Please let everyone know if the HV mode highway behavior changes after the service this week. I suspect that the October Campaign updates will be applied. So that you do not need to make a second visit, you might want to call the dealer on Monday to make sure that the climate control replacement module is available at the dealership. LeoP
When and if we get a more complete set of Clarity codes, we could just program an OBDII display app (such as Torque) to show many of the things you want to know. I use such to show engine rpm and related data when I want to better understand our Clarity's behavior. One might even be able to use the Android based center screen to run such and app. LeoP
To get the gear icon to come on and stay on I have to be smooth, no punching it! Probably easiest with cruise control although its not hard to be smoother and steadier speed than what this cruise control provides.
My drive is about 33 miles each way on straight freeway. After experimenting with various modes I feel that the simplest technique for me is simply putting the car in Sports mode as soon as I leave home and as soon as I leave work. I leave it in this mode constantly and never make any changes. I like Sports mode because it is more "spirited" and also because I can use the regen paddles very effectively (it doesn't turn off during my drive). Also, Sports mode seems to get me all the way to work on mainly EV mode. On the way back from work the battery gets depleted and I see the engine start to engage about 20 miles from home. However, this still feels quite smooth and enjoyable and I am always intrigued by the fact that it still seems to shift between battery and engine mode as I approach home. Therefore, even when the battery is "empty" ie: on 2 bars, the regen braking and the ICE keeps feeding it such that I switch between EV and ICE modes for the last leg of my trip. I really find this quite easy and efficient, and I don't really sweat the small stuff ie: cost of kilowatts vs. fuel, minor revving sound etc.
The three basic drive modes are EV drive mode, HV drive mode, and Engine drive mode. You don't get to select these modes, the i-MMD system does that. EV drive mode is when the battery and traction motor are powering the car. HV drive mode is when the battery and the ICE-powered starter motor/generator combine to feed electricity to the traction motor. Engine drive mode is when the gear icon appears to indicate the i-MMD system has engaged the Engine-drive clutch so that the ICE is mechanically connected through gears to drive the front wheels. It turns out that this direct connection is the most efficient method of powering the car in some instances, such as when the load is light at expressway speeds. When you switch the Clarity to HV Mode, regardless of which of the other 3 modes is in effect, the Intelligent Multi-Mode Drive (i-MMD) system will try to maintain the battery at its current state of charge (SOC) and use the internal combustion engine (ICE) to power the car and recharge the battery as necessary. When you select HV Mode, you're indicating you want to switch from primarily battery-powered travel to primarily ICE-powered travel. However, HV Mode doesn't use the ICE all the time. It picks from any of the three basic "drive modes," according to which it decides is the most efficient at any given moment. The three basic drive modes are EV drive mode, HV drive mode, and Engine drive mode. You don't get to select these modes, the i-MMD system does that. EV drive mode is when the battery and traction motor are powering the car. HV drive mode is when the battery and the ICE-powered starter motor/generator combine to feed electricity to the traction motor. Engine drive mode is when the gear icon appears to indicate the i-MMD system has engaged the Engine-drive clutch so that the ICE is mechanically connected through gears to drive the front wheels. It turns out that this direct connection is the most efficient method of powering the car in some instances, such as when the load is light at expressway speeds. HV Charge Mode is the least-efficient way to drive a Clarity PHEV because it runs the engine at high RPMs to propel the car and recharge the battery at the same time. It's main purpose is to get a charge back into the battery before the next mountain if you just used up most of the charge on the previous mountain. Honda decided to limit HV Charge Mode to charging the battery to 58% of full charge. When the battery reaches 58% of full charge, HV Charge Mode switches to HV Mode.[/QUOTE] Thanks for this. Very informative. However I still have a problem. I'm only a 3 week owner and have studied the available information a good bit. Today I drove 200 hilly (and cold) highway miles in HV mode. The battery stayed charged to the 58% or so level. But during acceleration, the engine revved uncomfortably. At high speeds (high 60's), mid speeds (50's) and even 30's going up a hill. My understanding is that the IMM selects how the HV performs in these modes. So is there nothing to be done? Is it normal for the engine to rev so loud? Interestingly, the latter half of the trip was mostly downhill and the engine did not rev even on upgrades. I'm confused.
I believe the engine sounds so loud because we get used to the wonderfully quiet EV Drive mode. Honda could have used a larger engine, such as the 2-liter powerplant in the Accord Hybrid, but that would consume more gasoline, which would conflict with the design goals for the Clarity PHEV. In one of the papers published by Honda engineers, they're very happy they could downsize the engine to provide superb economy while still achieving the performance goals they had set for the car. The compromise they accepted was that the wimpy 103-hp engine sometimes has to work hard to move this 2-ton car. As loud as the revving engine sounds, none of the posters who have connected OBDII scanners have reported revs higher than 4,550 RPM, if my memory serves. Still not as loud as a run-of-the-mill economy 4-banger hitting 6,000 RPM.
I completely agree that we become warped by the quiet of EV mode, so when the engine revs to what would be "normal" for a traditional car, we panic. However, I continue to be mystified and rather annoyed by the unpredictability of the engine. I don't expect there to be correlation between my pressing the accelerator and the engine rpm, but sometimes the negative correlation makes my brain hurt. Frankly, with the exception of when it's directly coupled to the drivetrain, in my humble opinion the engine should either be OFF, running at whatever the most efficient speed is, or in panic mode because the controller has detected that maximum power is required. Since OFF doesn't really count as a speed, we should observe exactly two speeds unless it's in direct-drive, and even in direct-drive the rpm range is small.
My opinion: I have found running the SOC charge closer to 25% in cold weather (below 20F) seems to keep the engine RPM's better controlled. I run highways and hills, and use an OBDII recorder: 3000 rpm's at highway speeds is okay, with occasional 3500. Running 3500 and hitting 4000 rpm's was annoying for me. I have been able to keep my drives pleasant since adjusting my HV mode operation. I normally run EV till EV miles gets to about 25% of full charge. If you are running higher SOC and the noise starts, it can normally be stopped by running EV and getting the charge level reduced. Extra information: The gear mode runs the engine rpm's about 36.5 times the mph speed. 60 mph is about 2190 rpm, and this is a quiet highway drive.
Extra extra information: The battery charging and discharging performance is non-linear, especially at low temperatures. My experience with control systems is non-linear systems are harder to control, and my impression is the ICE rpm controller does not handle the non-linearity well. Obviously, just my opinion...
That's why I, insightman, has not continued my tradition of purchasing the newest Honda Insight. I still love my gen-1 Insight, but it's more than a dozen years old so it's time for a new car. I really enjoy driving my wife's Clarity PHEV because I can spend so much time avoiding the sound of the engine. The idea of driving a lesser i-MMD hybrid, such as the Insight or Accord Hybrid that runs its engine at seemingly random RPMs most of the time, turns me off. Time to write yet another letter to Honda, begging them to sell me the Europe-only Urban EV.
So my experience hasn't been typical. I was seeing very frequent high RPM sounds often when running in HV mode, and still get high RPM 100% of the time if EV range hits zero. I also had a really difficult time keeping EV from hitting zero, as it would literally just tick-down to zero when in HV mode. Important to note my first 4 months of ownership, I *never* saw the gear icon. So at one point KentuckyKen suggested I reboot my car by disconnecting the 12V battery and then re-attach- which I did. It initially caused a large number of scary alarms which cleared by driving around in my local neighborhood. Anyway, after doing so, for the first time *ever* I now routinely see the elusive gear icon. For me the icon for gear *only* turns on when on flat ground or slight down-hill. It *never* turns on up hill, even a slight hill. It seems to be the small 103HP gas engine efficiently propelling the car forward when there isn't too much resistence. Also when the gear icon appears, in HV mode, I see my car (for the first time ever) retain EV range while in HV mode. Now since I live in Oregon, hills and mountains are literally a more common experience than flat. That's our geographic reality. My car *cannot* ever retain EV range in HV mode, but now that I get the gear icon occassionally it is much, much better! So what I do: - If my total trip is less than 26 total miles, I stay in EV mode all the way. I get home and plugin. My car frequently reports like 32 EV miles after a full charge but consistently cannot actually do 32 EV miles. It will consistently do 26. - If my trip total will definitely exceed 26 miles, I start before I leave home, in the driveway, and press HV. This has the best chance of preserving EV miles on my journey. For my typical journeys this typically but not always avoids 0 EV range. I still lose EV range in HV mode, just not as fast as I used to. - My car sounds aweful anytime EV range hits zero-- it's obnoxiously loud. I simply spend extreme effort not to let this happen, not ever. And god forbid I have to do long press HV to get EV range back up, which does work, but man does it get even louder then. I avoid HV charge mode (if I can) like the plague. I am under the impression my experience is not normal, but you may have a Clarity that behaves more like mine. i.e. one that requires specific discipline to drive comfortably. -Dan PS: One might ask why I like Clarity given my contraints: Most days my commute is 20 miles total. That means 100% EV, quiet driving. I sometimes go 6 weeks without HV mode at all. Also, despite what I consider uncomfortable noise, even when my car hits 0 EV, I've measured my MPG at the advertised 44 to 40 MPG which I consider awesome.
My experience of angry bees is uphill at more than 70 mph. When i slow down to under (and/or lower the heater fan speed) the engine sound becomes more normal. I am always driving in ECON/HV and don't press the accelerator very far down because my legs are not long enough. (Wnen I drive in ECON mode I have never felt the accelerator go past the click point.)
Dan, What is build date for your Clarity? What is ambient temperature? Glad that you are able to enjoy the EV ride! Extra info: I did see a Honda R&D report of field testing the Clarity. Showed heater KW consumption, but the low temperature on the chart was 0C - representing Japan winter season results. It is very difficult to set up a control system without 'real world' experience - I wonder if they worked with the 1.5L in cold climates?
An opinion with which I agree. This car simply does not like very cold weather. The degradation of the battery with temperature and the need to use significant power from the battery for heat explains a lot of this. But I think you have hit on another factor. As you point out in a subsequent post, "Winter" as defined in Japan is different than "Winter" in Canada and northern US. I think your speculation that the field testing of the car never explored what are my everyday temperatures is probable. This factor also plays into our continuing frustration in trying to understand the logic of how the car operates; I think it becomes less predictable in cold weather.
