How do cars calculate engine load?

Introduction

Engine load is a measure of how hard the engine is working. It is used to control the fuel mixture, ignition timing, and other engine parameters. There are two main methods for calculating engine load: the volumetric efficiency method and the manifold absolute pressure (MAP) sensor method.

Volumetric efficiency method

The volumetric efficiency method calculates engine load by measuring the amount of air that is flowing into the engine. This is done using a mass air flow (MAF) sensor. The MAF sensor is located in the intake manifold and measures the mass of air that is flowing through it. The engine control unit (ECU) uses this information to calculate the volumetric efficiency of the engine.

Volumetric efficiency is a measure of how well the engine is filling its cylinders with air. A high volumetric efficiency indicates that the engine is filling its cylinders well, while a low volumetric efficiency indicates that the engine is not filling its cylinders well.

The ECU uses the volumetric efficiency to calculate the engine load. A high volumetric efficiency indicates that the engine is working hard, while a low volumetric efficiency indicates that the engine is not working hard.

MAP sensor method

The MAP sensor method calculates engine load by measuring the absolute pressure in the intake manifold. The MAP sensor is located in the intake manifold and measures the pressure of the air that is flowing into the engine. The ECU uses this information to calculate the engine load.

The MAP sensor method is less accurate than the volumetric efficiency method, but it is simpler and less expensive.