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Discussion Starter · #21 ·
It makes sense if you think about it. If you didn't accelerate and depending on how long of a downhill stretch your battery would become full quickly. Once it becomes full your engine fires up to burn off the regenerated energy instead of storing it in the battery. By accelerating when needed you're preventing the battery from reaching max capacity and allowing yourself to coast down in EV mode as long as possible.
The scenario you’re describing also makes sense, but that’s not what was happening in this case. Most downhill stretches lasted 30 seconds or less in my case, so the battery never reached past 75% full, whether I coasted or gassed and banked.

After observing the fuel economy reading for a few months I eventually realized that the most emphatic MPG gains happened after stretches of downhill + regen, so I experimented with artificially making that happen whenever I could and that was the result.
 

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Well gravity plus your acceleration is pushing you downhill faster. The regenerative braking increases the rate of recharge the faster you're going. At least to a certain point cause Honda definitely set a threshold to prevent the battery from overheating. So in the end you're most likely making more energy than using on that stretch.
 

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Wow. What a great idea! I'll have to try it!!

My thinking is that the small amount of energy used to accelerate gives a much greater than usual speed increase, due to gravity's extra push. Thus, as the braking begins you got much more energy coming out than was put in. The mpg increase comes from more efficient capture of the potential energy located in the cars' movement from top of a hill to the bottom.

Another possibility is the mpg increase for most of the trip was due to a tail wind, and not the downgrade. Possible I suppose, but I prefer the other explanation.
 

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Discussion Starter · #26 ·
The mpg increase comes from more efficient capture of the potential energy located in the cars' movement from top of a hill to the bottom.
Yep, that’s my guess too. Seems that downhills are a sort of “multiplier” of any acceleration you put in. Presumably there is a point of diminishing return; I wouldn’t expect that flooring it on a downhill would be very efficient, but a light tap goes a long way for very little cost.

Another possibility is the mpg increase for most of the trip was due to a tail wind, and not the downgrade. Possible I suppose, but I prefer the other explanation.
I was watching the mpg gauge pretty closely. Performance was pretty standard for the entire trip, except for the very noticeable bump after using the above strategy. Very interesting indeed!
 

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I recently got a record high (for me) 78.8 mpg for a tank full. My prior record high was 77.x. I think that 78 figure is a false high because I suspect slightly less than a full tank at fill up (due to 1.5 mpg spread between car's mpg and calculations from gas pump and odometer. Normal spread is 0.75 mpg).

It has been sunny-er and warmer prior to last fill up. Some daily 50 mile drives have been above 80 mpg when 78 - 79 is ordinarily the best I can do. I got a one time personal best 83.x last year when the traffic gods, wind speed, direction, and battery warming sunshine were all in alignment. Also I'm up to 46k miles, the oem tires are getting worn, and that can help mpg.

I agree with Andrew 28 that a large number of uncontrolable driving conditions make a big difference. But still, there is a lot one can do, to better one's mpg within those conditions. For example awrxmcr has a higher lifetime mpg than I (70 mpg), but all his Insight driving seems to be below 50 mph. He uses other vehicles for highway trips.
I bought my honda insight 2021 last year . I have drove 2500 miles and my mpg is 42 . Most of my trips are very short under 5 miles . I have come to know that short trips kill mpg . Can someone please guide me to achieve high mpg for these short trips . If it is possible to drive in ev mode for very short trips.
 

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I bought my honda insight 2021 last year . I have drove 2500 miles and my mpg is 42 . Most of my trips are very short under 5 miles . I have come to know that short trips kill mpg . Can someone please guide me to achieve high mpg for these short trips . If it is possible to drive in ev mode for very short trips.
I have the same challenge, and haven't found much of a solution.

For me the big mpg killer is the engine warm up process when first driving the car in the morning. That same warm up process happens during the day, when I turn off the car for a brief period, even though its warmed up after lots of driving. The ev system is very sensitive to temperature. It likes warmth, but not hot. So I park in a place where I can catch the morning sun (if there is any) and warm up the interior and HV battery. This leads to slightly faster recharging and possibly shorter engine warm up process.

It may help to do your long trip first, to get the wheels turning during the warm up process, where the engine really is cold after sitting all night. Then, do the short trips, while the engine is actually warm, from previous driving. Keep pushing the ev button on the center console, its telling the computer you wand ev mode !!
 

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I've done 70 to 80 mpg when it's warm. I've even managed to get 90 mpg on a 30 minute drive from the gym. You just have to use that regen paddle any time you're going down any sort of incline, no matter how short it is. Use the regen paddle while coming to red lights and stop signs. Avoid hard acceleration. On really steep inclines max out the regen and gently press the accelerator to keep your forward momentum, but only accelerate enough to keep the battery regen needle in the green section. For short inclines I hit the paddle once and do my best to keep the regen in the green or right on the bar that separates blue & green. If you do this be sure not to tailgate because your attention will need to be on the gauge off and on throughout your trip. Hypermilers like tailgating because it causes a wind draft over the top of the car instead of coming up from the front grill. It works, but it's extremely dangerous. I mean is saving a few gallons worth totaling your car? In short, learn when to use those paddles and use them often and you can easily get the epa rated 56 mpg even when the weather is colder.
 

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I have the same challenge, and haven't found much of a solution.

For me the big mpg killer is the engine warm up process when first driving the car in the morning. That same warm up process happens during the day, when I turn off the car for a brief period, even though its warmed up after lots of driving. The ev system is very sensitive to temperature. It likes warmth, but not hot. So I park in a place where I can catch the morning sun (if there is any) and warm up the interior and HV battery. This leads to slightly faster recharging and possibly shorter engine warm up process.

It may help to do your long trip first, to get the wheels turning during the warm up process, where the engine really is cold after sitting all night. Then, do the short trips, while the engine is actually warm, from previous driving. Keep pushing the ev button on the center console, its telling the computer you wand ev mode !!
One thing I have noticed is that if you go above 40 miles an hour in the first 10 minutes of start up - the engine will continue to run for a while no matter what the weather is.. If you stay at 40 or below, the car will cycle into EV mode.. I am not sure why it does this, but on your next trip - if possible, stay below 40mph.
 

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I've done 70 to 80 mpg when it's warm. I've even managed to get 90 mpg on a 30 minute drive from the gym. You just have to use that regen paddle any time you're going down any sort of incline, no matter how short it is. Use the regen paddle while coming to red lights and stop signs. Avoid hard acceleration. On really steep inclines max out the regen and gently press the accelerator to keep your forward momentum, but only accelerate enough to keep the battery regen needle in the green section. For short inclines I hit the paddle once and do my best to keep the regen in the green or right on the bar that separates blue & green. If you do this be sure not to tailgate because your attention will need to be on the gauge off and on throughout your trip. Hypermilers like tailgating because it causes a wind draft over the top of the car instead of coming up from the front grill. It works, but it's extremely dangerous. I mean is saving a few gallons worth totaling your car? In short, learn when to use those paddles and use them often and you can easily get the epa rated 56 mpg even when the weather is colder.
I love your detailed write up above!! I'm doing all the above to get outstanding mpg. I've developed some subtle refinements / improvements on the above. FYI below.
1.Use declines to regen via paddle or foot off the accelerator. Also use declines to pick up speed.
2. Use ev mode / push ev button on inclines, standing start acceleration, or speed up while cruising to avoid high ICE rpm. On long inclines, use the limited ev mode near the top of the hill. All this also maximizes the benefits of electric motor over ICE.
3. As above, moderate acceleration to the green / blue line, to prevent cancel of ev mode.
4. I do normal following distance. But with a 20 mph head wind and cruising 40+mph, normal following distance can negate the mpg loss due to that head wind. So seek I someone to follow.
 

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One thing I have noticed is that if you go above 40 miles an hour in the first 10 minutes of start up - the engine will continue to run for a while no matter what the weather is.. If you stay at 40 or below, the car will cycle into EV mode.. I am not sure why it does this, but on your next trip - if possible, stay below 40mph.
Yes!!,, staying under 40 mph can be a very frustrating thing!!! My daily drive includes many miles in a 40 mph speed limit, with lots of inclines and declines. Its a daily traffic challenge, cause I'm faster than the slow cars, a little slow for many, but a source of anger for those who like a steady 45 -50 mph speed.
 

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One thing I have noticed is that if you go above 40 miles an hour in the first 10 minutes of start up - the engine will continue to run for a while no matter what the weather is.. If you stay at 40 or below, the car will cycle into EV mode.. I am not sure why it does this, but on your next trip - if possible, stay below 40mph.
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There's apparently a heat recovery device on the 3rd gen hybrid powertrain according to Honda.
 

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Not sure the connection between the two, as I lose ev access above 40 mph with a warm engine. Though ev access returns after a long time, 20 - 30 minutes+ at 40 mph, OR reducing speed to 30 mph or less.
At the time, I was thinking the heat recovery device could be the reason why the engine stays on longer at 40mph+. The engine generates more energy at higher speeds so the heat recovered would be more significant.
 

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I can't say how people get 80+, but I can tell you how I'm getting 65-78mpg.

I don't need to drive on the highway for my commute.

Combine that with a feather foot in acceleration, downshifting paddles approaching lights and stop signs, and there you go. Very simple. I've only owned the car about 3 weeks and it came simply for me.

As far as highway driving, I'll give you an example. I recently went to Prescott, AZ for Thanksgiving dinner at The Palace (Wyatt Earp frequented the place long ago) from San Tan Valley, AZ. If you know anything about Prescott, it's a very high elevation by comparison to the Valley. 90% or more of the trip is fairly level, but at one point you're driving cliff side climbing up an extremely sharp incline hill for several miles. Once in town, the entire town keeps going uphill the entire way to the restaurant. On the cliff side highway, my engine was near pegged, screaming, to go up the mountain pass. Despite the near laughable 75mph speed limit (which the Honda actually was able to do, surprisingly!), the incline is so bad, traffic near the top slows to 35 or less as RVs and semi trucks are damn near running out of any steam to make it to the top. The rest of the trip I did all I could, and still despite all my efforts, I only got 41.5mpg.

Now, on the way back, I got 68.8 if memory serves me right. So a lot of it has to do with elevation changes. You CAN get good gas mileage on the highway, but it's far harder.

If I just drive around town to do simple errands like go to Walmart or Walgreens I religiously get 78mpg plus.

I hope this helped. It depends how you drive, elevation, and speed. 45mgh or less driving, especially in town with lights to stop you along the way is the best way to keep up extremely high mpg. Drive like a combination of a scared teen learning how to drive and a blind grandmother, and you should get an idea of how to achieve what I've done. If I even go so much as 47mph in a 45, I recharge/coast back to 45.
 

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I can't say how people get 80+, but I can tell you how I'm getting 65-78mpg.

I don't need to drive on the highway for my commute.

Combine that with a feather foot in acceleration, downshifting paddles approaching lights and stop signs, and there you go. Very simple. I've only owned the car about 3 weeks and it came simply for me..............
Yup that's how I do it.!!!
If ya can get 78 mpg, just a little more to 80. Two tips, if ya want to give it a go.
1. Check cold tire, tire pressures. That is, first thing in the morning after a cold night. I run 40psi front 39 rear.
2. Battery management. Plan terrain sensitive battery charging and ev run opportunities. I seek minimal ICE rpm for battery charging and ev only for acceleration (standing start, hill climb, or increase in cruising speed).

Per post above keep it at or below 40 mph because of denied ev access.

If my memory is accurate my best has been 81.5 mpg for about 52 miles. (details at fuelly.com click link below)
 

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If my memory is accurate my best has been 81.5 mpg for about 52 miles.
That is about the same as my personal best for a drive from Phillipsburg, NJ to Monmouth Junction, NJ (Princeton) back when I had an awesome work commute for the Insight. I miss those days!

Advice on cold tire temps is probably the number one best thing to do. Other than that, it's all about battery management and controlling ICE usage.
 

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Advice on cold tire temps is probably the number one best thing to do.
YES Yes. I agree.

A long time ago when I was driving a gen 2 Insight I got curious about how much mpg benefit I was getting from all I was doing to increase mpg. Its a hard thing to measure, but I did some comparisons of doing or not doing x or y and then seeing what the mpg impact was.

I did this over several fill ups. I looked at mpg impact of tire pressure, basic good mpg driving habits (avoiding hard acceleration or braking, coasting, hitting the green traffic lights, etc), and hypermiler techniques, the kind of thing we often talk about here. I found that just a little more air in the tires made a huge mpg increase (40%). An amount that was surprisingly similar to the mpg improvement from avoiding jackrabbit starts and aggressive and fast driving style (40%). Also, surprisingly small, was the relative additonal benefit of hypermiler stuff (only 20%).
 
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