Cruze Oil and Water Temperatures

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882
Location
North Carolina
On a recent trip to the Gatlinburg Tennessee area my travels included a climb up "Black Mountain" at Old Fort on I-40. This climb consists of a mile or two of solid uphill grade at @ 55MPH. At the beginning of the grade my oil temp was logged at 238F with coolant at 224F.(Dashawk) After a mile or so of WOT in 6Th gear on the grade the oil was at 215F and the coolant was 212F !!!!! GM has some very interesting engine management going on here. I believe that this is part of their economy regimen. I understand that the ECM has control of the coolant "thermostat". Maybe it has some control of the engine oil heat exchanger too? Another thing that this automobile does in the name of economy: The alternator is modulated by engine load. If the vehicle is decelerating or coasting in gear the alternator charges to about 14VDC. If the drive-train is loaded the alternator charges less with the battery voltage sometimes dropping as low as 12.6VDC. So there is a very small hybrid effect in that the vehicles battery is charged more during deceleration. In essence the vehicles alternator is providing some braking effect during deceleration. I am liking this car more and more for it's engineering prowess and economy. 2011 Chevy Cruze ECO 1.4 6MT. Mild hypermiling regularly yields >50MPG on the highway (calculated and indicated). cool Rickey.
 
Messages
1,746
Location
Rochester, NY
Originally Posted By: Drew99GT
It has a cooling system thermostat that's controlled by the ECM??? Not the traditional wax spring valve type?
Yep. All in the name of mpg!
 
Messages
15,128
Location
Canada
I suspect there is quite a bit of 'Volt' engineering in the Cruze...probably far more than GM admits. Impressive for an econo-car!
 

Rickey

Thread starter
Messages
882
Location
North Carolina
Cut and paste from GM Powertrain: "The coolant thermostat's operating point is electronically controlled to optimize engine temperatures during different phases of operation to enhance fuel efficiency. The engine control module monitors sensors and controls the thermostat based on mapping that takes into account the wide range of engine operating conditions, including temperature and load." http://www.gmpowertrain.com/VehicleEngines/PowertrainProducts.aspx And yes the variable air shutters certainly affect coolant temperature and efficiency as well. If I am understanding GM's technical description of this engine correctly; it has an electronically controlled coolant thermostat. The indicated oil temperatures are a point of interest too. Rickey.
 

Rickey

Thread starter
Messages
882
Location
North Carolina
Originally Posted By: Mark_Walk
If you drove for more than a mile at WOT how fast were you going?
About 55MPH... steep and prolonged uphill grade.
 
Messages
6,318
Location
Canton, GA
Originally Posted By: Rickey
On a recent trip to the Gatlinburg Tennessee area my travels included a climb up "Black Mountain" at Old Fort on I-40. This climb consists of a mile or two of solid uphill grade at @ 55MPH. At the beginning of the grade my oil temp was logged at 238F with coolant at 224F.(Dashawk) After a mile or so of WOT in 6Th gear on the grade the oil was at 215F and the coolant was 212F !!!!! GM has some very interesting engine management going on here. I believe that this is part of their economy regimen. I understand that the ECM has control of the coolant "thermostat". Maybe it has some control of the engine oil heat exchanger too? Another thing that this automobile does in the name of economy: The alternator is modulated by engine load. If the vehicle is decelerating or coasting in gear the alternator charges to about 14VDC. If the drive-train is loaded the alternator charges less with the battery voltage sometimes dropping as low as 12.6VDC. So there is a very small hybrid effect in that the vehicles battery is charged more during deceleration. In essence the vehicles alternator is providing some braking effect during deceleration. I am liking this car more and more for it's engineering prowess and economy. 2011 Chevy Cruze ECO 1.4 6MT. Mild hypermiling regularly yields >50MPG on the highway (calculated and indicated). cool Rickey.
I remember going down that mountain in my big rig with TMC. Always had to make sure your in the right gear before going down that baby. DO NOT WANT TO MISS A GEAR going down, thats for sure.
 
Messages
1,589
Location
NC
This stuff is cool but i think i will steer clear of all this as long as i can. I keep my vehicles for a long time and have to fix them as they break. When i see stuff like this that has so much computer controlled gadgetry and so many sensors, i cant help but think how much of a troubleshooting nightmare it will become.
 

Rickey

Thread starter
Messages
882
Location
North Carolina
Originally Posted By: jstutz
This stuff is cool but i think i will steer clear of all this as long as i can. I keep my vehicles for a long time and have to fix them as they break. When i see stuff like this that has so much computer controlled gadgetry and so many sensors, i cant help but think how much of a troubleshooting nightmare it will become.
I remember the same type comments when we switched from point fired ignition to solid state fired ignition. I WAS one of the skeptics!!! Diagnostics are actually much simpler now, the car will literally tell you what is broken...usually HeHe. The expense of repair is what scares me. And I do most of my own troubleshooting and repair. Rickey.
 
Messages
168
Location
Charlotte, NC
Originally Posted By: Drew99GT
Originally Posted By: NHGUY
Cant wait til these are out of warranty and all this high tech stuff acts up....
That's what scares me as well.
I don't know if its high tech or not but my mom has a 2006 impala and she had the electronic throttle go on it, not once but twice and that was a few hundred bux to replace each time.
 
Messages
10,008
Location
Upstate NY
I've seen the same things with my Eco. At least this stuff is easy to get to, with nothing in the way. One advantage of having a dinky little 1.4 in a midsize car engine bay is plenty of room to work.
 
Messages
19,479
Location
Chicago Area
Ford has a variable thermostat for a while. Hotter in cruise than when delivering power. Keeps the thermal efficiency up - less heat lost to the cyl walls, CC, coolant, andn more for power. Alternators charge by demand. Amps change. I am not sure why they modulate the voltage. A minimal addition/subtraction.
 

Rickey

Thread starter
Messages
882
Location
North Carolina
Originally Posted By: Vikas
What are the pros and cons of dropping a gear or two rather than trying to take that grade in 6th at WOT ?
Tried dropping to 5Th with same MPH on another trip. Lost a few indicated MPG. It appears that this tiny engine makes best economy by lugging.
 
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