US 4,291,383 AGranted

Spark plug load testing for an internal combustion engine

AssigneeUnited Technologies Corporation

InventorsRinaldo R. Tedeschi, Gary G. Full

Life of this patent

Estimating the term…

Loading patent…

Abstract

The spark voltage waveform at the secondary of the ignition coil of an internal combustion (IC) engine is sensed over a plurality of successive engine cycles. The instantaneous sub-cyclic position of the engine crankshaft is measured at successive crankshaft angle increments within each engine cycle and each sensed spark voltage signal is identified by the instantaneous value of crankshaft position at which it appears, thereby providing identification of each spark voltage signal with an associated cylinder of the engine. The number of samples for each cylinder together with the peak KV voltage magnitude and time duration of each are measured and the maximum, minimum and mean values of peak KV and spark duration for the spark signals associated with each cylinder together with the number of samples obtained are compared with the values obtained for each other cylinder to provide an indication of the relative sub-cyclic ignition efficiency of the ignition secondary circuit and the individual cylinders.

Claims5

Dependent claims

Apparatus for indicating the efficiency of the ignition system of an internal combustion (IC) engine connected at its crankshaft to the drive shaft of an engine load, the ignition circuitry providing secondary voltage signals as the spark plug voltage signal to each engine cylinder in each engine cycle, in the presence of associated ignition circuitry primary voltage signals, comprising:

first voltage sensing means for sensing the presence of each primary voltage signal and for providing a Lo-Coil voltage signal indicative thereof;
second voltage sensing means for sensing the actual magnitude of each secondary voltage signal and for providing a Hi-Coil voltage signal indicative thereof;
position sensing means, responsive to the interconnected engine crankshaft and load drive shaft, for providing engine crankshaft position signals indicative of the actual crankshaft angular position at successive crankshaft angle intervals in each engine cycle, said crankshaft angle intervals being less than that associated with a cylinder sub-cycle;
and
signal processing means, responsive to said Lo-Coil voltage signals, said Hi-Coil voltage signals, and said crankshaft position signals, and having memory means for storing signals including specification signals defining the required crankshaft position of each cylinder spark plug voltage signal in each engine cycle in terms of actual crankshaft angle value,
for sampling, in response to each of said Lo-Coil voltage signals in a common engine cycle, and registering in said memory means, each of said Hi-Coil voltage signals and said crankshaft position signal appearing simultaneously therewith, and
for providing ratio signals of the actual magnitude of each of said Hi-Coil voltage signals sampled in a common engine cycle divided by the average value of all of said Hi-Coil voltage signals sampled in the same engine cycle, said ratio signals providing in combination an indication of the relative spark efficiency of the engine.

4 more elements

The method of indicating the efficiency of the ignition system of an internal combustion engine operating with a crankshaft connected engine load, the ignition system providing spark plug voltage signals to each cylinder in each engine cycle, comprising the steps of:

sensing the actual position of the engine crankshaft at successive crankshaft angle intervals in each engine cycle and providing crankshaft position signals indicative thereof, each crankshaft angle interval being less than that associated with a cylinder sub-cycle;
measuring together the actual magnitude of each spark plug voltage signal and the values of all of said crankshaft position signals appearing simultaneously therewith to provide, in each engine cycle, signals indicative of the actual magnitude of each spark plug voltage signal and signals indicative of the range of actual crankshaft angles associated with each;
ascribing each of said ranges of measured crankshaft angle values to a different cylinder spark ignition event in a common engine cycle;
and
comparing the actual magnitudes of the spark plug voltage signals ascribed to each cylinder ignition in a common engine cycle with the actual magnitudes of the spark plug voltage signals ascribed to all other cylinders in the same engine cycle, to provide the indication of ignition system efficiency.

2 more elements

Dependencies are inferred from the claim text.