technologies and methods for reducing vehicle emissions and fuel consumptions final

7/30/2019 Technologies and Methods for Reducing Vehicle Emissions and Fuel Consumptions Final

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Chapter 1

Automotive Manufacturers and Reasons for Reducing Vehicle

Emissions and Fuel Consumptions

1.0 Introduction:

Modern European automotive manufacturers face strict emission legislation standards and

strict customer demands for improved fuel efficiencies while maintaining vehicle drivabilitys

and performances. Customer demands for improved fuel efficiencies are mainly caused due to

the growing concerns about oil shortages and their unstable rise on cost.

Emission legislation standards such as the euro v and the upcoming euro vi are put into place

by the European Union in order to reduce the phenomenon of the Global Warming and to

reduce environmental issues that are caused from vehicle emissions. The three types of

vehicle emissions that affect the environment and tend to speed the phenomenon of the global

warming are the carbon dioxide (CO2), Hydrocarbons (HC) and Oxides of Nitrogen (NOx).

To improve fuel economy and tailpipe emissions, the automotive manufacturers have

introduced a number of inventions. Those inventions can identified as efficiency

improvements known as variable valve actuation, direct injection, cylinder deactivation, and

force induction techniques.

Due to the fact that emission regulation standards are constantly becoming stringent, the

automotive manufacturers had to combine those technologies with the following strategies:

Engine Downsizing: is the method in which the capacity of an internal combustion engineis reduced for improving vehicle harmful emissions and fuel consumptions.

Hybridization: is the method in which vehicles are powered by two or more distinctsources for improving vehicle harmful emissions and fuel consumptions.

Alternative Fuels: is the method in which vehicles are powered by the use of non-conventional fuels known as biofuels, hydrogen and electricity for reducing vehicle

harmful emissions and replacing the needs for fossil fuels.

This document includes a comparison analysis between the different approached followed by

the automotive manufacturers to reduce vehicle emissions and improve fuel consumptions

and specify which method is more effective and efficient for the future.

In this chapter (chapter 1) the aim is to investigate and discuss the issues that have forced the

automotive manufactures to develop various technologies for reducing vehicle emissions and

improving fuel consumptions. The main issue areas that will be under review and discussion

are the global warming, regulations and oil shortages.


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1.1 Global Warming:

Global Warming is the rise in temperature of the Earths atmosphere due to greenhouse gas

emissions such as carbon dioxide and other pollutants which trap heat (solar radiation) near

the earths surface that would otherwise escape the Earth. According to Jeremiah & Elizabeth

This pollution comes largely fromcars, power plants, factories and homes when we burn

fossil fuels such as coal, oil and natural gas, as well as from other human and natural

processes. Cars and Global Warming (p8. 2005)

The main green house pollutant that is produced by the automotive vehicles during the

combustion of fossil fuels (Diesel or Petrol) is carbon dioxide (CO2). Carbon dioxide is a

product of an insufficient or incomplete burning process during combustion process. Carbon

dioxide is not the only greenhouse pollutant produced by the internal combustion engines;

there are other hazardous emission products such as CarbonMonoxide (CO), Hydro Carbons(HCs), Oxides of Nitrogen (Nox) and Particulate Matters (PMs). Compression Ignition

Engines are particulate matter free.

According to Bert et al, greenhouse emission generally and globally has accounted for energy

supply for about 26%, industry 19%, gases released from land-use change and forestry 17%,

agriculture 14%, transport 13%, residential as well as commercial and service sector 8% and

waste 3%. Climate Change (p27. 2007)

The Figure 1.0 below represents the greenhouse gas emissions of transportation which include

the motor vehicle sector and its impact to the environment. It can be seen that transport

emissions are considerable increased at year 2004 compared to the year 1990.

Figure 1.1.0 (Climate Change (p29. 2007))

Due to the increase of greenhouse gas emission and the negative effects to the environment

and health, the European Union has placed various strict emission legislation standards to

minimize the negative phenomenon of the Global Warming and its effects associated with

health and the environment. (See next page emission standards)


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1.2 Emission Regulations:

The tables 1.1 and 1.1 below represent the limitations to pollutant gas emissions put in force

by the European Union in order to limit as much possible the negative effects and impact of

road vehicles on the environment and health.

According to the official website of the European Union and nextgreencar.com, the euro

standards below are put in place by the European Union in order to cover vehicles of category

M1 (Passenger Vehicles) with a reference to mass not exciting 2610kg.

Table 1.2.0 (euro standards for diesel powered vehicles of category M1)

Compression Ignition Engines (Diesel)

Stage Date CO HC HC + NOx NOx PM PN

(g/km) (g/km) (g/km) (g/km) (g/kg) (*/kg)

Euro 1 1992.07 2.72 (3.16) - 0.97 (1.13) - 0.14 (0.18) -

Euro 2, IDI 1996.01 1.0 - 0.7 - 0.08 -

Euro 2, DI 1996.01 1.0 - 0.9 - 0.10 -

Euro 3 2000.01 0.64 - 0.56 0.50 0.05 -

Euro 4 2005.01 0.50 - 0.30 0.25 0.025 -

Euro 5a 2009.09 0.50 - 0.23 0.18 0.005 -

Euro 5b 2011.09 0.50 - 0.23 0.18 0.005 6.01011

Euro 6a 2014.09 0.50 - 0.17 0.08 0.005 6.01011

Euro 6b 2015.09 0.50 - 0.17 0.08 0.005 6.01011

Table 1.2.1 (euro standards for petrol powered vehicles of category M1)

Positive Ignition Engines (Petrol)

Stage Date CO HC HC + NOx NOx PM PN

(g/km) (g/km) (g/km) (g/km) (g/kg) (*/kg)

Euro 1 1992.07 2.72 (3.16) - 0.97 (1.13) - - -

Euro 2 1996.01 2.2 - 0.5 - - -

Euro 3 2000.01 2.30 0.20 - 0.15 - -

Euro 4 2005.01 1.0 0.10 - 0.08 - -Euro 5 2009.09 1.0 0.10 - 0.06 0.005 -

Euro 6a 2014.09 1.0 0.10 - 0.06 0.005 6.01011

Euro 6b 2015.09 0.1 0.10 - 0.06 0.005 6.01011

The above tables represent the emission legislation changes from 1992 (Euro 1) to 2015 (Euro

6). It can be seen that the upcoming official legislation standards (euro 6) for emissions are

reduced. For diesel engines, Hydrocarbons and Oxides of Nitrogen must be reduced from

0.23g/km to 0.17g/km. For petrol engines, Carbon Dioxide must be reduced from 1.0g/km to

0.1g/kg.


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1.3 Oil Shortages:

According to Dr. M. King Hubbert the first geoscientist who has studied the peak oil effect,

he stated that the oil in the US would peak in 1970 and it will follow a bell-shape curve. The

prediction is proven to be true. Peak oil is defined as the critical point at which reservoirs

can no longer produce increase amounts of oil, basically is the point at which maximum

production is reached and afterwards no matter how many wells are discovered in a country,

production begins to decline. Jonah (p7. 2008)

Dr. Kenneth Deffeyes, a geologist and former oil and mining consultant who worked with Dr.

Hubbert, he used Huberts method to determine the peak point of the worlds oil production.

Dr. Deffeyes came to a conclusion that the worlds oil production is more likely to peak at the

end of 2005. Deffeyes (p43. 2006)

Similarly to Dr.Kenneth Deffeyes conclusion, a German non-profit group of European

Scientists and few parliamentarians performed a comprehensive study according to when the

worlds oil production is more likely to peak. Their results indicated that the oil peak is

already happened in 2006.) (See figure 1.1 worlds oil Peak Point)

Figure 1.3.0 (Oil Peak Point)

Schindler (p12. 2008)

The downside effects of the Peak point are the prices of crude oil per barrel. Once peak point

is reached, the next step is shortfall (see figure 1.1). Shortfall is the period at which the oil

demands outstrip the available supply; basically the demands of oil are greater than what is

available for use, as a result this causes the prices of oil to bid up. As the oil prices bid up,

which is the current case worldwide; fuels for modern transportation become more expensive.

In order to save fuel and costs, automotive manufacturers invent various technologies thatwill be reviewed further in this report. (See automotive inventions and systems next page)


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Chapter 2

Engine Downsizing and Combined Technologies for

Reducing Vehicle Emissions and Fuel Consumptions.

2.0 Engine Downsizing:

In this chapter the aim is to review the principle of engine downsizing and combined

technologies. In this chapter, the author will specify the advantages and disadvantages of

engine downsizing and combined technologies regarding to vehicle emissions and fuel

consumptions.

Driven by the customer demands for improved fuel economy as well as from emission

legislation standards for reduced emissions, most of the engine manufacturers have turned

towards to engine downsizing as one of the most efficient ways to meet these requirements.

Engine downsizing is the conversion of engines from larger to smaller. Apostolos et al (p1.

2010)

The main reason most automotive engine manufacturers have been drawn towards reducing

the size of an internal combustion engine, is due to the advantages that are on offer compared

to larger engines. Those advantages can be expressed as low cost due to the reduction of

material, less overall cost of ownership, less weight and more installation space, less

resistance to inertia, and in some specific areas of the engine less frictional resistance between

rotating components. Brown et al (p61-62. 2010)

The downside of reducing the capacity of an internal combustion engine is that the

performance and power of the engine is lowered. In order to overcome this problem, Attard et

al is expressing that for downsized engines to be comparable to their larger counterparts, the

specific output performance must be increased by a ratio equal to the reduction in engine size.

Turbocharging seems to be the most acceptable solution meeting the requirements, with high

pressure ratios achievable and well documented improvements in efficiency. Attard et al

(p1. 2009)

The reason most automotive manufacturers have used the principle of force induction(turbocharger/supercharger) to improve the specific output performance of downsized

engines, is due to the customer requirements for improved fuel efficiencies for better fuel

economy and emission legislation standards for lower taxation.

In addition to force induction, downsized internal combustion engines can be combined with

other technologies and minimize the current issues of emissions and fuel consumptions.

Those technologies can be classified as direct injections or otherwise called in-cylinder

injection, variable valve timing/or actuation, cylinder deactivation and etc. All available

technologies will be discussed and analyzed in the following pages of this report including

force induction.


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2.1 Force Induction:

The most efficient way to achieve the principle of force induction for reducing vehicle

emissions and fuel consumptions is by the use of a turbocharger. A turbocharger is a device

that forces air into the engines cylinders under a pressure which is higher than atmospheric .

In simple terms, a turbocharger during operation results to an increase of air mass more than

that of a naturally aspirated engine. The result of such as a device is that the charge air within

the engine cylinders will increase the power density.

According toHilliers (p122. 2011) the advantages of a turbocharger are:

1. Higher torque for acceleration from low speeds2. Lower exhaust noise and emissions3. And better fuel economy

The main reason turbochargers lower emissions and improve fuel consumptions is due to

exhaust gas recirculation and more complete burning process. Exhaust gas recirculation is

achieved when the energy containing molecules which are produced during exhaust stroke,

instead of exiting the engine directly throughout the exhaust system are redirect to the turbine

to power the compressor. As a result this tends to reduce harmful emissions. (See figure 2.1

below)

Figure 2.1.1

AR TURBO (arturbo.co.uk)

In turbocharged engines fuel efficiencies are improved due to two reasons; the first reason is

that turbocharged engines convert a greater amount of fuel into useful work compared to

naturally aspirated engines and the second reason is that turbocharged engines are more

thermal efficient than naturally aspirated engines.

According to Jarut (p342. 2010), turbocharged engines are more thermal efficient than

naturally aspirated engines due to the fact that turbochargers increase the intake air pressure

prior entering it into the engine cylinders.


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Some other reasons that make turbocharged engines more fuel efficient than non-

turbocharged engines is that they can be designed to be smaller and lighter compared to larger

engines for the same power output (see page 5).

As known operating with less weight results to less fuel consumptions, and having smallerengines, the frontal area of the vehicles can be reduced for better aerodynamic drag. Less

aerodynamic drag results to lower fuel consumptions. Brown et al (p61. 2010)

A single turbocharger (single-stage turbocharging) as mention above offers a wide range of

advantages. Despite the fact that a single-stage turbocharger is an acceptable and efficient

solution for upgrading the lowered performance of downsized engines, turbochargers in the

recent automotive/motorsport sector are improved even further by becoming a dual-stage

turbochargers. (See dual-stage turbocharging below)

Figure 2.1.2

MAN (mandieselturbo.com)

A dual-stage turbocharger is a device which combines the operational function of two

turbochargers joint together under a synchronization which is set by the responsible

manufacturer or user. According to Byungchan (p11/12, 2009) the immediate benefit of

installing a dual-stage turbocharger to an internal combustion engine is that the specific power

level across a broad range of speeds is improved. This effect is due to that the boost levels

provided to the engine cylinders by a dual-stage turbocharger is much higher than that

provided by a single-stage turbocharger.

In addition to the above, a dual-stage turbocharger can provide a better overall efficiency at

high intake manifold pressures (compared to a single-stage turbocharger) due to the reasonthat the compression of the engine is done in two stages instead of one.


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The downside of a single-stage turbocharger is that is unable to offer the levels of efficiency

provided by the dual-stage turbochargers because at high intake manifold pressures in excess

of 3.5 bars or more, the efficiency of single-stage turbocharger becomes unacceptably low

whereas the dual-stage turbocharger operates more efficiently as the pressure ratio at each

stage is well within the efficient region in the performance map.Byungchan (p12, 2009)

Another advantage of the dual-stage turbochargers over the single-stage turbochargers is that

they are effective in reducing the possibility to what is so called compressor surging.

Compressor surging is a high pitch vibration which originates from the compressor side of the

turbocharger.

Surging is caused when a breakdown of the gas flow takes place and a reversal of air

scavenging though the turbochargers diffuser and impeller blades into the compressor. This

then causes a rise of vibrations which are referred as surging. Surging must be avoided due

the reason it may lead to damage of both, turbocharger and engine.

Dual stage turbochargers minimize the effect of surging because the pressure ratio created by

the turbocharger is divided into two smaller steps without affecting the mass of the flow rate.

Basically the first stage occurred by the first and smaller turbocharger is more robust in terms

of the surge limit.

Lastly, by using dual-stage turbochargers the transient behavior of the engine duringoperation is improved even further because of the two turbochargers combined to one. The

smaller turbocharger is a high pressure turbocharger and the larger turbocharger is a low

pressure turbocharger.

By configuring the two turbochargers together with an appropriate engine matching, this type

of turbocharger provides significantly better boosting characteristics at steady and transient

conditions. The smaller turbocharger at its high pressure stage provides more power to the

compressor enabling a higher boost at early state of acceleration and steady state of low speed

operation. The large turbocharger on the other hand offers sufficient pressure ratio from

medium to high engine speeds from where the smaller turbocharger is unable to provide the

engine cylinders with sufficient pressure.

The downside of dual-stage turbochargers related to downsized engines is that extremely

downsized engines may not be able to operate efficiently with the adaption of two

turbochargers. This is due to the reason that the exhaust gas energy produced during

combustion process may not be sufficient to operate or drive the turbines efficiently.


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In order to boost up the power and torque outputs of extremely downsized engines, there is an

alternative solution to this problem. The alternative solution is a single variable geometry

turbocharger or otherwise called variable nozzle turbocharger. (See variable geometry/nozzle

turbocharger bellow)

Figure: 2.1.3

Fast Motoring (fastmotoring.com)

The variable geometry turbochargers offer some capacities that the single and dual-stage

turbochargers are not able to provide to extremely downsized engines. Firstly, variable

geometry turbochargers are able to operate with the gas energy which is produced by the

operational function of extreme downsized engines (dual-stage turbochargers face some

disadvantages in this case) and secondly are able to supply enough power to the compressor

to create the boost pressure which is required for low speeds and transient conditions from

where single geometry turbochargers which are fixed are unable to provide efficiently.

The main advantage of variable geometry turbochargers is that they reduce turbo lag. Turbo

lag is the time required for an internal combustion engine to produce boost pressure between

transients, basically is a delay due to large requirements of energy from the engine to operate

the turbocharger to produce the required boost pressure needed.

The reason variable geometry turbochargers reduce turbo lag is due to the pivoting vanes

which are integrated into the turbo. The pivoting vanes are able to change the speed and angle

of the exhaust gas as it enters the turbine rotor. Then the vanes of the variable geometry turbo

during low speeds are set so that the compressor blades are positioned at the most efficient

angle possible. This in combination with the engine boost requirements judged by the engine

manufacturer helps to reduce the turbo lag during operation.


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According to Hawley et al (p.148-149, 1999) a comparison test between a fixed geometry

turbocharger and a variable geometry turbocharger related to NOx, Smog, and specific fuel

consumptions has indicated that the variable geometry turbocharger is more efficient.

The results received from the tests (eleven mode tests) indicated that the variable geometry

turbocharger contributed to lower NOx emissions apart from mode number five. The smogresults where similar for both turbochargers but the specific fuel consumption results

indicated that the internal combustion engine is more fuel efficient with the operation of

variable geometry turbocharger as a force induction device. (See table of results below)

Figure 2.1.4

Further improvements to downsized internal combustion engines can be achieved with the

adaption of a device which is called charge air cooler which is most often adapted to engines

which are turbocharged.

An intercooler is a component which is also known as a heat exchanger or charge air cooler.

The main use of an intercooler is to reduce the charge intake heat that a turbocharged engine

has put into the engine cylinders during the intake stroke. In a turbocharged engine the

intercooler is positioned between the turbocharger and the intake manifold as shown below.

Figure 2.2

Popular Mechanics (popularmechanics.com)

The figure 2.2 above represents how the charge air temperature it has been increased by the

action of the turbocharger to force air by compression into the engine cylinders. Due to the

fact that the density of the air at the end of the intercooler is increased, the results are: more

efficient combustion process, lower emissions, and more power output.


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2.3 Direct Injection:

The two major fuel delivery systems which provide fuel within the late technologically

advanced engines are known as port indirect injection systems and direct injection systems.

The main difference between the two systems is that port indirect injection systems deliversthe fuel into the engine cylinder by the use of an intake port behind the intake valves and the

direct injection systems by delivering the fuel directly into the engine cylinders. Both

systems offer a number of advantages and disadvantages. In the case of fuel economy and

reduction of harmful emissions, direct injection systems are more efficient. (See direct

injection system below)

Figure: 2.3 (Car and Driver (caranddriver.com))

The reason direct injection systems are more efficient than indirect injection systems is due to

the fact that they allow more accurate control over fuel metering (stoichiometric air/fuel

mixture) and precise injection timing.

Because the injector nozzles are placed to spray fuel directly within the engine cylinders, the

injectors can be relocated accordingly to the most efficient position for optimal spray pattern

within the engine cylinders.

The results of such a system are internal cooling due to efficient fuel evaporation, higher

knock margin allowing higher compression ratios, more complete combustion process, higher

power outputs, less emissions, and lastly improved fuel consumptions. Jones et al (p48-49.

2011)and Brown et al (p61. 2010)

Zhao et al (p512. 1999) states that the GDI (Gasoline Direct Injection) engines which are

under the use of charge stratification (concentrating the spraying of the fuel close to the spark

plug rather than throughout the whole of the combustion chamber) offer the potential for
http://www.caranddriver.com/photos-10q2/346575/direct-injection-artists-rendering-photo-347093


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2.4 Variable Valve Actuation:

Variable valve actuation is referred to as variable valve timing (VVT), variable valve lifting

(VVL) or both systems together (VVTL).

Variable valve timing is the continuous change in valve timing in relation to the processing

signals of the ECU. The electronic control unit of the vehicle processes input signals related

with engine speed and load and then operates the cam timing actuators to shift the angle of the

camshaft/camshafts clockwise or anticlockwise. (See figure 1.5 below)

Figure: 2.4

2carpros (2carpros.com)

At slow engine speeds the electronic control unit of the vehicle sends signals to the variable

valve timing module in order to alter the inlet valves so they open late (retard the timing).

Due to late inlet valve openings, all the exhaust gases would be expelled through the exhaust

valves and the cylinders will be filled with fresh air. As a result, this leads to a good burning

of the air/fuel mixture and therefore the engine will operate smoothly and stable at idle.

At high engine speeds on the other hand, the electronic control unit of the vehicle, advances

the valve timing (inlet valves are open earlier). By advancing the inlet valve timing at high

engine speeds, fresh mixture can be drawn into the engine cylinders due to the depression

caused by the flow of the exhaust gases though the exhaust valve. This increases the

volumetric efficiency of the engine which improves power and torque outputs. A well know

variable valve timing systems are the BMWs Vanos Systems and Toyotas VVT-I Systems.

Similarly to variable valve timing, variable valve lifting is the continuous change in valve

lifting periods in relation to the processing signals of the ECU. The electronic control unit of

the vehicle processes input signals related with engine speeds and loads and then operates a

third camshaft or actuators to increase or decrease the opening periods of the exhaust or inlet

valves. (See figure 1.6 next page)


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The figure below represents the variable valve lifting system that Audi uses to improve

vehicle efficiencies on Q5 models.

Figure: 2.5

Wheels 24(wheels24.co.za)

When the engine is operating at low to medium engine speeds, the valve opening periods are

set accordingly to allow sufficient air to enter the engine cylinders for providing a goodengine performance and stability. At high engine speeds, the valve opening periods are

increased by increasing the valve openings which provide an increase in volume efficiency.

When the engine intake valves open for a longer duration, more fresh air can enter the engine

cylinders increasing the power output of the engine. The same applies for exhaust valves

which result to a better scavenging.Hilliers (p127. 2011)

Both systems (VVT and VVL) including VVTL, lower vehicle emissions and improve fuel

consumptions. The reason for this is due to that the ECU of the vehicle can sense when the

vehicle is cruising, and set the timing to what is called maximum valve overlap. Maximum

overlap can allow some of the exhaust gases to be recirculated back into the engine cylinders

for reducing emissions, and as a part of air/fuel mixture is replaced by exhaust gases, less fuel

is needed.


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2.5 Cylinder Deactivation:

According to Croistorescu et al (p1. 2010), Cylinder deactivation is part of a tool that the

auto industry is using to improve fuel economy and reduce CO2emissions. This technology

allows the engine to operate with a reduced number of cylinders when the power demands are

low and the vehicle is cruising at highway roads.

By deactivating engine cylinders, the internal combustion engine reduces fuel consumptions

and emissions while still having the flexibility to demand more power when needed. The

system allows the driver to operate on two, three or four cylinders, depending on the driving

conditions. (See example figure 2.6 below, deactivation from six cylinders to four and then

to three)

Figure: 2.6

Honda (Honda.co.nz)

The downside of conventional internal combustion engines is that during cruise speeds they

operate with a low percentage of the vehicles available power using partial throttle openings.

This tends to limit the amount of air entering the engine cylinders making the combustion

process incomplete which results to an increase amount of a fuel consumptions and

emissions.

As mention, by utilizing a system such as a cylinder deactivation system, a specific number of

cylinders can shut down, and during cruising modes, the pumping losses can be reduced. This

is due to large amount of throttle valve openings. In simple terms, when the cylinders are shut

down, the throttle valve openings must increased in order to equal the speeds that the engine

would achieved with all cylinders in operation.

With larger throttle valve openings, the engine can breathe more easily and the piston drag is

reduced.


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Chapter 3

Alternative Fuels for Reducing Vehicle Emissions and Fuel

Consumptions.

3.0 Biofuels:

In this chapter the aim is to review the available type of alternative fuels that take the biggest

attention to the automotive industry and their ability to reduce the level of vehicle emissions

and provide the dependence from fossil fuels.

Biofuels are fuels that are produced from plats such as corn and sugar canes or animal based

materials such as fat. These fuels are generally referred to as biomass. According toRamage

et al (p51. 2008), biofuels provide the opportunity to sustainably produce liquid fuels,

reduce oil imports, and reduce carbon dioxide emissions for the transportation sector because

the CO2 emitted from theircombustion is captured in the next plant growth cycle.

In this document, the specific fuel type that will be discussed the most is the one receiving the

biggest attention to the automotive and motorsport industry. This fuel is identified as Ethanol

or Bioethanol when combined with a fossil fuel.

According toRobert et al (p49-50. 2008), the main produces of Ethanol in the world is the US

and Brazil. The amount of ethanol produced in the United States in 2006 was 18.4 billion

liters within areas of 5.1 million hectares. In Brazil the amount of ethanol produced was 17.8

billion liters with areas of 2.9 million hectares. Together in 2006, United States and Brazil

have produced 36 billion liters of ethanol which is less than 1 percent of the petroleum use.

According to a Brazilian physicist, Professor Jose Goldemberg, the production of Ethanol in

the future will increase. Production in Brazil is expected to be increased for about double the

amount by the Year 2015, in the United States approximately triple the amount by the year

2022, and in Europe production will increased for about 15 billion liters of Ethanol per year

by 2022. At that point, ethanol could replace 6 percent of the gasoline used in theworld.

Robert et al (p50. 2008)

Despite the fact that the availability of the ethanol increases, the downside of this fuel is the

cost and energy content. The price of ethanol is unstable, which means that it can be more or

less expensive than petrol. This issue is due to the following factors:

Prices of corn and sugar canes Production costs Transportation costs and taxes

According toRamage et al (p51. 2008), the energy content of ethanol is approximately two-

thirds that of gasolinethus, 35 billion gallons replaces about 24 billion gallons of gasoline.


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However, the octane rate of the ethanol is higher than gasoline, which means that the engines

can tuned and optimized to operate at higher compression rations and be more efficient.

Ethanol blends (Bioethanol) are study and found that when used as an alternative fuels for

internal combustion engines contribute to lower CO emissions, particularly when the mixtures

are rich; this is due the fact that the available oxygen contained within the ethanol fuel

molecule is higher than what is available within a conventional fuel molecule. More oxygen

within a fuel molecule results to a more complete combustion process reducing CO

emissions.

The effects of ethanol blends related to NOx emissions are found to be lower than

conventional fuels especially when the ratio of the ethanol blend is increased. When the

ethanol blend mixture is increased, the enthalpy of evaporation also increases resulting to a

lower pre-combustion and lower flame temperature lowering the in-cylinder temperatures.

As mention above in section 2.3 of this document, the formation of NOx emissions is due tothe high in-cylinder temperatures. It can be seen from this statement that the cooling effects

which are provided by the use of ethanol blends, helps to reduce the NOx emissions more

than conventional fossil fuels.

Another benefit of ethanol blends over conventional fuels is the laminar burning velocity.

According to Turner et al (p2000, 2010) a test comparison between ethanol, petrol and a

DMF (Dimethylfuran) fuel has indicated that the ethanol is approximately faster by 30%.

From this it can be seen that the ethanol mixtures have shorter combustion durations which

lead to the reduction of NOx emissions even further.

The downside of ethanol blends is that conventional vehicles must be modified in order to

operate and run on ethanol blends, or specially designed and put in production by official

automotive manufacturers. Vehicles that are modified or designed to operate with ethanol

blends are known as flex-fuel vehicles.

According to Alberto (p154, 2010) the modifications required to be done to conventional

vehicles in order to run on ethanol blends are as follows. Hardware and engine control

modifications, specially selected materials that provide the appropriate durability to withstand

the increase compression ratios which are produced by ethanol blends (components such asvalves, valve seats, engine studs and etc), and lastly, the fuel delivery system must be

modified using ethanol compatible materials for efficient and effective injection functionality.

Despite the fact that ethanol blends reduce vehicle emissions, the production of ethanol leads

to some environmental issues. The first environmental issues produced by the production of

ethanol is the large amounts of land which are required to be sacrificed in order to produce the

corps for obtaining ethanol. When large amounts of land are sacrificed, the problems arise are

soil erosion, deforestations, fertilizer run-off and salinity. In addition to this problems,

disposal of water fermentation liquors during the end of each process leads to major

environmental problems. EasyChem (easychem.co.au)


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3.1 Electricity:

Electricity is a basic part of the nature and it is one of the most widely used forms of energy.

This type of energy is known as a secondary energy source due to the fact that is produced by

other means of energy such as oil, coal, natural gas, nuclear power and etc.

With the use of chemical reactions, electricity can be stored into batteries or otherwise stored

into capacitors using the principle of separation (atom separation).

Due to the fact that electricity is a form of energy able to be stored, the automotive industry

found the opportunity to use this energy as an alternative fuel to resolve the current issues

related to fuel consumptions and emissions. Vehicles that are purely powered by electric

energy are known as Electric vehicles (EVs). (See electric vehicle in figure 3.1 below)

Figure 3.1.0

Daily News (nydailynews.com)

Pure electric vehicles have only one energy source which is the electric energy which is

stored within the battery or any other means of electric storage device. The consisting

components of EVs in addition to the energy storage device are the traction motor, power

electronics and subsystems which make sure that the EV components communicate and

function as designed and programmed.

The energy storage device (fuel cell) is responsible for providing the electrical energy to the

electric motor to propel the vehicle. For both, fuel cell and the traction motor there is a

controller. The role purpose of the fuel cell controller is to control the charging and


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discharging faces of the fuel cell. The traction motor controller is responsible to control the

speed or/and torque of the motor by controlling the power electronics. Each controller

contains a sub-controller known as interface for receiving signals and power of high and low

voltages (see figure 3.1.1). High voltages are received from the propulsion system and low

voltages are received from certain specific devices such as sensors. The voltages are then

channelized by the interface controller and directed to the traction motor or the fuel cell for

controlling.

Figure 3.1.1 (Electric Vehicle Schematic)

Chris et al (p33, 2011)

It can be seen from the above figure that EV systems consist of various systems. One of the

most important systems is the vehicles controller. The vehicle controller is responsible of

making decision according to the various signals received from the various sensors around the

vehicle such as velocity, load, and driver petal position to adjust the torque needed from the

traction motor. In addition, this controller is able to receive additional signals such as the fuel

cell state of charge and make decisions whether to present regenerative braking energy to

recharge the fuel cell or not.

All information signals in an EV system related to the vehicles operating conditions are

transmitted between to the various systems discussed above using a controller area network

otherwise known as CAN bus. CAN bus is a computerized network from where a single wire

contains multiple information signals multiplexed together. This type of network then

prioritizes the signals in relation to the importance of each one. For example, information

signals related to door switches reconsidered not very important and they can delay. Signals

on the other hand which are related to the braking system, are considered safety signals (very

important signals) and they must transmitted to their direction gate immediately.

The advantages and disadvantages of using such a system are detailed in the next page of thischapter.


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According toKenber et al (p8-9. 2012) the advantages of electric vehicles are:

Running Costs: One of the main benefits of electric vehicles is the reduced costs of refueling

due to the fact that electricity is much lower on cost compared to fossil fuels.

Road Tax: Vehicles which are powered purely by electricity using an electric storage device

such as battery are road tax free.

Capital Allowances: Cars with CO2 emissions of 110g or less receive a 100% capital

allowance in their first year of purchase. This concession is currently valid until 2013

Vehicle Grants: The government is offering a grant to cover 25% of the cost of an electric

vehicle (up to five thousand pounds per vehicle).

Environmental Issues: Electric vehicles produce zero emissions therefore no impact to the

environment during driving cycle.

Operational Benefits: Vehicles which are powered by 100% by electricity contain fewer

moving components therefore less maintenance and less failures. The use of electric motors

make electric vehicles perfect for start and go application due to no gear and clutch

movements. Lastly, electric vehicles are less noise.

According toArgueta (p6. 2010) the disadvantages of electric vehicles are as follows:

Limited in the distance that can be driven before the complete failure of the battery. Accessories, such as air conditioning and radios drain the battery. Heavier car due to the electric motors, batteries, chargers, and controllers. More expensive because of cost of the parts.

Lastly, the AEA Energy and Environment Group (p5. 2007) states the following as an

important disadvantage of electric vehicles:

Although electric-powered vehicles create zero orfewer emissions than petrol or diesel cars

when in use, there are emissions released when the anymains electricity used is actually being

produced. These emissions should be taken into accountwhen assessing the net environmental

benefits of EVs. If renewable energy is used to generate the electricity then the impact on the

environment is much less than other vehicle technologies. If nonrenewableenergy is used,

then the environmental benefits are reduced. In addition, hybrid electricvehicles cause greater

pollution during manufacture and disposal than conventional vehicles..


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Chapter 4

Hybrid Eclectic Technology for Reducing Vehicle Emissions

and Fuel Consumptions.

4.0 Hybrid Eclectic Vehicles:

In this chapter the aim is to discuss the benefits that are offered by the use electric hybrid

vehicles related to the reduction of vehicle emissions and fuels consumptions. In addition to

this, in this part of the report the author will compare the three main types of electric hybrid

vehicles and their advantages.

Hybrid Electric vehicles combine at least two energy converters, usually the internal

combustion engine and the electric drivers (electric motors). According toBrown et al (p68.

2010) the main aim of a hybrid electric vehicle is to provide the equivalent power, range,

and safety as a conventional vehicle while reducing fuel consumptions and harmful

emissions.

In this chapter, the aim is to discuss and compare the three main architectures of hybrid

electric vehicles. These are the series, parallel, and series/parallel architectures. The

comparison will include how each one of them is used for satisfying the objectives of

reducing vehicle emission, improving fuel efficiencies and performance.

As mention above hybrid electric vehicles are means of transportation which are powered by

the combination of an internal combustion engine and an electric motor or motors. When the

two power devices are connected in series, the architecture is called series hybrid architecture.

When the two power devices are connected in parallel, the architecture is called parallel

hybrid architecture.

The series hybrid architecture is a type of arrangement in which the mechanical drive is

provided to the vehicles wheels only by the electric motor. The parallel electric architecture

is the type of arrangement in which the mechanical drive is provided to the vehicle s wheels

by both, the electric motor and the internal combustion engine. Lastly the series/parallel

architecture combines both, power to wheels only by the electric motor or power to the

wheels by using both, the internal combustion engine and the electric motor.

The main advantage of hybrid electric architectures over pure eclectic architectures (electric

vehicles) is that the electric motor or motors of the system can be either used to provide drive

to the wheels, or become a generator when appropriate to capture kinetic energy which is

usually lost though the brakes and transmission. This is used to recharge the systems

batteries (or any other means of energy storage device such as flywheel and capacitors) which

is not able with the function of pure electric vehicles.

According to Chris et al (p11, 2011) the area where pure electric vehicles are limited in

driving range, the HEVs extend the driving range by capturing kinetic energy which is usually

lost though the brakes (regenerative braking). More details for HEVs are discussed in the

next pages of this document.


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4.1 Series Hybrid Electric Vehicles:

The main energy converter of series hybrid vehicles is the fossil fuel which is used to power

the internal combustion engine. Once the internal combustion engine is powered, the fuels

chemical energy is converted into mechanical and then into electrical with the use of an

alternator/generator which is mechanically linked to the engine.

The electrical energy produced by the generator will be then used to power eitherthe systems

electric motors, or used to charge the systems batteries. It is important to note that the

electric energy can be directed to both, electric motors and batteries. The direction of the

electrical energy is depended on the driving conditions and the ECUs programmed

judgments.

In this architecture the engine is decoupled from the vehicle wheels and as a result the engine

speed can be controlled independently from the vehicle speed (see figure 4.1.1). According toChris et al (p12, 2011) the advantage of this separation is that it simplifies the control of the

engine which can allow the engineers to set the engine to operate at its optimum speeds for

achieving the best fuel economy.

Figure 4.1.1


According to a TCRP report (p7, 2009) the advantages and disadvantages of series hybrid

architectures are as follows:

Advantages and Disadvantages of Series Hybrid Electric Archi tectur es

Advantages Disadvantages

Engine configuration is relative easy and

simple to control

This architecture is most suited to city-type

driving only

Engine is able to operate in the regions of its

peak efficiency

There are large energy losses by the

generator and motor

Engine is more efficient at modest speed and

at high load, this results in superior FEIt has relatively large battery energy losses

Allow the optimization of the engine

technology

Engine, generator, motor, and the energy

storage device contribute to vehicle mass

Can reduce severe transient load demands on

the engine leading to lower emissions---------------------------

This architecture has excelled dynamicperformance at low speed and acceleration

---------------------------


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4.3 Series / Parallel Hybrid Electric Vehicles:

A series / parallel architecture is the type of configuration which incorporates the features of

both, series and parallel architectures. Due to the ability of incorporating both features, the

series / parallel configuration is able to operate as a series or a parallel HEV.

When a series / parallel configuration is compared with the series hybrid architecture, the only

difference is an additional mechanical link which connects the internal combustion engine

with the differential. By adding a connection link, the internal combustion engine is able to

directly propel the vehicle the same way parallel HEVs do.

In the case of comparing between a series / parallel configuration and a parallel configuration,

the only difference is that the series / parallel configuration uses an additional electric motor

which is used as a generator. In this way, the traction motor of the vehicle is able to receive

electric energy from the generator and then propel the vehicle in the same way series hybrid

vehicle operate. (See series / parallel architecture below)

Figure 4.3.1


Hybrid electric vehicles which operate based on series / parallel architectures offer better fuel

efficiency, drivability and lower emissions. This is due the reason that series / parallel

architectures combine all the advantages of both, series and parallel architectures (see page 20

& 21). The downside of this architecture is the additional weight and complexity due to more

operating components in addition to increased cost.


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4.4 Plug-in Hybrid Electric Vehicles:

The architectures discussed above can offer further improvements by storing electricity from

an external source into the systems batteries prior driving. These hybrid electric vehicles are

called plug-in hybrids (see figure below).

Figure 4.4.1

Auto21 (auto21.uwinnipeg.ca)

By recharging the energy storage device to maximum prior driving, the distance the vehicle

can travel is extended even further than the distance the standard hybrid electric vehicles can

travel. Due to the extended driving distance of the vehicle, the refueling process is reduced.

The results are better fuel savings and a significant reduction of emissions.

Another advantage of plug-in hybrid electric vehicles is the energy cost savings. Because the

plug-in hybrid electric vehicles use electricity for the initial driving range of the driving cycle

as well as to parts of the driving cycle, the energy costs are lowered due to the fact that the

cost of electricity is lower than fossil fuels.

However, the cost of plug-in hybrid electric vehicles is higher than the cost of the alternative

type of hybrid electric vehicles of the same category (e.g. cost of plug-in series hybrid electricvehicles is higher than the cost of standard series hybrid electric vehicles). This is mainly due

to the increased number of components used.

Lastly, the maintenance costs of plug-in electric hybrid vehicles as well as standard hybrid

electric vehicles are lowered than conventional vehicles. This is due to the excessive use of

regenerative braking which increases the life of the brake pads and brake fluid. Since the

engine is able to shutdown during regenerative braking, the intervals of the engine such as oil

and other maintenance services can last for longer period.


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Conclusion:

This paper provides a review description between the three most technologically developed

approaches that are used by the automotive manufacturers in order to reduce the vehicle

emissions and fuel consumptions. Basically, the sole purpose of this review was to

investigate and identify the path that is most likely to be taken and followed by the

automotive manufacturers in order to meet the upcoming emission legislation standards for

improving the current problems related with the environment, and the issues related with the

customer demands and oil shortages.

The three recent technological developed approaches that were discussed in this document

were the engine downsizing, alternative fuels and vehicle hybridization. During the review

undertaken, it was found that each of the approaches studied and discussed, offered unique

efficiency perspectives.

Between the different approaches discussed, the least developed is found to be the method of

using alternative fuels. Firstly electricity, the potential of electricity as a power source offers

the advantage of zero emissions and low cost of refueling once electricity is cheaper than

fossil fuels. The downside of this approach on the other hand is that it is limited in mileage

range. This is due to the inability of refueling sufficiently and effectively. The time required

to recharge an electric vehicle is approximately eight hours, making the vehicle ineffective for

constant and long driving patterns.

In addition, electric vehicles face the disadvantage of limited power and top speed (for a

commercial EV approximately 70mph) which makes them unattractive to vehicle customers.

Lastly, EVs are becoming more unattractive to customers due to the cost of ownership.

Electric vehicles cost approximately 30,000, much more expensive than small size

conventional vehicles.

Regarding to ethanol as an alternative fuel, ethanol is a fuel which offers a wide range of

advantages. Ethanol blends contain a higher octane number than conventional fuels making

ethanol more resistive to detonation and pre-ignition. In addition, ethanol reduces the engines

in-cylinder temperatures and its oxygen content is higher than conventional fuels. As a result,

internal combustion engines are able to operate at higher compression ratios leading to a more

complete combustion with fewer emissions and more power outputs.

The disadvantage of ethanol is its availability. In countries such as the USA and Brazil

ethanol is widely used and is available at most fuel stations. In European countries such as

UK, Germany and France, ethanol blends are not as much available as in the USA and Brazil

making ethanol difficult to find. In addition, the potential of ethanol in the automotive


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industry is low; the season for this is due to the fact that most automotive manufacturers such

as BMW, HONDA, FORD, TOYOTA and others disapprove ethanol (disapprove blends over

15% ethanol). The reason for this, is due to that ethanol attracts carrion. According to

automotive manufactures the use of ethanol in internal combustion engines lead to a rabid

corrosion which affects components such as the vehicles fuel delivery system. This may

become very costly to vehicle owners when malfunction due to ethanol usage. Amanda

(dailycaller.com, 2011)

Another disadvantage of ethanol is the issues related to the environment. During the

production of ethanol the two main problems arise are soil erosion and deforestation. Soil

erosion is caused due the disposal of water liquors during the end of each production process,

and deforestation because of the large amounts of land required for growing crops to obtain

ethanol.

Lastly, ethanol becomes more unattractive to drivers due to cost. Ethanol prices are unstable,

sometimes are higher than fossil fuels and sometimes lower than fossil fuels. The ethanol

prices are mainly depended on the amount of corps or sugar canes produced each season and

transportation costs. In addition, vehicle running costs may become more expensive due to the

low energy content of ethanol. This is depended on the efficiency of the internal combustion

engine.

The disadvantages of using alternative fuels lead most of the automotive manufacturerstowards engine downsizing and vehicle hybridization. The main advantage of engine

downing is the low cost of ownership. In addition to this, engine downsizing offers good fuel

efficiencies and emission reductions up to the requirement levels. The potential of engine

downsizing for the future is highly supported by many automotive manufactures due to the

fact that they can be combined with late technological advanced systems such as the ones

discussed in chapter two of this document. This improves even further the efficiencies of the

downsized engine.

Finally, vehicle hybridization is another method which is highly supported and followed by

many automotive manufactures. This is due to the reason that unlike pure electric vehicles,

hybrid electric vehicles are not depended only by external recharging sources and are also

able to be combined with efficient downsized engines for superior fuel efficiencies and

extreme reduction of vehicle emissions. The only downsized of hybrid electric vehicles is

that they contribute to high weight and are more expensive than conventional downsized

vehicles.

It is important to note that some automotive manufacturers support the idea of pure electric

vehicles but their vehicles are not supported by drivers due to the disadvantages discussed

above.


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Rony Argueta. (2010). University of California Santa Barbara.A Technical Research Report:

The Electric Vehicle. 9 (1), p6.

AEA Energy and Environment Group . (2007). sustainable energy Ireland.Hybrid Electric

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technologies and methods for reducing vehicle emissions and fuel consumptions final

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