Squeezing extra MPG out of P&G (EOC WHILE KEEPING THE CAR ON??)

[101Volts]

Thanks. Here's a contribution: Downhill (If it's steep enough,) Putting the 2000 Dodge Caravan 3-Litre into low gear shuts off the fuel injectors.

[jedi_sol]

Originally Posted by 101Volts

Thanks. Here's a contribution: Downhill (If it's steep enough,) Putting the 2000 Dodge Caravan 3-Litre into low gear shuts off the fuel injectors.

Yes, coasting in gear activates Dfco. If you are going down a steep hill, dfco in gear is fine because you will not gain too much speed and the injectors shut off. However, dfco in gear is not beneficial with the pulse and glide technique on flat roads because you will lose too much speed on the glide, thus you have to pulse again too quickly.

Pulse and glide (engine on neutral coast) is the second best option when compared to engine off neutral coast.

I discovered that in my car, I can greatly improve the efficiency of the traditional pulse and glide engine on neutral coast by blipping the throttle during the glide portion. The fuel injectors appear to shut off for a split second every time I step off the throttle, therefore, by continuously blipping the throttle, I can keep the injectors off for a major portion of the glide, thus simulating engine off coasting, while keeping the car on.

[jedi_sol]

i found my voltage meter. Need to research where to tap into the fuel injector wires so i can monitor injector voltage in my car while driving

[j12piprius]

Originally Posted by jedi_sol

I discovered that in my car, I can greatly improve the efficiency of the traditional pulse and glide engine on neutral coast by blipping the throttle during the glide portion. The fuel injectors appear to shut off for a split second every time I step off the throttle, therefore, by continuously blipping the throttle, I can keep the injectors off for a major portion of the glide, thus simulating engine off coasting, while keeping the car on.

That's an interesting idea. However, my car uses .14 gallons an hour while coasting in neutral. Wouldn't constant blipping of the throttle use more than that?

[Fat Charlie]

It might. That's the fun part of modding and hypermiling: what works for me in my car on my route might not work for me in your car on my route. But it might work better for me in my car on your route or any other combination, and I haven't even mentioned weather.

[jedi_sol]

Originally Posted by johnlvs2run

That's an interesting idea. However, my car uses .14 gallons an hour while coasting in neutral. Wouldn't constant blipping of the throttle use more than that?

When i "blip" my throttle, its more of a gentle continuous tap. it's not the kind of "blip" i would use when rev matching the engine/transmission (similar to your learning of bump starting )

On my car, the scangauge shows that when i step off the gas and shift to neutral, the fuel injectors cut off for a split second. Then every time i tap my throttle, the scanguauge shows 9999mpg. So the ecu is detecting "step off throttle...cut fuel...step off throttle...cut fuel...step off throttle...cut fuel."



So there is definitely a correlation between speed/throttle position/fuel injectors.

Here is my ABA TESTING:

I changed up my testing method to eliminate more variables. This time, I drove up to 50mph, shifted to neutral to coast, then when I hit 40mph, I hit RESET on Torque, then when I hit 20mph, I hit RESET AGAIN. This way, I only measure the amount of fuel used while coasting. I eliminate the variable of my foot accelerating too hard.

I also measured using 6 decimal spaces, to allow more accurate detail in fuel used.

A1 Runs – Straight neutral coasting from 40mph down to 20mph
0.003973
0.003607
0.003754
0.003500
0.003657
0.003907
A AVERAGE – 0.003733 gallons/fuel used

B Runs – Blipping throttle while coasting from 40mph down to 20mph to simulate EOC event
0.0015200
0.0007780
0.0001470
0.0009400
0.0007230
0.0006480
B AVERAGE – 0.0007926 gallons/fuel used

A2 RUNS
0.003673
0.003458
0.003368
0.003382
A2 AVERAGE – 0.00347 gallons/fuel used

A averages – 0.00362 gallons used
B averages – 0.0007926 gallons used

78.11% improvement over traditional P&G

However, this phenomenon may only be present in cars with "throttle by wire." I'm not sure if this phenomenon occurs with older cars with "throttle by cable/butterfly."

Since you have an Ultra gauge, and if you are curious, i urge you to see if this technique might work on your Civic.

[elhigh]

This is amazing. It's like finding a button-press combo for unlimited ammo in your favorite shooter game.

[jedi_sol]

Originally Posted by elhigh

This is amazing. It's like finding a button-press combo for unlimited ammo in your favorite shooter game.

Should I go find some eggs? Lol

[bestclimb]

Is your data logger recording what scangauge reports as fuel consumption or actual injector operation?

Any news on getting an mpguino (or other direct injector duty cycle monitoring) into the mix?

As I understand most OBD fuel monitoring is based on airflow. With foot off throttle and open loop once up to temp = fuel off. If there is some parameters at low RPM that result in open loop operation with the foot off the throttle it could be tainting the results. (would be interested to have that misconception cleared up if I am incorrect)


This find seems almost too good to be true. I have noted that my ultragauge reports 999999 for a, um, noticeable, period of time after the engine rpm has stopped dropping and is idling (indicating that unaccounted for fuel may be being burned). I still think it's a possibility that indirect calculation of fuel consumption lends itself to the possibility of this being an artifact.

Your data definitely indicates that further investigation is in order. A way to get comparatively close to EO(ff)C performance out of engine idling coasting while keeping brake booster and power steering systems pumping is pretty awesome.


Could a signal to the solenoid that actuates the idle air control system automate this? I am guessing not as it seems to be linked to the throttle position sensor (which may be spoofable)

Ohh idea for another test. Monitor engine RPM, spoof the throttle position sensor and see if the ecu reports injector cut off.

not trying to criticize as I am really hoping this effect is workable.

[oldtamiyaphile]

I tried this with the MB100 fitted with an MPGuino, and it didn't work.

Today I tried it with UFI and SGII and got simular results to those posted. Unfortunately, the technique only works when rolling. Although UFI has stop-start, the engine off means no A/C. It would have been awesome if I could sit stationary and keep the A/C on with a 70% fuel saving.

Either way, it's a very distracting way to drive, paying attention to SG and the revs at the same time while trying to blip the throttle the correct amount. For DBW throttles it could easily be automated though.

I will point out that UFI doesn't have a hot wire AFM (or a throttle plate) so SG doesn't exactly produce very meaningful results. This really needs to be verified via MPGuino, then automated via Arduino