Engine Management Systems and Sensors

This assignment delves into the intricacies of engine management systems, covering essential components like sensors and their functions (e.g., oxygen sensor, mass airflow sensor). It further examines five primary pressure charging systems – turbochargers, superchargers, twin-scroll turbochargers, electric superchargers, and roots blowers – detailing their operation, advantages, disadvantages, applications, and limitations. The assignment aims to provide a comprehensive understanding of these critical aspects of modern automotive technology.

Abstract
This paper describes about the features of 5 types of sensors and actuators. Further, in
this report, investigation and disadvantages on different types of pressure charging systems
and its effect on an engine power are also given.

Contents
1. Introduction.......................................................................................................................................3
2. Types of sensors............................................................................................................................4
2.1 Oxygen Sensor (O2 Sensor).....................................................................................................4
2.2 Throttle Position Sensor (TPS Sensor).....................................................................................5
2.3 Engine Coolant Temperature Sensor (ECT)............................................................................6
2.4 Crank Position Sensor (CPS)...................................................................................................7
2.5 Knock Sensor...........................................................................................................................8
3. Actuators.......................................................................................................................................9
3.1 Exhaust Gas Recirculation (EGR)...........................................................................................9
3.2Fuel Pressure Regulator..........................................................................................................10
3.3 Fuel Pump..............................................................................................................................10
3.4 Electronic Throttle Control....................................................................................................11
3.5 Valve Timing Actuator..........................................................................................................11
4. Types of Pressure Charging Systems...........................................................................................12
4.1 Mechanically driven (supercharge)........................................................................................12
4.1.1 Power Increase and Limitation...........................................................................................12
4.2 Exhaust driven Turbocharger.................................................................................................13
4.2.1 Power Increase and Limitation...........................................................................................13
4.3 Electrically driven (Electronic Turbocharger)........................................................................14
4.3.1 Power Increase and Limitation...........................................................................................14
4.4 Chemical boosting (NOS)......................................................................................................15
4.4.1 4.3.1 Power Increase and Limitation...................................................................................15
5. Conclusion.......................................................................................................................................15
6. References.......................................................................................................................................16

1. Introduction
Numerous parts of an automotive makes up an engine but without having sensors and
actuators engine does not work appropriately. However, operation of engine is totally relying
on sensors and actuators and control on emission would not possible without them. Thus,
each component is significantly important in the engine machine and there are many sensors
and actuators in the engine. As a result, features of some sensors and actuators along with the
names, symbols, their single waveforms will be determined and also different types of
pressure charging systems with its pros-cons will also be demonstrated.

2. Types of sensors
2.1 Oxygen Sensor (O2 Sensor)
Fuel mixture information is gathered from the oxygen sensor. Further, PCM/ECU
uses the fuel mixture information for the purpose to rearrange the mixture of air/fuel.
A poor sensor of oxygen will result in using of more fuel and more radiations will
produce. The cause behind the poor sensor of oxygen is due to its oldness and also due to an
oil consuming engine.
 Symbol of an O2 sensor in a wiring diagram.
Figure 2 was retrieved from http://ww2.justanswer.com/uploads/Speedytimzalez/2010-02-08_233129_sdfgsfg.gif on
13.10.15
 Oscilloscopic illustrates waveforms of four different status of an oxygen sensor.
Figure 3 was retrieved from http://www.aa1car.com/library/o2chart.gif on 13.10.15

In case of standard operation circumstances, the good waveform goes up to a height
of more than 60v and goes as low as 0v. While in case of rich operation circumstances, the
range falls between 35v to 72v along with low oxygen utilisation. Further in case of poor
operation condition oxygen utilisation is high. A bad oxygen sensor will be running slow.
2.2 Throttle Position Sensor (TPS Sensor)
The position of throttle will be informed by the TPS sensor to ECU. Further, the
information will be used by the ECU for changing the spark timings as well as fuel mixture.
 The diagram shows the symbol of a throttle position sensor in a circuit.
Figure 4 was obtained from http://econtent.autozone.com:24991/znetrgs/repair_guide_content/en_us/images//
0900c152/80/06/7e/3b//medium/0900c15280067e3b.gif on 13.10.15
 Oscilloscopic demonstrate a good and bad waveform of a TPS and illustrates all
changes.

A good waveform generally starts with 0v at the time when throttle is sealed and
when the throttle is completely unlocked a good waveform starts with 5v. Likewise,
variations will take place in case of bad waveform.
2.3 Engine Coolant Temperature Sensor (ECT)
The temperature of the engine is examined through the ECT sensor. Signals are being
sent to the ECU for the purpose of amending extensive range of ignition and also for the
purpose of monitoring radiations.
To augment the driveability, a rich fuel mixture is needed. As and when the engine
extents at its maximum temperature, the ECU starts to use the indicator from the O2 Sensor
in order to differ the mixture of fuel.
 A symbol of the engine coolant temperature sensor is shown below.
 Below graph shows the waveform of coolant temperature sensor and exemplify how
its resistance declines as temperature inclines.
Figure 5 was obtained from http://www.aa1car.com/library/tps_waveform.gif on 13.10.15

As and when the temperature begins to upsurge, the temperature sensor of 20, 000
Ohms starts to decline. At 190 degrees Celsius, conflict will be lower than 500 Ohms.
2.4 Crank Position Sensor (CPS)
For observing the engine rpm, CPS sensor is required in order to inform the ECU
about the situation of crankshaft for regulating the spark timings and fuel delivery in the
proper order.
The another purpose of the CPS sensor is to inform the ECU for the purpose of regulating
the futile speediness of the engine.
 Figure shows the symbol icon of a Crank Position Sensor
Figure 6 was retrieved from http://www.slantsix.org/articles/dibiase_efi/chart.jpg 13.10.15

 Below diagram depicts the two waveform of a position of a crankshaft sensor and
exemplifies what is happening.
Above diagram depicts that the effect of CPS sensor tolerates to remain constant but rate
increases with engine rpm. While in the Magnetic Crank Sensor, amplitude and rate increases
with the engine rpm.
2.5 Knock Sensor
Figure 7 was obtained from http://www.justanswer.com/car/4axj7-hi-own-hyundia-excel-98-
model-car-stalls-wen-warms.html#re.v/149/ on 16.10.15
Figure 8 was retrieved from http://www.aa1car.com/library/crank_waveform.gif 16.10.15

Monitoring the vibration caused by ignition while sending the signals to ECU is the
function of knock sensor. When the signals are sent, the ECU briefly delay timings in the
meantime the engine is being underload to save the engine from the sparks.
 The illustration below shows the knock sensor symbol along with its connection
harness.
 Oscilloscopic shows the normal waveform of the knock sensor.
Above diagram shows the straight line which are maintained by the waveform of the
knock sensor but sometimes it rises to 5v.
Figure 9 was gotten from http://ww2.justanswer.com/uploads/goodwrench9124/2010-02-
21_152533_maf_sensor.gif on 16.10.15
Figure 10 was obtained from http://patrickmsblog.blogspot.co.nz/2010_09_01_archive.html

3. Actuators
3.1 Exhaust Gas Recirculation (EGR)
The purpose of EGR is to regulate the volume the deplete gas which is re-
circulated to ignition for reducing the radiations of nitrogen gas and also reduce
the fuel consumption.
 A symbol of EGR is shown in the wiring diagram below.
Figure 11 was retrieved from http://ww2.justanswer.com/uploads/EU/eurotec/2013-05-29_201322_84925762.gif
16.10.15

 A normal operation of EGR waveform.
The oscilloscopic depicts the EGR operation and also depict the method to recycle a minor
capacity of exhausted gas back into the initiation process of engine to decrease the nitrogen
gas.
For the purpose of regulating the amount of
gas being recycled, ECU controls EGR and
many devices that works along with the ECU.
3.2Fuel Pressure Regulator
The function of fuel pressure regulator is to monitor the fuel pressure continuously
and also retains the appropriate fuel
atomization. The job of fuel pump is to
force fuel to dazed the holding pressure
spring
inside to
the fuel
regulator.
Hence,
remaining fuel is
reverted back to the tank.
Figure 12 was retrieved from https://www.picoauto.com/library/automotive-guided-
tests/egr-solenoid-valve 16.10.15

3.3 Fuel Pump
In the car fuel system, fuel pump has 2 significant characters. The primary role is to
sieve the fuel in the tank before forcing to the injectors. The subsequent role is to pressurise
the fuel and pumps the injection system of the vehicle.
3.4 Electronic Throttle Control
To link the throttle with the accelerator pedal is the function of the Electronic throttle
control. Secondly, Electronic throttle control switches all the automated linkages. This is
prepared from the three machineries. Initially, the accelerator pedal has 2 sensors. Next,
throttle valves open and shut by an electronic motor. Lastly, the ECU unit gathered all the
data which is recovered from the electronic throttle control unit and its sensors.
Figure 13 was retrieved from http://forums.nicoclub.com/how-to-set-your-fuel-pressure-via-an-adjustable-fpr-fuel-pressure-regulator-
t214558.html 16.10.15
Figure 14 was obtained from http://www.netlink.net/mp/volks/htm/elec.htm 16.10.15

The benefits of the electronic throttle control are not easily witnessed by the users of
car. It aids the incorporation of features such as constancy control, transaction control, and
cruise control etc.
Figure 15 was obtained from http://toyotanews.pressroom.toyota.com/album_display.cfm?album_id=621&section_id=411
16.10.15
3.5 Valve Timing Actuator
There are significant effects of valve timing actuator on car radiations, fuel saving and
also on power. Further above impacts differs every time according to the engine conditions
for instance speed, load etc. The valve timing actuator is required for altering the scheduling
of the valve lift in the engine.

4. Types of Pressure Charging Systems
4.1 Mechanically driven (supercharge)
The supercharger is a pressure charging system which functions similar to an air
compressor that surges the thickness of the air pressure which is delivered to the engine.
Moreover, the supercharger unit supplies the oxygen to each cycle of the engine which causes
burying of more fuel thereby rises the power in the combustion engine.
Crankshaft is connected to the supercharger unit via belt, shaft, gear or through chain.
Therefore, when the power supplies, the supercharger starts functioning by pulling air in and
out from the ejection section.
 Figure shows the physical look of the supercharger unit and how it operates.
4.1.1 Power Increase and Limitation
There are number of benefits of supercharger unit like the trust from the low rev as it
does not require exhaust gas. Additional benefit is that it gets fast response from the throttle.
There is also very less mechanical stress (Hub Pages , 2011).
Figure 17 was obtained from http://www.cobaltss.net/forums/forced-induction-50/supercharger-vs-
turbo-40571/ 16.10.16

There is also a disadvantage to the supercharger unit is that it does not fetch
maximum performance because of its inherent system constraint.
Regarding the fuel consumption, the supercharger unit will consume the highest
amount of fuel due to inability to get the advantage from the exhaust gas (Hub Pages , 2011).
4.2 Exhaust driven Turbocharger
The turbocharger unit is also a pressure charging system which speeds the
effectiveness of the engine as well as supplying additional air into
the combustion engine. The turbine forces more air and more fuel at
the similar time in the combustion engine.
The major dissimilarity between supercharger unit and the
turbocharger unit lies with the connection which means turbocharger
unit is associated through turbine which is thereby devoted to the
exhaust gas of the engine. While supercharger unit is associated
through belt, chain etc. Another dissimilarity is that supercharger is
less efficient and productive than turbocharger unit but at the same
time it is less respondent than the supercharger unit.
Thus, the mixture of supercharger and the turbocharger is termed as twin charger.
Turbocharger unit application is found in many transport like trucks, airplanes, trains
as well as light motor vehicles.
4.2.1 Power Increase and Limitation
Pros:
 A substantial rise in engine horsepower.
 For the purpose of producing enormous power small engines will be facilitated.
 Small Engines increases the fuel savings as well as better fuel efficiency is also
enhanced (Car throttle , 2011-2015).

Cons:
X Turbochargers needs time to wind up and be able to supply improvement to the
wheels.
X Turbochargers are aimed so that exhaust gas flow is sufficient to supply extra boost to
the engine and that is why they cannot work in the vast range of rpm.
X There might be a volatility in the car because of some large turbochargers that reaches
to the edge which causes sudden increase in horsepower (Car throttle , 2011-2015).
4.3 Electrically driven (Electronic Turbocharger)
The concept of the electrical pressure supercharger is same as that of traditional
supercharger because the traditional supercharger uses an electrical motor to force the air
instead of belt or chain. Thus, when the air is forced, the fuel is very much consumed which
results in producing more horsepower in the engine.

4.3.1 Power Increase and Limitation
Electrical superchargers are same as that of traditional superchargers because
traditional superchargers are powered by the electricity. Further the traditional superchargers
are very expensive ranges between $ 1800 to $ 2800 whereas the Electrical superchargers are
not expensive and its cost is less than $ 80. Moreover, fuel consumption is also same.
There are also drawbacks relating to the electrical superchargers. First drawback is that the
performance is not same again as the traditional supercharger because of its design. Second
drawback is that airflow is also limited that would not produce boost (Cars Direct , 2012).
4.4 Chemical boosting (NOS)
To boost the vehicles and to increase the horsepower, the chemical boosting (NOS) is
the technology. For example, when nitrogen gas is incorporated into 300 degrees’ Celsius
heat temperature then it gets alienated into nitrogen and oxygen and then it is incorporated in
to the engine, huge amount of oxygen will be available in the engine. Hence, fuel mixture
will be enormous thereby enable the engine to produce more power consequently.
To boost up gasoline engines, Nitrous oxide is best way to provide the dramatic horse
power.
One more advantage is that it augments and upgraded the performance of the vehicles
when the NOS vaporises, it becomes cold which is important for cooling the intake air down
and permits the more oxygen flow in the engine.

4.4.1 Limitation
There is a disadvantage to the nitrous oxide which is related to its bulkiness. The
engine needs big amount same as that of gas. Also when it is turned into a liquid form it again
requires a good volume of space.
A 5000cc engine that runs 4000rpm approximately uses 10, 000 of oxygen gas every
minute which is thereby equal to 0.2 litre of gasoline.
5. Conclusion
This report demonstrates some main parts of the Engine management area. Further
this paper has also described five main sensors with its functions and detailed description and
also mentioned symbols in wiring diagrams.
Moreover, in this report 5 main types of pressure charging systems accompanied with
its functions, impacts, applications and limitations are also described.

6. References
AutoTap. (2012). Introduction to Engine Management Systems. Retrieved from AutoTap :
http://www.autotap.com/techlibrary/Intro_to_Engine_Management.asp
Autotronics . (2010, September 20). TTEC 4826– Engine Electronic Control Systems Off Car
. Retrieved from Autotronics :
http://patrickmsblog.blogspot.co.nz/2010_09_01_archive.html
Car throttle . (2011-2015). Engineering Explained: The Pros And Cons Of Turbochargers Vs
Superchargers. Retrieved from Car throttle.com :
https://www.carthrottle.com/post/engineering-explained-the-pros-and-cons-of-
turbochargers-vs-superchargers/
Cars Direct . (2012, October 31). The Pros and Cons of an Electric Supercharger. Retrieved
from Cars Direct : http://www.carsdirect.com/aftermarket-parts/the-pros-and-cons-of-
an-electric-supercharger
Cobaltss. (2010-2015). Supercharger Vs Turbo. Retrieved from Cobaltss:
http://www.cobaltss.net/forums/forced-induction-50/supercharger-vs-turbo-40571/
Continental . (2015). Sensors & Actuators. Retrieved from Continental :
http://www.continental-automotive.com/www/automotive_de_en/themes/
passenger_cars/powertrain/sensors_actuators_en.html?page=4
Hobbs, M. (2009, December 11). GMs Variable Valve Timing. Retrieved from Diagnostic
News : http://www.diagnosticnews.com/gms-variable-valve-timing/

HowStuffinMyCarWork. (2015). How the fuel pressure regulator works:. Retrieved from
HowStuffinMyCarWork:
http://www.howstuffinmycarworks.com/Fuel_pressure_regulator.html
Hub Pages . (2011, March 31). Advantages and Disadvantages of Supercharger. Retrieved
from Hub Pages : http://daffodil2010.hubpages.com/hub/Advantages-and-
Disadvantages-of-Supercharger
LaunchPoint . (2014, July 07). Electromechanical Valve Actuator for Variable Valve Timing.
Retrieved from Your Partner in Innovation :
http://www.launchpnt.com/portfolio/transportation/electromechanical-valve-actuator/
Toyota . (2010). 2010 Toyota Electronic Throttle Control. Retrieved from Toyota:
http://toyotanews.pressroom.toyota.com/album_display.cfm?
album_id=621&section_id=411
Wikipedia . (2015, October 09). Superchrager . Retrieved from Wikipedia :
https://en.wikipedia.org/wiki/Supercharger