Battery management requires a lot of computer logic. The simple act of plugging in an EV to a charger involves a complex handshake for negotiating the amount of power to deliver, which the control unit figures out by reading the sensors in each battery cell, and routes the electric power to the appropriate cells. Same thing for discharging the battery to power the vehicle, and recharging the battery from regenerative braking while driving.
No matter how you slice it, an EV requires much more computing functionality under the hood than an ICE vehicle, just for the basic powertrain management.
I’m not totally sure. Even an ICe car now is insane for all the modules. Sure I can see battery management in an ev being robust but I’m sure it could still be pretty simple. Look at just injectors and cam sensors in an ice vehicle and the engine harness, its insane. Not to mention the entertainment bullshit that needs all its own modules.
Yeah, modern cars are basically engineering marvels. Even when a lot of this stuff was mechanically controlled it really was something amazing to see just how precisely every little moving part did its perfectly timed function, thousands of times per minute across all 4 (or 6 or 8 or more) cylinders, pushing power through the transmission and differential and wheels.
That said, I still think that trying to understand the physical ground truth of the electrochemical energy stored in each of the 5000+ cells by reading sensor data on voltage, current, impedance, temperature, and a log of how many times each cell has been charged or discharged, does require greater electronic complexity and more sophisticated programs to manage, than an ICE control unit does.
an EV requires much more computing functionality under the hood than an ICE vehicle
Not true. Modern ICE vehicles need an ECU for fuel maps, they use throttle position mapping, sensor feedback for emissions, knock, fuel sensing. Far more subsystems and computer modules than EVs.
No matter how you slice it, an EV requires much more computing functionality under the hood than an ICE vehicle, just for the basic powertrain management.
I’ve got ECU reads with full DAMOS data (memory addresses of maps) for my two cars, one from 2001 (Bosch EDC15P) and one from 2007 (Bosch EDC16CP34). If you’re willing to download the demo version of WinOLS, I can send you the WinOLS projects if you want to see how much was going on in there even back in 2001, let alone 2007. I unfortunately don’t have an EDC17 ECU or any of the petrol ECUs physically available, but I believe can give you full bench reads of some of them since I downloaded a huge torrent that would extract into a few terabytes of data for different vehicles.
Or if you don’t want all that, let me just give you an example of one tiny sliver of functionality in an EDC 16 diesel ECU, the actual fuel being sprayed. We’ll completely ignore even very closely related things like boost pressure.
The car is running and in gear. The driver presses on the fun pedal. First off, there are multiple maps for each thing based on mode (Sport/comfort) and possibly the gear you’re in (for torque limiters). The value of this pedal is translated into a “driver’s wish” value in Newton-meters of torque based on current RPM (in different RPM ranges this is limited to a different number). Multiple things are now calculated based on RPM and driver’s wish: Among the fuel ones are: injection quantity (mg/stroke), fuel rail pressure (controlled by a valve on the rail as well as a metering valve on the pump), start of injection, duration of injection - actually those latter two may have been based on iq rather than dw, but it doesn’t matter much since those are very tightly related. You now have multiple different maps that limit either the driver’s wish or injection quantity and the lowest limiter applies: Smoke limiter (limitation map by air flow and RPM), torque limiter (limit simply by RPM and pedal position), potentially gear-specific torque limiters, though these could also come from the TCU. I think there may have been one or two others.
Now, before injection there’s actually pre-injection, this warms up the cylinder to get a better burn for the main event. The main event is usually aimed such that start of combustion (not start of injection) occurs fairly close to top dead center of a piston. Working on older cars like the EDC15 I believe Bosch said the delay is one millisecond (which you need to calculate in degrees of crankshaft rotation), but I think for the EDC16 and 17 ones it might be less than one millisecond since the pre-ignition is there to help. If your start of combustion is too far before top dead center, you raise cylinder pressures and temperatures and create more noise. If your end of injection is too far after top dead center, you waste fuel (bad for wallet), increase exhaust gas temperatures (bad for turbo) and put out black smoke (bad for everyone). The only time having a late end of injection is sensible is if you’re building a diesel for tractor pulls or drag racing and you want to get that last percent of power out of it. For how start of injection and duration are actually applied on the ECU: It takes the fuel quantity being asked after all the limiters and fuel or coolant temperature, then based on those it’ll choose a start of injection map (or rather, it interpolates between different maps) and based on the start of injection it interpolates between different duration maps. Rail pressure itself is also consulted, though I’m not yet 100% sure how since my EDC16 car is stripped down to repair a leak and I haven’t gotten into tuning it yet, I only started doing this this summer and I’ve only had time to work on my older EDC15 car which has unit injectors and thus no rail pressure to speak of.
Oh and fuel temperature also needs to affect everything because we calculate in mg/str, but the actual sensors measure fuel volume and as you know, density changes with temperature.
There’s also post-injection, but that’s irrelevant for everyday driving, that’s used to raise exhaust temperatures to initiate a regen burn in the diesel particulate filter every 200-1000 km.
Now, here are SOME of the other things that also get handled by this ECU and I won’t go into detail on how any of these work because it would take a day to write out this comment: Starting and stopping the engine, asking for a certain boost pressure based on multiple maps, asking for a certain airflow based on multiple maps (those two are of course heavily interrelated), reporting fault codes, operating exhaust-gas recirculation, operating cooling for the aforementioned exhaust-gas recirculation, operating cooling for the engine itself, creating swirl in the intake manifold to improve burn at lower RPMs.
And remember, this is just the engine controller, there’s also a transmission controller that’s also specific to ICE vehicles.
To me this is all fairly simple and even at very high mileages I can keep these vehicles running well for cheap to the point that EVs are incredibly cost-prohibitive for me. Your average person, however, would have to take it to a shop if something goes wrong and if the mechanic is dishonest or just doesn’t know how things work in a modern car, a simple 1 hour fix with a cheap part can turn into hours upon hours of troubleshooting along with playing parts darts with sensors and actuators and stuff. Because there are actual mechanics out there far less knowledgeable than myself, a hobbyist.
which the control unit figures out by reading the sensors in each battery cell
Tesla Model S battery has like 7000 cells. They’re 18650s, same things that go in e-cigarettes. Trust me, there is NOT a sensor in each battery cell. There may be multiple per module, sure, but it’s still at most a few hundred and likely a few dozen sensors per battery pack.
Even that could be minimized, a car doesn’t need to have a wiring diagram that rivals a nervous system in complexity. You could definitely get away with cutting down a modern EV or ICE computer system with minimal or no loss to functionality, hell you may even make it safer overall if you scrap worthless shite like lane assist or cruise control.
Battery management requires a lot of computer logic. The simple act of plugging in an EV to a charger involves a complex handshake for negotiating the amount of power to deliver, which the control unit figures out by reading the sensors in each battery cell, and routes the electric power to the appropriate cells. Same thing for discharging the battery to power the vehicle, and recharging the battery from regenerative braking while driving.
No matter how you slice it, an EV requires much more computing functionality under the hood than an ICE vehicle, just for the basic powertrain management.
I’m with you on user interfaces, though.
I’m not totally sure. Even an ICe car now is insane for all the modules. Sure I can see battery management in an ev being robust but I’m sure it could still be pretty simple. Look at just injectors and cam sensors in an ice vehicle and the engine harness, its insane. Not to mention the entertainment bullshit that needs all its own modules.
Yeah, modern cars are basically engineering marvels. Even when a lot of this stuff was mechanically controlled it really was something amazing to see just how precisely every little moving part did its perfectly timed function, thousands of times per minute across all 4 (or 6 or 8 or more) cylinders, pushing power through the transmission and differential and wheels.
That said, I still think that trying to understand the physical ground truth of the electrochemical energy stored in each of the 5000+ cells by reading sensor data on voltage, current, impedance, temperature, and a log of how many times each cell has been charged or discharged, does require greater electronic complexity and more sophisticated programs to manage, than an ICE control unit does.
It is pretty amazing!
Sure I can see that. Still an ev could be very simple besides the charging computer. No other techs really needed.
Not true. Modern ICE vehicles need an ECU for fuel maps, they use throttle position mapping, sensor feedback for emissions, knock, fuel sensing. Far more subsystems and computer modules than EVs.
I’ve got ECU reads with full DAMOS data (memory addresses of maps) for my two cars, one from 2001 (Bosch EDC15P) and one from 2007 (Bosch EDC16CP34). If you’re willing to download the demo version of WinOLS, I can send you the WinOLS projects if you want to see how much was going on in there even back in 2001, let alone 2007. I unfortunately don’t have an EDC17 ECU or any of the petrol ECUs physically available, but I believe can give you full bench reads of some of them since I downloaded a huge torrent that would extract into a few terabytes of data for different vehicles.
Or if you don’t want all that, let me just give you an example of one tiny sliver of functionality in an EDC 16 diesel ECU, the actual fuel being sprayed. We’ll completely ignore even very closely related things like boost pressure.
The car is running and in gear. The driver presses on the fun pedal. First off, there are multiple maps for each thing based on mode (Sport/comfort) and possibly the gear you’re in (for torque limiters). The value of this pedal is translated into a “driver’s wish” value in Newton-meters of torque based on current RPM (in different RPM ranges this is limited to a different number). Multiple things are now calculated based on RPM and driver’s wish: Among the fuel ones are: injection quantity (mg/stroke), fuel rail pressure (controlled by a valve on the rail as well as a metering valve on the pump), start of injection, duration of injection - actually those latter two may have been based on iq rather than dw, but it doesn’t matter much since those are very tightly related. You now have multiple different maps that limit either the driver’s wish or injection quantity and the lowest limiter applies: Smoke limiter (limitation map by air flow and RPM), torque limiter (limit simply by RPM and pedal position), potentially gear-specific torque limiters, though these could also come from the TCU. I think there may have been one or two others.
Now, before injection there’s actually pre-injection, this warms up the cylinder to get a better burn for the main event. The main event is usually aimed such that start of combustion (not start of injection) occurs fairly close to top dead center of a piston. Working on older cars like the EDC15 I believe Bosch said the delay is one millisecond (which you need to calculate in degrees of crankshaft rotation), but I think for the EDC16 and 17 ones it might be less than one millisecond since the pre-ignition is there to help. If your start of combustion is too far before top dead center, you raise cylinder pressures and temperatures and create more noise. If your end of injection is too far after top dead center, you waste fuel (bad for wallet), increase exhaust gas temperatures (bad for turbo) and put out black smoke (bad for everyone). The only time having a late end of injection is sensible is if you’re building a diesel for tractor pulls or drag racing and you want to get that last percent of power out of it. For how start of injection and duration are actually applied on the ECU: It takes the fuel quantity being asked after all the limiters and fuel or coolant temperature, then based on those it’ll choose a start of injection map (or rather, it interpolates between different maps) and based on the start of injection it interpolates between different duration maps. Rail pressure itself is also consulted, though I’m not yet 100% sure how since my EDC16 car is stripped down to repair a leak and I haven’t gotten into tuning it yet, I only started doing this this summer and I’ve only had time to work on my older EDC15 car which has unit injectors and thus no rail pressure to speak of.
Oh and fuel temperature also needs to affect everything because we calculate in mg/str, but the actual sensors measure fuel volume and as you know, density changes with temperature.
There’s also post-injection, but that’s irrelevant for everyday driving, that’s used to raise exhaust temperatures to initiate a regen burn in the diesel particulate filter every 200-1000 km.
Now, here are SOME of the other things that also get handled by this ECU and I won’t go into detail on how any of these work because it would take a day to write out this comment: Starting and stopping the engine, asking for a certain boost pressure based on multiple maps, asking for a certain airflow based on multiple maps (those two are of course heavily interrelated), reporting fault codes, operating exhaust-gas recirculation, operating cooling for the aforementioned exhaust-gas recirculation, operating cooling for the engine itself, creating swirl in the intake manifold to improve burn at lower RPMs.
And remember, this is just the engine controller, there’s also a transmission controller that’s also specific to ICE vehicles.
To me this is all fairly simple and even at very high mileages I can keep these vehicles running well for cheap to the point that EVs are incredibly cost-prohibitive for me. Your average person, however, would have to take it to a shop if something goes wrong and if the mechanic is dishonest or just doesn’t know how things work in a modern car, a simple 1 hour fix with a cheap part can turn into hours upon hours of troubleshooting along with playing parts darts with sensors and actuators and stuff. Because there are actual mechanics out there far less knowledgeable than myself, a hobbyist.
Tesla Model S battery has like 7000 cells. They’re 18650s, same things that go in e-cigarettes. Trust me, there is NOT a sensor in each battery cell. There may be multiple per module, sure, but it’s still at most a few hundred and likely a few dozen sensors per battery pack.
Even that could be minimized, a car doesn’t need to have a wiring diagram that rivals a nervous system in complexity. You could definitely get away with cutting down a modern EV or ICE computer system with minimal or no loss to functionality, hell you may even make it safer overall if you scrap worthless shite like lane assist or cruise control.
That’s not a privacy issue.
The computers are issues when they include sensors, logging, storage, and uploading your data to others.
Its not the compute, its the data collection, built in ads and driver data sold to insurance companies that is the issue.