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Can the car engine stop and go be disabled?

Wirko said:
My experience with start/stop in my 2015 VW (manual transmission, diesel) has only been good. The battery is only one, it's bigger than in a petrol car but this is true for diesels in general. The engine starts instantly as it's already warm - I'd say in half a second or faster. It won't automatically stop when the engine is still cold or when the A/C works hard to cool the cabin. The car has 200,000 km on the odometer but it's been 90% on highways, therefore little city driving.
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It's definitely not annoying on highway and you don't really use it, and therefore the system will last longer than on cars that use it in city driving. I don't have it in my car, but when I drive the company's car, I'm always like: "What the f* happened, the engine stopped", and I look at the instrument table to look for any faults and then I realize that the Start/Stop is on after I press the clutch :P
 
AusWolf said:
Someone correct me if I'm wrong, but it's a diesel-only feature, right?

If you haven't bought the car, just look for a petrol (gasoline) version of it. Modern petrol engines are far more efficient than old ones, so you wouldn't be saving much with diesel anyway, unless you do long journeys on a regular basis.
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my dads car is also gasoline and has it.
 
Would refrain from anything diesel now, price wise you wont be happy. Diesel and petrol are at a similar price level already and that wont improve... Also, emission limitations in cities will some day bite you; possibly when you want to sell it off again.

Shrek said:
It's a bit later AFTER I bought the wrong car!
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Start stop is beneficial for emissions and waste of fuel from about 8 seconds of stationary onwards. Wouldnt worry, it is beneficial.
 
Vayra86 said:
Would refrain from anything diesel now, price wise you wont be happy. Diesel and petrol are at a similar price level already and that wont improve...
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But a diesel engine is more efficient.
 
Shrek said:
But a diesel engine is more efficient.
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Highway/open road use yes, city no. City driving is really bad for diesel engines.
 
Shrek said:
But a diesel engine is more efficient.
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This was true maybe 10 years ago, but petrol has come a long way. Even my sporty Fiesta ST can match some less efficient diesel engines in fuel economy at motorway speeds.
 
Night said:
Highway/open road use yes, city no. City driving is really bad for diesel engines.
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That was true decades ago. Not so much after the advances made in the late 1990's. Modern diesel engines are very efficient regardless of use-case-scenario.

AusWolf said:
This was true maybe 10 years ago, but petrol has come a long way. Even my sporty Fiesta ST can match some less efficient diesel engines in fuel economy at motorway speeds.
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This is also true, but not as much as you'd think.
 
trust me, you get used to it
 
Shrek said:
But a diesel engine is more efficient.
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Barely today. And it really depends where you drive too. For its efficiency you pay initially in extra engine/car prices, generally.

Diesel always only paid off at long distance/high mileage situation combined with a lower price per unit.
 
lexluthermiester said:
That was true decades ago. Not so much after the advances made in the late 1990's. Modern diesel engines are very efficient regardless of use-case-scenario.
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My Octavia II RS Facelift sees around 8-9L per 100 km ratio during city driving when there's heavy traffic. I get around 3.2-3.5L/100 km while driving 100 km/h on the open road. It's a 2.0 TDI. Yes, I would agree they're more efficient now, but there's more things to consider if you're using a diesel powered engine when driving mostly through city traffic. Diesel engines in cars were designed to be most efficient at highway/open road use, that efficiency drops down terribly when you're in city traffic. The most important part is that you're clogging the engine in general, that includes clogging the intake manifold, exhaust manifold, EGR valve(s), DPF system. You'll also get more ash in the engine oil, diesel engines prefer high exhaust gas movement. None of those repairs will be cheap if you decide to use a car with a diesel engine primarily for city use. Worst thing you can do to a diesel engine (for first ignition of the day) is driving just a few kilometers/miles while oil and antifreeze haven't reached working temperatures, and then turning it off. Do that a few times, and you'll be getting a DPF regeneration cycle in no time acompanied by soot buildup on the parts I already mentioned. Have fun completing that DPF regeneration cycle while in traffic :)

Gasoline engine with mild hybrid system ALL the way for city.
 
A well engineered S/S system should be invisible to the driver. Ours keeps all systems running, including cabin HEVC, while engune is not burning. If the cabin gets too warm, the engine kicks back on to run the compressor. Or, in winter, get the core temp back up.

Personally, diesel engines are good for extreme performance, and for me, high mpg is not a metric. 0-100, yes. 24k lb towing, yes. 20kw generator, yes.

And, mpg for diesel now doesnt consider the stupid premium price of the fuel. Almost doubke the price for 10% more mpg?
 
This feature saves a shit-ton of gasoline. I get that people don't like it, but if it works, it works.

I dunno, maybe get a PHEV / Hybrid vehicle next, that doesn't need to do the stop-and-go thing? ICE engines are least efficient at 500rpm or so. By stopping entirely and using an electric motor for that period (however brief), you cut out the least-efficient portion of your travels. Its kind of absurd how much gasoline this stupid trick saves, especially in stop-and-go traffic.

Hybrid/PHEV has enough "oomph" that the gasoline engine doesn't need to turn on (you use reserve battery power instead). So its a bit smoother in practice. But if you're a mild-hybrid / mostly-ICE car, you don't have large enough battery banks to do anything but basic stop-and-go every time. (These engines have a beefier starter, unlike the old Lead-acid batteries of yore. So these engines can be start-stopped safely and repeatedly. The extra battery-oomph also helps keep the air-conditioner running, radio, etc. etc. running when the engine shuts off. )
 
Pointless technology that introduces wear unless it's integrated with a hybrid system IMO.

AFAIK you can get a mechanic to modify or tune your ECU to change settings like this.
 
lexluthermiester said:
Most vehicles use very little fuel while at idle. It saves very little fuel in fact. All vehicles use most of the fuel for acceleration, maintaining speed and cruise operations. A very small fraction is used during moments at idle.
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A cold engine in -25C is not exactly effectient. And it's not really about saving fuel, it's about minimizing exhausts in cities, which probably is a good thing.
 
Modern cars are significantly over engineered, with way too much electronics, in order to offer "features" and provide 1-2% greater fuel efficiency. They could be a lot cheaper, more reliable and simpler to work on if they cut out BS like this feature. At the cost of what, 1-2% of efficiency? Combustion engines peaked in the early 2000s, and since then every advancement has been excuses to make the system more locked down and impossible to work on, forcing consumers to pay for OEM parts, IMO.

I drive a 2002 2.2L Renault Movano with 70,000 miles, zero issues, MOT and insurance is cheap, economy and power is great.

Ideal car = Solid state battery with 500 km + range, Skoda approach to electronics (minimal), Toyota approach to reliablility and Kia approach to cost.

If you're going to take this approach CDA, cylinder deactivation is superior.
 
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EV's also don't have S/S ;)

Press pedal, poof youre gone... whenever I step into an ICE now, I'm like 'jesus man, so much to do, so many buttons in the interior, wtf...'

I mean yes there is still the range problem, but in every other way... what an upgrade, damn.
 
lexluthermiester said:
Most vehicles use very little fuel while at idle. It saves very little fuel in fact. All vehicles use most of the fuel for acceleration, maintaining speed and cruise operations. A very small fraction is used during moments at idle.
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Break-even point is 10-seconds in this particular Department of Energy test. Any red-light that lasts longer than 10 seconds is better to have shut-off the engine rather than keep idling.

Start/stop is surprisingly "fine" for the engine. Most of the "costs" associated with startup is with regards to the "cold start" scenario (which is very bad for engine parts / other stuff). But because a 15-second start/stop or 30-second start/stop pattern has the engine remain the same temperature (indeed: engines remain warm for 30+ minutes), you're really not losing much with regards to "cold start" issues. The oil is still circulating through the engine, the parts are warm / hot and still functioning, etc. etc.

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I think that Hybrid/PHEV technology to simply not use gasoline below XXX RPM (probably 1000 RPM or so??) is a better idea of course. Full electric at the lowest RPM saves even more fuel and "subsumes" the start/stop methodology. Still, the science seems set, even for very small passenger cars, the ~10 second break-even point shows that start/stop is surprisingly a good strategy.
 
dragontamer5788 said:

Break-even point is 10-seconds in this particular Department of Energy test. Any red-light that lasts longer than 10 seconds is better to have shut-off the engine rather than keep idling.

Start/stop is surprisingly "fine" for the engine. Most of the "costs" associated with startup is with regards to the "cold start" scenario (which is very bad for engine parts / other stuff). But because a 15-second start/stop or 30-second start/stop pattern has the engine remain the same temperature (indeed: engines remain warm for 30+ minutes), you're really not losing much with regards to "cold start" issues. The oil is still circulating through the engine, the parts are warm / hot and still functioning, etc. etc.

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I think that Hybrid/PHEV technology to simply not use gasoline below XXX RPM (probably 1000 RPM or so??) is a better idea of course. Full electric at the lowest RPM saves even more fuel and "subsumes" the start/stop methodology. Still, the science seems set, even for very small passenger cars, the ~10 second break-even point shows that start/stop is surprisingly a good strategy.
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In that PDF, Table 1 & 2 tell the real story, their own numbers seem to tell a different tale. Also, that was just a 4 cylinder engine. Makes me wonder what the effect with 6 and 8 cylinder models might be.
 
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lexluthermiester said:
In that PDF, Table 1 & 2 tell the real story, their own number seem to tell a different tale. Also, that was just a 4 cylinder engine. Makes me wonder what the effect with 6 and 8 cylinder models might be.
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The first tests were done on larger vehicles, for some reason.

An Engine Start/Stop System for Improved Fuel Economy

During city traffic or heavily congested roads, a vehicle can consume a substantial amount of fuel idling when the vehicle is stopped. Due to regulation enforcement, auto manufacturers are developing systems to increase the mileage and reduce emissions. Turning off the engine at traffic lights and r
www.sae.org www.sae.org
In 2004, this system was designed for and integrated into a 2003 GMC Envoy and is capable of starting the vehicle's engine very quickly and quietly.
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Baseline vehicle fuel economy was measured for the OEM configuration and after installation of the start/stop system using standard chassis dynamometer fuel economy test procedures. This testing demonstrated 5.3% improvement in the city cycle and found approximately a 4.0% improvement in the highway drive cycle due to regenerative braking.
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I dunno what kind of engine a GMC Envoy is, but probably bigger than the 4-cylinder of the other test.
 
dragontamer5788 said:
I dunno what kind of engine a GMC Envoy is, but probably bigger than the 4-cylinder of the other test.
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It seems there were two variants, inline 6 and V8.
en.wikipedia.org

GMC Envoy - Wikipedia

en.wikipedia.org en.wikipedia.org

Good article BTW. It does highlight one of my other concerns with this technology, the electrical load on the battery.

dgianstefani said:
Modern cars are significantly over engineered, with way too much electronics, in order to offer "features" and provide 1-2% greater fuel efficiency. They could be a lot cheaper, more reliable and simpler to work on if they cut out BS like this feature.
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Could not agree more with this point!
 
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