StressCraxx wrote:GrUmPyBoDgEr wrote:Maybe I can throw a bit of light on the subject, having worked on such systems for a number of petrol engines made by a German car maker.
That company uses such a device on many of its present production engines.
The heat exchanger is usually mounted on the oil filter housing, where it can easily tap into the lubrication system to get direct access to the oil.
Coolant is then taken from the engine cylinder head & fed back into the coolant system where a pressure drop is available.
Due to the "work" put into the oil by the oil pump the stream of oil passing through the heat exchanger is capable of giving off some heat into the coolant.
That coolant is at that time (start-up) restricted to a flow that runs through only the cylinder head & crankcase & remains so until the engine thermostat opens & permits coolant to flow through the radiator.
This set-up can improve/increase the the engine warm up time & subsequently reduce fuel consumption & more importantly emissions.
When everything is hot the coolant temperature is usually kept at a temperature below 120?C whereby the engine oil will also be kept at approximately that temperature, that being not only safe for oil which oxidises at temperatures above 160?C, not at all good for longevity but also oil at higher operating temperatures is thinner without losing its lubrication properties will reduce the internal engine friction & provide an improvement on fuel consumption at the other end of the engine operating scale.
The idea of putting an oil cooler into the engine cooler (=Radiator) would provide no significant improvement in engine warm up because the coolant in the radiator is cut off from the engine until the engine is fully warmed up & the thermostat then opens.
Cheers
John
John,
You are on the money. Some of us who race Formula Ford use the water/oil heat exchangers sandwiched to the oil filter to bring the oil temperature up to 180F+ so the oil thins enough to reduce pumping losses and friction. Oil at 100C operating temperature is 1/2 the viscosity of oil at 40C. Dyno results from a reliable engine builder shows 100C oil is good for 2 to 3 HP, with no other changes. Proper scraping and windage control, crankcase vacuum from the dry sump, can make significant power from the bottom end by reducing drag and pumping losses.
I am investing in several low cost solutions to take advantage of the above.
Regards,
Dan Wise
Hi Dan,
quite right; the transfer of heat from oil to coolant or from coolant to oil can be advantageous in many respects.
That is, that either the heating or the cooling of one or other of the fluids can improve performance and/or economy.
I have experience of a very efficient windage tray in a 6 cylinder engine.
It worked brilliantly as part of the lubrication system but the performance guys moaned at me about a power loss of 1Kw.
I was forced to introduce a couple of 25mm breather holes into the tray.
They got their 1Kw back & luckily the windage tray suffered no measurable difference
Cheers
John