Ignition system with improved temperature and voltage compensation

US4253442A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Werner Jundt · Ludwigsburg, DE
• Bernd Bodig · Leinfelden, DE
• Gerd Hohne · Ludwigsburg, DE
• Georg Pfaff · Schifferstadt, DE
• Gerhard Sohner · Schorndorf, DE
• Bernd Kalkhof · Reutlingen, DE

Key dates

• Filing date: Jul 26, 1979
• Grant date: Mar 3, 1981
• Expiry date: Jul 26, 1999

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F02P3/051
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

The voltage across a capacitor is changed in a first direction while the current in the primary winding of the ignition coil increases to a predetermined value less than the value required for ignition and is thereafter changed in a second direction until ignition takes place. The voltage across the capacitor is applied to the inverting input of a difference amplifier constituting a threshold stage controlling the initiation and termination of current flow through the ignition coil. The two changes are symmetrical when the engine speed remains constant. The residual voltage across the capacitor at the end of the second change is maintained until the start of the next subsequent first change, so that the time at which the threshold stage switches in, that is the time at which primary current starts to flow in the ignition coil changes as a function of the residual voltage in the capacitor.