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Android-based Scopebox User’s Manual
4 Automotive Ignition waveform
The ignition system is the system which has greatest impact on the
performances of gasoline engine, as the statistical data shows that nearly half
of the failures are caused by poor work of electrical system. And the
performance tests of engine often start from the ignition system. Nowadays
ignition system includes distributor and distributorless. Distributorless includes
independent ignition and simultaneous ignition.
1.
Distributor ignition system i.e. contact breaker with contact-controlled
ignition system (commonly known as the platinum) and contact breaker
with noncontact-controlled ignition system combined with magnet, hall
components or infrared.
2.
Independent ignition system: Each spark plug has its own individual coil
that sits right on top of it, also called coil on plug system. Crankshaft
sensor send out the ignition timing signal and cylinder identification signal
so that the ignition system can send out ignition signal to specified
cylinder in specified time, each cylinder has its independent ignition coil.
3.
Simultaneous
ignition
system:
Two
spark plugs share the same coil, also
called waste spark system. When two cylinder pistons reach top dead
center at the same time (one is compression, another is the exhaust), two
spark plugs will be ignited at the same time, at this time, the ignition for
the former cylinder is in high-pressure low temperature gas mixture, the
ignition is valid, while for the latter one is in low-pressure high temperature
exhaust gas, the ignition is invalid.
The scopebox can test and analyze the secondary signal for various engine
ignition systems.
4.1 Secondary-distributor ignition analysis
Connections: Plug the BNC end of secondary ignition pickup into
CH1/CH2/CH3/CH4 channel of the scopebox, and then connect the
high-voltage clip to high-voltage line, and crocodile clips to ground.
Tips: Common ignition sequence (the specific sequence is subject to the