How come our cars don't come with a tachometer

No tach since you don't have any direct control: you can't shift, can't over rev, can't even control when the ICE runs.

Tom

 

Some of us use CAN-View to see the ICE RPM among other things...

<div class='quotetop'>QUOTE(qbee42 @ May 5 2006, 07:10 PM) [snapback]250515[/snapback]</div>

Actually, we do have control over ICE rev, the "gas" pedal.

 

<div class='quotetop'>QUOTE(ScottY @ May 5 2006, 04:14 PM) [snapback]250516[/snapback]</div>

Technically, because it's throttle-by-wire (and computer), the ICE revs only when it wants. Good thing it mostly matches what we want when we push that pedal, but sometimes there could be a very slight lag. Nothing new, as there's many cars now with throttle-by-wire.

 

Having a tach is actually really important for good mileage. See
http://techno-fandom.org/~hobbit/cars/prius-curves.gif and by
looking back and forth between the two plots you can see that kW
output maps rather linearly to RPM, and thus that you need to get
up around 1400-1500 rpm before you're decently loading the engine
and making it run efficiently. The whole principle behind pulse &
glide is to run the engine efficiently, or not at all, and a tach
is one very basic piece of instrumentation that helps you see it.
.
Toyota really dropped the ball on that one.
.
_H*

 

<div class='quotetop'>QUOTE(hobbit @ May 5 2006, 08:19 PM) [snapback]250624[/snapback]</div>

I agree about Toyota dropping the ball as far as I am concerned but I think that they did not want to over stress the average driver with too many details. I think that they want us to just drive it. They may have over looked the possibility that there just may be a segment of propeller head geeks who have to push the technology to the edge. Thanks to Norm for helping us scratch that itch!

 

<div class='quotetop'>QUOTE(hobbit @ May 5 2006, 11:19 PM) [snapback]250624[/snapback]</div>

I'd rather have a temp gauge. By the time a red overheat light comes on it's to late to do anything to avoid the problem.

 

<div class='quotetop'>QUOTE(jburns @ May 5 2006, 08:29 PM) [snapback]250630[/snapback]</div>

You can have that too with the CAN View.

 

The Lexus hybrids have a kW meter, the 600h has an RPM gauge actually...

 

I've never understood why conventional cars with automatic transmissions have tachometers.

 

Got a temp gauge.
http://techno-fandom.org/~hobbit/cars/ect/
which is also useful for telling me when I'll be able to get
into stage 4 or not [above 70 degC].
.
There are multiple answers -- CANView is the more "purist" approach,
possibly, doing everything in the digital universe with a single
connection to the car, but the direct-reading analog methodology
is also perfectly valid and in some cases it might be useful to
take an end-run around the computers. I'll probably go for a
CAN-view myself at some point too.
.
_H*

 

Why does CAN-view not work (according to their website) with the 2006 Prius?

 

<div class='quotetop'>QUOTE(larkinmj @ May 6 2006, 11:56 AM) [snapback]250739[/snapback]</div>

The 04/05 MFD is lower resolution and uses analog I/O (from what i read). The 06 MFD is higher resolution and uses digital I/O.

 

<div class='quotetop'>QUOTE(ScottY @ May 6 2006, 09:06 AM) [snapback]250743[/snapback]</div>

There's that, and the fact that some 2006 models appear to have the appearance of the older MFD, but with the newer digital I/O. The can-view guy is trying to sort this out. The most recent guess was the new digital I/O with older graphic software.

In any event, he's working on it.

 

<div class='quotetop'>QUOTE(asaulo1 @ May 5 2006, 04:44 PM) [snapback]250455[/snapback]</div>

The aproach of Toyota of not providing panel instrumentation in our cars is merely an incentive to "developers" like Norm D. (EFLIER) to brain storm his life and provide us with a user friendly CANview equipment and complement the techie side of us in our cars. [you] should have order one already

 

Huh? What'd I miss??

 

<div class='quotetop'>QUOTE(Florida Prius @ May 7 2006, 09:47 PM) [snapback]251244[/snapback]</div>

Umm I must have missed some thing too....??? :huh: :blink:

Lets see the Prius has a CVT transmission and no way to shift gears in a conventional way.. :huh:

There really isn't a need for a Tach, muchless a place to put one..

Hey guys watch this Im going to power shift my Prius from B to D.. :lol:


CVT what a concept B) !

Hmm Im just going to leave my 04 stock if any red idiot lights come on just shut down the car and call a tow.
The Can-View is more of a techie thing... Im not that techie.

 

<div class='quotetop'>QUOTE(priusguy04 @ May 7 2006, 10:17 PM) [snapback]251251[/snapback]</div>

Sorry for the late response I've been out of town. I agree a tach is less than important especially on a Prius but a temp gauge can save you a lot of trouble. I can give an example from more years ago than I care to admit. I was driving through the Mojave Desert with temps well above 100F. About 2/3s of the way up a long hill I noticed the temp gauge beginning to move into the red. Off went the air conditioner and up went the heat setting to maximum thereby dumping about 2 quarts of relatively cool uncirculated water from the heater core into the engine. The gauge steadied and then dropped a bit before reaching the top of the hill. A gauge can come in handy now and then.

 

<div class='quotetop'>QUOTE(jburns @ May 13 2006, 11:15 PM) [snapback]255074[/snapback]</div>

Been there done that in Prius. You can leave the A/C on and the heater off. Ain't no thang. In other words, the ICE coolant system is correctly sized for the heat it may be called upon to shed.

However, there would be a value in knowing the maximum HV battery temperature. If if approaches 45 oC, good time to turn ON the A/C, or take a break. For HV battery longevity, avoid higher temperatures.

Our MG1s may get kinda hot under heavy load (hotter than anything else in the vicinity, it seems), but I cannot tell you what temp is too high. But next time that I get to 105 oC, I'm pulling off the road.

Engine oil pressure is rather poorly informed by the warning light. This is an area where no CANview or miniscanner can help us, unless an additional pressure transducer is installed. And it's too bad because a couple of Prius have already died that way.

But ICE rpm? Entertaining sometimes, but not critical to know. Hobbit says to accelerate at 1400 rpm, at least for efficiency, and I'm sure he's right. I would say accelerate so that you can at least hear the engine running. It's about the same thing, or close enough for us duffers.

In summary I think that there are two important operating parameters that we *can* see in Prius, and one missing. There may be others important as well. If a tachometer thread is not the right place to discuss those, I'll follow you to a new thread.

 

<div class='quotetop'>QUOTE(hdrygas @ May 5 2006, 10:32 PM) [snapback]250631[/snapback]</div>

I would like a more accurate fuel gauge- something more than 10 little blocks that disappear.