Can somebody help look through the waveform below:
The red is cylinder 1 ignition, blue one is crankcase pluse from WPS500X. Fire oder is 1342.
From the waveform we can be told:
Cylinder 1 power stroke (or cylinder 2 exhaust stroke) has a higher pluse;
Cylinder 4 power stroke (or cylinder 3 exhaust stroke) has a higher pluse.
fire order.png (3.84 KiB) Viewed 5580 times
The high pluses are mainly caused by the power stroked or exhaust strokes? It is my first time look at the crankcase waveform, not very sure I am right or not. Many thanks.
Peak marked number 1 is the pulsation formed as a result of the power stroke of number 1 cylinder.
This pulsation is formed as air beneath the piston crown is displaced into the crankcase when the piston accelerates down the cylinder on the power stroke.
Additional contributing factors to this pulsation could be excessive blow-by gas as a result of worn pistons / rings and cylinders (Cyl 1) along with the effects of number 4 cylinder on the intake stroke.(Also traveling down the cylinder)
Cylinders 1 and 4 are companion cylinders meaning that they are both at TDC and BDC together. When cylinder 1 is at BDC on the power stroke, cylinder 4 is at BDC on the intake stroke
At these stages in their four stroke cycle the pressure above piston number 1 will be positive whilst the pressure above cylinder 4 will be negative.
Both pistons are contributing to peak/pulsation marked number 1 but the major contributing cylinder will be
number 1
Many thanks for your reply.
This engine burned oil, consuming 1.5L oil for about 1000km. Disassembled the engine and found carbon deposition in cyl 2 and 3 because of their worn piston rings.So it can answer why the pulsations of cyl 2 and 3 on the power stroke are weaker than the other two.
We can see the maximum compress pressure of cyl 3 is smaller than others during WOT.