Mechanical Gasoline Fuel-Injection System with Lambda Closed-Loop

Data from Bosch



Bosch K-Jetronic
Since their introduction, the Jetronic fuel injection systems have proved themselves millions of times over under the harsh conditions of everyday driving. This success is a result of the advantages which fuel injection can offer when considering today's demands for economy, performance, and cleaner exhausts. The K-Jetronic is a mechanical system in which the fuel is continuously metered in accordance with the amount of air drawn in by the engine. Using the Lambda sensor together with additional equipment for the Lambda closed-loop control facility, the K-Jetronic can already comply today with the exhaust-gas regulations of tomorrow. The construction and principle of operation of the K-Jetronic is dealt with in this Technical Instruction manual.
  • It must be stressed that the implementation of this system by Volvo on many of its cars, involves some modifications, according to car model, engine, year and country of issue.


Part 1

The engine's fuel requirements

Air-fuel ratio
Excess-air factor

Fuel-management systems

Electronically controlled systems
Mechanical systems


Fuel supply

Outline of system
Electric fuel pump
Fuel accumulator
Fuel filter
Primary-pressure regulator
Fuel-injection valve

Part 2

Fuel management

Mixture-control unit
Air-flow sensor
Fuel distributor
Control pressure
Differential-pressure valves
Mixture information

Mixture adaptation

Cold start
Load conditions
Acceleration response
Influencing the air-fuel mixture

Part 3

Electrical circuitry


Exhaust-gas techniques

Exhaust-gas composition
Catalytic after-treatment
Lambda closed-loop control
by Bob Isac ,


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