Does anyone have tips for getting the best mileage in the MMH/FEH on hilly terrain? My normal commute is 24 miles of rolling hills with a 45 or 55 mph speed limit and very little traffic except at the beginning and end.

I have been able to get a trip reading of up to 38 on the dash in my MMH AWD, which should be just about broken in. I have been trying to keep as much of the trip in the 1500-1800 rpm range when the ICE needs to be on. I often get the engine going higher (maybe up to 3000) when going downhill to gain as much speed as possible heading into the next hill. I then ease off right at the point of incline to 1500 rpm to maintain enough power to get up the hill. I also have several sections where I can coast a while before a stop. I allow the vehicle to coast down to 45 mph or so before these, shift to L, and then it moves to EV right at 40 mph. I can coast the rest of the way in D or N down to a stop.

I would appreciate any good ideas about drives in rolling terrain.

 

 

I have tried coasting down the hills, but it did not seem to work as well, since the engine ran at substantially higher RPM on the way up the next hill (it would require 3000+ RPM on a steep incline, which really seems to hit the mpg hard). I will give it another shot - especially in N on the down slope. I had used that method a lot with a non-hybrid standard transmission vehicle. The hybrid just seems to prevent me from maintaining speed without using a lot of power from ICE on the way uphill when I used this method in the past.

 

I have a pretty big hill west of my house (that I rarely drive up or down as most of my driving is N/S). It means that I can hit the top of hte hill at about 38 mpg (speed limit 40) and when I put it into N the car will acclerate all the way to 52+ mpg. I can usually get all the way home without using gas for the last mile. That said, the hit of about 7-9 mpg up the hill (2500-3K rpm) really hurts.

However, I do remember reading somewhere that the torque curve of the FEH (assume the MMH is the same) means the best accleration speeds are 1800, 2200-2400 and 3500+ rpms. The post said that between 3000 and 3500 RPMs the curve is horrible. So I would actually recommend acclerating up the hills at only 2400 RPMs or push it up to 3600-3800 RPMs.

 

With my Civic HX (manual), I either leave the gear selector in 5th gear or put it in neutral just before coasting down the hill. I then coast down the hill getting up to as many MPH as possible. If it is a small hill where my speed will drop down to the speed limit, I do not touch the accelerator. If it is a steep hill, as I approach the hill, I gradually accelerate just before I start to lose any of the speed in order to keep as much momentum as possible.

 

I have a lot of rolling hills on my daily commute (55mph 2 lane highways and interstate). I usually coast downhill in N and then accelerate near the bottom up to 55mph or even 60 depending on how long or steep the next hill is. I monitor instant MPG on my ScanGauge II and try to keep it at least in the 30mpg's if possible or high 20's. Depending on traffic I may drop down to as low as 45mph on the uphill portion. I try to keep RPMs around 2400 when possible, but sometimes have to go as high as 3000.

Using N will allow me to gain speed faster on the downhill, and glide longer if I have a stretch of flat before the next hill. However, some days I notice that my instant MPG is considerably lower on the downhill in N than if I coast in D. Not sure why that happens, but if it does, I leave it in D. This can take my instant MPG from somewhere around 100-110, up to 140 or higher.

If you want to coast in D you can cancel regen by very slightly pressing the accelerator. You can see this by watching the assist gauge, and it stays in the middle rather than showing the battery being charges. I prefer N though (I find it easier to shift to N than to control the pressure on the accelerator that lightly).

One other thing I try to do on the uphills: If my speed is bleeding off to much and I need to accelerate, I try to find flatter portions to do it on.

-- Rick

 

I live in a rural area with some large hills and other more minor rolling stretches. The best way I've found to really get better mileage is to keep your speed under 40 MPH. This might not be practical for you, but if you are driving on roads with a 45 speed limit and little traffic you should do OK. When I'm keeping the speed low and someone is closing from behind, I will accelerate to an appropriate speed and then pull over to let them by.

Staying under 40 lets you stay in EV mode as much as possible. Stay light on the pedal and accelerate on downgrades up to 40MPH and ease back off the pedal on inclines. As I'm sure you probably know trying to accelerate on even a slight incline over 30 MPH will cause the ICE to kick in. So try and avoid that. You can easily accelerate up to 40 on even slight downgrades.

If you have any larger hills, cruise slowly downhill in N and drop it into L when you are approaching 40 MPH. This will keep yourself in EV mode and give the battery a healthy recharge until you reach the bottom of the hill.

This kind of driving has allowed me to get consistent mileage between 40-50 MPG all summer in my '08 FWD. This all obviously assumes very light traffic and that you aren't in any hurry. Be safe and courteous and good luck.

 

Sounds like something I would do!

GaryG

 

I'm honored!

 

Unfortunately, I cannot really spend most of my drive going under 40mph, since my commute would just end up too long (it is 40-45 minutes each way).

I do follow the method of accelerating up to just under 40 in EV when possible and shift to L. This works great when I don't have another hill to go up right away. If I do, I need to maintain such a high rpm to have enough speed up the next hill that it seems to reverse the gain I got in EV. I don't have a scangauge, so I cannot tell exactly, but it appears to me that the benefit I get from going downhill and gaining speed with rpm around 1500-1800 gives me sufficient speed to get up the next hill in the same rpm range and maximize the mpg. When I try to use EV or going downhill, the amount of power that I need to expend when the vehicle has the most resistance (going up the next hill) appears to eliminate the gain.

I needed to drive a long way on rolling expressways in the past week with 60 to 70 miles per hour speed limits, and it appeared that using N on the downhill portions of these roads really paid off (perhaps a 3 mpg gain over several hundred miles). Using N substantially has been the only way I have been able to exceed the EPA highway ratings by very much. I don't get these results at all when I use N on rolling terrain in the 45 miles per hour speed limit roads. Using N going downhill only works well for me in this situation if I have a long section of relatively flat road after a big hill. I do have one section that allows me to come down a big hill and then maintain enough momentum up the next hill that I can then coast down it and roll over the third - sort of like a roller coaster. I can go about 2 miles without pressing the accelerator more than a touch.