US 4,391,262 AGranted

Ignition system for an internal combustion engine

AssigneeRobert Bosch GmbH

InventorRichard Schleupen

Life of this patent

Estimating the term…

Loading patent…

Abstract

To provide sufficient ON-time to store adequate electromagnetic energy in an ignition coil (5, 6), even under high-speed engine operations, in which the ON time of an electronic ignition breaker switch (7, 8) and the OFF or ignition instant thereof is determined by a signal (U16) derived from an a-c type signal source, a signal processing stage (32) is interconnected between the signal source and the ignition signal triggering stage (9) which includes an integrator (27) which commences to integrate when, after an ignition event, the voltage from the signal source (16) has dropped to a predetermined level (Up), the integrated voltage being compared with a threshold level (Uc) to start the ON period of the switch (7, 8) even though the voltage from the signal source (16) may be below that reference level (Up), the output from the integrator and from the signal source being connected to an analog OR-gate (21, 30, 31, 33) which passes the higher one of the two signals, the integrator (27) thereupon being reset to permit commencing of integration upon the next cycle when the generator output voltage (U16) has again passed through the reference level (Up).

Claims8

Dependent claims

Ignition system for an internal combustion engine having

means (16) operating similarly to an a-c generator for generating an ignition signal (U16);
an ignition coil (5, 6);
a controlled switch (7, 8) controlling current flow through the ignition coil;
and a signal processing stage (32, 9) interconnecting the signal generating means (16) and the controlled switch (7, 8) for rendering the controlled switch conductive, to store electromagnetic energy in the coil, at an instant of time during which the ignition signal changes in value in a first predetermined direction, and rendering the controlled switch non-conductive, and hence interrupting current flow through the coil and cause a high-voltage ignition pulse to appear thereacross, at an instant of time during which the ignition signal changes values, and in opposite direction,
wherein, in accordance with the invention,
the signal processing stage includes means (32) deriving a first control signal portion (Ua-Ub) occurring in advance of the peak value of the ignition signal, and having an at least approximately uniformly changing rate in said first direction during at least part of the time when the ignition signal changes level or value in the opposite direction;
and means (33) combining said first control signal portion and the ignition signal at a time (Ub) when both the ignition signal and the first portion of the control signal are changing in said first direction, and said ignition signal is at a level below its peak value (Us),
so that the differential, in a voltage-time diagram of the control signal portion (Ua-Ub) and the ignition signal portion below the peak thereof (Ub-Us) will have the same sign.

5 more elements

Dependencies are inferred from the claim text.