Heading to Mammoth Mountain from the Bay Area
- Thread starter Agzand
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Went to flagstaff in march, that’s about 8k ft elevation, the car had no issues going up.
Just make sure your battery is not depleted and use hv mode.
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Just make sure your battery is not depleted and use hv mode.
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stacey burke
Active Member
Use HV DO NOT USE EV UP and then go to HV. Start fully charged and run HV from the start and remember any time you turn off the car it goes back to EV and you need to be in HV for your trip...
So to give a short report, we made it on time last night. I used HV for 95% of the time and the car didn’t loose much battery charge. The echo summit pass on US50 (just before Lake Tahoe) and Luther pass on 89 were both ok, the engine was not straining. These are both 7000+ ft and I was doing 65mph to 70 mph at some sections. The Monitor pass on 89 was a different story (steeper grades I guess) and I was doing 35 to 40 mph (it is a slower road) and engine was running much harder/noisier, to a point where my wife thought something might be wrong. Then there was the section on 395 which is all elevated (around 7000 ft) and the pass around Bridgeport, again I did 55-70 mph and the engine was running hard but not like the the Monitor pass. I am not sure if there was a headwind, but for some reason the engine was working harder than the similar conditions on US50. If I was in a high powered ICE car probably I would have gone 5 mph faster in this 100 mile section.
Finally if we had a Tesla, I don’t think we could have done this trip at this time of the day (we got there at 1 am). So overall I would say the car performed well for such a difficult route, but it is not something that suits this type of car, and if I were Honda I would put a 2 liter engine in this car.
Finally if we had a Tesla, I don’t think we could have done this trip at this time of the day (we got there at 1 am). So overall I would say the car performed well for such a difficult route, but it is not something that suits this type of car, and if I were Honda I would put a 2 liter engine in this car.
4sallypat
Active Member
If you had a Tesla, where would you recharge in Mammoth ??
Agreed on the 2L choice for the ICE for the Clarity....
Good trip report - I will be doing a similar trip from LA.
David Towle
Well-Known Member
Or a transmission with more than 1 speed or a CVT or a turbo.
Yes, a turbo engine works better in high elevations, but that will add another layer of complexity. A 2L engine won’t cost more or weigh much more than the current 1.5 engine.
You need to remember that the engine rarely propels the car(only in ideal situations such as flat roads and steady speed), it always charges the battery and the electric motor propels the car. Bigger engine just means a bigger “charger”.
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Fast Eddie B
Well-Known Member
Much of the time, sure.
But a bigger, torquier engine could expand the “gear mode” range, so as to encompass a wider range of driving situations. Not making a case for a larger engine - I think the smallish engine in the Clarity is in the “Goldilocks Zone” for most drivers most of the time.
In one of the papers written by Honda's engineers, they were very pleased they could achieve all their goals for the Clarity PHEV using an ICE with only 1.5 liters of displacement.
The beauty of the i-MMD hybrid system is its relative simplicity compared with other plug-in hybrids like the Volt or Prius Prime. The extra complexity of the Engine drive ("gear mode") clutch and single-speed gearbox was included only to provide the maximum efficiency possible when driving at steady speeds greater than 45 mph, which happens often during many long-distance drives. A multi-speed transmissison or a CVT would be much heavier without providing increased efficiency and a turbo would burn more gasoline.
MPower
Well-Known Member
My experience is that counter-intuitively it seems to be very noisy when you running HV at these lower speeds where it is quite happy to tool along quietly at faster speeds even going uphill (as long as you are not exceeding about 70 mps). But I have frequently experience much noisier engine noise in HV at 45 mph. I don't understand why. I usually turn HV off for these bits of the trip unless I need to conserve battery in which case I just put up with the noise.
David Towle
Well-Known Member
A 2 speed could be done in less than 50 pounds. The advantages of turbos are they can be designed with a torque curve that matches the load, allowing a single speed connection to be usable over a wider speed range. Something around 1 liter could be lighter too.
Here's a Toyota turbo Atkinson
Those options would increase the cost and the size of the Clarity PHEV's powerplant and gearbox, not to mention software development costs. It's easy to imagine why Honda wouldn't want to make big changes to the i-MMD blueprint for the low-production Clarity PHEV. All cars are the result of many compromises. My opinion is that the compromises Honda made in the design of the Clarity PHEV are easy to justify. (Of course, I'm a well-documented Clarity fan-boy, so my opinion is no surprise.)
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I think a 1.5L engine could work well if the car had a smart navigation-aided power train management. For example if I could enter the route in HondaLink app and tell them that I want to get there with 30% battery charge, then the car could have used 40% additional battery charge for the most demanding sectors. The calculations can be done on a server and results transferred to the app. This is something that can be done with existing power train, but needs some software expertise that Japanese car companies are reluctant to do.
I wonder if 1.5l engine is partially dictated by tax schemes in Japan, because sub 1500cc engines are taxed differently in that country.
David Towle
Well-Known Member
Of course, every car includes endless compromises, and I love my Clarity too.
We engineers like to dream of how to make things better, even though our real job 98% of the time is to make them cheaper.
Francisco Chanes
New Member
I have also been making trips to Mammoth here in California (sea level to 8000 ft). My concern is running the ICE at high rpm for extended periods. I'm assuming the Honda engineers have done their homework on this. While running uphill, the ICE seems to hit a rev limit at 5800 rpm which seems high to me. Others have posted here that since it is acting as a generator, the high rpm's are not a factor. Just hard for me to run a car at that rpm.
So to wrap this report up, we drove back yesterday and since we were losing 7000 ft of elevation, it was an easier trip. We started with about 90% charge (I charged in the hotel the day before.) The first episode of high revs was the pass after Mono Lake before Bridgeport, the engine was running relatively high and my wife driving in HV mode, she slowed down a bit to about 50 mph to avoid very high revs. This was a relatively short climb. Then it was easy sailing until Carson Valley, where we took Nevada SR-207 to climb from Mottsville (El. 4700 ft.) to Daggitt pass (El. 7339 ft) in about 8 miles. This is a steep road with 6-7% average gradient for about 8 miles. Here the engine was again running high and we drove about 40 mph, it was not very pleasant but it also didn't feel like the engine blowing up.
One thing that I noticed during these steep runs was that when we stopped there was some sort of clutch smell. Not sure if this is the direct drive clutch or some other mechanism, but I noticed twice.
Last data point, from South Lake Tahoe we had just one climb left, so I used EV sport mode and climbed from Meyers in Lake Tahoe basin (about 6350 ft) to Echo Summit (7377 ft). The car had much more pep here and my EV range dropped from 37 miles to about 21 miles during this climb (from about 70% to 50%).
So I think if you are driving just one or two steep grades, it is a viable option to use EV sport mode and some battery charge to reduce the strain on the engine.
If I was going to do this trip again, I would use EV sport for some of the climbs and I will also use HV charge mode to regain battery charge during easier and downhill sections of the road.
One thing that I noticed during these steep runs was that when we stopped there was some sort of clutch smell. Not sure if this is the direct drive clutch or some other mechanism, but I noticed twice.
Last data point, from South Lake Tahoe we had just one climb left, so I used EV sport mode and climbed from Meyers in Lake Tahoe basin (about 6350 ft) to Echo Summit (7377 ft). The car had much more pep here and my EV range dropped from 37 miles to about 21 miles during this climb (from about 70% to 50%).
So I think if you are driving just one or two steep grades, it is a viable option to use EV sport mode and some battery charge to reduce the strain on the engine.
If I was going to do this trip again, I would use EV sport for some of the climbs and I will also use HV charge mode to regain battery charge during easier and downhill sections of the road.
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