Better Highway MPG with cruise or without cruise?

[landar]

That be the question. I contend that while the average speed will undoubtedly vary more without using cruise control, the MPG will be better if you control the speed via the gas pedal. The reason being is that the cruise will hammer the engine and even downshift on some upgrades (with subsequent lower MPG) whereas I can back off on the speed a little and keep from downshifting. Then on the downhill I can pick up speed and maybe go a little above the average without guzzling more gas. I know many believe you can not beat the cruise control for constant, steady, good gas mileage but that has not been my experience. Am I alone in this observation/thinking?

[RSQ Pilot]

Originally Posted by landar

That be the question. I contend that while the average speed will undoubtedly vary more without using cruise control, the MPG will be better if you control the speed via the gas pedal. The reason being is that the cruise will hammer the engine and even downshift on some upgrades (with subsequent lower MPG) whereas I can back off on the speed a little and keep from downshifting. Then on the downhill I can pick up speed and maybe go a little above the average without guzzling more gas. I know many believe you can not beat the cruise control for constant, steady, good gas mileage but that has not been my experience. I am I alone in this observation/thinking?

Flatlands I cruise, Mountains I control...
whatever works

[2010exl]

I have also found this to be true. Cruise control is too aggressive on the hills and will maintain the set speed "at all costs". I have gotten much better mpg without cruise control on the hills.

[N_Jay]

I have always wondered if a county intuitive strategy would actually be best. Maintain or even accelerate up hill. (you are already pushing the power curve so why not shorten the time).
Coast down hill, no gas mean no fuel at all. (Since cars shut off the fuel when in downhill coast above a minimum engine speed.)

Thoughts??

[landar]

Originally Posted by N_Jay

I have always wondered if a 'counter intuitive' strategy would actually be best. Maintain or even accelerate up hill. (you are already pushing the power curve so why not shorten the time).
Coast down hill, no gas mean no fuel at all. (Since cars shut off the fuel when in downhill coast above a minimum engine speed.)

Thoughts??

Ok, that seems to makes some sense. If the engine is more efficient in a higher torque band then maybe it would get better mileage. It does seem somewhat counter-intuitive to what I have observed. Of course, hybrids do not make a lot of sense to me either. You burn gas to run an engine to charge a battery to run an electric motor. There are several levels of energy conversion and each has losses. The idea, I believe, is that the engine runs in an steady, efficient torque band to charge the battery and that is (slightly) more energy efficient than running the engine from low to high RPMs and directly driving the wheels when accelerating.

On the other hand, MPG is Miles per Gallon. It does not matter that you got up the hill in shorter time. Time does not enter into the equation in the strict MPG sense. It only matters that you went x distance using a certain amount of fuel.

[N_Jay]

Originally Posted by landar

Ok, that seems to makes some sense. If the engine is more efficient in a higher torque band then maybe it would get better mileage. It does seem somewhat counter-intuitive to what I have observed. Of course, hybrids do not make a lot of sense to me either. You burn gas to run an engine to charge a battery to run an electric motor. There are several levels of energy conversion and each has losses. The idea, I believe, is that the engine runs in an steady, efficient torque band to charge the battery and that is (slightly) more energy efficient than running the engine from low to high RPMs and directly driving the wheels when accelerating.

On the other hand, MPG is Miles per Gallon. It does not matter that you got up the hill in shorter time. Time does not enter into the equation in the strict MPG sense. It only matters that you went x distance using a certain amount of fuel.

The issue with TIME is that you are running the engine in a less efficient manner for less time. Making some rash assumptions that the losses from lower gears and higher engine speed are related to systemic losses rather then just lower base efficiency, the lass time spent in that mode the less the loss and the greater the percentage of generated energy (used fuel) is applied to useful work, and less to non-productive work.

Now consider that the entire downhill portion you use no fuel, you almost entirely recapture the added momentum you carry crossing the top of the hill at a higher speed.

[RSQ Pilot]

Originally Posted by RSQ Pilot

Flatlands I cruise, Mountains I control...
whatever works

I forgot to mention...this is critacally important when driving the V10 Ford motor home towing the CR-V...every 10th of a mpg increase is welcome. LOL

[iggibar]

The cruise control gets worse mileage if it comes to roads that deal with many hills. In that scenario, I prefer driving it. But, if the roads are pretty level, the cruise does fine.

For some stupid reason, the cruise control on the Pilot, as well as all the other Hondas I've driven, like to drop about 4-5mph, then GUNS it to reach the desired speed. This ticks me off so much when driving on areas that have even a small amount of hills. Also, when on cruise, it likes to give it a LOT of gas when going up a hill, but lets go when going even slightly down a 1* grade. I wish it would do the opposite, because that's what I do when driving, and I net way better mpgs!