Figured out a hypermiling trick today
#11
Re: Figured out a hypermiling trick today
AT 55 miles per hour with your foot off the gas. My scan gauge would show the engine at idle or maybe 1000 rpm. Gas consumption reads about .02 gallons per hour.
The only time I see what I would call a fuel cutoff would be only when the car is in the EV mode. Then the scan gauge would show, no rpm, no GPH at that time.
Any long coasting you would need to start when the battery is near full charge. The downfall of coasting in neutral is that the engine will sure cool fast if the weather is cold. Coasting during the summer on a hot day, no air conditioning. I bet the electric air conditioning works only when the car is in drive. That may be the same for the heater.
The only time I see what I would call a fuel cutoff would be only when the car is in the EV mode. Then the scan gauge would show, no rpm, no GPH at that time.
Any long coasting you would need to start when the battery is near full charge. The downfall of coasting in neutral is that the engine will sure cool fast if the weather is cold. Coasting during the summer on a hot day, no air conditioning. I bet the electric air conditioning works only when the car is in drive. That may be the same for the heater.
Last edited by rburt07; 01-01-2008 at 11:43 AM.
#12
Re: Figured out a hypermiling trick today
If your over 40 miles per hour and shift into neutral the engine will remain spinning at about 1000 rpm in the fuel-cut mode. If your cruising below 40 miles per hour in the EV mode and then slap it into neutral, you can go as fast as you dare (within reason) down a hill and the engine rpm will still be zero. I think the issue over- revving MG1 is overstated. Prius owners have documented MG1 rpm's of about 9800 rpm at about 68 miles per hour using their CAN-view (sorry I can't find the exact reference). I believe the max rpm of 10,000 for the MG1 is the same in both the camry and the prius. I personally wouldn't want to push the car over 65 miles per hour in neutral for fear of melting something. Has anyone gone over 70 miles per hour in neutral? -Ed
#13
Re: Figured out a hypermiling trick today
Hmmm......
Why would the fuel consumption be different?
If the car were at 55mph in drive (with your foot off the gas), it would be in fuel cutoff mode, so would be consuming 0 fuel, the same as if you have it in neutral. Granted, you've lessened the drag, but at the cost of no regeneration. This might be a better trick in a non-hybrid car.
Later!
Dang
Why would the fuel consumption be different?
If the car were at 55mph in drive (with your foot off the gas), it would be in fuel cutoff mode, so would be consuming 0 fuel, the same as if you have it in neutral. Granted, you've lessened the drag, but at the cost of no regeneration. This might be a better trick in a non-hybrid car.
Later!
Dang
#14
Re: Figured out a hypermiling trick today
No, fuel cut mode cuts the fuel supply.
"Most" cars do it above a certain rpm. The transmission keeps the engine spinning, so fuel isn't needed. The ECU will not open the injectors, so you are using no fuel. If you have a scangauge or the like, you can see this on the display.
....unless for some reason because of the CVT the Camry doesn't do fuel cut mode but it seems to. Mine goes to "0" on the display when I'm coasting.
Later!
Dang
"Most" cars do it above a certain rpm. The transmission keeps the engine spinning, so fuel isn't needed. The ECU will not open the injectors, so you are using no fuel. If you have a scangauge or the like, you can see this on the display.
....unless for some reason because of the CVT the Camry doesn't do fuel cut mode but it seems to. Mine goes to "0" on the display when I'm coasting.
Later!
Dang
#15
Re: Figured out a hypermiling trick today
Later!
Dang
#16
Re: Figured out a hypermiling trick today
As far as the neutral/fuel-cut subject goes. If your going faster than 42 miles per hour in drive and then take your foot off the gas, your in fuel cut (no fuel consumed). If your going faster than 42 miles per hour and shift it into neutral, your consuming fuel (not fuel-cut) albeit a small amount.
Last edited by LOL TCH; 01-02-2008 at 03:09 AM.
#17
Re: Figured out a hypermiling trick today
Yes. Neutral at high speed with 0rpm is a bad thing.
As far as the neutral/fuel-cut subject goes. If your going faster than 42 miles per hour and take your foot off the gas, your in fuel cut (no fuel consumed). If your going faster than 42 miles per hour and shift it into neutral, your consuming fuel (not fuel-cut) albeit a small amount.
As far as the neutral/fuel-cut subject goes. If your going faster than 42 miles per hour and take your foot off the gas, your in fuel cut (no fuel consumed). If your going faster than 42 miles per hour and shift it into neutral, your consuming fuel (not fuel-cut) albeit a small amount.
#18
Re: Figured out a hypermiling trick today
When in fuel cut, the computer does not "turn on" the injectors to inject any fuel. Only the transmission spinning the engine keeps it turning, so no fuel is consumed.
I must admit "neutral" in a CVT is a bit confusing. Seems like it would be hard on it matching the pulleys when you put it in drive while moving.
Later!
Dang
I must admit "neutral" in a CVT is a bit confusing. Seems like it would be hard on it matching the pulleys when you put it in drive while moving.
Later!
Dang
#19
Re: Figured out a hypermiling trick today
I believe I said neutral at a high rate of speed is bad. Click here to get an idea of what happens to the ICE and two MG's at different settings. Remember that the wheels are tied to MG2. Set the ICE to zero and increase MG2 (therefore vehicle speed). MG1 will red line at 6500 rpm. This was based on an earlier generation of Prius with a max MG1 rotational speed of 6500. I believe the Camry has a max MG1 speed of 10,000 rpm. Did you notice that it red lines at at 42 miles per hour? To prevent any damage to MG1, Toyota designed the engine to kick in. Now increase the ICE. The value of MG1 will become less negative. All is now safe. Now imagine that your driving in the EV mode and you put the car in neutral as you approach a downhill. The engine RPM is zero and will remain zero no matter how fast you go. Wheel speed (MG2) is increasing to 70 miles per hour. I think you can guess what will happen to MG1. Unless Toyota has some sort of built-in safe guard, your going to smoke MG1. Any takers up for the challenge?
Dang, Pulleys?
-ed
#20
Re: Figured out a hypermiling trick today
So...to summarize for those of us who don't have the head for understanding the upper level physics....
Let me ask one question (and hopefully get a really simple answer
For the average driver, who wants to keep his/her car in good and safe driving condition, using neutral when the car is in motion is .... GOOD / BAD
Let me ask one question (and hopefully get a really simple answer
For the average driver, who wants to keep his/her car in good and safe driving condition, using neutral when the car is in motion is .... GOOD / BAD