Is Stop-Start system costly on the long run?

wazza

Here is another one for you to go with the DPF topic i started here

Been looking at the Seat Altea range. Nice cars. They have a standard diesel version and a special version called ecomotive. The eco version has a stop-start system. Basically when you come to a stop at the traffic lights the engine switches off. When depressing clutch, engaging gear the engine starts automatically. Due to this the eco version shows improved fuel consumption and low emissions which means your road tax is free.

Was wondering the following..

1. when you start the car does it use more fuel (a rich mixture) like in the good old days when cars were fitted with carburattor?

2. more importantly how much strain will it put on the starter motor, especially if you do a lot of town driving? The cost of replacing the starter motor can wipe off the fuel/tax savings. True you can switch off the stop-start system and also components are supposed to be more reliable. Years back asked a taxi driver why they don't switch their engine off while waiting for customers, the reply was the cost of replacing the starter motor was more than the cost of fuel used. True they will also have loss of earnings.

What are your views?

Dave_Z

I think stop-start is a bit of a gimmick really. Certainly in my everyday driving i spend very little time sat at traffic lights. And you'd need to spend a long time sitting at lights to save any noticeable amount of money. Not least because many of the cars with this technology are already very efficient. If you had a massive V8 it might be worth something.

Pew_Pew_Pew_Lasers!

Stop-start engines are designed to stop the engine in a specific position, to make starting easier, so don't worry about the starter motor or fuel consumption.

It must be a worthwhile system as EU manufacturers are all beginning to use it. Hardly a surprise now that the EU wants to regulate the manufacturer's Co2 output, and not just the manufacturer's cars.

goldspanners

Pew_Pew_Pew_Lasers! wrote: »

Stop-start engines are designed to stop the engine in a specific position, to make starting easier, so don't worry about the starter motor or fuel consumption.

ive never heard of this before. how do they acheive this? i thought the engine would stop as normal at the same 2 positions all the time.

harveybobbles

...also what happens in winter if you have your heater on, heated seats, heated screen etc...? Will the extra load of firing all those up be false economy?

I personally can't see any benefit or point in the start/stop system...

vikingaero

goldspanners wrote: »

ive never heard of this before. how do they acheive this? i thought the engine would stop as normal at the same 2 positions all the time.

There's an optimal position for the engine to be restarted, so the engine aligns the pistons in that position. I've read about it but as a non-tech I can't explain it better than that!

johnnyroper

personally dont see the benefit of this system myself justa case of car makers being seen to do the right thing in terms of co2,i also think starter motor/ring gear wear will be increased along with increased stress on DMF in diesels.
as for engine position it stops while 1 piston is on the combustion stroke of cycle so it can start back up again without much turning of starter motor.

Mankysteve

If you think ahead and coast in gear upto lights and stopping modern engine ECU will pretty much cut out the fuel delivery all together.

johnnyroper

Mankysteve wrote: »

If you think ahead and coast in gear upto lights and stopping modern engine ECU will pretty much cut out the fuel delivery all together.

very true coasting in gear saves fuel over coasting in neutral as fuel injection is turned off.

wazza

johnnyroper wrote: »

very true coasting in gear saves fuel over coasting in neutral as fuel injection is turned off.

that is the practice is use :money:

Pew_Pew_Pew_Lasers!

vikingaero wrote: »

There's an optimal position for the engine to be restarted, so the engine aligns the pistons in that position. I've read about it but as a non-tech I can't explain it better than that!

Some have stronger starter motors, and power the belt-driven devices (AC etc) from an electric motor instead.

I can't see that its a bad thing tbh, particularly in urban areas where there is normally lots of standing traffic. Lower emissions has to be a good thing.