First "Road trip" and a bit confused with HV

The reason I asked about your updates is that our Clarity has had the 18-089 (EVTC and 3-way Valve) and the 18-091 (HV mileage fix, current version of 18-069) software updates in early October. I think that the 18-089 update has changed how the engine and HV system operates. A couple of weeks ago, the engine started in our garage when I turned the heat on for freezing rain conditions. This was the first time the engine had started since the software update. I do not think this was a system check (no mention on display). The engine seemed louder to me but this could be subjective. After reading some comments in this forum about how the engine operated in HV mode, we took the Clarity out on a freeway drive to see if things had changed. We have driven the Clarity on the freeway for a hour or so every six weeks or so to exercise the engine as the Clarity is used entirely in EV mode normally. This last time, in HV mode the engine did not stay locked to the drive train all of the time when the speed was over 45mph. Instead, the engine disconnected when additional power was needed up hills of more than mild grade. The engine revved up to 3500+ rpm (rather than about 2500 rpm when locked in at 70mph - we had a tachometer display from a connected OBD2 dongle). Previously, the extra power needed was taken solely from the LiPo battery for the same grades and speeds. Also, on going down mild grades, the engine disconnected and shut off. Previously, the engine would stay locked in. Finally, the engine was more noticeable (a bit louder?), even when locked in than previously.

The above is not all for the worse. I think that the possible increase in noise, especially at startup idle (1500 rpm), may be caused by a change in the VTEC controlled valve timing to help with warmup and overall engine efficiency. The change in lock in behavior in HV mode at freeway speeds may be a change to help in the overall efficiency of the power train system. It seems, for our 100 mile trip (about 80 miles with the engine running), that the gasoline mileage increased as it appears we used less gasoline (by the gauge and the HV mileage change) than previously. This is something we can check the next time we add gasoline (later this month). Honda has stated that the VTEC valve timing can be changed for either efficiency or power operating modes. And, a gasoline engine, even an Atkinson-cycle one, works more efficiently at larger throttle openings and optimum rpm. So, perhaps Honda has found some better VTEC and drive-train settings to produce better highway mileage in the HV mode and to keep the LIPo battery at a constant state of charge. This comes at the slight expense of, perhaps, a bit quieter HV operation at freeway speeds with a slight "angry bees" sound when a moderate amount of extra power is needed. I think that on balance, the software updates are good, especially for those that had the "multiple system warnings" (as we did).

As Kentucky Ken has said, the Clarity is one of the best cars I have driven and this is so even after the software updates. We are very happy with our Clarity.

LeoP

 

LeoP

All I can say is ditto.

I have the exact scenario as you...great write-up. You saved me the time...lol

Like you, I am still deciding if its overall good. The Clarity runs fine. The frequency of the clutch engaging seems less and seems to disengage with more frequency as well. I haven't really heard much change in the engine sound except as noted where in the past the clutch engaged seemingly more often when more power was needed. Still no real discernible pattern or logic to when the clutch engages or disengages in HV mode.

I guess I need to drive it more in HV mode to try and get a better sense on the processes. I already drive the Clarity in HV mode 2-3 days a month to give the ICE a good run which is how I noticed the subtle changes in the first place.

Hadn't really ciphered on the gas but I will be sure to check for any noticeable change next fill up. Unfortunately, this is also the first tank where I put pure gas (no ethanol) in. Be interesting to see though.

Like I say...still ciphering.

Good post.

 

Clarity Newbie and LeoP,

Did you notice a change in MPG after the updates? I took my Clarity in for the A01 maintenance and my dealer forgot to do the software update (my HV range still says 1000 miles). I didn't bother to bring it back because the range estimate thing didn't bother me and it always ran fine in HV mode, giving me between 48 and 52 mpg (that's driving between 50 - 65 mph -- I'm a slowpoke). On my long drives, I did notice that the clutch engaged for only a few minutes before switching out to other modes and then back again. I figured all that "busyness", although somewhat disconcerting but otherwise imperceivable, was what maximized my MPGs (plus always having a good charge on the battery).

 

@leop and @Clarity_Newbie, thanks for the observations on the behavior after the updates. Could you track your mpg some more and let us know it got better or worse after the 18-089 update? I wonder if the change you’ve noticed is a result of Honda addressing the potential problem of gas getting in the oil by having the motor try to warm up faster, run longer, etc.
More real like info will help. Thanks again for keeping us updated. It will also help me decide if I won’t to get the update.

 

PHEV

I haven't really tracked the MPG difference but I plan too. Unfortunately, the last fill-up I pumped in pure gas (non-ethanol) so any noticeable increase will be due to ??? I've been getting in the low 50's myself in HV mode so sounds like our experiences prior to updates is similar.

I requested the valve update only when I went in but my dealership applied all available updates despite my request otherwise. What is done is done so now I get to play with the results. In reality, the Clarity runs fine. Just some nuances to figure out like the clutch frequency engage/disengage. I have had the updates for a month now and I don't think there are any egregious errors...this whole machine is being fine tuned on the fly...but that is what we signed up for being the first year model run.

I think its unfortunate prospective buyers are reading these forums and getting the wrong idea about the Clarity but then again that is what forums are for...folks to read up on a car of interest before buying...yin and yang.

More info on MPG will be posted when more data is collected.

Hope this helps.

Good luck.

 

KentuckyKen

Plan is to more closely track MPG since LeoP suggested that. Unfortunately, I filled up with pure gas (non-ethanol) this last go-around so I've already skewed results potentially...lol

I've already looked into the oil-in-gas issue and I can say that as of yesterday, I notice no unusual odor from the dipstick and the level on the dipstick is where it should be. So far so good on that.

I requested the valve update only when I went in but my dealership applied all available updates despite my request otherwise. What is done is done so now I get to play with the results. In reality, the Clarity runs fine. Just some nuances to figure out like the clutch frequency engage/disengage. I have had the updates for a month now and I don't think there are any egregious errors...this whole machine is being fine tuned on the fly...but that is what we signed up for being the first year model run.

Continued good luck!

 

I think we should be OK on the gasoline in oil problem. That's for the turbocharged engine in the CR-V. And it's not a problem if you let your CR-V engine warm up properly. Clarity's engine is not turbocharged and the engine design is very different. There hasn't been a problem I'm aware of for any non-turbocharged Honda engine. If you're worried though, just make sure you drive for at least 10 - 15 miles after you switch to HV.

 

To me all the worries about gas in the oil on CRVs is a big nothing. 2 stroke engines, including cars in the old days, worked just fine being lubed with 95% gas/5% oil, modern ones are 98-99% gas!. (Yes I recognize they had roller bearings instead of plain bearings but here we're probably talking 95% oil/5% gas) And today's engines are designed for very thin oils anyway.

 

@leop @Atkinson Some more follow-up data.

As a reminder, I received the full slate of TSB updates in late October. Since then, I have taken a few hours here and there to drive it in various modes trying to assist you folks in figuring out the changes since the update.

One thing I noticed when driving the Clarity in various modes...the one time I purposely let the Clarity get to 0 EV range...when the HV mode kicked in as designed...the engine gear appears much more often and stays linked longer then when I activate HV mode on purpose using the button.

As in @leop case, the gear icon does not engage as often nor stay engaged as long when in HV mode as before the updates. I will test this out again next week when I have time.

I still do not notice much more engine noise than before the updates. The one thing I hear more frequently is the engine whine when the computers request more power especially going up hill. Even then, the engine noise is more than tolerable...just runs more than before.

@KentuckyKen asked about gas mileage and oil level...it seems I am getting slightly better mpg in HV mode BUT since I just changed to 89 octane, non-ethanol gas this last tank...hard to figure what is the main reason. Hopefully more concrete numbers after couple fill-ups.

Also, oil level remains within normal range and no noticeable gas-in-oil.

Hope this helps.

 

Higher octane likely to have zero mpg benefit, as discussed many times in the past

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Non-ethanol is the key.

 

I wonder if Honda tried to prevent angry bees by increasing the rpms of the ICE so it would do a bit more battery charging, or at least prevent the battery drain while in HV mode.

 

When I take a long trip, I let the battery go down to about 50% before I switch to HV. The ICE maintains the EV at the level I switch to HV, but the ICE seems to work harder charging the battery at higher voltages. EV range goes up and down, but stays pretty close. I drive hills of NY. I tried HV charge to start a trip, when the battery was full, thinking the ICE would allow the battery to go down to 57% before recharging, but it just said the battery was already full.

 

If you start HV charge when the battery is low it will charge up to 58%. If you try to use HV Charge above 58% it will just revert back to HV.

 

Just did a 1000 mile road trip from Miami to Savannah,GA. Mostly in Hybrid mode on i95. MPG in pure HV mode is about 46-47 when speed is around 70mph, When speed is 75mph MPG is around 45.5-46, when speed go near 80mph I see the MPG drops below 40 on the range estimate screen.

The EV range doesn't drop down when in HV traveling long distance. If I started the drive with 40mile EV range at end of 300 mile trip I would still have about 40 mile EV range left so no HV does not consume EV battery that much, or it recharges it back to about same level.

Super fuel efficient Hybrid I must say.

Attachment shows last 4 trips.

 

This is why I don't feel guilty pushing the HV button when I am established on the highway. I dislike driving in HV in the city, but feel that the car performs fine on the road as a hybrid.