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本帖最后由 ayuanx 于 8-12-2015 22:20 编辑
Normal engine temperature is around 190-205 degrees.
If you are asking about the Turbo Charger Temperature itself, it will run around 700-900 degrees and can get as high as 1200 degrees
Before we talk about actual peak temperature levels, we need to again discriminate between upstream (pre-turbocharger) and downstream (post-turbocharger) locations for the temperature sensor. Under high load conditions, there will be a large difference between upstream and downstream EGT. As the exhaust gas expands across the turbine and provides the energy to drive the air compressor, it's pressure and temperature are both markedly reduced.
There is a consensus of international sources which suggest that sustained gas temperatures in excess of 720 ºC (~1330 ºF) upstream of a diesel turbocharger will result in progressive and irreversible damage to components in contact with the gas. These may include piston crowns, exhaust valves/seats, manifold and, most commonly in the case of turbo-charged engines, the turbo-charger housing, exhaust turbine and waste gate.
A pre-turbo measurement is an 'absolute' measurement - that is, it is the actual temperature to which the turbine blade tips, the wastegate and the turbine housing are being subjected. The temperature drop across the exhaust gas turbine is difficult to quantify. It will vary with load, speed and will be different for every engine design. A post-turbo measurement requires assuming a 'worst case' temperature drop across the turbine and subtracting that from 720 ºC to arrive at a suitable limit for downstream EGT.
I have measured almost 200 ºC difference between turbo inlet and outlet temperatures on my Land Rover 2.5L 300Tdi under full load conditions, so I recommend 520 ºC (~970 ºF) downstream as a safe limit for such installations. This will be quite safe in the vast majority of cases but it is also probably overly conservative in some cases, especially large capacity, relatively low-boost (i.e. <10 psig) standard engines.
Very high EGTs will usually occur only at full throttle and high load conditions, such as driving up a steep grade or towing heavy loads. Further, these conditions will usually need to continue for some tens of seconds before EGT climbs to peak levels. This is because the exhaust manifold (and turbocharger, in the case of downstream installations) acts as a large heat sink and absorbs heat from the exhaust gas for some time after the engine begins working at full load. This is not a problem as this slightly lagging measurement probably more closely matches the metal surface temperatures in the turbocharger which are, after all, our main concern.
A stock-standard factory turbo-diesel may never generate an EGT higher than, say, 650/500 ºC (we'll use 'upstream'/'downstream' values for the rest of this discussion, OK?), due to the conservative factory set-up and their need to keep the engine 'safe' under most foreseeable conditions. But it may still generate high EGTs under abnormal conditions which cause an air flow restriction or lower than specified boost pressure (high altitude, very high ambient temperatures or failures such as blocked air hoses, air leaks, fouled intercooler etc.).
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发表于 8-12-2015 10:28:52
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发表于 8-12-2015 19:31:56
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