we have an engine runs well but when due to some protection, controller unloads it and reapplies load--the fire comes out of stack momentarily--what could be reasons -Is it issue of fueling at that moment or issue of improper turbine pressure- we are also seeing exh valve breakage on the engine too after a service of 16 months
2006-10-02 02:54:43 · 6 answers · asked by w111 t 1 in Science & Mathematics ➔ Engineering
Perhaps the fuel is not adjusted automatically to coincide with the load adjustment. The fuel will continue to be injected at the old rate when only a small amount is really needed. Much of the remaining fuel would be exhausted. However on the next stroke the fuel would be adequate and exhaust very hot. This would then ignite the extra fuel from the first stroke that is trying to exit the exhaust.
2006-10-02 10:08:56 · answer #1 · answered by baudeagle 4 · 0⤊ 0⤋
The 'fire' coming out of the stack is a sure sign that incomplete combustion is occuring. But that's not too surprising if your controller is applying 'step' loads to the engine. Diesels are designed to run under fairly constant loads. When you suddenly unload a diesel it causes a combination of compressor turbine overspeed and over fueling.
And I'm not too surprised that the exhaust valves are suffering. The valve stem isn't designed to withstand all that extra heat caused by exhaust gasses that are still combusting (burning) as they pass over the valve stem out the exhaust port. And once the valve stem starts to crystalize, it's not long at all until it snaps.
You really need to get the load controller working properly or you're going to continue to have these problems.
Doug
2006-10-02 10:07:33 · answer #2 · answered by doug_donaghue 7 · 0⤊ 0⤋
Hysteresis- the fuel system can not account for the sudden changes in load, if the fuel system is able to detect the changes in load before the event then it can adjust the fuel for the up and coming event and reduce the flow of fuel accordingly. If the fuel system is controlled electronically, you should examine the sensors, they are probably damaged.
2006-10-02 10:47:19 · answer #3 · answered by treb67 2 · 0⤊ 0⤋
Incomplete combustion. Transient increase of fuel while the pistons are still moving too slow.
If it were a gas powered engine you might find a way to advance the spark, but your diesel has no spark.
2006-10-02 10:05:26 · answer #4 · answered by Roy C 3 · 0⤊ 0⤋
the timing of the engine is off. valve breakage is caused by the piston hitting the valve.
2006-10-09 16:14:06 · answer #5 · answered by offroadin27 1 · 0⤊ 0⤋
unburned fuel
2006-10-02 10:02:44 · answer #6 · answered by aldo 6 · 0⤊ 0⤋