Department of Process Engineering

       Department of Process Engineering    
Module: Technical English X
  Bachelor Year X – Semester X   Case Study (Problem-Oriented Method)    XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX                                                                 Submitted to:                                                                    



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DepartmentAcademic Departments
Issue Date17/01/2016

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Programme: Process Engineering.

Module Code: TENG-V

Module Title: Technical English V.

Name: Amira Obaid, Iman Ahmed, Shamsa Sais, Wafa Abdullah

IMCO student ID number: 004441-17, 004713-18, 004364-17, 004362-17

Class: PE3B

Signature Amira, Iman, Shamsa, Wafa .                                                   Date: 9 May 2021

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Table of Contents

Executive Summary:                                                                                                                   1

Introduction:                                                                                                                               2

Findings:                                                                                                                                      2

Analysis and discussion:                                                                                                              3

Alternatives and solutions:                                                                                                         4

       Diesel oxidation catalyst (DOC):                                                                                 5

       Diesel particulate filter (DPF):                                                                                     5

       Selective catalytic reduction (SCR):                                                                            5

Implementation plan and Recommendation:                                                                            6

Conclusion:                                                                                                                                  8

Reference:                                                                                                                                   9

Executive Summary:

Diesel engines emissions and releases are a major source of pollution especially for air pollution. This impacts the environment directly at the same time of it has negative effect to the human health and body. Moreover, the combustion rate of diesel is fast which increases the rate of emission released to the air.

There are many solutions can be done to reduce the emission and toxic gases especially NOx down to 90% only by using a selective catalytic reduction (SCR) method with the used diesel. Also, diesel particulate filter (DPF) is used in vehicle engines which reduces PM emissions from exhaust gas by physical filtration.

 These emissions could deeply impact on human health as Nitrogen oxide which generated at high pressure and temperature. This gas can form nitric acid with water in the lung, skin, and mucous membrane. Moreover, this gas effect on environment and cause acidic rain.

Therefore, this case study has dealt with diesel engine emission and its toxic releases and their impact to the environment.


Climate change is a serious and global environmental threat caused by people and their way of life. Diesel is used in engines and heavy vehicles that transport goods, public transport, and electricity generators, as well as some types of diesel used to power ship engines. Harmful diesel emissions considered as one of the biggest problems causing massive amounts of pollution on the planet. Diesel engines have several advantages that make it the most preferred, usable, and most widely used.

In addition, emissions from diesel engines has a five major pollutant which are: carbon monoxide-CO, hydrocarbons-HC, sulfur dioxide SO2 , particulate matter-PM and nitrogen oxides-NOx . In this case study, we would like to discuss how harmful diesel emissions can operate with greater impact with fewer emissions. Details of this problem are explained in this study to emphasize its importance. Also, some suitable solutions were proposed to reduce these emissions and obtain an environment free of diesel pollutants harmful to humans and the entire Earth.


  • The working principle of diesel engine and its working parameters that is required to operate the engine.
  • Emissions production and toxic gases released by combustion of diesel due to the high parameters of temperature and pressure.
  • The released gases impact on the human health and body which can causes many diseases for respiratory system and nervous system.
  • The impact of emissions on the environment which causes air and water pollution. This can affect the living creatures in the environment very bad.

Analysis and discussion:

The combustion of diesel occurs in engines of cars, trucks, planes, and many types of equipment in industries. It is converting chemical energy contained in the diesel into mechanical energy. The diesel must be mixed with oxygen to achieve the process. Air (oxygen) is compressed into a combustion chamber with approximately 40 bar pressure. Due to the huge compression in the chamber, the air heats up directly to 1000°F.Then, diesel is pushed into the chamber of the compressed air using a fuel injector, where the ignition is started. Combustion of diesel and high pressure pushes the piston of the engine outward that is running the crankshaft.

Toxic emissions are released from engines while the composition of the diesel fuel is processed. These gases are released into the atmosphere through the exhaust pipe or the thrust nozzle. Gases emitted by the wind are distributed which affects the environment and humans. When the rate of combustion is increased will cause to emit more harmful gases and the influences will be more. The most harmful emissions are carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), and hydrocarbons.

 Carbon monoxide is released with high concentration which negatively affects the nervous system of people. Breathing of Carbon monoxide can cause lethargy, headaches, dizziness, and vomiting. In addition, Exposure to high levels of carbon monoxide over long periods of time can be caused an increased risk of heart disease. Nitrogen oxide is produced from nitrogen gas and oxygen under conditions of high pressures and temperature in the engine chamber. Its poisonousness relates to its ability to create nitric acid with water in the lung, skin, and mucous membrane.

This gas is an environmental concern because of its character in smog formation. Further, Nitrogen dioxide and sulfur dioxide reacts with oxygen in the air which caused acid rain that influences agriculture, plants, and animals. Spreading diesel emissions into the atmosphere leads to air and water pollution. It leads to injured birds which may cause them to fall into the sea. Furthermore, marine organisms will be influenced which negatively affects the healthy food of humans. Toxic gases will pollute the air which can contribute to increasing global warming.

Alternatives and solutions:

Nowadays, the interest in protecting the environment has become a topic of central concern. Due to the importance of this problem, many policies have been imposed around the world in recent years to limit the harmful effects of diesel engine emissions on human health and the environment. A lot of research has been done on both emissions of diesel exhaust pollutants and techniques for controlling after treatment emissions.

Emission control systems for diesel engine vehicles were created as a solution to reduce these emissions. The governments processed to the requirements for permissible exhaust emission standards, So Europe has developed Euro standards which have continuously been lowered since (1993) with the Euro I to Euro VI, respectively.

The table provided, shows Euro standards for M1 and M2, N1 and N2 vehicles as defined in Directive 70/156/EC with reference mass ≤2,610 kg. Regulations in Euro standards become progressively essential over time. In contrast to the Euro I standard, the Euro VI standard reduced CO, HC, NOx, and PM emissions by 66, 76, 95, and 98%, respectively. The Euro VI standard for heavy-duty vehicles took effect on September 1, 2014. (Delphi et al. 2012). Day after day, stricter emission values have obligated car manufacturers to work to reduce pollutant emissions from vehicles.

CO (g/kWh)HC (g/kWh)NOx (g/kWh)PM (g/kWh) 
Euro I4.
Euro II41.17.00.15
Euro III2.10.665.00.13
Euro IV1.50.463.50.02
Euro V1.50.462.00.02
Euro VI1.

Euro standards of European Union for heavy-duty vehicles (Delphi et al. 2012)

The emission control systems are DOC, DPF, and SCR systems especially which is for heavy-duty diesel engines are considered separately.

●       Diesel oxidation catalyst (DOC):

The DOC primary function is to oxidize HC and CO emissions. Furthermore, DOCs help to reduce the mass of diesel particulate emissions by oxidizing some of the hydrocarbons that are adsorbed onto carbon particles (Chen and Schirmer 2003; Wang et al. 2008). DOCs can also be used with SCR catalysts to oxidize NO into NO2 and increase the NO2:NOx ratio.

●       Diesel particulate filter (DPF):

DPFs have been used in vehicle production since 2000. They are typically made of cordierite (2MgO–2Al2O3–5SiO2) or silicon carbide (SiC) honeycomb structure monolith with the channels blocked at alternate ends to remove PM emissions from exhaust gas by physical filtration.

●       Selective catalytic reduction (SCR):

Selective Catalytic Reduction (SCR) is an advanced active emissions control technology system used in diesel engines. This technology is one of the most cost-effective and fuel-efficient technologies available to help reduce diesel engine emissions. is designed to permit nitrogen oxide (NOx) reduction reactions to take place in an oxidizing atmosphere. It is called “selective” because it reduces levels of NOx using ammonia as a reluctant within a catalyst system.

The chemical reaction is known as “reduction” where the DEF is the reducing agent that reacts with NOx to convert the pollutants into nitrogen, water and tiny amounts of CO2. The DEF can be rapidly broken down to produce the oxidizing ammonia in the exhaust stream. SCR technology alone can achieve NOx reductions up to 90%. Figure 1 shows the typical SCR system with DOC.

(Figure 1) Typical SCR system with DOC

Implementation plan and Recommendation:

Diesel exhaust after treatment systems includes DOC, DPF, and SCR. It is the most in-demand components, particularly for heavy-duty diesel engines. DOCs raise the exhaust temperature for DPF recycling and convert NO to NO2 to improve SCR machine conversion performance. To transform NOx emissions to N2, NH3 is used as an unwilling and is injected into the exhaust gas. The heat of fuel exhaust gas has a significant impact on pollutant reduction. For instance, the DOC, DPF, and SCR are examples of diesel exhaust after treatment schemes.

These are the most in-demand materials, associated with heavy diesel engines. DOCs raise the combustion temperatures for DPF recovery and switch NO to NO2 to improve SCR machine conversion performance. To transform NOx emissions to N2, NH3 is used as a reducing agent and is injected into the waste heat. Also, the temperature of diesel waste heat has a major impact on particulate matter pollution. Other variables influencing the performance of such after treatment technologies include exhaust gas space acceleration and emission form. Catalysts based on Pt and Pd is the most widely used by DOC and SCr.

Other parameters that influence performance include emission form, space velocity, and emission type. Another critical factor in eliminating emissions is the number of contaminants in the exhaust gas and the temperature of the liquid. PM pollutants are an assemblage of very smaller pieces of partially burned gasoline, partially burned lube oil, mineral composition of fuel oil and cylinder lubricated condoms oil, or sulfates and water.

 It has proven some modern technologies for some companies after doing some serious research. For example, TJI technology significantly improves the ignition process, increasing fuel consumption and lowering emissions. It operates by combining a limited amount of air and fuel in a pre-chamber, which is a small cavity apart from the central combustion chamber. As this combination is ignited, turbulent jets of hot radicals flood the main chamber.

For the two-stroke opposed piston design, pistons are arranged around a central shaft that delivers torque to the transmission. The design provides two combustion events per cylinder, per engine revolution, which is teaming up with aches Power to create a three-cylinder Gasoline Compression Ignition (GCI) version of this engine. The aim is to achieve a 50 percent increase in automobile fuel economy. Our times more than a conventional four-stroke engine. The latest technology is the Mobile Carbon Capture (MCC) has the potential to capture up to 25% of the CO2 released from a vehicle’s exhaust. The technology has a wide range of industrial and consumer uses. MCC technology has been successfully demonstrated in a Ford F-250 pickup truck and a medium sized Toyota Camry passenger vehicle by one group

(Figure 2) innovating across the vehicle to drive efficiency and lower emissions.(Aramco,2021)



In conclusion, diesel fuel combustion is one of the most processes that used to operate heavy vehicles and engines in many applications. The compressed diesel is mixed with the oxygen in the chamber where the chemical energy is converted to mechanical energy. However, this process leads to emits poisonous gases in the form of black smoke in the atmosphere. It negatively affects the environment, animals, and humans. hydrocarbons (HC), carbon monoxide (CO), nitrogen dioxide (NO2), and sulfur dioxide (SO2) are some types of emissions that released into the atmosphere and affect the environment and healthy. The details of this problem and its effect are examined briefly in the analysis and discussion stage. We came up with some of alternative solutions for this problem and analyze these solutions in the discussion stage. The best recommendation on reduce emissions of diesel ignition is TJI technology. It improves the rate of combustion diesel process while increasing fuel consumption and reducing the emitted gases. It operates by mixing a limited amount of oxygen and fuel in the chamber. This way will achieve an increase of 50% in fuel economy. More details of the improving process were covered in the implementation plan and recommendations stage. The governments must study this issue and pursue providing appropriate solutions that save humans and the environment from emissions.



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