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Fiat 500 at CES 2008  (Source: DailyTech/Brandon Hill)
Bosch Start-Stop system reduces fuel consumption and emissions by 8%

Reducing emissions and improving fuel economy is a huge area of investment for many carmakers. Most people equate this type of technology with hybrid or electric vehicles, but Bosch has a system that helps improve fuel economy and reduce emissions on diesel and gasoline motors as well.

The system is called the Bosch Stop-Start System. Bosch and Fiat announced recently that the Fiat 500 would use the systems and Bosch went so far as to claim that 50% of European vehicles would have the Stop-Start system by 2012.

Bosch has been making the system since 2007 and reports it has already delivered 500,000 of the special starters to BMW and Mini. In the Fiat 500, Bosch says the Stop-Start system would be available with the Dualogic automated manual transmission and the 1.2-liter engine. Fiat does say it plans to install the system on other vehicles as early as 2009.

The Fiat 500 will also use a Bosch engine control unit including Bosch software that analyzes the sensor data to start and stop the engine of the vehicle. Stefan Asenkerschbaumer, president of Bosch Starter Motors and Generators division said, "In 2008, roughly five percent of all new vehicles in Europe are equipped with a start/stop system. By 2012, we estimate this will be every second newly registered vehicle—most of them with Bosch technology."

The Bosch Stop-Start system works by turning the motor of the vehicle off when the vehicle is stationary. An example is if a driver pulled up to a stop light, the Stop-Start system would turn the motor off while at rest. When the driver put a foot on the clutch pedal to put the car back in gear, the engine would start back up.

Bosch says that the system reduces fuel consumption and CO2 emissions in the urban component of the New European Driving Cycle (NEDC) by up to 8%. To ensure that the starter lasts with the significantly increased stop/start cycles, critical components of the special starter have been strengthened. Bosch says it increased the service life of starters used in the Stop-Start system compared to a normal starter. The bearings in the new starter were strengthened, the commutator is strengthened, and the planetary gear was improved as well.

The system has other components including control software, a battery sensor, crankshaft sensor, and sensors at the pedals. A high-efficiency alternator and a deep-cycle electric battery are part of the system.

A few specifics on the system remain unclear. For instance, presumably the system won’t function if the driver doesn't place the vehicle in neutral. Bosch isn't specific on that aspect of the system. Another concern is how long the vehicle will be able to remain with the engine cut off in high power usage scenarios like summer with the air conditioner running or in winter with the heater on.

Bosch doesn’t specify if the system would automatically restart the vehicle if it were still stationary if the battery started to get too low on power. Presumably, the system would restart so the driver won’t be left with a dead battery.

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and what about other wear components?
By tastyratz on 12/5/2008 11:12:11 AM , Rating: 4
If the engine is constantly being started your looking at additional wear. While as a whole the fuel consumption is lowered, the engine requires more fuel during crank (which while it hasn't started will wash the rings of their oil somewhat. Also the engine will see oil pressure drop off. over 90% of lubrication related wear is during startup. hot starts are NOT as bad as cold starts, but bad nonetheless. This also starts the engine immediately prior to a load requirement on the non properly oiled engine (when clutch is depressed and they want to accelerate off the line)

While their gas mileage will go up, they will certainly see an increase in main bearing and piston ring sales! Deep cycle or not they will also blow through batteries like they are going out of style.

If it activates when the clutch is depressed, how many people will not find the lag of the engine start acceptable?

RE: and what about other wear components?
By KernD on 12/5/2008 11:20:35 AM , Rating: 2
This is also a really bad idea for cold places where the first start after the night, or work day is already tough on the batteries. I know the engine won't cool down much, but still it's asking for trouble, your car will get cold while the engine is off.

RE: and what about other wear components?
By Solandri on 12/5/2008 5:02:11 PM , Rating: 5
Starts are only bad because the engine parts aren't fully lubricated (oil has dripped down). If the engine is off for about a minute at a red light, the oil won't have dripped significantly, and the start will generate no more wear and tear than keeping it running. Well, maybe the starter motor will get more of a workout, but I assume they account for that in the car's design.

Cold engines are a problem because they're operating at a temperature that's outside the engine's designed operating parameters. So they result in incomplete combustion and wasted fuel. Since the whole point of this is that it saves fuel, it would seem the cooldown at a red light is not enough to waste more fuel than it saves.

RE: and what about other wear components?
By wookie1 on 12/5/2008 6:07:17 PM , Rating: 4
I think you're forgetting about the parts that require oil pressure to keep oil in place, such as main bearings. Residual oil on the bearings without oil pressure is not that helpful due to the loads.

RE: and what about other wear components?
By Samus on 12/6/2008 10:29:58 PM , Rating: 2
I drove a Mini with this system last time I was in London and the start is reasonably efficient. It starts the engine back up in 180 degrese (half a crank cycle) which takes a few tenths of a second, faster than you depress the clutch pedal.

However, it was pretty cold there in November and I wasn't very satisfied with the lack of heat after 20 seconds of the engine being off...for example when I was waiting for a train or a long traffic signal. I also thought it was annoying the headlights dimmed considerably when the vehicle was off. I doubt my Mini had a deep cycle battery or efficient alternator like they are saying it should, because I wouldn't have noticed this otherwise.

On a side note, I was able to trick the system by keeping the car in gear and holding the clutch in. The engine would never turn off. I don't normally drive like this, though. I try to relax at a stop and sometimes even pull the parking brake just to give my feet a rest. London's a bitch to drive in.

RE: and what about other wear components?
By KernD on 12/7/2008 10:43:01 PM , Rating: 3
It's not only the oil that's thicker when it's cold. Here in Canada we get many days with less than -30 degree Celsius, at those temperature the battery itself is less powerful, so at a trafic light how will it do all you need AND restart the enigne. If you have a long way to go in the city, it will drain the battery, and your not talking about a mini's engine here, but a full size V4.

By Fireshade on 12/9/2008 6:50:32 AM , Rating: 3
That's why the Stop-start system has -amongst others- a battery-sensor that goes with some clever electronics logic. It is perfectly possible for Bosch to program measures in diverse situations. They have a solid reputation in low-level car-electronics (ignition, injection, ABS, etc.).

RE: and what about other wear components?
By trisct on 12/5/2008 11:33:12 AM , Rating: 2
Look at the type of car they are targeting - 1.2 liter engine subcompact cars. Those engines spin up in less than a second anyway if they're warm. The Bosch system will work similarly to the stop-start on something like a Toyota Prius, it will have access to battery voltage and engine temperature sensors to avoid low temperature starts and low battery voltage. Note also that they are selling this along with their engine controller system, which already has all that info.

As far as people wanting to accelerate off the line they usually don't wait until the light turns green to depress the clutch and put the car in gear, I would think.

RE: and what about other wear components?
By Souka on 12/5/08, Rating: -1
By 306maxi on 12/5/2008 12:39:16 PM , Rating: 5
Funny thing is when I am in gear at the lights in my car and I take my foot of the clutch my car goes forward too.....

Ultimately the person driving the car is responsible for what it does and the car reacts no differently in this way than a normal car with a manual transmission.

RE: and what about other wear components?
By bigboxes on 12/6/2008 12:03:51 AM , Rating: 2
Who puts their car in neutral at a light? I have an automatic, but in the past when I drove a manual I always left the clutch in and shifted into first after stopping.

RE: and what about other wear components?
By EricMartello on 12/6/2008 12:51:12 AM , Rating: 5
Why would you sit at a red light with your foot on the clutch, putting wear on the throw-out bearing? Leave it in neutral until the light is about to turn green - cleverly gauged by glancing at the perpendicular lights and waiting for them to turn yellow.

By feraltoad on 12/6/2008 9:53:32 PM , Rating: 3
I just start reading at red lights until people start honking and cheering for me to go. They're always so enthusiastic.

By Davelo on 12/7/2008 12:38:30 AM , Rating: 2
Yep. In Germany the light turns yellow just before turning green to tell drivers to put the car back in gear and get ready to go.

By jRaskell on 12/9/2008 12:34:48 PM , Rating: 3
I've driven several hundred thousands miles over the years with a number of vehicles I've owned, and never had a throw-bearing failure. I've also never talked to anybody who has personally experienced a throw-out bearing failure in their vehicle either.

The truth is, cycling any sort of metal spring is as fatiguing, if not moreso than just leaving it compressed for the brief periods of time we're talking about here.

Do you also heavily utilize engine braking in an effort to reduce wear on your brake system?

RE: and what about other wear components?
By walk2k on 12/5/2008 12:40:07 PM , Rating: 3
But how will the douches in riced-out Civics rev their engines at me??

By OAKside24 on 12/5/2008 11:02:48 PM , Rating: 3
By keeping clutch pressed, not shifting to neutral. Or when engine stop technology dominates the world by blaring their latest "engine rev simulation" track.

By FITCamaro on 12/5/2008 1:32:24 PM , Rating: 3
Well put. I don't think this would work well in a big engine either.

RE: and what about other wear components?
By TomZ on 12/5/2008 1:44:05 PM , Rating: 1
If the engine is constantly being started your looking at additional wear. While as a whole the fuel consumption is lowered, the engine requires ...

Do you think that Bosch hasn't considered all these kinds of design challenges? Maybe you could offer your consulting services to them, LOL.

RE: and what about other wear components?
By tastyratz on 12/5/2008 2:42:10 PM , Rating: 2
good point.
Someone invented it, clearly there will be no valid alternative opinions/considerations/arguments. Shame on me for questioning them with my feeble questions.

Did you see anything mentioned anywhere regarding things other than' the starter?
Its not going to cause an engine to wear through these expensive things in 5k miles - but it WILL significantly increase their need. The only way to resolve the oil pressure would be an oil accumulator with an electrically triggered solenoid based on TACH signal presence.

Combine that with the extra money for the starter and battery, plus new replacement schedule - I bet consumers really start seeing diminishing returns.

but who cares whats in a landfill if we save the earth with a little less oil?

RE: and what about other wear components?
By TomZ on 12/5/2008 3:04:39 PM , Rating: 3
My point is that Bosch is a company full of career experts who have worked on these types of automotive systems for decades. Heck, Bosch invented a lot of the technology that is commonly used in vehicles today. So I think they are probably aware of the challenges and how to overcome them.

Actually, if you Google around a bit, a lot of the issues brought up by posters here have already been addressed by Bosch in their design. They're just not reported in this DT article.

RE: and what about other wear components?
By Alexvrb on 12/5/2008 6:25:17 PM , Rating: 1
Yeah except Bosch isn't a car manufacturer. They don't care *that* much about the durability of the engines in question. They made a solution to boost fuel economy, fix its major and obvious issues (super beefy starter, sensors/controller, deep cycle battery that is also suited to constant starts) and leave it up to the manufacturers to figure out the "petty stuff".

Bosch profits from selling all these components. So in a way, as long as the components in the system aren't breaking prematurely, they benefit from selling them initially, and from selling eventual replacements. A lot of parts for German cars are expensive enough to begin with, I can't imagine how much that super starter of theirs is going to cost to replace.

By Darkskypoet on 12/6/2008 9:37:14 AM , Rating: 1
Yeah, and Bosch's largest customers are Car Manufacturers. So Yes, they do care about things like Engine Longevity... Because the car manufacturers that have been extending their power train warranties like crazy (now 100,000 miles / 160, 000 Km for Gm, and others) aren't going to want to induce expensive fleet wide engine problems. Such problems that would make their cars and brand look pretty bad.

And since this isn't a last night invention, either, I am sure they would have process, and we established design practices, that they would supply to the firms in question to minimize engine wear, etc. Bet you the little fiat engine got upgraded, or was a recent design, lately.

By walk2k on 12/5/2008 2:48:44 PM , Rating: 3
Yeah you better show them this blog, they maybe don't even know about engine wear!

ANYway I the problem with wear is that the oil settles in the pan. I wonder if they use some kind of oil pump to keep the oil flowing (and hot) while the engine is stopped in traffic.

RE: and what about other wear components?
By RoberTx on 12/6/2008 4:10:51 AM , Rating: 2
I work in industrial maintenance as an electronics tech and electrician. I'm not a big fan of Bosch electrical products. I'm not a big fan of any German electrical products. Germans can complicate the hell out of a simple concept.

By RoberTx on 12/6/2008 4:13:23 AM , Rating: 2
Indramat is even worse if not the worst.

By bugzrrad on 12/5/2008 1:47:05 PM , Rating: 2
By NovoRei on 12/6/2008 12:01:40 AM , Rating: 3
I already drove a car with start-stop.

Its at least 3 times faster than normal start-up. It dont work when the engine is cold.

By carl0ski on 12/6/2008 12:40:40 AM , Rating: 2
a pretty old fashion viewpoint.

This was always true with engines however there are lots of marketing gimmick advances in Oil viscosity and magnetic oils that delay the rate of oil drip into the sump.

My only concern would be the initial drain on the battery of restarting an engine but that is probably what this bosch tool resolves, maybe large capacitor is constantly used in restarts opposed to drain on the battery?
but hell look at the engines this is being implemented with
1.8 litre fiat probably turnover that a dozen times on one battery

RE: and what about other wear components?
By Screwballl on 12/6/2008 9:45:17 AM , Rating: 2
2 points:

additional wear

agreed, that is something I suspect they are looking into, with newer systems and a small block like this, I would assume a sort of hybrid system would be a bit more useful that the explained start-stop system. Use battery powered motors up to a certain speed then kick on the engine. A hybrid drive system similar to the Prius. Which takes me to the second point:

2) I suspect this is something that may do decent but nowhere close to the 50% they stated. Maybe 5%... People are getting lazier all the time with all these extra gadgets and radios and cell phones and whatever else, which is why it is almost impossible to find a manual/stick shift in any American vehicle sold since 2000. Sure there are a few and almost always a sports car, but not normal every day vehicles. I remember when the mileage standards always had 2 sets, one for automatic, and another for the manual which was always 2-5 mpg higher in the city.

I see this as a product doomed to "also ran" status in a few years (by 2012). People are getting used to automated systems, by 2012 we will be that much closer to cars that drive themselves.

By Screwballl on 12/6/2008 10:23:46 AM , Rating: 2
bah lack of edit sucks...

the point in #1 was meant to say something like using battery power in 1st gear and then when it it put into 2nd the engine starts.

By 16nm on 12/9/2008 1:38:51 PM , Rating: 2
It sounds like you are saying the engineers have some design challenges before them. They better get cracking!

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