Originally Posted by
Thetyim
^
Un-fucking-believeable
The Toyota MightyX had a radiator that coped marginally. Any slight restriction and you could be in trouble.
The 3 litre 5L engine had serious cooling problems and had to be replaced earlier than anticipated.
Now you say that the Vigo D4D has cooling problems.
Someone needs their arse kicking.
They should be over designing their radiators after the previous failures.
This is the inside track.
The thermodynamic cycle for an engine - gasoline, or diesel normally works out how much power can be extracted from the cycle. With this, comes an amount of heat, also as a function of the thermodynamic cycle. For both gasoline & Diesel cycles, the heat-transfer rate, to power evolution is around 72%.
This means that ALL heat losses from the system - radiator, exhaust, block external etc amounts to around 72% of the engine power rating. I have trended the relationship between radiator design capacity (power) & engine power going back some years. Around 10 years ago it was around 120% & has slowly gone down until - Vigo - sits at 72%. This means that the slightest hangup anywhere in the system will have the radiator overheating & the engine in trouble.
Even large trucks are moving very close to this thermodynamic limit of 72%.
So, as engines evolve more power per unit space package, & underhood real-estate remains at a premium, the radiator itself is now the principle design problem for modern engines.
Oh, let's go hydrogen fuel-cell - you say. Wonderful - you need 3 radiators instead of one!!!
BTW, this part of the thermodynamic cycle analysis is not taught in standard text books - that's why the new designers haven't yet cottoned onto the issue.