Adaptation in the ECU comes in 2 parts. The first is the ODB2/EOBD adaptation for emission control.
This is fine tweaking of of the maps to counteract wear and tear, dirty injectors and air leaks.
For example, the ECU will have a programmed target lambda on a car. If the fuel filter becomes clogged, the car will start to run a little lean.
Short term adaptation is carried out almost immediately from feedback from the lambda sensor.
It's worth noting that narrowband lambdas can only measure excess oxygen, so rich conditions can't be measured apart from the fact there is no oxygen left, so it isn't able to know how rich the mix is. Likewise, the narrow range won't show too much details on how lean due to the response of the sensor.
Electronic throttle control systems may seem a little silly. After all, if a mechanical throttle control system works, why make it more complicated?
While it's true that electronic throttle control adds complications, it also adds a number of benefits. The first is decreased maintenance. Mechanical throttle systems, because they are made up of a lot of moving parts, are subject to a lot of wear. Over the life of the car, the various components can wear out. By comparison, an electronic throttle control system has comparatively few moving parts -- it sends its signals by electric impulse, not moving parts. That reduces wear and the amount of maintenance needed on the system.
In this age of electronic throttles, even the throttle usage is learned by the ECU, a quick two to three taps of the accelerator will let ECU know that car needs to better response, so ECU will treat each position of accelerator with little added % of throttle value from the base map. Usually it will be max of about 10%.
I am not sure but I feel even it slightly advances the start of the injection in the timing cycle.
The reactivity of the sensor isn't too quick either, so after about 3000-4000 rpm it can't react quick enough to provide anything useful so the car operates in the dark based on the programmed info.
From the info collected from the short term adaptation (below 3500-ish rpm) the car builds a picture of the general state of play.
If it has been adding extra fuel through the short term trim, it then gets added to a long term bank.
Sources
Bergholdt, Brad. "Under the Hood: Electronic Throttle Control is Complicated, But Precise." McClatchy-Tribune Information Services. February 26, 2010. [March 8, 2010].http://dailyme.com/story/2010022600004464/hood-electronic-throttle-control-complicated-precise.html
Lienert, Anita. "Toyota's Electronic Throttle Control and Electromagnetic Interference Testing Presentation." February 23, 2010. [March 8, 2010].http://www.insideline.com/toyota/toyota-throttle-control-and-electromagnetic-interference-testing-presentation.html
O'Donnell, Jayne. "Could electronics be what's causing runaway cars?" USA Today. February 23, 2010. [March 8, 2010].http://www.usatoday.com/tech/news/2010-02-23-Electromagnetic23_CV_N.htm
Pico Technology. "Electronic Throttle Control." Pico Technology. [March 9, 2010]http://www.picoauto.com/applications/electronic-throttle-control.html
Rhee, Joseph. "Toyota Slams Sudden Acceleration Research of Auto Expert as Unrealistic." ABC News. March 8, 2010. [March 8, 2010].http://abcnews.go.com/Blotter/RunawayToyotas/toyota-slams-sudden-acceleration-research-auto-expert-unrealistic/story?id=10042858&page=1
Ross, Brian. Expert Recreates Sudden Acceleration in Toyota." March 4, 2010. [March 8, 2010].http://abcnews.go.com/Blotter/video/testing-toyota-9914148?tab=9482930§ion=1206853&playlist=1363488
Thomas, Ken and Stephen Manning. "Toyota disputes critic who blames electronics." The Associated Press. March 8, 2010. [March 8, 2010].http://www.google.com/hostednews/ap/article/ALeqM5iNwJcVe09iBDYjmKOaeF4IU9vGRwD9EAOO0O0
Toyota. "Comprehensive Analysis Raises Concerns About Gilbert Congressional Testimony, ABC News Segment." Toyota. March 8, 2010 [March 8, 2010].http://pressroom.toyota.com/pr/tms/electronic-throttle-control-154300.aspx
This is fine tweaking of of the maps to counteract wear and tear, dirty injectors and air leaks.
For example, the ECU will have a programmed target lambda on a car. If the fuel filter becomes clogged, the car will start to run a little lean.
Short term adaptation is carried out almost immediately from feedback from the lambda sensor.
It's worth noting that narrowband lambdas can only measure excess oxygen, so rich conditions can't be measured apart from the fact there is no oxygen left, so it isn't able to know how rich the mix is. Likewise, the narrow range won't show too much details on how lean due to the response of the sensor.
Electronic throttle control systems may seem a little silly. After all, if a mechanical throttle control system works, why make it more complicated?
While it's true that electronic throttle control adds complications, it also adds a number of benefits. The first is decreased maintenance. Mechanical throttle systems, because they are made up of a lot of moving parts, are subject to a lot of wear. Over the life of the car, the various components can wear out. By comparison, an electronic throttle control system has comparatively few moving parts -- it sends its signals by electric impulse, not moving parts. That reduces wear and the amount of maintenance needed on the system.
In this age of electronic throttles, even the throttle usage is learned by the ECU, a quick two to three taps of the accelerator will let ECU know that car needs to better response, so ECU will treat each position of accelerator with little added % of throttle value from the base map. Usually it will be max of about 10%.
I am not sure but I feel even it slightly advances the start of the injection in the timing cycle.
The reactivity of the sensor isn't too quick either, so after about 3000-4000 rpm it can't react quick enough to provide anything useful so the car operates in the dark based on the programmed info.
From the info collected from the short term adaptation (below 3500-ish rpm) the car builds a picture of the general state of play.
If it has been adding extra fuel through the short term trim, it then gets added to a long term bank.
Sources
Bergholdt, Brad. "Under the Hood: Electronic Throttle Control is Complicated, But Precise." McClatchy-Tribune Information Services. February 26, 2010. [March 8, 2010].http://dailyme.com/story/2010022600004464/hood-electronic-throttle-control-complicated-precise.html
Lienert, Anita. "Toyota's Electronic Throttle Control and Electromagnetic Interference Testing Presentation." February 23, 2010. [March 8, 2010].http://www.insideline.com/toyota/toyota-throttle-control-and-electromagnetic-interference-testing-presentation.html
O'Donnell, Jayne. "Could electronics be what's causing runaway cars?" USA Today. February 23, 2010. [March 8, 2010].http://www.usatoday.com/tech/news/2010-02-23-Electromagnetic23_CV_N.htm
Pico Technology. "Electronic Throttle Control." Pico Technology. [March 9, 2010]http://www.picoauto.com/applications/electronic-throttle-control.html
Rhee, Joseph. "Toyota Slams Sudden Acceleration Research of Auto Expert as Unrealistic." ABC News. March 8, 2010. [March 8, 2010].http://abcnews.go.com/Blotter/RunawayToyotas/toyota-slams-sudden-acceleration-research-auto-expert-unrealistic/story?id=10042858&page=1
Ross, Brian. Expert Recreates Sudden Acceleration in Toyota." March 4, 2010. [March 8, 2010].http://abcnews.go.com/Blotter/video/testing-toyota-9914148?tab=9482930§ion=1206853&playlist=1363488
Thomas, Ken and Stephen Manning. "Toyota disputes critic who blames electronics." The Associated Press. March 8, 2010. [March 8, 2010].http://www.google.com/hostednews/ap/article/ALeqM5iNwJcVe09iBDYjmKOaeF4IU9vGRwD9EAOO0O0
Toyota. "Comprehensive Analysis Raises Concerns About Gilbert Congressional Testimony, ABC News Segment." Toyota. March 8, 2010 [March 8, 2010].http://pressroom.toyota.com/pr/tms/electronic-throttle-control-154300.aspx
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