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Ignition and fuel
Published in Andrew Livesey, Motorcycle Engineering, 2021
First, we will look at some of the details of the CDI concept. The distributor has an electronic trigger device instead of the cb points. On the outside of the distributor is an amplifier unit. The switch, coil, and battery remain the same. The distributor may be incorporated in the alternator or end of the crankshaft. The reason for the move to CDI was to get a stronger spark at the plug for the higher compression ratios of the modern engines. That is about 40kV instead of 10 or 15kV on the older engines. The principle is for the LT supply to charge a capacitor to about 350V. When the system is triggered – and, of course, you cannot do that with cb points – the 350V goes to the coil and is converted to 40kV compared to 12V of a normal system being taken to 10kV.
Ignition Diagnostics in EGR- and Air-diluted Methane/Air Mixtures Using Spark Induced Breakdown Spectroscopy
Published in Combustion Science and Technology, 2022
Laura Merotto, Thomas Kammermann, Patrik Soltic
Although φ and pressure effects in methane/air mixtures were successfully investigated using INSIDE, local mixture concentration measurements in EGR-diluted conditions was up to date not addressed, due to the lack of information on carbon contributions. The spectral emissions from the plasma formed between the spark plug’s electrodes are affected by the amount and time scale of the energy delivered by the ignition system (Maly 1984). In particular, the measured intensity of the spectral emissions is expected to be higher when a higher power is provided. In capacitive discharge ignition (CDI), the spark duration is shorter (between tens and hundreds of microseconds) than the one typical of standard inductive systems (1–2 milliseconds), thus providing higher power to the spark plug when compared to the standard inductive ignition. Therefore, in this work a CDI system is used. To the authors’ knowledge, this is the first time a CDI ignition system is applied to a SIBS-based diagnostics in engine relevant conditions. The same spectral lines for hydrogen (Hα), nitrogen (N746) and oxygen (O777) as in the previous investigations are considered. Additionally, a carbon line contribution is identified and measured. The relationships between the measured atomic peak intensities ratios and the mixture dilution are investigated, showing that different trends are obtained when different dilution strategies are applied.