the injection pump.
With the costs of a water injection system running in the $600 range, and gasoline (91 octane) at $4.50 a gallon, its a question of life cycle costs vs expense reduction (being able to use 89 octane gas) to recover the initial investment. IF the cost per gallon differential is 25 cents, one would have to buy 2400 gallons of gas just to recover the investment. Over three years, 2400 gallons is about 800 gallons a year and at 25 MPG average one would have to be driving more than 20,000 per year for three years!
While I would LIKE to try water injection on MY 2007 2.4L NA SS, the math does NOT provide any incentive.
With the costs of a water injection system running in the $600 range, and gasoline (91 octane) at $4.50 a gallon, its a question of life cycle costs vs expense reduction (being able to use 89 octane gas) to recover the initial investment. IF the cost per gallon differential is 25 cents, one would have to buy 2400 gallons of gas just to recover the investment. Over three years, 2400 gallons is about 800 gallons a year and at 25 MPG average one would have to be driving more than 20,000 per year for three years!
While I would LIKE to try water injection on MY 2007 2.4L NA SS, the math does NOT provide any incentive.
We are releasing a gas saving water injection system for n/a and turbo vehicles. We did our final testing over the weekend driving from Atlanta to Daytona. Our best test got mileage of 35.2 without water injection, 38.7 with. That is a 3.5 MPG gain or about 10%. Our worst test got 31.7 without the water injection 33.7 with. The tests were on our 2006 Lotus Elise.
It also uses about 1 gallon per 200-250 miles (depending on how you set it up). Running 100% water yielded the most gas mileage gain.
Our system was setup to run a 25% duty cycle at and above 3000 RPM. For your vehicle if you dont want to do RPM you can do frequency based MAF. If you get a 10% gain in fuel economy it would take roughly 1 year to recoup your costs based on your numbers.
Take care.
07-07-2008, 06:37 PM
#5
Senior Member
wouldnt the same results be achieved by just leaning out the cruising stoich value?
as thats effectively whats being done by adding water to combustion....
the O2 sensor cannot distinguish the two....
as thats effectively whats being done by adding water to combustion....
the O2 sensor cannot distinguish the two....
07-08-2008, 09:07 PM
#6
Member
Thread Starter
Join Date: 05-18-07
Location: Bloomington, IL
Posts: 288
Likes: 0
Received 0 Likes
on
0 Posts
It figures that with water injection after the MAF that you'll get increased piston pressure for a given throttle position or a given piston pressure at a lower throttle position.
coolingmist -
The injection pump and its controller are going to be critical for a cruise / accelleration gas saver because a 2.4L VVT NA Cobalt needs to start injection at about 2100 RPM for highway / interstate and moderate increases in speed when city driving. Some control to increase or decrease the injection rate and RPM start would be nice....remote control from the drivers position would be even better.
If you can get 10 percent improvement in gas mileage can you also get 10 percent increase in HP? That'd be about 15 HP or so and I'd have rethink my earlier statement IF the price is right.
07-10-2008, 09:59 PM
#7
New Member
Join Date: 05-28-05
Location: Atlanta
Posts: 10
Likes: 0
Received 0 Likes
on
0 Posts
I think you are right about the ECU leaning out the injectors when water is injected. And that's why you can't get much HP increase with a NA engine controlled by a untuned E67 ECU.
It figures that with water injection after the MAF that you'll get increased piston pressure for a given throttle position or a given piston pressure at a lower throttle position.
coolingmist -
The injection pump and its controller are going to be critical for a cruise / accelleration gas saver because a 2.4L VVT NA Cobalt needs to start injection at about 2100 RPM for highway / interstate and moderate increases in speed when city driving. Some control to increase or decrease the injection rate and RPM start would be nice....remote control from the drivers position would be even better.
If you can get 10 percent improvement in gas mileage can you also get 10 percent increase in HP? That'd be about 15 HP or so and I'd have rethink my earlier statement IF the price is right.
It figures that with water injection after the MAF that you'll get increased piston pressure for a given throttle position or a given piston pressure at a lower throttle position.
coolingmist -
The injection pump and its controller are going to be critical for a cruise / accelleration gas saver because a 2.4L VVT NA Cobalt needs to start injection at about 2100 RPM for highway / interstate and moderate increases in speed when city driving. Some control to increase or decrease the injection rate and RPM start would be nice....remote control from the drivers position would be even better.
If you can get 10 percent improvement in gas mileage can you also get 10 percent increase in HP? That'd be about 15 HP or so and I'd have rethink my earlier statement IF the price is right.
We can do anything you want. The "remote control" is available but it will add a good $240 bucks to the price.
There are 5 ground outputs that can be programmed different. you can pulse each of the grounds differently based on whatever you want. So you could set up 5 different RPM buckets and make the on time longer as you increase in RPM (or FREQ MAF) or what ever input you want.
Take care,
David
I forgot to mention, you can integrate your speed sensor into it as well if you want to reference MPH.
David
Last edited by coolingmist; 07-10-2008 at 09:59 PM. Reason: Automerged Doublepost
07-13-2008, 01:47 AM
#8
Senior Member
Join Date: 05-16-07
Location: Florida
Posts: 1,135
Likes: 0
Received 0 Likes
on
0 Posts
I have not done any dyno testing yet, I plan to this fall.
We can do anything you want. The "remote control" is available but it will add a good $240 bucks to the price.
There are 5 ground outputs that can be programmed different. you can pulse each of the grounds differently based on whatever you want. So you could set up 5 different RPM buckets and make the on time longer as you increase in RPM (or FREQ MAF) or what ever input you want.
Take care,
David
I forgot to mention, you can integrate your speed sensor into it as well if you want to reference MPH.
David
We can do anything you want. The "remote control" is available but it will add a good $240 bucks to the price.
There are 5 ground outputs that can be programmed different. you can pulse each of the grounds differently based on whatever you want. So you could set up 5 different RPM buckets and make the on time longer as you increase in RPM (or FREQ MAF) or what ever input you want.
Take care,
David
I forgot to mention, you can integrate your speed sensor into it as well if you want to reference MPH.
David
07-13-2008, 10:29 AM
#9
Member
Thread Starter
Join Date: 05-18-07
Location: Bloomington, IL
Posts: 288
Likes: 0
Received 0 Likes
on
0 Posts
Water requirement
See the report on the effects of water injection on NA engines at:
http://www.turbotuning.net/Artikel/naca-wr-e-264.pdf
Note: for maximum fuel economy in a 2.4L a very fine water mist MUST BE DELIVERED CONSTANTLY at a rate of 12.5% to 25% of the Fuel Mass Consumed
Water = 8.3 lbs per gallon
Gasoline = 6.15 lbs per gallon
Air weighs .080645 lb per cubic foot with 12lbs of air required per 100 HP.
At 60 mph and 30 MPG, one can calculate 2 Gallons of Gasoline required per hour or
(2 x 6.15) 12.3 lbs of gasoline.
The maximum water consumption will be calculated as 12.3 x .25 = 3.075 lbs
The minimum water consumption will be calculated to be 12.3 x .125 = 1.5375 lbs
Converting water lbs to water gallons:
3.075/8.3 = 0.37 gallon of water maximum per hour at 30 miles per gallon of gasoline or
1.5375/8.3= 0.185 gallon of water minimum per hour at 30 miles per gallon of gasoline
The maximum (0.37 GPH) and minimum (0.185 GPH) CONSTANT FLOW RATES are what is needed to produce fuel economy. If that cannot be provided by your water injection system you will need to change nozzle size, number of nozzles, add cut off solenoids, water pressure pump, and or controller.
I'm sure there will be challenges to my calculations and statements. I have no interest in any Vendor's companies nor do I have any agenda except continued dialog to improve fuel economy by water injection in 2.4L NA Cobalts.
http://www.turbotuning.net/Artikel/naca-wr-e-264.pdf
Note: for maximum fuel economy in a 2.4L a very fine water mist MUST BE DELIVERED CONSTANTLY at a rate of 12.5% to 25% of the Fuel Mass Consumed
Water = 8.3 lbs per gallon
Gasoline = 6.15 lbs per gallon
Air weighs .080645 lb per cubic foot with 12lbs of air required per 100 HP.
At 60 mph and 30 MPG, one can calculate 2 Gallons of Gasoline required per hour or
(2 x 6.15) 12.3 lbs of gasoline.
The maximum water consumption will be calculated as 12.3 x .25 = 3.075 lbs
The minimum water consumption will be calculated to be 12.3 x .125 = 1.5375 lbs
Converting water lbs to water gallons:
3.075/8.3 = 0.37 gallon of water maximum per hour at 30 miles per gallon of gasoline or
1.5375/8.3= 0.185 gallon of water minimum per hour at 30 miles per gallon of gasoline
The maximum (0.37 GPH) and minimum (0.185 GPH) CONSTANT FLOW RATES are what is needed to produce fuel economy. If that cannot be provided by your water injection system you will need to change nozzle size, number of nozzles, add cut off solenoids, water pressure pump, and or controller.
I'm sure there will be challenges to my calculations and statements. I have no interest in any Vendor's companies nor do I have any agenda except continued dialog to improve fuel economy by water injection in 2.4L NA Cobalts.
07-15-2008, 09:45 AM
#11
Member
Thread Starter
Join Date: 05-18-07
Location: Bloomington, IL
Posts: 288
Likes: 0
Received 0 Likes
on
0 Posts
NOTHING currently available
For those interested in improving the fuel economy of a Cobalt by using water injection, there is little if NOTHING available from the "Vendors" for NA applications.
After much internet research, I've found the following issues are not addressed by those selling commercial water injection systems.
1. For water injection to provide any fuel economy, there must be a constant water spray - a very fine mist at a rate of 12.5% of the fuel mass rate. This means the pressure pump must run all the time and I have found little information on constant duty cycle water injection pumps capable of running for hours.
2. Nozzle sizing for economy and power in 100% duty cycle must be sized much smaller (0.1 GPH to 0.3 GPH) than those used in Forced Induction, demand (low duty cycle) conditions which can use 1 GPH to 3 GPH nozzles.
3. Multiple Nozzles with solenoid shut-offs and advanced controllers are needed to provide the required varying water flow rates for transitions in RPM, load (in economy) and power, as well as when using windshield washer fluid in colder months (less water more alcohol means the flow rate requirement doubles with WWF) in a 100% duty cycle pressure system.
I believe Water Injection can provide a 12.5% increase in fuel economy OR power in a NA application IF someone will take the time to experiment with the right water flow rates rather than trying to use the big nozzle systems in pulse mode.
I'm anticipating expert flaming......
After much internet research, I've found the following issues are not addressed by those selling commercial water injection systems.
1. For water injection to provide any fuel economy, there must be a constant water spray - a very fine mist at a rate of 12.5% of the fuel mass rate. This means the pressure pump must run all the time and I have found little information on constant duty cycle water injection pumps capable of running for hours.
2. Nozzle sizing for economy and power in 100% duty cycle must be sized much smaller (0.1 GPH to 0.3 GPH) than those used in Forced Induction, demand (low duty cycle) conditions which can use 1 GPH to 3 GPH nozzles.
3. Multiple Nozzles with solenoid shut-offs and advanced controllers are needed to provide the required varying water flow rates for transitions in RPM, load (in economy) and power, as well as when using windshield washer fluid in colder months (less water more alcohol means the flow rate requirement doubles with WWF) in a 100% duty cycle pressure system.
I believe Water Injection can provide a 12.5% increase in fuel economy OR power in a NA application IF someone will take the time to experiment with the right water flow rates rather than trying to use the big nozzle systems in pulse mode.
I'm anticipating expert flaming......
07-15-2008, 11:26 AM
#12
Senior Member
that all makes sense.
but as i said above....its alot of dicking around, for the same result as leaning out your stoich mix.
thats all the water is doing, it is doing nothing whatsoever for actual efficiency....
all its doing, is fooling the O2 sensor into thinking its fuel (it cant tell the difference)
therefore the sensor is telling the PCM that its running rich, and it therefore leans out the mixture....
thereby using less fuel.
but as i said above....its alot of dicking around, for the same result as leaning out your stoich mix.
thats all the water is doing, it is doing nothing whatsoever for actual efficiency....
all its doing, is fooling the O2 sensor into thinking its fuel (it cant tell the difference)
therefore the sensor is telling the PCM that its running rich, and it therefore leans out the mixture....
thereby using less fuel.
07-15-2008, 11:30 AM
#13
Senior Member
iTrader: (1)
Join Date: 05-17-06
Location: New York
Posts: 3,697
Likes: 0
Received 0 Likes
on
0 Posts
just a thought to add fuel to the fire even thought the water injection is being mixed in with fuel id there a serious chance that serious problems can occur regarding rust but its just a thought im here to learn
07-15-2008, 02:51 PM
#14
Senior Member
yea, adding water to a stock fuel system intentionally is a horrible ideal
I would certainly never want to run water through the high pressure pump or injectors based on my experience w/ diesel pumps/injectors being killed off easily by water.
I would certainly never want to run water through the high pressure pump or injectors based on my experience w/ diesel pumps/injectors being killed off easily by water.
07-15-2008, 06:38 PM
#15
Member
Thread Starter
Join Date: 05-18-07
Location: Bloomington, IL
Posts: 288
Likes: 0
Received 0 Likes
on
0 Posts
Water Injected into Intake!
Water is injected into the intake air stream as a very fine mist / vapor NOT through the fuel system. (although that has been done in racing using an emulsified mix)
I have been considering using the SRI tube as the point of injection.
Perhaps installing four solenoid controlled nozzles at the labels or in the rubber elbow (it may be a cheaper part to ruin and replace)
The advantages of Water Injection are:
You can use lower 87 octane fuel - the water makes it well over 104 octane,
You use less fuel - from a leaner fuel air mix,
You get cooler cylinder temps in lean fuel conditions with water injection.
I have been considering using the SRI tube as the point of injection.
Perhaps installing four solenoid controlled nozzles at the labels or in the rubber elbow (it may be a cheaper part to ruin and replace)
The advantages of Water Injection are:
You can use lower 87 octane fuel - the water makes it well over 104 octane,
You use less fuel - from a leaner fuel air mix,
You get cooler cylinder temps in lean fuel conditions with water injection.
07-24-2008, 04:25 PM
#16
Senior Member
Join Date: 05-15-08
Location: Cuba, New York
Posts: 1,464
Likes: 0
Received 0 Likes
on
0 Posts
And the benefit to using less gas is you not only fill up less, but if enough people start using less gas (large, huge, massive amounts of people) it could drop the price of fuel a penny a month 
But seriously, if we all used less gas it could really benefit us by lowering prices. If we could just get everyone in the country to cooperate.
But seriously, if we all used less gas it could really benefit us by lowering prices. If we could just get everyone in the country to cooperate.
07-25-2008, 09:11 AM
#17
Member
Thread Starter
Join Date: 05-18-07
Location: Bloomington, IL
Posts: 288
Likes: 0
Received 0 Likes
on
0 Posts
The BIG "problem" (for me) is a WI system will cost well over $600 to do right and for the 6000 miles a year that I drive, it won't pay for itself. The other problem is Vendor support for NA applications.... that's what I have, a 2.4L NA engine and NO one seems to have a kit solution for continuous misting at 12.5% fuel mass consumption.
Thread
Thread Starter
Forum
Replies
Last Post