4x4 CR-V tested on rollers. What a complete failure!!! - Page 3
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Thread: 4x4 CR-V tested on rollers. What a complete failure!!!

  1. #21
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    Quote Originally Posted by williamsji View Post
    Basically a large array of different sensors exist in the CX-5 to sample a range of different conditions and variables and from there try to predict in advance when dynamic traction from the rear wheels is required. An interesting concept and approach, but I have no idea how well it really works in real world conditions. I understand that the additional sensors number in the dozens on the CX-5... and personally... I would not want that for my normal every day driving. We have enough issues with all the electronics subsystems in these newer cars to begin with.. and more sensors and the controllers they feed is just more things to break or get out of calibration and since this involves wheel traction... I see this as overly complex for what is needed in an AWD vehicle.
    Being a development engineer with some automotive system management component experience, I view this rather differently. An SAE article some years back stated that the average vehicle had upwards of 100 sensors then, with the average number increasing by something like 10 additional per year. Modern safety semi-autonomous & connected vehicle system of the last few years has increased that number several fold. Electronics may not have true 6-sigma reliability yet, but there's no going back. Better get used to it. Or be prepared to keep your old vehicle forever.

    So if Mazda has joined the Audi / Subaru / BMW club in terms of AWD performance by simply making the addition of a dozen sensors and improved software, then kudos to them. I'll take that added measure of winter weather performance and light off road ability that a better performing AWD system brings any day. Honda does offer a better functioning system on their larger vehicles (Intelligent Variable Torque Management™ (i-VTM4™)), but chose not to include it on their smaller SUV's. And that's a shame in my book.

    In this discussion several have said that these vehicles lack a center differential. It might not look like the transfer case of an old style truck, but by definition, any system that has to port torque to both the front and real axle does have a center differential to apportion power. On Subaru and Audi it's in the tail shaft of the fore-&-aft mounted transmission. On Honda and Toyota the transverse mounted tranny has a second front differential to port power rearward (a PTO), and then the clutch system is mounted prior to the rear differential. So the center differential is 'split' into two segments, but in total the two parts do the same thing.

    Torsen and silicon fluid viscous plate limited slip differentials were a popular solution to preventing one lifted spinning wheel from killing a good thing. Perfect for true off-roading machines or for the days prior to modern electronics. But for most AWD vehicles sold today, the integration of VSC/ABS systems into the AWD systems gets the job done.
    Last edited by Fibber2; 04-04-2019 at 11:06 PM.
    2013 LX AWD (kids college car) Other vehicles past & present: 2014 & 2002 Subaru Outback, 2015 & 2008 Toyota Sienna, 2002 Honda Odyssey EX

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  3. #22
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    Quote Originally Posted by Fibber2 View Post
    It's kind of funny, really, but I find that those that simply dismiss questions without offering any real help are usually those that CANNOT answer the question. Those that are asking an honest question are being gaslighted....
    It is funny, that you make that inference with no possible way to back it up, and then misuse a big word like gaslighting as a follow-up. By the way, what is a dishonest question?

    To me, it's a question asked by someone who is perfectly capable of finding the answer on his own, but is not motivated enough to do the work, so he will ask you to do it for him. A perfect example of modern education. It's why we have whole generations of college graduates who cannot spell. My point being that, if he actually knew how to learn, he would not need to ask.

    Still, kudos on providing the turnkey information, which provides another redundant issue of it. Which doesn't demean you, or the information itself, it just provides another set of Cliff Notes. Like a calculator in math class. Just my opinion.
    Last edited by kloker; 04-05-2019 at 06:36 AM.
    Larry


    Now that I've learned my lesson, I'm supremely confident that next time I'll make a different mistake.


    2007 CR-V EX-L AWD Green Tea Metallic
    1991 Ford F250 Lariat Supercab LWB 4X4, 460 AT

  4. #23
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    Quote Originally Posted by Fibber2 View Post
    It's kind of funny, really, but I find that those that simply dismiss questions without offering any real help are usually those that CANNOT answer the question. Those that are asking an honest question are being gaslighted....

    In #9 (page 1) I described the basic architecture of the system and my surprise that it didn't perform better.

    To render an informed engineering opinion, I went back to Honda's own literature. As this is a Gen-4 page and the vehicle in the video is a Gen-4, letís dive into the Gen-4 fact book. Honda describes the system in use on the Gen-4 as Real Time AWD with Intelligent Control Systemô. They state that itís not as dynamic and advanced as the Intelligent Variable Torque Managementô (i-VTM4ô) system used on the larger vehicles, but this system works perfectly for small to midsize SUV models. Thatís your first tip-off to not expect miracles.

    The electronically controlled all-wheel-drive system replaces the previous-generation (Gen-3) CR-V's Real Time 4WDô, a hydraulically activated "dual-pump" system. Compared to the prior system, the electronically activated system offers a faster, more intuitive initial response when a loss of traction is detected.

    The capabilities of the system are prioritized to further support high fuel efficiency and all-around drivability on-road as well as off-road. Assisting the front wheels when it is beneficial, Real Time AWD instantly powers the rear wheels when starting from a stop, even on dry pavement, working in cooperation with Vehicle Stability Assist (VSA) and the new Motion-Adaptive Electric Power Steering (EPS). For comparison, the previous-generation Real Time 4WD was designed to allow the front wheels to slip a small degree before torque was transferred to the rear wheels and its primary benefit was at low speeds. Plus, it did not interact with VSA. The new Real Time AWD system can operate at all speeds when needed. The CR-V's all-wheel drive system's major components consist of the conventional front-wheel-drive system, a compact transfer case that distributes torque to a propeller shaft running the length of the vehicle, the rear differential, a new electronically-controlled hydraulic pump, a multi-plate clutch, and left and right rear-wheel driveshafts.


    So right off the bat, there's an expectation of some torque to the rears almost all the time, albeit pretty limited. You shouldn't have to wait for the fronts to spin before getting some benefit of AWD.

    The previous-generation Real Time 4WD system was mechanically actuated using a pair of hydraulic pumps (one driven by the front wheels and one driven by the rear wheels) along with a ball cam mechanism to operate the clutch that sent power to the rear wheels. If the front wheels began to turn faster than the rear wheels, as would be the case if they were spinning on snow or ice, the difference in pressure between the two pumps would cause the clutch to be engaged, sending power to the rear wheels. The ball cam mechanism was designed to help speed engagement. The system was designed to react to front wheelspin quickly and then send a portion of the vehicle's power to the rear wheels.

    Old system: front wheels spinning freely on zero traction surface (ice, or the rollers) should send torque to the rears. I also now understand the term "Dual Pump Fluid" on the quart bottles!

    The new Real Time AWD still uses a multi-plate clutch, similar to the clutches used in Honda automatic transmissions, to connect the propeller shaft to the rear differential. But in place of the twin hydraulic pumps and ball cam mechanism used previously, the system now uses an electric motor driving a single hydraulic pump, which operates the clutch. The electric motor is controlled by the Intelligent Control System, which means that the system can actively apportion power based on the conditions. The system doesn't merely react to front wheelspin; it minimizes wheelspin before it happens by sending power to the rear wheels accordingly.

    When starting on snow for example, the system sends power to the rear wheels right from the start, minimizing the potential for front wheelspin. The system can also detect when the CR-V is climbing a hill and send a greater amount of power to the rear wheels in cooperation with the newly added Hill Start Assist feature. Hill Start Assist maintains brake pressure briefly after the brake pedal is released, giving the driver time to accelerate and smoothly resume motion. The Intelligent Control System instantly assesses the road's slope angle using a G-sensor and the level of grip as detected by VSA in case of wheel spin, allowing added initial apportioning of torque to the rear wheels for smooth starts.


    New system: Proactive, not just reactive! It should respond faster and with the intelligence of using the VSA data and interaction to control wheel slip through active torque management. And it has a slope sensor! So we see a few things at play here. The combo of VSA and RT-AWD should have minimized free spinning of the front wheels by applying some brake force and apportioning torque to the rears. Why isnít that working?

    To answer some questions:

    1) Are the rears engaging at all? I think yes, based on the first roller test (F & R one side) where we see the rear wheel start to spin also after a small delay. Active management sends some torque to the rear, and eventually the VSA apportions some torque left to right, and the CR-V moves. So the basics of the system are sound where limited torque transfer is required.

    2) What happens when both front wheels spin, such as on a flat road where the fronts are on ice?

    a) The roller test is run flat, with very little slope. The G-sensor isnít detecting a hill, so torque to the rear is limited. You aren't likely to get all that's available.

    b) There isnít a whole lot of max torque available to the rears at best! How do we know that? Letís peak at the 2017 (Gen-5) data:

    The 2017 CR-V is offered with the updated Real Time AWD with Intelligent Control Systemô. Software and hardware upgrades result in an increase in engine torque (up to a total of 40-percent) that can be sent to the rear wheels, based on the driving conditions. The result is improved performance in low traction conditions when AWD comes into play. Elsewhere we read: For 2017, the maximum hydraulic pressure has been increased, resulting in a 57 percent increase in the available torque transfer to the rear axle.

    Interesting.... 40% absolute max, and increase of 57% over the Gen-4 system.... So whatís the MAX rear torque available on a Gen-4? Under 30% under ideal conditions. On basically flat ground with the G-sensor not engaged, itís probably down to 20%.

    And whatís the engine torque on a no-resistance roller set? Unless the VSA is in play to apply some resistance (keeps it in a lower gear and raises engine RPM), engine torque isnít great. So there isnít really much to send rearward to help it jump off the rollers.

    So maybe part of the question is why the VSA isnít helping more? I still think, even given the limitation of the system that it should have been able to muster sufficient torque transfer to leave the rollers.
    Thanks for showing the differences of between the systems of Gen 1-3 4WD and Gen 4 and later AWD.
    Basically the differeence between 4WD and AWD is this:
    4WD starts out with power to 2 wheels (2WD, FWD in this case) then adds power to the opposite set of wheels when needed.
    AWD starts out with power to all 4 wheels.

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  6. #24
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    Quote Originally Posted by kloker View Post
    It is funny, that you make that inference with no possible way to back it up, and then misuse a big word like gaslighting as a follow-up. By the way, what is a dishonest question?
    Fair enough! What I really don't like? Mean spirited people and rude replies....

    Look, I'm a moderator on other AutoGuide car boards. I handle things differently. You'll note that I ask very few questions. I research, and am usually the one ANSWERING questions.

    But I also know that many can't, or even if they had access to Japanese journals and patent databases would never understand what they read. To me, tech questions are better than Sudoku. If I don't want to respond, I leave it alone. If I find it interesting, I'll engage and yes, dive deep and do my homework to draw an informed response.

    I didn't like the answers to Mike and others, so I hit back on their behalf. I was on my last company's Automotive Council, and had resources at my fingertips. Plus conference discussions. It's great getting to have lunch with an engineering director at a major European mark to talk tech, and then be able to bring that to a chat board.

    To me, it's a question asked by someone who is perfectly capable of finding the answer on his own, but is not motivated enough to do the work, so he will ask you to do it for him. A perfect example of modern education. It's why we have whole generations of college graduates who cannot spell. My point being that, if he actually knew how to learn, he would not need to ask.

    Still, kudos on providing the turnkey information, which provides another redundant issue of it. Which doesn't demean you, or the information itself, it just provides another set of Cliff Notes. Like a calculator in math class. Just my opinion.
    Last edited by Fibber2; 04-05-2019 at 07:03 AM.
    2013 LX AWD (kids college car) Other vehicles past & present: 2014 & 2002 Subaru Outback, 2015 & 2008 Toyota Sienna, 2002 Honda Odyssey EX

  7. #25
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    Quote Originally Posted by kloker View Post
    ...
    To me, it's a question asked by someone who is perfectly capable of finding the answer on his own, but is not motivated enough to do the work, so he will ask you to do it for him. A perfect example of modern education. It's why we have whole generations of college graduates who cannot spell. My point being that, if he actually knew how to learn, he would not need to ask.
    ...
    The OP creates the thread and asks "why wasn't the power transferred to the rear?"
    Your reply:
    Quote Originally Posted by kloker View Post
    AWD is not the same as 4X4. Do your research.
    Some of us responded that there are other vehicles that pass this test that are not 4WD. I've owned several 4WD and AWD vehicles throughout my driving life, so I'm quite aware of the differences. Your reply came across as someone that may need to do some research.

    Fibber2 adds one of the best posts I've ever seen in this forum and you criticize him for it?

  8. #26
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    Quote Originally Posted by crveee View Post
    Thanks for showing the differences of between the systems of Gen 1-3 4WD and Gen 4 and later AWD.
    Basically the differeence between 4WD and AWD is this:
    4WD starts out with power to 2 wheels (2WD, FWD in this case) then adds power to the opposite set of wheels when needed.
    AWD starts out with power to all 4 wheels.
    In my opinion, a good AWD system puts out at least some power to all wheels all the time. The bias might be different depending on the 'intent' of the vehicle. Sporty tends to favor more to the rear. Pedestrian favors more to the front. But, the mark of a decent system is it's ability to rapidly respond to changing conditions and change the apportionment sufficiently to effect positive change. Helpless wheel spinning really shouldn't happen.
    2013 LX AWD (kids college car) Other vehicles past & present: 2014 & 2002 Subaru Outback, 2015 & 2008 Toyota Sienna, 2002 Honda Odyssey EX

  9. #27
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    This is such old news. This scenario played out a while back with another similar test. Honda basically said there will always some sort of grip and the scenario will never occur in real life (100% no grip on both front tires). Honda has a very conservative programming in their AWD. They updated the software and gave the crv back without their safe guards for overheating/excessive strain and it passed the test. Obviously you'd like it to pass the test anyway, but in every day driving etc which is what 100% will do in a CRV it will work and be more than adequate.

    End of story.

    Sent from my LG-H933 using Tapatalk

  10. #28
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    To me, this is much ado about little. All I know is that my 2016 CRV and previous 2001 AWD Escape would and will go where a FWD will not and I have never been stuck with either. I don't care how they go about it and I don't care. I have gotten my true 4X4 F-0150 stuck but it was where I would not have dared to take the CRV or Escape.

  11. #29
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    Quote Originally Posted by Fibber2 View Post
    No, it's not full time locked center differential 4WD. We get that. But the idea of AWD is that it should manage to engage the rear wheels when conditions call for it.

    On the Honda and Toyota systems, the vehicles are in FWD mode most of the time. The drive shaft to the rear spins, but it is not coupled to the differential itself until needed in the interest of fuel economy and wear. Wheel speed sensors and computer control should monitor front wheel slip and on demand engage the electromagnetic clutch to bring the rear wheels on line. Yes, there will be a delay, but it should eventually work!

    I find this result to be disappointing. Granted I'm used to the Subaru system, which like Audi does port some torque to the rears all the time in varying proportions via a transmission tail shaft clutch. Still, I bought my kid a CR-V believing that it would do what it's supposed to when needed.

    So what am I missing? How is this video false? What conditions would satisfy the computer monitoring system and engage the rear diffy clutch??
    I gotcha. Let me go back to page one with you and see if I can explain my response: The reason the test video is invalid is that the test bed does not give the CR-V's computer indication of slippage, which is why it doesn't engage. Wheel slippage is inconsistent, non-linear, and uneven. The computer takes data from all four wheels to determine when it exceeds the set parameters in terms of a recognizable pattern. The test bed does not provide those conditions in a way that convinces the computer. If it did, the system would activate. If you think of it in terms of ABS, this test bed would provide a similar result, because it would not provide data that would activate the ABS braking. So, my question to you would be this: How would you modify the test bed to make that happen? I can't say, but I'm not sure that particular arrangement could be. I would definitely be interested to hear your thoughts on that, and I'm sure we all would be.

    The reason I replied as I did back on page one was that I know that there are about a hunnert & eighty- seven bazillion YouTube videos that, instead of showing a questionable test bed, show the system working, in real world conditions, just fine. Which, to me, shows clearly that the test bed is inadequate to the job. Well, that plus the fact that this entire discussion was posted in another thread just a couple of months back, with the same information given, except for the video in this one.

    Fair enough! What I really don't like? Mean spirited people and rude replies....

    Look, I'm a moderator on other AutoGuide car boards. I handle things differently. You'll note that I ask very few questions. I research, and am usually the one ANSWERING questions.

    But I also know that many can't, or even if they had access to Japanese journals and patent databases would never understand what they read. To me, tech questions are better than Sudoku. If I don't want to respond, I leave it alone. If I find it interesting, I'll engage and yes, dive deep and do my homework to draw an informed response.

    I didn't like the answers to Mike and others, so I hit back on their behalf. I was on my last company's Automotive Council, and had resources at my fingertips. Plus conference discussions. It's great getting to have lunch with an engineering director at a major European mark to talk tech, and then be able to bring that to a chat board.
    My replies were not intended to be rude or mean, and I was not the only critic to voice my opinion. I was simply voicing my opinion that the poster would be well advised to learn more before he took the video at face value. But I will take your point that I could have been more diplomatic. As could you have also been in your reply to me. However, I am not unappreciative of your contribution to the thread, in fact the opposite is true, and I did specifically say that. I will also concede to a lack of patience and diplomatic ability that would make me a poor moderator. That comes from a lifetime of training folks in skills that could get them killed if they didn't get it right. So I kind of have a tendency to expect folks to use their heads for something besides a hat rack. But then I grew up in a world where that was expected of everyone, which is not the world we live in now. That said, this thread did develop into something beneficial, which is on you. So, thanks!
    Larry


    Now that I've learned my lesson, I'm supremely confident that next time I'll make a different mistake.


    2007 CR-V EX-L AWD Green Tea Metallic
    1991 Ford F250 Lariat Supercab LWB 4X4, 460 AT

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  13. #30
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    Quote Originally Posted by Mike728 View Post
    Some of us responded that there are other vehicles that pass this test that are not 4WD. I've owned several 4WD and AWD vehicles throughout my driving life, so I'm quite aware of the differences. Your reply came across as someone that may need to do some research.

    Fibber2 adds one of the best posts I've ever seen in this forum and you criticize him for it?
    I didn't say you weren't, and I also didn't criticize Fibber2's post.
    Larry


    Now that I've learned my lesson, I'm supremely confident that next time I'll make a different mistake.


    2007 CR-V EX-L AWD Green Tea Metallic
    1991 Ford F250 Lariat Supercab LWB 4X4, 460 AT

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