How do ICE fare worse in freezing temperatures? Their thermal efficiency goes UP with the colder environmental temperature. Remember the Carnot efficiency: (Th - Tc)/Th. The lower the cold system temperature (Tc), the higher the efficiency.
I get less mpgs in the winter than in summer.
Starter motors and alternators and engine oil and coolant are a bother at very low temperatures, but then so are batteries.
It depends on how you measure "efficiency". You may be able to generate a greater brake specific horsepower in colder temperatures, but that does not translate to increased fuel economy during normal over the road operating conditions. Since cold air is more dense, there is a larger quantity of oxygen molecules being drawn through then engine at a give engine RPM. That requires additional fuel to be injected to achieve a stoichiometric fuel air ratio. That same dense air produces greater wind resistance as well. Also, in cold weather, engines typically spend a significantly greater percentage of their operating time below normal operating temperature which also increases fuel consumption due to friction loses from cold, thick oil as well as the extra fuel injected by the ECU to prevent misfires and heat the catalytic converters more quickly.
—” Their thermal efficiency goes UP with the colder environmental temperature. “
Yes, a nice Delta-T and all that...
On an ICE most of the energy is lost to the atmosphere.
But... The hot-vapor engine did all this running unheard of high temperatures at an extremely lean air/fuel ratio, in seeming violation of accepted internal-combustion-engine physics.
Smokey Y. was a true gearhead guru.
Some of his exploits will be remembered for many generations.