Bosch introduces new start-stop system
At the Geneva Motor Show this week a number of car-makers, including BMW, Daihatsu, Lotus and others, either showed or talked about cars equipped with start-stop systems to help improve fuel economy and emissions. Basically, the idea of start-stop is give some of the benefit of a hybrid at minimal cost, by shutting off the internal combustion engine whenever the vehicle comes to a stop, and then re-starting as soon as the brake is released. The manufacturers of the systems that were displayed were Valeo and Bosch.
The Bosch system goes into production this month and will be installed on the updated BMW 1-series. The Bosch system basically consists of a beefed up starter motor, along with some electronic control that monitors, the accelerator, brake and clutch positions and the battery voltage. If the battery voltage is too low, the system disables, but otherwise functions to improve mileage up to eight percent in urban driving. Obviously highway driving will be unaffected, but that's not a bad improvement for a system that requires no other changes to the drive-train.
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[Source: Robert Bosch GmbH]
Reader Comments (Page 1 of 1)
Taymoor 1:46AM (4/07/2009)
Hi
I beleive this start stop need to go along with a Learning Mode which alows the ECU to control the engine stop with the feedback from drive cycle. For instance in rush hours with so many start stop the sophisticated system should recognize that it need not to stop the engine.
Maybe in some advanced version could be coupled with the GPS and with the feed back from the traffic load, could manage the start-Stop more efficiently with less damage to the engine and more benefit to the fuel economy and emission reduction.
Another point is that today cars are equiped with fuel economy indicators; why not use the same system to estimate/calculate the fuel economy over a period of a trip and decide if stoping the engine will benefit the total energy consumption in the specific driving cycle or should it be left running. This is also what can be combined with the above mentioned Learning Mode.
Taymoor
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raghu 4:49AM (8/18/2009)
Hi,
The Bosch start/Stop system will really reduce co2 emmisions & saves fuel but at the same time this system damages the engine in rush hours when the engine have to start and stop too many times. For this if the system is integrated with a safety switch, so that if the driver identifies as the vehicle has to stop & start too many times in rush hours & turns off the safety switch, then the start/stop system is disabled so now engine will run normally without much damage & battery life is not affected.
whenever there is not much traffic driver will turn on the safety switch & the start/stop system will work & saves fuel &reduce the co2 emmisions.
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pdx 11:51AM (3/08/2007)
Most of the damage to an engine happens at startup. These engines will have drastically shorter usable lifetimes unless they have re-engineered how oil gets to the cylinders, and I hope people using these engines use damn good oil...
Also, the batteries are going to take a significant hit, likely reducing their usable life - and at a minimum a gell cell battery will be required I would imagine.
So to make no other modifications to the powertrain, this seems like it might be one of those good in the short term, but in the long term does more damage than good.
However I am sure that if an engine was designed around this - then it could be better managed...
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Der Alte 3:36AM (3/09/2007)
For the last long while, BMW has cared nothing for the durability of their vehicles past the warranty period. So long as it makes it four years with no problems, that is all that matters. BMW realizes that most of their customers buy new every few years and trade up to a new Bimmer when the warranty expires. Building a car that is bullet proof beyond the warranty period doesn't make them any extra money. Mercedes has caved to this thinking too where marketing is king...engineers just have to design a car that performs well and impresses with no requirement as to whether engine or any other systems will only last 7 or 8 years. If it can get through the warranty period with little to no maintenance (as evidenced by BMW's insanely long oil change cycles that started when routine servicing became free during the warranty period), and be dolled up for the local dealer's CPO program to keep them happy, it benefits them nothing to see a car last longer than that. BMW and Mercedes can get away with this because their brands are now almost entirely based on image...a fashion statement essentially. My worry is that this line of thinking will only spread further througout the auto industry as time progresses. Cars are now largely disposable items. Longevity for some brands is certainly not the badge of honour it used to be.
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MikeW 5:14PM (3/09/2007)
The damage happens at cold starts, which is not happening here. (Thick oil, large bearing clearances)
The answer to the planned obsolescence, would be to have an electric motor spin the engine's own oil pump prior to startup in order to 'complete' the oil circuit.
This would preclude crankshaft gerotor oil pumps, and would require so sort of decoupling mechanism (thrust actuator integrated with the motor to allow the pump to spin free from the chain drive)
and if the starter is only a 2 kilowatts and runs only 0.5 second to restart the engine, that isn't very much energy drawn from the battery.
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SAM 9:10AM (8/14/2007)
Hello,
The Automatic Start/Stop in a way presented by BMW and also the High Precision Injection are already invented by Telcopol Ltd (in Finland) and they are subject to their IPRs (patents). For more information please see www.telcopol.com email: vazvan@telcopol.com . So it sounds ridiculous that now BMW claims to have developed such innovations. BMW first must obtain a license from Telcopol for infringing their IPRs!
SAM
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LUIZ CARLOS MORALES 5:47AM (11/10/2007)
The start-stop device is a dream of most of the people who cares about environmental protection since it can reduces CO2 emittions. My concern however is about how could it operate in rush hours when the engine have to star and stop too many times.
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