Gasoline Fuel-Injection System K-Jetronic
Published by: © Robert Bosch GmbH, 2000 Postfach 30 02 20, D-70442 Stuttgart. Automotive Equipment Business Sector, Department for Automotive Services, Technical Publications (KH/PDI2). Editor-in-Chief: Dipl.-Ing. (FH) Horst Bauer. Editorial staff: Dipl.-Ing. Karl-Heinz Dietsche, Dipl.-Ing. (BA) Jürgen Crepin. Presentation: Dipl.-Ing. (FH) Ulrich Adler, Joachim Kaiser, Berthold Gauder, Leinfelden-Echterdingen. Translation: Peter Girling. Technical graphics: Bauer & Partner, Stuttgart. Unless otherwise stated, the above are all employees of Robert Bosch GmbH, Stuttgart. Reproduction, copying, or translation of this publication, including excerpts therefrom, is only to ensue with our previous written consent and with source credit. Illustrations, descriptions, schematic diagrams, and other data only serve for explanatory purposes and for presentation of the text. They cannot be used as the basis for design, installation, or scope of delivery. We assume no liability for conformity of the contents with national or local legal regulations. We are exempt from liability. We reserve the right to make changes at any time. Printed in Germany. Imprimé en Allemagne. 4th Edition, February 2000. English translation of the German edition dated: September 1998.
Since its introduction, the K-Jetronic gasoline-injection system has proved itself in millions of vehicles. This development was a direct result of the advantages which are inherent in the injection of gasoline with regard to demands for economy of operation, high output power, and last but not least improvements to the quality of the exhaust gases emitted by the vehicle. Whereas the call for higher engine output was the foremost consideration at the start of the development work on gasoline injection, today the target is to achieve higher fuel economy and lower toxic emissions. Between the years 1973 and 1995, the highly reliable, mechanical multipoint injection system K-Jetronic was installed as Original Equipment in series-production vehicles. Today, it has been superseded by gasoline injection systems which thanks to electronics have been vastly improved and expanded in their functions. Since this point, the K-Jetronic has now become particularly important with regard to maintenance and repair. This manual will describe the K-Jetronic’s function and its particular features.
Combustion in the gasoline engine The spark-ignition or Otto-cycle engine 2 Gasoline-engine management Technical requirements 4 Cylinder charge 5 Mixture formation 7 Gasoline-injection systems Overview 10 K-Jetronic System overview 13 Fuel supply 14 Fuel metering 18 Adapting to operating conditions 24 Supplementary functions 30 Exhaust-gas treatment 32 Electrical circuitry 36 Workshop testing techniques 38
Combustion in the gasoline engine
Combustion in the gasoline engine
The spark-ignition or Otto-cycle engine
The spark-ignition or Otto-cycle1) powerplant is an internal-combustion (IC) engine that relies on an externallygenerated ignition spark to transform the chemical energy contained in fuel into kinetic energy. Today’s standard spark-ignition engines employ manifold injection for mixture formation outside the combustion chamber. The mixture formation system produces an air/fuel mixture (based on gasoline or a gaseous fuel), which is then drawn into the engine by the suction generated as the pistons descend. The future will see increasing application of systems that inject the fuel directly into the combustion chamber as an alternate concept. As the piston rises, it compresses the mixture in preparation for the timed ignition process, in which externallygenerated energy initiates combustion via the spark plug. The heat released in the Fig. 1 Reciprocating piston-engine design concept OT = TDC (Top Dead Center); UT = BDC (Bottom Dead Center), Vh Swept...