WAI increases economy in O2 sensor/feedback fuel injected cars by reducing throttling losses at part load. EGR works the same way.
CAI hurts FE at part throttle, but it does improve power at full throttle. |
I have completed my experiment and here are the results HAI wins by .........10.1mpg See the link below.
https://www.gassavers.org/showthread.php?t=10415 |
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$$ with which you can buy a box of cookies?
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But the cookies make you gain weight, which hurts your mpg...
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Cookies give you a sugar rush, which enables you to put more energy into hypermiling strategies that require lots of attention, like EOC.
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You test was not accurate. You drove less than 100 miles per test and the mileage wasn't even the same between the 2 tests. And it's way to easy to pump an extra half gallon when you only used 1.5 gallons. Nice try but you FAIL. |
When you're talking a distance like that, 4/10 of a mile is statistically insignifigant. He drove 130.8 miles. The same trip back to back. At our standard hypermiling speed of 55 MPH he would have spent a minimum of 2.38 hours on the road. Are you offering to set up your vehicle, drive in a 300 mile circle, one with, and one without HAI back to back? That's going to be one heck of a day driving 600 miles, at 55 MPH that's just shy of 11 hours on the road.
-Jay |
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The imperfections of modern fuel injection are clearly demonstrated by the efforts of manufacturers to achieve Homogenous Charge Compression Ignition in gasoline engines. Homogenous Charge means the fuel and air mixture is truly evenly distrubuted in the combustion chamber. That same mixture is ignited by compression alone without any spark whatsoever. The result is a 25% improvement in economy as well as the elimination of the catalytic converter with virtually zero regulated emissions. Why would manufactirers spend tons of money to improve a system if your statement about it being perfect was true? The fact is the present systems look much better when compared to the old carburetor types, however there is still a massive potential for improvement. Google HCCI if you really want to learn that there is much room for improvement over the present system that you describe as perfect. By perfect you imply that there is no room for improvement in fuel distribution because modern engines are fuel injected. HCCI proves without any doubt that modern systems are far from perfect. The attached photo is my mileage from my trip yesterday. 65 MPG for 355.5 miles. Almost all of it was highway. The EPA highway rating for my car is 50 MPG. My modifications are a 40% grille block and 44 PSI air in the tires. Temperatures ranged from just above freezing to 65 degrees. Driving was from eastern Virginia to Blacksburg Virginia with elevation changes of 2000 feet. The grille block also retains heat in the engine compartment that increases the air temp to the intake system on the engine. How much of the improvement was driving style, grille block, or tire pressure, or warm air would be difficult to distinguish, but the net overall improvement is 30%. Also consider that that is on 10% ethanol fuel which has a lower energy content than non ethanol fuel. Also notice the fule guage is reading half a tank. That is a 10.5 gallon tank. regards gary |
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A SCIENTIFIC test needs to be done. Strick a car on a dyno, stabalize the coolant and oil temps, set a steady speed and maintain the same external air temps and use a scan guage to measure instand MPG and then switch from a external air inlet to an engine compartemt inlet and measure the difference. |
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I'm saying that in that particular vehicle it works. 10 MPG is well beyond any conceivable margin of error for this test. I would agree that more testing needs to be done, but I don't buy the "Every car would have it already" argument. I can tell you that 2 of my 3 vehicles that I own have it setup from the factory. Manufacturers aren't solely concerned about mileage. They have to make sure the car passes emissions, and has good power. High HP numbers sell cars. WAI/HAI lowers these numbers. Yea, an affordable car can be made that gets great mileage, but if that was the only reason people bought cars was for high mileage numbers then everybody would either have a Geo Metro or Civic VX in their driveway. Do a search on the site. There are many others that claim to have positive results with WAI. For some reason Saturns do extremely well with WAI/HAI.
I'm just saying I wouldn't dismiss it so quickly. |
I can't disagree that a really well controlled series of tests would be great. That said, however, we can say something in the absence of them. Copied from the HAI experiment thread:
When there's uncertainty, I just use the following: (chance of success)*(estimate of benefit) + (fun of trying) vs (cost & effort to try) + (chance of damage)*(estimated cost of damage) In this case everything on the right hand side is very low. Since the chance of success is mixed, and some people are claiming a good sized benefit I think it's worth giving a shot. You may assign different values to these parameters than I do, and rightly so. |
More good reading:
https://www.nextautos.com/auto-shows/...inject-engine/ Quote:
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-BC |
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And I love the thread you have in you signature about doing a SCIENTIFIC experiment: https://www.gassavers.org/showthread.php?t=2 |
Warm air allows larger throttle openings and higher effective compression.
Warm air also allows less fuel to be injected for the same mass of air consumed. Fuel delivery systems add fuel based on temperature as well as mass. The power delivered by any engine is a direct function of the EFFECTIVE compression. Put a vacuum guage on your engine, keep the revs low, in the 1500 to 2500 range in the highest gear the vehicle can handle. Accelerate with the highest load, lowest revs, and lowest vacuum, without applying enough throttle to get into full load enrichment. Voila, the secret to the pulse portion of hypermiling. The concept that making a vehicle more powerful is basically flawed, when you are talking about an economy strategy. This is clearly demonstrated by the difference in mileage between a Civic SI and a Civic VX. Understand "effective compression". All engines create power utilizing the difference between compression pressure and combustion pressure. The highest effective compression (lowest vacuum reading) is the highest effective combustion pressure for any given mass of fuel delivered. Take a 2.5 liter 4 cylinder engine on a dyno. Put a 20 HP load of the engine. Measure the fuel consumption at 1700 RPM. Then place a 50 HP load at the same speed and you get 30 more hp, for half the fuel it takes to get the first 20 HP. That is due to effective compression being maximized. If you have any manifold vacuum you are proportionately reducing the effective compression, as well as efficiency. Diesels solve the problem by elimination of the throttle butterfly. regards gary |
There's more than throttling losses at partial load. Frictional losses don' t decline quickly with load, so they become a greater proportion as it decreases. This diminishes economy. Diesels suffer from this too. Variable compression can help get around this, but is a much more complicated mechanism.
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I can name at least 10 different sources of losses.
regards gary |
I just wanted to make sure people were aware that there's a lot going on to make big engine's bad. I didn't mean to nitpick.
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A good read is to look at what Honda did to make the VX the non hybrid mileage champ of the Honda line from 92-95.
I actually have design for a valveless variable compression rotary piston engine. It has an additional capability of destroking itself completely and storing energy in its own spinning mass as a flywheel. Combined with an Infinitely Variable, in wheel transmission at each wheel. it provides a potentially game changing powertrain configuration. regards gary |
I am doing engine design work as well, but can't talk about it. IP issues suck. Be careful.
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