geordi wrote:
What other stuff are you referring to? Temperature changes in relation to load and cooling conditions. Running down the highway means excessive amounts of cold air (all air is cold when the engine is at 200 degrees) blowing across the radiator. Assuming that your temp gauge is calibrated to accept 200 degrees as "normal" then this amount of cooling air should pull the gauge needle down as the temperature drops. Highway operation is easy on an engine, only a handful of HP are required to maintain speed.
In city traffic, very little airflow is cooling the radiator and there is a lot of high-demand acceleration from starting-and-stopping driving. The fan may help move air, but chances are that the coolant will be 20-25 degrees higher than highway operation. If the temp gauge responded to this, people would think that their engines were overheating while being in city traffic, when they are not.
Climbing mountains is even more heavy loading than city traffic. The engine is working hard, adding more heat to the system. Only when the temperature rises outside the "normal" range is the gauge programmed to move - because THEN, the engine is actually starting to run hot. This is the only situation that requires the driver to alter their behavior - either by slowing down, stopping for a break, shifting gears... Etc. The engine is outside the normal safe range, so the temp gauge starts to indicate this.
But as long as the engine is within the range of acceptable temperatures, neither too cold nor too hot, then the gauge means very little.
I mostly agree with this; however, geordi, you are not accounting for the fact that a properly operating thermostat valve will stroke open and closed in between fully closed and fully open during operation of the vehicle... it will operate within a range during normal operation. This will definitely even out temperature fluctuations in the engine.
In fact, when the other Jeff and I were testing our prototype 2 years ago, the OBDII reader in Jeff's CRD was hooked up and reading actual temperatures under a variety of driving conditions in different types of weather. Once his CRD was up to full operating temperature it stayed rock solid and unwavering at 203 degrees Fahrenheit. This is mainly because we followed the advice of the engineer at Stant Corporation that I consulted, and used a larger thermostat valve, (
and a larger housing to match it), that allows for more coolant flow under high load/demand conditions.
The smaller the temperature fluctuations, the better the engine runs. This is the main reason why I put so much effort into developing the Model 001. We knew it would not be too difficult to get the engine temperature up, what we were mainly concerned with was overheating in hot weather and under heavy load conditions, and with temperature fluctuations. None of this occurred with the testing of the Model 001 prototype.
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