New Owner/New Theory on ECT button

You are absolutely right. The engine management, in ECT, is quite different. You have more dynamic compression in your cylinders in ECT mode. When not in ECT mode, you are in a leaner burn mode with less dynamic compression. While this is more chemically efficient, you will have less torque.

 

Overall, with the automatic transmission model, ECT likely alters transmission shift points and overall behavior, the Otto/Atkinson cycle, intake/exhaust valve timing, and fuel injector pulse.

 

100% miss information... compression is static, unless you fitted one of those fancy Nissan motors to your truck

 

ECT does not do anything special with Otto/Atkinson, valve timing, or fuel mapping... yes those things are variable dependent of throttle input and engine load, but the ECT button doesn't "retune" your ECU when you press it.

ECT retranslates movement of the gas pedal with throttle angle and holds gears longer. Less gas pedal movement = more throttle angle, hence the feeling of "more power" for a similar gas pedal angle compared to non-ECT. That's it... it's not that crazy a feature!

 

Do you own a 2016?

Are you an engineer?

 

You are not correct. Only the static compression ratios are static. Dynamic compression ratios are controlled by piston speed, pressure differentials (throughout the induction system and cylinder head), and valve timing. Dynamic compression ratios are the "effective" or "real" compression ratios. Torque is partially (and mostly) a product of dynamic compression.

 

That is not true. The ECM adjusts the load maps during ECT mode. What are you basing your claims on rhouse?

 

A piston will compress the same volume of air in the same volume of space no matter how quickly it moves, given temperature / density of air remains constant. Valve timing is the only thing that alters "dynamic compression" because it influences the volume / timing of air introduced into the cylinder...

I own a 2017.

See post #18.

Where is your source of information?

 

What are "load maps"? Load is a calculated result of airflow per RPM, it won't change. Requested Torque what you're referencing?

And how are you guys speaking to this with any confidence. Unless you're in there looking at the tables, at best all we can do is speculate what it's doing.

 

Dynamic compression ratio is not impacted by "piston speed". Volumetric efficiency has an impact on cylinder pressures and that is rpm dependent, but this is not how dynamic compression ratios are defined.

 

This is closer to correct, but still wrong. Volumetric efficiency is an RPM dependent property that has an impact on cylinder pressures but this is not how dynamic compression is defined. Dynamic compression will be impacted by valve timing, as you mentioned, and especially when speaking about atkinson vs. otto cycle, so ECT MAY have an impact there based on whether or not it's commanding otto cycle only, but we can't know that unless we can see the maps or track valve timing.

 

Hi first time Tacoma owner here. I got a 2017 off road dcsb about a month ago and I have the same problem with incline whether on cruise control or not. Could you explain to me what the transmission tsb is? Is it covered under warranty or is it a maintenance type of update. Any info would be great. I'm at 2500 miles and want to take care of my truck properly.

 

Let's separate the concept of volumetric efficiency with the simplistic definition of compression... of course RPM has an impact on overall system efficiency with how much air you can cram into the cylinders, but it doesn't alter the physical constant of compression.

Take one stroke of a piston... if you move it slowly or if you move it quickly, the compression ratio is the same.

 

You are correct in that I am speculating. You are correct that load is calculated. Most engines work on a speed density/mass flow strategy and load is calculated based on a number of inputs, and I would speculate, one of them is "is ECT active".

Piston speed does impact dynamic compression. When a piston moves faster, relatively speaking, than the incoming air column can adequately supply, then the cylinder filling will be less, and thus, dynamic compression will be lower. This is usually combatted by retarding the intake cam lobe or lengthening the intake lobe duration when piston speeds increase. But then, it is always a compromise with clean burning emissions, low end torque, and fuel economy.

 

At this point, I cannot confirm, but I think Atkinson gets the boot in ECT mode.

 

You're using the terms incorrectly. Dynamic compression ratio is variable based on number of cylinders, bore, stroke, length, static compression ratio, valve timing, boost (if applicable) and atmospheric pressures. It is a RATIO and is not used to describe variability based on EFFICIENCY. Cylinder pressure is the term you're wanting to use when discussing impact from volumetric efficiency.

 

My theory is Toyota pulled a VW of sorts, in that "D" was designed to game the dyno.

 

Scooby, we may be dancing around the same thing. Volumetric Efficiency is simply a percentage of say 3.5L (in our case) that actually gets ingested, and used to oxidize the fuel, in 720 degrees of crankshaft rotation. I know you already know that, but I am sharing this for the other viewers. Dynamic compression ration is causal to cylinder pressure. Actually, Cylinder pressure is caused by dynamic compression, thermal expansion, and low cylinder seal leakage.

 

This seems very valid, at least to bypass CAFE while in ECT.

 

If you did a dyno test in ECT mode, you would get the same results as in regular ol D