The Motronic injection system was first introduced in 1979 by Bosch. This system is one of the varieties of car engine management systems, which successfully combined the functionality of electronic fuel supply and electronic ignition systems.

For this reason, Motronic is often referred to as the unified system of fuel injection and ignition. No matter what fuel injection system is installed on your car, you can always give it away for recycling and get a considerable amount of money:

Types of Motronic system

Currently, the Motronic system is represented by the following main types:

Mono-Motronic – a central fuel delivery system;

MED-Motronic – direct fuel delivery system;

KE-Motronic – distributed fuel delivery system;

M-Motronic – pulsed fuel delivery system;

ME-Motronic is a more advanced version of the M-Motronic system, equipped with an electrically controlled throttle valve.

However, we can say that all the above types of fuel injection systems are based on the Jetronic system.

We will consider the design features and operating principle of the system on the example of the M-Motronic.

How the Motronic system is designed

The construction of the Motronic injection system consists of input sensors, electronic type control unit and execution mechanisms.

The sensors are designed to capture any operating condition of the internal combustion engine. The Motronic system includes a huge number of input sensors to perform the necessary functions.

These include detonation, shaft speed, air flow, coolant and oxygen temperature, camshaft operating position, inlet air temperature, and damper operating position sensors.

The unit receives the signals that come from the input sensors and converts them into clear commands for the execution mechanisms.

The main functional purpose of the control unit is:

performing the dosing of the desired volume of TS depending on the volume of incoming air;

creation of a spark for fuel injection ignition;

control of the additional boost;

change of operating phases of gas distribution;

control of the toxicity of the exhausted gases

A standard control unit consists of a microprocessor, an input signal converter, memory blocks – permanent and on-line, and an amplifier.

Execution mechanisms

The actuating mechanisms in the Motronic injection system are represented by the following elements:

fuel injectors;

ignition coils;

electric actuator of the fuel pump;

valves in the exhaust and timing systems;

How the Motronic system works

The principle of operation of the M-Motronic is quite simple and straightforward. The input sensors transmit signals to the control unit, reporting the necessary data on the state and parameters of the engine operation.

The information is then carefully processed on the basis of programs which are stored in the permanent memory of the power unit. In order to make the necessary calculations and calculations the RAM is used.

As a result of such calculations ready signals are formed with further transfer to actuating mechanisms.

For clarity of the occurring process, let’s consider operation of the system in any internal combustion engine. The fuel pump is used to supply fuel from the tank through fuel filters to the distribution mechanism, and then to the injectors.

An accumulator is used as the distributing mechanism, which serves to distribute the fuel mixture evenly. The operating fuel pressure in the distributor is controlled by a pressure regulator. If the pressure is too high, the excess fuel is discharged back into the fuel tank.

Based on the information from the input sensors, the control unit calculates the correct amount of fuel to be fed into the engine cylinders and sends a signal to the magnets that open the fuel injectors.

This takes into account other data on air and refrigerant fluid temperature, the amount of incoming air, the number of crankshaft revolutions, the toxicity level of the exhaust gases, etc.

Each operating cycle of the engine directly depends on the coordinated and efficient operation of all elements and mechanisms of the fuel system.


Leave a Reply

Your email address will not be published. Required fields are marked *