General Overview

LH fuel injection system

General

The Bosch LH-Jetronic Luftmassenmesser Hitzdraht) fuel injection system, comprising a mass air flow sensor incorporating a filament (hot-wire sensor), combines the best features of different fuel injection systems with measurement of the air mass, i.e. the density of the induction air is taken into account - unlike earlier fuel injection systems.

In the LH-Jetronic system, the air mass consumed by the engine is measured, which means that allowance is made for the composition of the air (temperature, pressure and humidity). Measurement of the air mass is performed by the mass air flow sensor with the hot- wire sensor, which measure the air upstream of the inlet manifold.

This method provides a more exact measure of the quantity of oxygen supplied to the engine by the air mass, which determines the quantity of fuel required for efficient combustion.

In all previous fuel injection systems, only the air volume (quantity of air) and/or the atmospheric pressure has been taken into account.

The LH system has the following advantages over earlier types of fuel injection:
- Compensation for temperature variations.
- Adjusts the quantity of fuel to the quantity of oxygen at high altitudes.
- Fewer components.
- Lighter.
- Fewer moving parts.
- Wider scope for adapting the quantity of fuel to actual needs (warm-up period/acceleration phase).