Stop Start Technology
Discussion
I've posted this a few times before, on other Stop/start threads, but I'll tell you what I can about the system I know....
Stop start works by stopping the engine at one of 2 crankshaft postions - Either Cylinder 1 or cylinder 4 at TDC firing Thus holding engine compression. The PCM assists this by adding additional alternator load to stop the engine at the right point.
For this to occur, the engine must be up to normal operating temperature, the vehicle stationary, in neutral, with the clutch pedal released.
When restarting (i.e. when the clutch pedal is depressed) the PCM runs the starter motor just enough to generate engine rotation, injects fuel anto the relevant cylider and fires the spark plug, leading to combustion taking place. In the system which I know most about (which happens to have the quickest restart time of any system) restart takes less than 0.2 second - Less time than it takes to get the car into gear.
There are a number of conditions that must also be met for SS to occur.
Batteries fully charged (there is a main battery for normal engine operation, and sub battery only used for SS operation)
Low demand on the heating system
Low (ish) electrical demand
Engine fully up to temperature
The vehicle is not moving
No doors are open
Vehicle in neutral
Clutch pedal released
If the AC/heater demand is high, the vehicle will automatically restart
If the electrical demand is high, the vehicle will automatically restart
If the vehicle speed increases (i.e it rolls forwards of backwards) the vehicle will automatically restart
If a door/the bonnet/boot is opened, it will cancel automatic restart
If the ignition is cycled off, SS is cancelled
If the steering wheel is turned, it will automatically restart
In all cases of auto restart, the SS warning light flases for 3 seconds to warn the driver that restart is going to occur
In relation to the electrical system, the vehicle runs two different batteries - This leads to a problem with charging, as putting the same charging current into both would kill the smallest battery very quickly. As a result, the system uses a charging system similar to a caravan split charge system - By monitoring sub battery charge status and temperature, it can cut the charging to the sub battery when it is either fully charged or too hot, this prolongs the life of the sub battery.
As the starter is only being used for a very short time period, there should be no excessive wear to it (Although after a given number of cycles, it has to be repaced (This is equivalent to about 25,000 SS cycles though, which is estimated to be around 200,000 miles)
The system is actually very clever, and ultimately, more and more manufacturer are going to be fitting SS systems to mainstream production vehicles in the near future as a way of reducing getting around the ever more strict Euro emission legislation, it's even likely that diesels will be getting it some time soon too.
The system I work with has so far been pretty much bullet proof with no reported falures of any parts of teh system - And if you don't like it, all systems have an overide button to switch the SS system off (although everytime you restart the car, the default setting is on, so it has to be switched off on eery drive cycle)
Stop start works by stopping the engine at one of 2 crankshaft postions - Either Cylinder 1 or cylinder 4 at TDC firing Thus holding engine compression. The PCM assists this by adding additional alternator load to stop the engine at the right point.
For this to occur, the engine must be up to normal operating temperature, the vehicle stationary, in neutral, with the clutch pedal released.
When restarting (i.e. when the clutch pedal is depressed) the PCM runs the starter motor just enough to generate engine rotation, injects fuel anto the relevant cylider and fires the spark plug, leading to combustion taking place. In the system which I know most about (which happens to have the quickest restart time of any system) restart takes less than 0.2 second - Less time than it takes to get the car into gear.
There are a number of conditions that must also be met for SS to occur.
Batteries fully charged (there is a main battery for normal engine operation, and sub battery only used for SS operation)
Low demand on the heating system
Low (ish) electrical demand
Engine fully up to temperature
The vehicle is not moving
No doors are open
Vehicle in neutral
Clutch pedal released
If the AC/heater demand is high, the vehicle will automatically restart
If the electrical demand is high, the vehicle will automatically restart
If the vehicle speed increases (i.e it rolls forwards of backwards) the vehicle will automatically restart
If a door/the bonnet/boot is opened, it will cancel automatic restart
If the ignition is cycled off, SS is cancelled
If the steering wheel is turned, it will automatically restart
In all cases of auto restart, the SS warning light flases for 3 seconds to warn the driver that restart is going to occur
In relation to the electrical system, the vehicle runs two different batteries - This leads to a problem with charging, as putting the same charging current into both would kill the smallest battery very quickly. As a result, the system uses a charging system similar to a caravan split charge system - By monitoring sub battery charge status and temperature, it can cut the charging to the sub battery when it is either fully charged or too hot, this prolongs the life of the sub battery.
As the starter is only being used for a very short time period, there should be no excessive wear to it (Although after a given number of cycles, it has to be repaced (This is equivalent to about 25,000 SS cycles though, which is estimated to be around 200,000 miles)
The system is actually very clever, and ultimately, more and more manufacturer are going to be fitting SS systems to mainstream production vehicles in the near future as a way of reducing getting around the ever more strict Euro emission legislation, it's even likely that diesels will be getting it some time soon too.
The system I work with has so far been pretty much bullet proof with no reported falures of any parts of teh system - And if you don't like it, all systems have an overide button to switch the SS system off (although everytime you restart the car, the default setting is on, so it has to be switched off on eery drive cycle)
RESSE said:
Back in 1986 in I had a VW Polo Formel E (1300cc/B registration), and it had a switch on the dashboard, and when said switch was engaged the engine would cut out if you were:
1. Stationary for more than x seconds.
2. In Neutral.
Novelty back then, or can anyone give details of other cars with this OEM supplied bit of kit?
BL/Austin Rover had a similar sytem in use at about the same time on the Meastro - Unsuprisingly, it wasn't very reliable!!1. Stationary for more than x seconds.
2. In Neutral.
Novelty back then, or can anyone give details of other cars with this OEM supplied bit of kit?
Superhoop said:
it's even likely that diesels will be getting it some time soon too.
VW based Diesels already have it. My old man's Passat TDI has stop start, as does my next door neighbours Seat Leon.I even know of a Passat TDI Auto which has stop start.
Also, in these, it is possible to switch it off permanantly.
AndrewTait said:
Superhoop said:
it's even likely that diesels will be getting it some time soon too.
VW based Diesels already have it. My old man's Passat TDI has stop start, as does my next door neighbours Seat Leon.I even know of a Passat TDI Auto which has stop start.
Also, in these, it is possible to switch it off permanantly.
The best thing about them, if you press the "cancel" stop start button while the engine is stopped, it doesn't restart automatically. Great fun when it's your mates car and the button is in the centre of the dash, and easy to press without notice at a set of traffic lights
jon- said:
AndrewTait said:
Superhoop said:
it's even likely that diesels will be getting it some time soon too.
VW based Diesels already have it. My old man's Passat TDI has stop start, as does my next door neighbours Seat Leon.I even know of a Passat TDI Auto which has stop start.
Also, in these, it is possible to switch it off permanantly.
The best thing about them, if you press the "cancel" stop start button while the engine is stopped, it doesn't restart automatically. Great fun when it's your mates car and the button is in the centre of the dash, and easy to press without notice at a set of traffic lights
I have stop start in my Bluemotion Golf. I've also found that the stop start doesn't work if you've just reversed. It also seems to have maximum time that the stop start keeps the engine "off" before automatically switching the engine back on.
1. Starting a car doesn't cause engine wear, it's driving the car on cold oil that causes engine wear. It'll drain the battery, but as far as I know stop/start cars use different batteries to counter-act this. Naturally, it'll wear the starter motor too, but I'm sure they design them to cope in a stop/start car.
2. As mentioned above, this technology is a configurable option on many cars. For example, my parents have it on their car and my Mum, for whatever reason, doesn't like it, so she has it switched off and my Dad has it switched on. It may even do this automatically on their keys along with the climate control temperature, seat, mirrors, radio presets etc.
3. I've always got frustrated in traffic queues, especially on hot days, where everyone sits with their engines running pumping fumes around everywhere and making a load of unecessary noise. I was stuck for two hours in Preston the other week and wanted to sit quietly and read a book - for the whole two hours the cars around me had their engines running and radiator fans roaring. It would have been nicer to sit in silence! Equally, the idiot who sits outside my house for ten minutes every morning with his rattly diesel engine running wakes me up every day!
4. Regarding this:
No it doesn't. It depends on the car. Some cars even need their Sat Nav destination re-entering after a stop/start.
2. As mentioned above, this technology is a configurable option on many cars. For example, my parents have it on their car and my Mum, for whatever reason, doesn't like it, so she has it switched off and my Dad has it switched on. It may even do this automatically on their keys along with the climate control temperature, seat, mirrors, radio presets etc.
3. I've always got frustrated in traffic queues, especially on hot days, where everyone sits with their engines running pumping fumes around everywhere and making a load of unecessary noise. I was stuck for two hours in Preston the other week and wanted to sit quietly and read a book - for the whole two hours the cars around me had their engines running and radiator fans roaring. It would have been nicer to sit in silence! Equally, the idiot who sits outside my house for ten minutes every morning with his rattly diesel engine running wakes me up every day!
4. Regarding this:
PSBuckshot said:
HellDiver said:
PSBuckshot said:
I never understood why people like this.
It isn't much hassle to use the strange, key shaped device that turns.
Because turning off the key makes the radio, the heater fan, the lights, etc, etc all stop working.It isn't much hassle to use the strange, key shaped device that turns.
jon- said:
The best thing about them, if you press the "cancel" stop start button while the engine is stopped, it doesn't restart automatically. Great fun when it's your mates car and the button is in the centre of the dash, and easy to press without notice at a set of traffic lights
Yes, fantastic fun for the drivers held up behind the car too I imagine.From what I've experienced over the years at junctions, roundabouts etc., old people seem to have been (unwittingly) employing this system in all manner of cars for several decades.
Edited by LotusOmega375D on Monday 17th October 13:39
Edited by LotusOmega375D on Monday 17th October 14:40
jesta1865 said:
Justayellowbadge said:
I've always considered stop and start technology to be a minimum requirement in a car.
subtle very subtle.i have always wondered about the wear on a turbo on one of these engines, i was always told to wait 10 - 15 seconds at idle when i stop in a turbo car to let it slow right down before it loses oil pressure.
is the oil now kept up to pressure by an electric pump or has turbo technology moved on loads?
Superhoop said:
I've posted this a few times before, on other Stop/start threads, but I'll tell you what I can about the system I know....
Stop start works by stopping the engine at one of 2 crankshaft postions - Either Cylinder 1 or cylinder 4 at TDC firing Thus holding engine compression. The PCM assists this by adding additional alternator load to stop the engine at the right point.
For this to occur, the engine must be up to normal operating temperature, the vehicle stationary, in neutral, with the clutch pedal released.
When restarting (i.e. when the clutch pedal is depressed) the PCM runs the starter motor just enough to generate engine rotation, injects fuel anto the relevant cylider and fires the spark plug, leading to combustion taking place. In the system which I know most about (which happens to have the quickest restart time of any system) restart takes less than 0.2 second - Less time than it takes to get the car into gear.
There are a number of conditions that must also be met for SS to occur.
Batteries fully charged (there is a main battery for normal engine operation, and sub battery only used for SS operation)
Low demand on the heating system
Low (ish) electrical demand
Engine fully up to temperature
The vehicle is not moving
No doors are open
Vehicle in neutral
Clutch pedal released
If the AC/heater demand is high, the vehicle will automatically restart
If the electrical demand is high, the vehicle will automatically restart
If the vehicle speed increases (i.e it rolls forwards of backwards) the vehicle will automatically restart
If a door/the bonnet/boot is opened, it will cancel automatic restart
If the ignition is cycled off, SS is cancelled
If the steering wheel is turned, it will automatically restart
In all cases of auto restart, the SS warning light flases for 3 seconds to warn the driver that restart is going to occur
In relation to the electrical system, the vehicle runs two different batteries - This leads to a problem with charging, as putting the same charging current into both would kill the smallest battery very quickly. As a result, the system uses a charging system similar to a caravan split charge system - By monitoring sub battery charge status and temperature, it can cut the charging to the sub battery when it is either fully charged or too hot, this prolongs the life of the sub battery.
As the starter is only being used for a very short time period, there should be no excessive wear to it (Although after a given number of cycles, it has to be repaced (This is equivalent to about 25,000 SS cycles though, which is estimated to be around 200,000 miles)
The system is actually very clever, and ultimately, more and more manufacturer are going to be fitting SS systems to mainstream production vehicles in the near future as a way of reducing getting around the ever more strict Euro emission legislation, it's even likely that diesels will be getting it some time soon too.
The system I work with has so far been pretty much bullet proof with no reported falures of any parts of teh system - And if you don't like it, all systems have an overide button to switch the SS system off (although everytime you restart the car, the default setting is on, so it has to be switched off on eery drive cycle)
Apologies for the bump. I have a question to which I am unable to find an answer elsewhere.Stop start works by stopping the engine at one of 2 crankshaft postions - Either Cylinder 1 or cylinder 4 at TDC firing Thus holding engine compression. The PCM assists this by adding additional alternator load to stop the engine at the right point.
For this to occur, the engine must be up to normal operating temperature, the vehicle stationary, in neutral, with the clutch pedal released.
When restarting (i.e. when the clutch pedal is depressed) the PCM runs the starter motor just enough to generate engine rotation, injects fuel anto the relevant cylider and fires the spark plug, leading to combustion taking place. In the system which I know most about (which happens to have the quickest restart time of any system) restart takes less than 0.2 second - Less time than it takes to get the car into gear.
There are a number of conditions that must also be met for SS to occur.
Batteries fully charged (there is a main battery for normal engine operation, and sub battery only used for SS operation)
Low demand on the heating system
Low (ish) electrical demand
Engine fully up to temperature
The vehicle is not moving
No doors are open
Vehicle in neutral
Clutch pedal released
If the AC/heater demand is high, the vehicle will automatically restart
If the electrical demand is high, the vehicle will automatically restart
If the vehicle speed increases (i.e it rolls forwards of backwards) the vehicle will automatically restart
If a door/the bonnet/boot is opened, it will cancel automatic restart
If the ignition is cycled off, SS is cancelled
If the steering wheel is turned, it will automatically restart
In all cases of auto restart, the SS warning light flases for 3 seconds to warn the driver that restart is going to occur
In relation to the electrical system, the vehicle runs two different batteries - This leads to a problem with charging, as putting the same charging current into both would kill the smallest battery very quickly. As a result, the system uses a charging system similar to a caravan split charge system - By monitoring sub battery charge status and temperature, it can cut the charging to the sub battery when it is either fully charged or too hot, this prolongs the life of the sub battery.
As the starter is only being used for a very short time period, there should be no excessive wear to it (Although after a given number of cycles, it has to be repaced (This is equivalent to about 25,000 SS cycles though, which is estimated to be around 200,000 miles)
The system is actually very clever, and ultimately, more and more manufacturer are going to be fitting SS systems to mainstream production vehicles in the near future as a way of reducing getting around the ever more strict Euro emission legislation, it's even likely that diesels will be getting it some time soon too.
The system I work with has so far been pretty much bullet proof with no reported falures of any parts of teh system - And if you don't like it, all systems have an overide button to switch the SS system off (although everytime you restart the car, the default setting is on, so it has to be switched off on eery drive cycle)
Mrs NO has a 2015 Mini auto with Stop/Start.
It works as intended but she had asked what happens if the car is involved in an accident when stationary? EG waiting at a zebra crossing with her foot on the brake, Stop/Start in stop, then hit from the back. Would the engine restart? Potentially causing her to drive across a zebra crossing in use - if the accident caused her to lift her foot.
Is the answer to select neutral or does the system have a fail safe?
All informed responses will be appreciated. Variations on Mrs NO having a problem with her rear will be expected but less welcome!
NailedOn said:
Apologies for the bump. I have a question to which I am unable to find an answer elsewhere.
Mrs NO has a 2015 Mini auto with Stop/Start.
It works as intended but she had asked what happens if the car is involved in an accident when stationary? EG waiting at a zebra crossing with her foot on the brake, Stop/Start in stop, then hit from the back. Would the engine restart? Potentially causing her to drive across a zebra crossing in use - if the accident caused her to lift her foot.
Is the answer to select neutral or does the system have a fail safe?
All informed responses will be appreciated. Variations on Mrs NO having a problem with her rear will be expected but less welcome!
No difference if the car didn't have stop/start, surely.Mrs NO has a 2015 Mini auto with Stop/Start.
It works as intended but she had asked what happens if the car is involved in an accident when stationary? EG waiting at a zebra crossing with her foot on the brake, Stop/Start in stop, then hit from the back. Would the engine restart? Potentially causing her to drive across a zebra crossing in use - if the accident caused her to lift her foot.
Is the answer to select neutral or does the system have a fail safe?
All informed responses will be appreciated. Variations on Mrs NO having a problem with her rear will be expected but less welcome!
NailedOn said:
Apologies for the bump. I have a question to which I am unable to find an answer elsewhere.
Mrs NO has a 2015 Mini auto with Stop/Start.
It works as intended but she had asked what happens if the car is involved in an accident when stationary? EG waiting at a zebra crossing with her foot on the brake, Stop/Start in stop, then hit from the back. Would the engine restart? Potentially causing her to drive across a zebra crossing in use - if the accident caused her to lift her foot.
Is the answer to select neutral or does the system have a fail safe?
All informed responses will be appreciated. Variations on Mrs NO having a problem with her rear will be expected but less welcome!
not quite sure I understood, but if stop start has operated then she would have been in neutral anyway, wouldn't she? + if she lifted of the brake 'cos of the accident then she would be pushed across the crossing regardless of stop startMrs NO has a 2015 Mini auto with Stop/Start.
It works as intended but she had asked what happens if the car is involved in an accident when stationary? EG waiting at a zebra crossing with her foot on the brake, Stop/Start in stop, then hit from the back. Would the engine restart? Potentially causing her to drive across a zebra crossing in use - if the accident caused her to lift her foot.
Is the answer to select neutral or does the system have a fail safe?
All informed responses will be appreciated. Variations on Mrs NO having a problem with her rear will be expected but less welcome!
Thanks for the replies. The car engages gear as soon as Stop/Start starts. So the engine is off and as soon as you take your foot off the brake, drives. Our Mini is an auto so no manual clutch is involved.
The brake is effectively a 'Live Mans Switch' in that once pressure is released, the car goes. Only at a few mph. But it goes.
The brake is effectively a 'Live Mans Switch' in that once pressure is released, the car goes. Only at a few mph. But it goes.
V8LM said:
NailedOn said:
Apologies for the bump. I have a question to which I am unable to find an answer elsewhere.
Mrs NO has a 2015 Mini auto with Stop/Start.
It works as intended but she had asked what happens if the car is involved in an accident when stationary? EG waiting at a zebra crossing with her foot on the brake, Stop/Start in stop, then hit from the back. Would the engine restart? Potentially causing her to drive across a zebra crossing in use - if the accident caused her to lift her foot.
Is the answer to select neutral or does the system have a fail safe?
All informed responses will be appreciated. Variations on Mrs NO having a problem with her rear will be expected but less welcome!
No difference if the car didn't have stop/start, surely.Mrs NO has a 2015 Mini auto with Stop/Start.
It works as intended but she had asked what happens if the car is involved in an accident when stationary? EG waiting at a zebra crossing with her foot on the brake, Stop/Start in stop, then hit from the back. Would the engine restart? Potentially causing her to drive across a zebra crossing in use - if the accident caused her to lift her foot.
Is the answer to select neutral or does the system have a fail safe?
All informed responses will be appreciated. Variations on Mrs NO having a problem with her rear will be expected but less welcome!
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