Windshield Wiper Weirdness
I own a 2000 Nissan Xterra. I just turned 100k miles on it and I still love it as a vehicle. It is a lot of fun to drive and has not given me much of any trouble. I plan on driving it for at least another 50k miles. There is one main feature that drives me nuts though. This is the variable windshield wiper setting. For some reason, Nissan decided to use a strange algorithm when choosing what values to use for each preset on the variable wiper control. The problem seems to be in the fact that there is such a jump between what we will call position 2 and 3. This can be seen when the wipe rate (wipes/min) is plotted for each setting:
The thing that appears when all of the speed settings are plotted together, is that the change in rate is neither linear nor logarithmic. It is more of a hybrid. This is not a problem on its own but when we look at there the transition occurs, we get a loss of sensitivity right at the spot where we need it (between 2 and 3). It is also interesting if we look at the wipe separation and the wipe duration.
We see that there is a very large change in wipe separation between 2 and 3. We also see that there is no change in wipe duration between 2 and 3. It seems that this change in wipe separation is what is most noticeable (and irritating) to me as a user.
One fix would be to add one more value (between 2 and 3) to the variable selector and to place it at 6 or so (I’m not too picky). Another solution would be to move settings 3, 2, and 1 (wrt separation) so that they have more of a logarithmic curve (without slowing setting 3 too much). Either way I’d be happy to have a setting that would be just right in mist or light snow conditions and a more logical transition between each setting.
6 Responses to “Windshield Wiper Weirdness”
Although the diligence you’ve applied to your analysis of wiper performance is very impressive, one would have to conclude that, overall, it has it’s flaws. The fact that you totally ignored the locomotive aspect of the system, the wiper motor, introduces some degree of question as to the validity of the statement that the algorithms applied by Nissan are suspect. The wiper motor, being a synchronous inductive device, is susceptible to any fluctuations in input voltages. These fluctuations may be due to a battery that has exceeded it’s useful life or an alternator that may not be performing up to output specification. Without a companion analysis of these crucial metrics, a believable determination on overall wiper performance, and the design criteria that went into it, is preposterous. The load imparted on the wiper motor “between 2 and 3” may be such that, with a degraded electrical system, the logical conclusion would be that the algorithms are suspect.
The bottom line is this: Do your homework kid and Good Luck at the U. Go Gophers!
Quite true; well played. I should have explained possible sources of error as well as ongoing experimental extensions to eliminate sources of potential error. I hope to soon conduct a study using a much larger sample size which should control for any outliers. As such, I did control for a degraded electrical system. Not long before the study, I replaced the battery and had a full independent electrical analysis conducted, so this should prevent any large confounding variables or lack of ecological validity. Again, your point is valid and extension studies will account for this.
Thanks, I can’t wait to start up. I think it’s going to be pretty dang fun. Although, I’m probably not going to have time for fun wiper studies like this!
This post is the greatest! I love it!
Thanks! I’ve found that there are certain things in the world that drive me crazy enough to do some extra analysis on. Then my geek side comes out in full force.
I’m mostly concerned with your use of the word “dang.” I refuse to believe that medical school is going to be “pretty dang fun.” I hope that in addition to teaching you everything you need to know to cut open someone’s skull that they give you guidance about proper ways to describe fun. :>
Sadly, I think my writing and speech will only become more unreadable and incoherent in medschool; given what I have seen so far.
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