US 4,903,676 A · Method and arrangement for improving the starting ability of an internal combustion engine during an engine start

Abstract

The invention relates to a method and an arrangement for improving the starting ability of an internal combustion engine during difficult engine starting conditions that result from cold weather or other external circumstances. Lower than normal engine starting speeds can occur during cold weather, for example. So as not to hinder an engine start, it is essential that the spark plugs be free from deposits and in their best condition. This is achieved by burning off any deposits present on spark plugs during an engine start attempt, when difficult engine starting conditions are detected. During an engine start attempt a comparison circuit ascertains whether or not one or more detected engine parameters have a lower value than in normal engine starting conditions. The comparison circuit sends a signal to the control unit controlling the ignition system, so that the control unit will initiate the generation of a plurality of sparks, instead of a single spark, at ignition time points. The resultant spark shower then burns off any deposits that are present.

Claims24

Dependent claims

A method for improving the starting ability of a four-stroke internal combustion engine of the type including an ignition system having a charging circuit for storing charge;

a coil for receiving discharges from the charging circuit;
and a spark plug having a pair of electrodes spaced by a gap, energized by the coil, and associated with a cylinder containing a piston;
the method comprising the steps of:
determining when a difficult engine starting condition exists;
when such difficult engine starting condition is detected, causing the charging circuit to discharge repeatedly across the spark plug gap when a crankshaft of the engine is positioned in a range between a position about 10.degree. before a top-dead center position and about 60.degree. after the top-dead-center position, irrespective of whether the piston is in its compression or exhaust stroke, thereby to produce a spark shower across the plug gap at each exhaust stroke, so as to burn off any deposits on the spark plug electrodes;
and
terminating the shower of sparks upon determining that a difficult engine starting condition has ceased.

4 more elements

Dependencies are inferred from the claim text.

Method and arrangement for improving the starting ability of an internal combustion engine during an engine start

Life of this patent

Method and arrangement for improving the starting ability of an internal combustion engine during an engine start

Life of this patent

Abstract

Claims24