OT: Why do cars have Tachometers?

The Natural Philosopher formulated the question :

Likewise here too.

Scott pretended :

A voltmeter serves that function since alternators began to be installed and I have one built in the dash, accessible via a button.

Any driver who does not know when the engine is about to explode should not be behind the wheel of any motorised vehicle in my opinion.

Nah turbo boost pressure guage much more useful

To tell you your turbo has blown? Nah. You know that from the black smoke...

How does a voltmeter tell you if the fault is with the alternator or the battery?

For a 1.2 litre Micra, 11 years old, I think I can tell by sound whether I am in the right gear. I can't say I have ever looked at the tachometer other than out of curiosity.

Voltage too high (as in >14.5v) - faulty alternator (suspect regulator). Voltage too low+engine running - suspect no charge from alternator Voltage too low+engine stopped - suspect battery discharged/faulty Voltage nominal, and then goes low after cranking - suspect battery

Personally I would spend the money on a multimeter which can be used anywhere, rather than on a panel voltmeter which might get used in anger once in a decade.

I think the IC engines in hybrids still drive the wheels directly when in use. They aren't like diesel electric trains. There's a combined electric motor/generator that charges the battery (including regenerative braking), drives the wheels and acts as a starter motor. Of course, designs may vary. I don't know what they do for variable gearing.

I suppose you want an oil pressure gauge too.

Well certainly not myself as I was never able to drive for obvious reasons. However, I wonder what sort of abuses are going on with electric cars these days? Brian

Understandable. Doing sixty in top gear will sound like it's being thrashed.

No, the engine goes via the planetary box, so they can add a bit of electric motor power or subtract some power for battery charging, while driving the wheels.

Thanks.

More useful than a tachometer though :-)

I'd need two voltmeters on my car. One with a range about 0-20V. The other about 0-1000V.

Not sure I'd learn anything from either.

The point is whether the speed of the IC engine is controlled by the driver or the software.

It would be more useful than a tachometer, given the choice. However, there is a dipstick. Apparently you can buy longer ones if it cannot reach the oil. .

I'm not so sure about basic spec vehicles having them, they seem to be a 'feature' (I'm not saying one many use but certainly they are listed as a feature).

Our Smart Car has one but it is in a 'pod' and I suspect a more basic one (ours is a mid range one) would have the pods, not least as the pods are in pairs, the other pod being a clock- there is already a digital clock on the dashboard.

Our hybrid lacks one, the space being used by a dial which displays the 'balance' between electric and petrol engine being used and if the battery is being charged by regenerative braking.

Our diesel motorhome has one, it is a bit of overkill as the dash also has a gizmo to indicate when to change gear up or down. The previous one (same make but an earlier model) lacked the gizmo although anyone used to driving should know when to change up/down etc.