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After the recent thread on TCS, I was curious how TCS evolved post 72 and so followed it forward...here's what I concluded.
TCS had a short history in emissions control technology (70-74) and its functions appear to have migrated into other systems. Tracing the evolution of TCS post 74 model year, TCS disappears in the wake of cat converters, EGR, Thermostatic Air Cleaner, HEI and EFE. GM "tinkered" with emission controls because the perfect technology did not exist.
Based on the recent TCS thread, the emissions control and fuel economy impact of TCS, was to
1. Reduce emissions on cold start-up,
2. Increase fuel economy while in high gear (penalty in low gear)
3. Reduce emissions while decelerating,
If I understand this technology, it reduced primarily HC emissions and CO emissions.
In late model C3s, the idle Solenoid is located in the position of the early model TCS (smallblocks) and its function is to increase idle for A/C equipped vehicles (anti-dieseling solenoid not unlike pre-TCS Vettes). It appears in 75, the idle solenoid was used with A/C applications to bump. Actually. it never went away!
Why the disappearance of TCS? Emission standards tightened in 73 and then again in 75, targeting in particular NOx emissions. New technologies such as EGR and later catalytic converters came along to take on similar emission control functions.
I’m curious if anyone has traced the evolution of TCS. For example, did the transmission spark Thermal Vacuum Switch (TVS) evolve from TCS? TVS controls vacuum source by tapping the coolant temperature but was also introduced on the GM fleet at the same time TCS saw its deput. Were they competing technologies with the same mission but found their mate with selected powertrain platforms?
Insights appreciated.
TCS had a short history in emissions control technology (70-74) and its functions appear to have migrated into other systems. Tracing the evolution of TCS post 74 model year, TCS disappears in the wake of cat converters, EGR, Thermostatic Air Cleaner, HEI and EFE. GM "tinkered" with emission controls because the perfect technology did not exist.
Based on the recent TCS thread, the emissions control and fuel economy impact of TCS, was to
1. Reduce emissions on cold start-up,
2. Increase fuel economy while in high gear (penalty in low gear)
3. Reduce emissions while decelerating,
If I understand this technology, it reduced primarily HC emissions and CO emissions.
In late model C3s, the idle Solenoid is located in the position of the early model TCS (smallblocks) and its function is to increase idle for A/C equipped vehicles (anti-dieseling solenoid not unlike pre-TCS Vettes). It appears in 75, the idle solenoid was used with A/C applications to bump. Actually. it never went away!
Why the disappearance of TCS? Emission standards tightened in 73 and then again in 75, targeting in particular NOx emissions. New technologies such as EGR and later catalytic converters came along to take on similar emission control functions.
I’m curious if anyone has traced the evolution of TCS. For example, did the transmission spark Thermal Vacuum Switch (TVS) evolve from TCS? TVS controls vacuum source by tapping the coolant temperature but was also introduced on the GM fleet at the same time TCS saw its deput. Were they competing technologies with the same mission but found their mate with selected powertrain platforms?
Insights appreciated.