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1. Engine Management Systems
A Brief Introduction
Presented by :

2. EMS is a type of electronic control unit
that controls the running of an engine by
monitoring the engine speed and ensure
optimal engine performance .
Introduction

3. The Engine Management System (EMS) is
responsible for controlling the amount of fuel
being injected and for adjusting the ignition
timing. Optimum functioning of the EMS
assures maximum engine power, with the
lowest amount of exhaust emissions and the
lowest fuel consumption.

4. Sensor
I/P
ECU
Stage Actuator
O/P
EMS SCHEMATIC

5. Sensors
Engine sensors in a vehicle are incorporated to
provide the correct amount of fuel for all operating
conditions. A large number of input sensors are
monitored by the engine control unit. Today, sensor
technology has become common in modern
vehicles. Sensors enhance safety of the people -
both on board and on road, control vehicle
emissions and make vehicles more efficient. In this
article, we will discuss different types of engine
sensors used in modern vehicles.

6. Mass Air Flow Sensor
(MAF)
The MAF sensor (electric
sensor) is an integral part
of the engine system. It is
located in a plastic covering
between the engine and
the air filter.
The purpose of MAF is to
calculate the amount of air
intake by the engine, in
terms of volume and
density
. For measuring the volume
and density of air, the sensor
uses either a hot wire or a
heated filament. After the
measurement, it sends a
voltage signal to the computer.
With this, the computer can
calculate the right amount of
fuel needed to maintain the
correct fuel mixture for every
operating condition. If there is
any fault in the MAF sensor, it
may result in rough idle,
stalling and poor fuel economy.

8. Throttle Position
Sensor (TPS)
The Throttle Position Sensor
(TPS) is a variable resistor
attached or mounted on the
throttle body and is operated by
moving along with the throttle
shaft or spindle. The TPS
changes the resistances as the
throttle opens and closes, and
sends a voltage signal to the
computer showing the angle or
position of the throttle
Thus, the TPS causes the Electronic
Control Unit (ECU) to use the data to
measure the engine load, fuel delivery
adjust timing, acceleration, deceleration
when the engine is idle or in wide open
throttle, and then makes the changes
according to the operating conditions. Fuel
rate is either increased or decreased to
achieve this.

10. The CTS measures the internal
temperature of the engine
coolant. It also senses the
changes in temperature and
sends a voltage signal to the
Powertrain Control Module
(PCM) for determining whether
the engine is cold or warming
up, is at normal operating
temperature or is overheating.
Coolant Temperature
Sensor (CTS)
The Coolant Temperature
Sensor (CTS) is a temperature
dependent variable resistor
located on the cylinder head or
intake manifold. The CTS is an
important sensor and the
operating strategy of the engine
depends on the signal it sends.
So, it is called the “master”
sensor.

12. Oxygen Sensor
The oxygen sensor is located
on the exhaust manifold. This
sensor monitors the amount of
unburned oxygen present in the
exhaust. When the fuel mixture
is rich, most of the oxygen is
exhausted during the
combustion. So, only a little
unburned oxygen will be left out
in the exhaust
Difference in the oxygen levels
creates an electrical potential,
which causes the sensor to
generate a voltage signal. This
helps the ECU to check the
quality of fuel mixture to make
the changes accordingly. The
sensor output will be high if the
fuel mixture is rich, and the
sensor output will be low if the
fuel mixture is lean

14. Manifold Absolute Pressure Sensor (MAP)
The MAP is a key sensor as it senses the engine load. It
is mounted on the intake manifold. It monitors the
difference between the air pressure in the intake
manifold and outside. This sensor responds to the
vacuum in the intake manifold and generates a voltage
signal accordingly. It then sends the signal to the PCM.
The input of the sensor is used for adjusting the fuel
mixture and ignition timing, according to the changes.

16. Knock Sensor
The Knock Sensor detects engine
knock and sends a voltage signal
to the engine and the engine
uses that signal to control the
timing

17. Knocking (also knock, detonation, spark knock, pinging orpinking) in
spark-ignition internal combustion engines occurs when combustion of
the air/fuel mixture in the cylinder does not start off correctly in response to
ignition by the spark plug, but one or more pockets of air/fuel mixture
explode outside the envelope of the normal combustion front.

18. Engine Speed Sensor
An engine speed sensor is attached
to crankshaft of car's engine and it
indicate the speed that crankshaft
is spinning. This information is
beneficial to control both the ignition
timing and EMS.

20. Engine Oil Sensor
It measures the oil pressure inside
the engine and gives an alert in
case of any problem with oil
pressure.

22. Crankshaft sensor
It is used to monitor the position and
rotational speed of crankshaft and these
information will be used by the EMS to
control the ignition system timing and other
engine parameters.

24. Camshaft Sensor
The Camshaft sensor determines
which cylinder is firing to establish
injector synchronization and coil
firing sequence in DIS systems
then only crankshaft sensor set
ignition timing, supply the signal
and measure the speed.

26. Multi-point fuel injection
In this system each cylinder has number
of injectors to supply/spray fuel in the
cylinders as compared to one injector
located centrally to supply/spray fuel in case
of single point injection system

28. Electronic
Fuel
Injection
System

29. ADVANTAGES
• Ease of Control
• Adaptable to multiple scenarios
• Very low cost compared to mechanical systems
• Occupy lesser space-compact engine bay
• Less complicated design
• Zero wear

30. AUTO TUNING
• Software on ECU known as a map
• New maps can be loaded to ECU [ process
known as re-mapping or flashing]
• Complete access to parameters such as fuel
injection quantity, boost pressure, ignition
timing, idle speed setting
• No costly equipment required, laptop, Tuner
EMS s/w & ODB cable
• Plug & play ECU’s with multiple maps
available.