Short journeys

It won't do the car any good at all.

However, hopping in it for a half mile drive also won't do it any good either.

The answer really is to not be such a lazy git and to walk.

You too, probably not deliberately (more's the pity), are missing most of the points being made.

You have a choice:

a) Continue to cause your engine more wear and tear than normal by making many short trips. b) Cause more wear and tear, and also waste more time by idling until the engine is warm and THEN making short trips. c) Use your car for less short trips.

Based on the information in your posts (c) is _probably_ the best choice, but certainly the least convenient. If it's impossible to do (c), then live with (a).

What you do is up to you. The advice you have been given, what ever aspersions it may cast on you, was mostly accurate.

What you think you asked is irrelevant. This is Usenet.

You came here appearing concerned about the excess wear that may be caused to your engine from making many very short trips. You proposed a solution that was likely to make things worse. We proposed an alternative solution that was likely to help.

You then got very defensive because that alternative solution was not something you liked. Either you feel guilty about being so lazy (whether through choice or not), or you are rather too easily offended to last long on Usenet.

It depends if the total losses are more one way than the other.

NiMH efficiency is not great, around 70% IIRC. This means that for every 1Kwh you put in, you get 700wh out. Add in say another 10% losses in the charger and discharger circuitry, and you've got around 60% of the energy you would have if you just connected the engine to the wheels.

The question is - which way does it burn more petrol, which isn't completely obvious, without rather a lot more study.

For a hybrid like this, the question is - at what points in the journey can the engine produce extra power with the least amount of extra fuel. This is likely to be at nearly full throttle, so a comparatively high speed commute might be a good candidate.

But, the engine is (IMO) unlikely to be 40% more efficient at 50MPH than at 25-30MPH, so it may not be an overall win. It's certainly not clear-cut either way.

And most people rightly questioned that if time is at such a premium, how you can afford the time to wait for the engine to warm up, but not the time to walk home to get the car if need be.

Ok, all other things aside - how old is the car, what car is it, how long were you hoping to keep it for, how many miles per year do you do in it, and how long have you had it so far? If you buy cars new or nearly new and trade them in just as the warranty expires then it's probably not going to be a major issue. It's also much less of an issue than it used to be, thanks to modern oils being really quite good, especially the fully synthetic ones. Also make sure you change the oil more often than the standard service interval (referred to in the handbook as 'extreme conditions') to keep things tip top, and don't worry too much. As long as you're relatively gentle on the short journeys then it shouldn't be a major issue - I'm guessing the majority of mileage will be done on longer journeys, will it?

Also, you could consider a diesel, as the fuel itself is a lubricant and protects the engine much better against wear on short journeys from cold starts. I think.

Twatting about walking the streets? It's a 5-10 minute walk at most. If you've got so little spare time in the day that that makes a serious dent in it, then you seriously need to think about your work/life balance, if you ask me.

And you got a lot of useful answers. Which you chose to ignore. The best advice was that if you're that concerned about engine longevity, that the best idea would be to do the short journey to work via other means.

Lol! just having a laugh.

I'm 20 stone and I can manage a 1 in 12 hill.

Yeah but this is usenet...

:p

The message from Conor contains these words:

Bloody lightweight.

Doesn't it use lead acid gel rather than NiMH?

Quite. Toyota have done their numbers on this, though.

Yes. The HSD Prius occasionally does strange things, like, changes what motor produces the power during a slight change of gradient, accelerator pedal use, or whatever. I don't pretend to understand it, of course not, other than it works (disclaimer: for me).

As you increase the load on the car, it uses both engines, type thing. Ascending the Grapevine on the freeway with cruise control at 70, four up, with luggage it drains the battery then slows down. ;)

Coming down it'll go for miles and miles on electrics only. Miles.

Efficiency isn't always the same as fuel consumption of course.

I think they use NiMH, which have higher capacity for a given weight and volume of batteries.

The car's computer works out for itself what it thinks the best thing to do is and stops and starts the engine as it sees fit. But what it has no way of knowing is that you're only travelling 400 yards and that in those circumstances, if the engine's cold and provided there's enough juice in the battery, it would be better for everyone not to start the engine. But I believe you can manually set it in "City Mode" as someone said for just that purpose.

But driving 6 miles from the freeway to your house at the end of a

Pass! Lithium Ion is an upgrade.

Yes, that was me.

In standard US specification it uses the petrol motor once your speed rises above ~20 mph, unless you add the City Mode (standard in the UK and European models), in which case it uses the battery more aggressively.

You've made my day.

OK - sad git can put your foot down but any trip under 5 miles is destroying your auto

I'm not entirely sure what you're on about.

I'd be surprised if anyone can find one. The steepest hill with a road on it that I can think of is near Crookes in Sheffield. Nab hill I think it's called, and that's probably a 1:3.

They're NiMH cells in the Prius. Lithium Ion is an upgrade until the batteries pack up after a couple of years...

Only make sure it has a basket, a bell that rings, and things that make it look good.

All the best, Angus Manwaring. (for e-mail remove ANTISPEM)

I need your memories for the Amiga Games Database: A collection of Amiga Game reviews by Amiga players

That's a lot steeper than 1:12 :-)