Electrical on-off-starting operation control system for engines requiring pre-heat time, such as automotive Diesel engines

US4075998A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Heinz Krauss
• Gunther Kauhl · Marbach am Neckar, DE
• Leo Steinke · Waiblingen, DE

Key dates

• Filing date: Feb 4, 1977
• Grant date: Feb 28, 1978
• Expiry date: Feb 4, 1997

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F02B3/06
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

To permit use of a standard starting switch customary in Otto engines to start automotive-type Diesel engines requiring energization of a glow plug, the "start" position of the control switch is unstable, for example spring-loaded, and returns the switch to "on" position upon release. The ON position also simultaneously forms the pre-heat switch position. The system includes a first relay having its connecting contacts connected to the glow plug and to a source of power, and a second relay forming a transfer switch with one terminal set connected as a self-holding circuit. The coil of the first relay is connected through the other set of transfer contacts of the second relay to the ON terminal of the switch to form the pre-heat circuit when the second relay is de-energized. The "start" position connects the starting motor. The coil of the second relay is energized from a common transfer junction either when the switch is in the "start" position or when a heater switch, included in the circuit of the glow plugs, has sufficient current flowing therethrough which also causes the glow plugs to become hot.