Cruising at 52mph = ~60 USMPG

[OuttaSight]

I completed a 330 mile business trip today and got my best numbers so far!

My first couple of trips have been with luggage and my wife and not keeping strictly to motorways and using the cruise control, as both times we were late to meet someone and part of the way I had to run at 70 mph.

This time the conditions were much better. I had to drive 160 miles out last night after the rush hour so no traffic hold-ups and just one stop for a drink / snack. I used the cruise control solidly set at 52 mph indicated (GPS said 80 km/h) and was by myself with just a small overnight bag. There was even a 15 mph average tail wind on the way out (according to the weather news before I set off).

I started with a just over half full tank and ran most of the way home on less than 1/4 tank (running on fumes at one point!). Coming home I made two pit stops for 5 litres and then later 10 litres of gas (I was testing how the fuel gauge reads with different known amounts of fuel added).

It was quite cool both ways (18C out, 24C return) and I didn't use the A/C at all - just the vent fan.

The MID reported a peak about 100 miles into the trip of 74.1 UKMPG (61.7 USMPG) and at the end of the 160 miles it read 72.1 (60.0).

On the return leg there was some stop-start traffic for a while and a slight head-wind but after 330 miles the MID read 71.1 (59.2).

One trick I used was to not use my foot to get to cruising speed. I'll use the gas pedal to pull away but once I'm doing more than 30 mph, I'll press the resume button and let the cruise control ease me up to 52. I'm also getting good at coaxing the IMA into full EV drive in slow 25 mph traffic using the power flow display.

It also helps to not creep along at 2-3 mph in heavy stop/start traffic while riding the brake. Instead I try to stop completely for a few seconds (allowing auto-stop to engage), let a gap build up in front and then just release the brake and creep forward without using any gas pedal at the creep assist speed of 5 mph until it's time to stop completely again.

I sorta used this technique on old manual cars too because I used to get cramp in my clutch foot from too many stop/starts. It also wasted gas as you have to rev the engine a bit when starting each time. So I used to just leave a big buffer gap to the next car so that while he was stop/starting, I'd just be creeping along at a steady 3 mph in 1st without using any gas pedal or clutch.

[wstander]

I have ask, how flat are your elevations?Any steep (7% rises) or is it mostly level land with gentle 10 feet rises and falls. (My normal commute is from 1,700 feet down to 59 feet and back with a few 3% and one 7% rise of 3 miles)

[Moviemike]

OuttaSight:
Really good numbers that are outtasight !
Nice tip about the using the curise control for acceleration. I've been lately wateching the rpm gauge, tryyyying to keep it at 2k or less while accelerating.
I've been able to get better mpg by turning off cruise control for easing up small hills and getting battery charge and max use of gravity to accelerate on the downhill, then return to cruise for the flatter portions of roadway.

wstander:
I'm considering a complaint to American Honda regarding the forced battery charging on the major up grades I encounter, but that you face every day. Any thoughts on this issue? What would be the best mpg method for tackling those 3 miles of 7% grade???

[bish79]

Originally Posted by Moviemike

What would be the best mpg method for tackling those 3 miles of 7% grade???

Drive at 30 MPH or less. That's how I got over 60 MPG in the mountains of Yellowstone. Then you can gain it all back on the downhill side. Unfortunately, that doesn't work with traffic riding your rear.

[OuttaSight]

Originally Posted by wstander

I have ask, how flat are your elevations?Any steep (7% rises) or is it mostly level land with gentle 10 feet rises and falls. (My normal commute is from 1,700 feet down to 59 feet and back with a few 3% and one 7% rise of 3 miles)

Nope, not on this run as it was out to Norwich in East Anglia, famed for its flatness . There were hills and dips long the way but nothing long or steep so I'd see the average MPGs drop a few 10ths while climbing and then gain it all back on the other side of the hill.

Google Maps - SE-E England

I live about half way from London to Brighton and took the M23, M25, A2 through London to avoid the toll bridge, M11, A11 to Norwich. Incidentally, you can see Lowestoft (SE on the coast from Norwich) where I bought my I2.

Probably the biggest hills were the grades of the M23 as it's a series of ridges that run E-W and the motorway is N-S. There's a big ridge along the side of the M25 but the motorway skirts around it rather than going over it.

Travelling by motorway is always more efficient as to qualify as a "M" class road it has to be grade limited to 4%. It's not the number of lanes that count. The M23 turns into the A23 going south because they didn't cut deep passes into the hills and so the grades exceed those allowable for an "M" class route. Some "M" routes are allowed short 5% grades where it really wasn't possible to blast a cutting but then have to have a dedicated "crawler lane" for trucks, caravans, etc. that can't make the minimum speed limit of 30 mph.

The highest change in elevation "M" class route in the UK is the M62 just West of Manchester that climbs to 372m (1,220ft) or the M6 that goes over the 312m (1,040ft) Shap pass in Cumbria (between the Lake District to the West and the Yorkshire Dales to the East) on the main route towards Scotland.

Google Maps - M6 - Shap Pass

I've travelled over the Shap pass many times going to Scotland and it's a long slog up hill over 15 miles. I used to annoy little 1.0 VW Polos because I had my Accord's cruise control set for 62 mph and they'd try to overtake me and then hit another tranche of grade and run out of steam while alongside me and have to fall back, then to try again at the next less steep bit, get past me and then I'd overtake them again at the next grade they couldn't hold speed on... The joy of a 2.2l engine

[buglermcd]

Accelerating with the cruise control is great in the I2. Especially with the ECON on.

I regularly reach 25mph with my foot, then set the cruise and hold down accel until I reach my cruising speed. Normally, the instant mpg display shows me getting 45-50 mpg, while accelerating.

With ECON off, the cruise control gives the engine a lot more gas, and the car accelerates much quicker, with pretty bad results.

[Moviemike]

Originally Posted by bish79

...Unfortunately, that doesn't work with traffic riding your rear.

ABSOLUTELY ! ! ...and without the useless battery charging it seems like the I2 could easily keep up with the slower traffic. As it is, the I2 provides more excitement in mountain climbing than I'd like.

...and thx for the tip. ...makes sense, the lower speed may keep the rpm's under the 2k figure for better mpg and is closer to the max. torque figure.