Final Tdi Diesel 01

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TECHINAL PAPER PRESENTATION

ON

ADVANCES IN TURBOCHARGED

DIRECT INJECTION (TDI) DIESEL

ENGINES

BY :- GHORPADE AMOL RAMBHAU

ROLL NO :- T3390821

GUIDE :- PROF. P. S. PURANDARE

DEPARTMENT OF MECHANICAL ENGINEERING

VISHWAKARMA INSTITUTE OF INFORMATION

TECHNOLOGY

PUNE -411048

YEAR:- 2009-10



CERTIFICATE

THIS IS TO CERTIFY THAT MR GHORPADE AMOL RAMBHAU

HAS COMPLETED HIS TECHNICAL PAPER PRESENTATION ON

THE TOPIC ADVANCES IN TURBOCHARGED DIRECT

INJECTION (TDI) DIESEL ENGINES UNDER THE GUIDANCE

OF PROF. P. S. PURANDARE.

GUIDE HOD

MECHANICAL ENGINEERING



ACKNOWLEDGEMENT

I acknowledge a deep sense of gratitude towards Prof. P.S. PURANDHARE, Department

of Mechanical engineering, V.I.I.T, Pune, for providing me with valuable and useful

information, guidance and co-operation in writing this report.

I would also like to thank VOLKSWAGEN INTERNATIONAL for providing me with

all the necessary knowledge and information about TDI engines in an open source format.

I would also like to thank all those who are indirectly involved with the paper – my

colleagues, friends, patrons and parents.



ABSTRACT

New challenges are driving the automotive industry forward. Given the calls for climate

protection, stricter international emissions standards, and the finite nature of the world’s oil

reserves, everything points to the advances in diesel engines, which have always offered better

mileage and lower emissions than comparable gasoline engines.

The TDI engine in particular has always been ahead in the run to achieve maximum fuel

efficiency compared to other diesel engine technologies. Volkswagen has many years' experience

in TDI technology. In many countries, TDI is a registered trademark of Volkswagen AG. The

TDI badge identifies all the Group's diesel-powered models featuring diesel direct injection and a

turbocharger. Characteristic features of the TDI engines are fuel economy, low emissions, high

pulling power (torque) and outstanding power efficiency. Functionality: A turbocharger supplies

the engine with fresh air, thereby providing optimum cylinder charging. After compression, the

diesel is injected directly into the cylinders at very high pressure by way of a nozzle. Effective

engine encapsulation keeps noise to a minimum, while hydraulic engine mounts ensure smooth,

low-vibration running.

Unit Injector developed by the VW group is an integrated direct fuel injection system for

diesel engines; combining the injector nozzle and the injection pump in a single component, the

pump of which is (usually) driven by the engine camshaft. Design of the Unit Injector eliminates

the need for high pressure fuel pipes, and with that their associated failures, as well as allowing

for much higher injection pressure to occur. The unit injector system allows accurate injection

timing, and amount control much better than common rail system .

We will be discussing various factors that have led to the current improvement in diesel

engines with a study of the Volkswagen 1.9 litre TDI engine.



CONTENTS

1.0 INTRODUCTION

2.0 MEETING THE CHALLENGE THROUGH ADVANCEMENTS

2.1 Engine Technologies

2.2 High-Pressure Fuel Injection

2.3 Electronic Fuel Injection

2.4 Cylinder Modifications

2.5 Turbocharger Advancements

2.6 Exhaust Gas Recirculation

3.0 STUDY OF THE 1.9 LITRE TDI ENGINE WITH PUMP INJECTION SYSTEM

3.1 Development of the engine

3.2 Technical Data

3.3 Distributor Pipe

3.4 Pump/Injectors

3.5 Drive Mechanism

3.6 Injection Cycle



3.6.1 High-Pressure Chamber Fills

3.6.2 Pre-Injection Phase Starts

3.6.3 Pre-Injection Phase Ends

3.6.4 Main Injection Phase Starts

3.6.5 Main Injection Phase Ends

3.7 Pump/Injector Fuel Return

3.8 Engine cycle

3.8.1 Pre-Injection Phase

3.8.2 Main Injection Phase

3.8.3 End of Injection

3.8.4 Injection Curve

3.9 Glow Plug System

3.10 Turbocharger

3.11 Intercooler

3.12 Exhaust Gas Recirculation (EGR)

3.13 Engine Management

4.0 FUTURE SCOPE

4.1 Volkswagen 1-litre car (235 mpg)

4.2 Bluemotion Technology



4.3 Volkswagen TDI Common Rail Technology

5.0 REFRENCES

1.0 INTRODUCTION

Over one hundred years ago, in a letter to his former tutor Carl von Linde, Rudolph

Diesel wrote: "I have some exciting news; I have found an engine which, according to my

calculations, consumes only approximately one tenth of the coal required by our contemporary

steam engines." With great conviction, Rudolph Diesel developed the first four-stroke diesel

engine from his initial mathematical calculations. Its high efficiency placed everything that had

gone before it in the shade. With equal conviction, there has been optimization of his invention

with newer techniques like common rail, direct injection and turbocharging. The objectives may

have changed somewhat, but the conviction with which Rudolph Diesel worked on his engine is

now a major means of automotive applications, ship propulsion and electrical power generation.



In its early stage, the gasoline engine wasn't very efficient, and other major methods of

transportation such as the steam engine fared poorly as well. We might see the words "diesel

engine" and think of big, hefty cargo trucks spewing out black, sooty smoke and creating a loud

clattering noise. This negative image of diesel trucks and engines has made diesel less attractive

to casual drivers - although diesel is great for hauling large shipments over long distances, it

hasn't been the best choice for everyday commuters. This is starting to change, however, as there

are improvements in the diesel engine to make it cleaner and less noisy.

In theory, diesel engines and gasoline engines are quite similar. They are both internal

combustion engines designed to convert the chemical energy available in fuel into mechanical

energy. Both diesel engines and gasoline engines convert fuel into energy through a series of

small explosions or combustions. The major difference between diesel and gasoline is the way

these explosions happen. In a gasoline engine, fuel is mixed with air, compressed by pistons and

ignited by sparks from spark plugs. In a diesel engine, however, the air is compressed first, and

then the fuel is injected. Because air heats up when it's compressed, the fuel ignites. Diesel fuel

has a higher energy density than gasoline. On average, 1 gallon (3.8 L) of diesel fuel contains

approximately 155x106 joules (147,000 BTU), while 1 gallon of gasoline contains 132x106

joules (125,000 BTU). This, combined with the improved efficiency of diesel engines, explains

why diesel engines get better mileage than equivalent gasoline engines.

2.0 MEETING THE CHALLENGE THROUGH

ADVANCEMENTS

2.1 Engine Technologies:

The first component of a clean diesel system is an advanced engine designed to minimize

NOx and PM in engine cylinders through combustion management. By altering the values of

parameters such as fuel injection timing, injection pressure, or combustion gas temperature, new

techniques are being developed to reduce the levels of these pollutants before the exhaust reaches

the after-treatment system. Today’s diesels use direct injection (DI), which refers to the method

by which fuel is inserted into the cylinders. Indirect-injection engines first mix fuel and air in a

“prechamber” outside the cylinder to assist in fully diffusing the fuel into the air before it is



injected into the main cylinder. Although indirect injection accommodates a thorough fuel/air

mixture, it incurs a fuel economy penalty due to energy losses caused by the prechamber. Direct-

injection engines overcome that fuel economy penalty by injecting fuel directly into the cylinder

yielding a significant efficiency gain.

2.2 High-Pressure Fuel Injection:

More complete mixing of fuel and air in the cylinder minimizes the creation of fuel-rich

areas that are the source of particle emissions during combustion. Today’s high- pressure fuel

injectors can spray fuel mist into the cylinders at extremely high pressures (around 20,000 to

30,000 pounds per square inch), accelerating diffusion and reducing engine-out emissions.

Because of the importance of fuel injection with respect to engine performance and emissions,

much research has been devoted to developing these high-pressure systems. They include-

The common rail system, keeps fuel under pressure at all times so that high-pressure fuel injection

can be obtained during any vehicle-operating condition. In this system, fuel is fed from a shared

reservoir through a “common rail” to all of the cylinders. This allows high atomization of the fuel

in order to reduce PM emissions.

Unit injectors in HEUI systems are controlled hydraulically by a high-pressure oil pump. The

hydraulic system controls the rate of injection, and computer-controlled electronics control the

overall amount of fuel that is injected into the cylinder. Consequently, the speed or period of acam lobe does not limit the injection process.

2.3 Electronic Fuel Injection:

In older diesel engines, the timing and amount of fuel injected into the cylinder were

determined by mechanical operations, higher loads caused injection of greater amount of fuel,

some of which was not completely burned and led to emission of soot. Advances in electronic

fuel injection have enabled to design engines that independently and precisely control the timing

of the fuel injection with respect to the piston position, and the amount of fuel injected into the

cylinder. Electronic sensors monitor the vehicle’s actions and engine performance (such as

exhaust temperature or combustion completeness), and adjust fuel injection parameters

accordingly to control both NOx and PM emissions.

One example of electronic injection control is so-called injection timing retard, where fuel is



injected later than normal, lowering combustion temperature and reducing NOx emissions.

Injection timing retard, however, adversely affects fuel economy and PM emissions. Other

techniques, such as pilot injections or post-injections, are used to reduce emissions or “prime” the

exhaust with excess hydrocarbons for more effective after-treatment control.

2.4 Cylinder Modifications:

Modifications to the design of the cylinder that aid in the mixing of fuel and air reduce

both NOx and PM emissions. Examples of such modifications include changing the shape of the

combustion chamber and piston bowl, increasing the number of valves per cylinder, and

incorporating spiral-shaped intake ports to increase “air swirl.”

2.5 Turbocharger Advancements:

The function of turbochargers is to boost the engine output by compressing air entering

the cylinder. Physically, a turbine powered by the engine’s exhaust drives the compressor. By

squeezing more air into the chamber, turbochargers provide the engine with greater power, as the

additional air accommodates the addition of more fuel. Turbocharging improves performance

while reducing PM due to the additional air in the cylinder. However, it also increases the

temperature of the intake air, which, in addition to elevating NOx production, works against the

intended goal of increasing air density.

To address this issue, sophisticated systems have been developed that include, for example “air-

to-air charge cooling,” which cools the charged air with ambient air (rather than a water- based

system). Cost and complexity limit use of these systems. Another advanced turbocharger design,



variable geometry turbines (VGT), separates the power of the turbine from the force of engine

exhaust so that the turbocharger can be optimized in a variety of operating conditions.

2.6 Exhaust Gas Recirculation:

Exhaust gas recirculation (EGR) is the technique of redirecting a portion of the exhaust

gas back into the engine cylinder to dilute the combustible gas and reduce the peak flame

temperature. Like other temperature-reduction techniques, this reduces NOx emissions but tends

to increase PM emissions. EGR is common in today’s vehicles. However, advances in EGR, such

as electronically controlled EGR or cooled EGR (where the exhaust gas is first cooled), are being

developed, though these advances add cost and complexity.

3.0 STUDY OF THE 1.9 LITRE TDI ENGINE WITH PUMP

INJECTION SYSTEM

The TDI engine, compared with previous diesels from Volkswagen and others, offers the

following benefits-

Fuel injection system with electronic control means more power, less smoke, less noise, and

even better fuel consumption. Both injection timing and quantity are electronically controlled on

all Volkswagen TDI engines. Previous Volkswagen diesels have used mechanical regulation of

the fuel injection system. The "cold start" handle for older VW diesels has been eliminated, and

the function that it served is now handled automatically by the engine controller.



Developments in turbocharger technology have culminated in the Garret VNT15 variable-

geometry turbocharger on the latest 4-cylinder TDI models. This design gives faster response

(less "lag"), and is capable of delivering boost starting at a lower engine speed and extending to a

higher engine speed with less back-pressure of the exhaust flow. Turbo lag with the VW TDI

engine is on the order of 0.25 second, which is not noticeable to the driver.

Electronically controlled emission control systems, including EGR (exhaust gas recirculation),

reduce emissions of NOx. Higher injection pressures and developments of fuel injector design

lead to less noise and lower exhaust emissions. Two-stage injector nozzles are used, to give a

gradual pressure rise and minimize the diesel “knocking” sound.

The open-type combustion chamber has less heat loss than the older prechamber design. As a

result, there is no need for glow plug operation at coolant temperatures above 9 degrees C, so

starting can be immediate. In addition, there is no need for an engine block heater, which was an

essential option for anyone with an older-design diesel in a cold climate. Updated glow plug

design compared to prevous models reduces the glow plug period to about 10 seconds even at

-10 degress C. The open combustion chamber allows the use of a lower compression ratio

(18.5:1 or 19.5:1 depending on model, compared to about 22:1 or 23:1 on older designs) This

reduces noise and vibration, and increases engine durability since the maximum pressure in the

combustion chamber is reduced

3.1 Development of the engine:

In association with Bosch, Volkswagen has succeeded in developing a diesel engine with

a solenoid valve controlled pump injection system suitable for use in passenger cars. The 1.9-

liter TDI engine with the new pump injection system meets the stringent demands for improved

performance and cleaner emissions.

The new 100 bhp (74 kW) 1.9-liter TDI engine with pump injection system was developed from

the existing 109 bhp (81kW) 1.9-liter TDI engine with a distributor injection pump and no

intermediate shaft.

A diesel engine with the pump injection system has the following advantages over an engine

with a distributor injection pump:



• Low combustion noise

• Low fuel consumption

• Clean emissions

• High efficiency

These advantages are attributable to:

• The high injection pressures of up to

27,846 psi (192,000 kPa / 1,920 bar)

• Precise control of the injection cycle

• The pre-injection phase

3.2

Technical Data –



• Type

Four-cylinder in-line engine with two

valves per cylinder

• Displacement

115.7 cu in (1,896 cm3)

• Bore

3.13 in (79.5 mm)

• Stroke

3.76 in (95.5 mm)

• Compression ratio

19.0 : 1

• Maximum power output

100 bhp (74 kW) @ 4000 rpm

• Maximum torque

177 lbs-ft (240 Nm) @ 1800 to 2400 rpm

• Engine management

EDC 16

• Firing sequence

1-3-4-2

• Emission Control

Bin 10 EPA Federal Emissions Concept, OBD II, catalytic converter, water-cooled EGR system

3.3 Distributor

Pipe:



A distributor pipe is integrated in the fuel supply line in the cylinder head. It distributes

the fuel evenly to the pump/injectors at a uniform temperature. In the supply line, the fuel moves

through the center of the distributor pipe toward cylinder 1at the far end. The fuel also moves

through the cross holes in the distributor pipe and enters the annular gap between the distributor

pipe and the cylinder head wall. This fuel mixes with the hot unused fuel that has been forced

back into the supply line by the pump/injectors. This results in a uniform temperature of the fuel

in the supply line running to all cylinders. All pump/injectors are supplied with the same fuel

mass, and the engine runs smoothly. The high pressure generated by the pump/ injectors heats up

the unused fuel so much that it must be cooled before it gets back to the fuel tank. A fuel cooler

is located on the fuel filter. It cools the returning fuel and thus prevents excessively hot fuel from

entering the fuel tank and possibly damaging the Sender for Fuel Gauge.

3.4 Pump/Injectors:

A pump/injector is a pressure-generating pump combined with a solenoid valve control

unit. Each cylinder of the engine has its own pump/injector. Thus there is no need for a high-

pressure line or a distributor injection pump.

Just like a conventional system with a distributor injection pump and separate injectors, the new

pump injection system:

• Generates the high injection pressures required.

• Inject fuel into the cylinders in the correct quantity and at the correct point in time.



Heart of the TDI engine- THE PUMP INJECTION SYSTEM

3.5

Drive Mechanism:



The camshaft has four additional cams for driving the pump/injectors. They activate the

pump/injector pump pistons with roller-type rocker arms. The injection cam has a steep leading

edge and a gradual slope to the trailing edge. As a result of the steep leading edge, the pump

piston is pushed down at high velocity. A high injection pressure is attained quickly. The gradual

slope of the cam trailing edge allows the pump piston to move up relatively slowly and evenly.

Fuel flows into the pump/injector high-pressure chamber free of air bubbles.

3.6 Injection Cycle:

3.6.1 High-Pressure Chamber Fills-

During the filling phase, the pump piston moves upward under the force of the piston spring and

thus increases the volume of the high-pressure chamber. The pump/injector solenoid valve is not

activated. The path is open from the fuel supply line to the high-pressure chamber. The fuel

pressure in the supply line causes the fuel to flow into the high-pressure chamber.

3.6.2 Pre-Injection Phase Starts-

The injection cam pushes the pump piston down via the roller-type rocker arm. This displaces

some of the fuel from the high-pressure chamber back into the fuel supply line. The Diesel

Direct Fuel Injection Engine Control Module J248 initiates the injection cycle by activating the

pump/injector solenoid valve. The solenoid valve needle is pressed into the valve seat and closes

the path from the high-pressure chamber to the fuel supply line. This initiates a pressure build-up

in the high-pressure chamber. At 2,611 psi (180 bar), the pressure is greater than the force of the

injector spring. The injector needle is lifted from its seat and the pre-injection cycle starts.

Injector needle damping: During the pre-injection phase, the stroke of the injector needle is

dampened by a hydraulic cushion. As a result, it is possible to meter the injection quantity

exactly.

Function: In the first third of the total stroke, the injector needle is opened undamped. The pre-

injection quantity is injected into the combustion chamber. As soon as the damping piston

plunges into the bore in the injector housing, the fuel above the injector needle can only be

displaced into the injector spring chamber through a leakage gap. This creates a hydraulic

cushion which limits the injector needle stroke during the pre-injection phase.

3.6.3 Pre-Injection Phase Ends-



The pre-injection phase ends immediately after the injector needle opens. The rising pressure

causes the retraction piston to move downward, thus increasing the volume of the high-

pressure chamber. The pressure drops momentarily as a result, and the injector needle closes.

This ends the pre-injection phase. The downward movement of the retraction piston pre-loads the

injector spring to a greater extent. To re-open the injector needle during the subsequent main

injection phase, the fuel pressure must be greater than during the pre-injection phase.

3.6.4 Main Injection Phase Starts-

The pressure in the high-pressure chamber rises again shortly after the injector needle closes.

The pump/injector solenoid valve remains closed and the pump piston moves downward. At

approximately 4,351 psi (300 bar), the fuel pressure is greater than the force exerted by the pre-

loaded injector spring. The injector needle is again lifted from its seat and the main injection

quantity is injected. The pressure rises to between 27,121 psi (1,870 bar) and 27,846 psi (1,920

bar) as more fuel is displaced in the high-pressure chamber than can escape through the nozzle

holes. Maximum fuel pressure is achieved at maximum engine output. This occurs at a high

engine speed when a large quantity of fuel is being injected.

3.6.5 Main Injection Phase Ends-

The injection cycle ends when the Control Module J248 stops activating the pump/injector

solenoid valve. The solenoid valve spring opens the solenoid valve needle, and the fuel displaced

by the pump piston can enter the fuel supply line. The pressure drops. The injector needle closes

and the injector spring presses the bypass piston into its starting position. This ends the main

injection phase.

3.7 Pump/Injector Fuel Return:

The fuel return line in the pump/injector has the following functions:

• Cool the pump/injector by flushing fuel from the fuel supply line through the pump/injector

ducts into the fuel return line.

• Discharge leaking fuel at the pump piston.

• Separate vapor bubbles from the pump/injector fuel supply line through the restrictors in fuel

return line.

3.8 Engine cycle:



3.8.1 Pre-injection phase-

To soften the combustion process, a small amount of fuel is injected at low pressure before the

start of the main injection phase. This is the pre-injection phase. Combustion of this small

quantity of fuel causes the pressure and temperature in the combustion chamber to rise. This

leads to quick ignition of the main injection quantity, thus reducing the firing delay. The pre-

injection phase and the “injection interval” between the pre-injection and the main injection

phase produce a gradual rise in pressure within the combustion chamber, not a sudden pressure

buildup. The effects of this are low combustion noise levels and lower NOx emissions.

3.8.2 Main injection phase-

The key requirement for main injection phase is formation of a good mixture to burn the fuel

completely if possible. The high injection pressure finely atomizes the fuel so that fuel and air

can mix well with one another. Complete combustion reduces pollutant emissions and ensures

high engine efficiency.

3.8.3 End of injection-

At the end of the injection process, it is important that the injection pressure drops quickly and

the injector needle closes quickly. This prevents fuel at a low injection pressure and with a large

droplet diameter from entering the combustion chamber. Fuel does not combust completely

under such conditions, giving rise to higher pollutant emissions.

3.8.4 Injection curve-

The injection curve of the pump injection system largely matches the engine demands, with low

pressures during the pre-injection phase, followed by an “injection interval,” then a rise in

pressure during the main injection phase. The injection cycle ends abruptly.

3.9 Glow Plug System:



The glow plug system makes it easier to start engine at low outside temperatures. It is

activated by the Control Module J248 at coolant temperatures below 9°C. The glow process is

divided into two phases-

1) Glow Period - The glow plugs are activated when the ignition is switched on and outside

temperature is below 9°C. The Glow Plug Indicator Light K29 will light up. Once the glow plug

period has elapsed, the Light K29 will go out and the engine can be started.

2) Extended Glow Period- The extended glow period takes place whenever the engine is started,

regardless of whether or not it is preceded by a glow period. This reduces combustion noise,

improves idling quality and reduces hydrocarbon emission. The extended glow phase lasts no

more than four minutes and is interrupted when the engine speed rises above 2500 rpm.

3.10 Turbocharger:

The function of the turbocharger is to increase the amount of air which enters the engine,

thus allowing the power and torque to be increased tremendously compared to an engine without

a turbocharger. A turbine is located in the exhaust from the diesel engine, and converts the

pressure of the exhaust gases to mechanical work on a shaft. A compressor wheel is driven by

this shaft, and draws air from the air intake, compresses it, and pressurizes the intake manifold of

the diesel engine. The shaft of the turbine and compressor is mechanically independent of any

connection to the rest of the engine - it spins freely on its own. The bearing on this shaft islubricated by engine oil, fed by a separate oil line from the vicinity of the oil filter, and the oil

drains into the crankcase through a drain pipe. The oil also serves to cool the turbine; there is no

connection to the engine coolant. Wastegate is present, which allows some of the exhaust to

bypass the turbine when the set intake pressure is achieved.

To improve

performance TDI engine



variable-geometry Garret VNT15 turbocharger. There is no wastegate, and all of the engine

exhaust passes through the turbine all the time. When the engine is running slowly, a set of

vanes inside the turbine housing move, to direct the exhaust gases through the turbine at a

shallower angle but a higher speed; this causes the turbine to spin faster, so that the turbo

compressor can reach the design boost level sooner. As the engine runs faster and the amount of

exhaust gases increase, the boost level starts going up; this is detected by the engine controls

which act to move the vanes toward a more open angle. This allows less energy to be transmitted

to the turbine wheel, so the boost level is reduced. Compared with the previous design, this

arrangement allows the design boost level to be developed faster and at lower engine speeds, and

allows more efficient operation with reduced exhaust back pressure at higher engine speeds.

3.11 Intercooler:

Another component in a turbo setup is the intercooler. After intake air passes through the

turbo, it heats up partly because of higher pressure. The ideal gas law states that when all other

variables are constant, if pressure is increased, so will temperature. An intercooler acts more like

a heat sink. After absorbing heat, the intercooler releases the heat into the ambient air. An

intercooler is an air-to-air heat exchange device used on turbocharged engines to improve their

volumetric efficiency by increasing intake air charge density through nearly isobaric (constant

pressure) cooling. A decrease in air intake temperature provides a more dense intake charge to

the engine and allows more air and fuel to be combusted per engine cycle, increasing the output

of the engine.

In a TDI

engine hot



compressed air passes through a small heat exchanger known as the intercooler. When heat is

removed, the density of the air increases, thus increasing the amount (by mass) of air which is

drawn into the engine. The objective is to make the air going into the engine cylinders as dense

as possible (pressurized and cooled) to allow maximum power output. From the intercooler, the

pressurized and cooled air goes to the intake manifold where it is mixed with a proportion of

exhaust from the EGR (exhaust gas recirculation) system for emission control purposes. This

mixture then goes into the engine cylinders.

3.12 Exhaust Gas Recirculation (EGR):

EGR system takes in gas at the exhaust manifold, sends it through a diverter valve, then

the EGR cooler, then through the EGR/diverter valve into the intake manifold. The purpose of

the EGR system is to reduce emissions. By mixing exhaust air back into the engine, it lowers

peak combustion temperatures under partial load and reduces NOx emissions anywhere from

50%-75%. The reason why putting exhaust gas (hotter than ambient air) into the intake stream

reduces NOx is because the free oxygen would otherwise turn into NOx.

The system is regulated by the car's computer to open or close to varying degrees depending on

load and other factors. At light load or idle, up to 30% of the intake air flow can be exhaust. At

heavier loads, the EGR valve begins to close and at a certain point, the car's computer closes the

EGR valve completely. The EGR system is connected on the high-pressure side of both theexhaust and intake systems. In TDI engines the EGR actually opens all the way during a

particulate filter regeneration cycle. In theory, it lowers temperatures at lighter loads when there

is less fueling and lower cylinder temperatures. At heavy loads with more fueling and higher

temperatures, the EGR system is closed so it does not reduce peak power at all. A side benefit of

an EGR cooler is faster engine warm up because the hot exhaust gasses give their heat to the

coolant.



3.13 Engine Management:

System Overview of 1.9-Liter TDI Engine EDC 16

The 1.9 TDI engines responses are electronically controlled by the Electronic Diesel

Control (EDC 16) system. This system is connected to the above mentioned sensors which relay

information to the EDC 16 and it accordingly controls the engine mechanisms.



4.0 FUTURE SCOPE:

4.1 Volkswagen 1-litre car (235 mpg)

Volkswagen is building the first 1 litre car in the world. The engine is a one-cylinder

diesel with an automatic, sequential direct manual gearbox. The crankcase and cylinder head of

the 0.3 litre engine were made of aluminium with a monoblock construction. In principle, the

one-cylinder SDI is not a derivation of a familiar engine, but a technologically highly

sophisticated new development. The aspiration diesel direct injection engine has an output of 6.3

kW at 4,000 rpm and helps the car weighing only 290 kg to a maximum speed of 120 km/h/75

mph. The pump-nozzle high-pressure injection with a six-hole nozzle and pre-injection supplies

working pressures of over 2,000 bar/29,400 PSI.

Technical Data-

Engine Principle 1-cylinder naturally-aspirated diesel with unit injector,

aluminium monobloc

Volume 299 cc

Bore x stroke 69 mm x 80 mm

Compression ratio 16.5: 1

Valves per cylinder 3

Valve timing Twin overhead camshafts

Engine weight (dry) 26 kg

Output 6.3 kW (8.5 bhp) at 4,000 rpm

Torque 18.4 Nm at 2,000 rpm



4.2 BlueMotionTechnology:

BlueMotion: This is the name for the most economical Volkswagen model in its class. A

remarkably low fuel consumption is achieved as a result of intelligent engine management,

optimized aerodynamics, tyres with optimal rolling resistance and longer gear ratio. All

BlueMotion models will come with the start-stop system and recuperation in the future

BLUE TDI: The high-performance diesel technology TDI is one of Volkswagen’s core

competencies. Blue TDI is a new concept that makes this technology even cleaner: exhaust

treatment reduces nitrogen oxides produced by up to 90 percent, making the Passat Blue TDI the

most environmentally-friendly diesel in its class. This concept brand already meets the Euro 6

emissions standard, which does not become obligatory until 2014.

4.3 Volkswagen TDI Common Rail Technology

VW diesel engines use one pump assembly per cylinder which relies on complex

electromechanical and electro hydraulic means to control the volume and timing of fuel

injection. Particulate filters which cut emissions, can be fitted to common-rail diesel-powered

vehicles, but they cannot be fitted to unit-injection diesel vehicles.

The reason, is the common-rail technology and its ability to inject fuel during the post-

combustion phase. The small secondary burst of fuel allows the temperature of exhaust fumes to

rise, allowing for the filtration of emissions-causing particles. The big difference is that the VNT

actuator on the new engine is driven by an electric motor instead of a spring/vacuum.



The engine pressurizes diesel fuel to about 20,000-28,000psi in an "accumulator rail" which is

commonly shared by all of the fuel injectors. A 3 piston high pressure fuel pump pressurizes this

accumulator rail. A bleed valve on the rail controls fuel pressure because pressure is a measure

of restriction. Compared to a timing belt driven injection pump, common rail's major advantage

is consistent fuel pressure and fuel injection totally independent of cam timing or engine rpm. A

change from 8 valve to 16 valve cylinder heads and better fuel atomization from common rail

diesel injection (CRD) can let the cars achieve a cleaner burn compared to earlier cars. A major

reason for the change to common rail injection is to meet the ever improving emissions

standards.

5.0 CONCLUSION

TDI engines are economical and smooth with high levels of torque (pulling power) and

good energy efficiency. TDI engines offer refined power delivery from low engine speeds all the

way up the rev scale. They provide high torque levels over a wide rev range and a high

maximum output.

All of the new of Volkswagen TDI clean diesel models are warranted to run on a

biodiesel blend known as B5, which consists of 5 percent biodiesel and 95 percent petroleum

diesel. Thus they seem to be cheaper on running costs and at the same time protect environment.

TDI diesel engines are comparable to Hybrid Electric Vehicles upto some level. Hybrid electric

is an expensive and unproven technology compared to the simplicity of the TDI. On the plus side

for Hybrid Electric Vehicles is the fact that they do very well in stop-and-go urban traffic, while

TDI engines perform better on long trips and their mileage decreases in the city.

To sell a diesel cars in the United States, Volkswagen had to pass the toughest emissions

standard in the world—Tier 2 Bin 5. Common rail is a high-pressure fuel injection system. The

injection pressure is stored in a high-pressure fuel reservoir that supplies all fuel injectors. In this

system the generation of pressure and the fuel injection processes are separate. The advantage of

common rail is that fuel can be delivered at higher pressure, giving better mixing with air for a

more efficient and cleaner combustion. Most Bluemotion vehicles control NOx emissions—one



of the biggest environmental hurdles facing diesels, along with particulate matter—by injecting a

urea-based solution into the exhaust system upstream from the catalytic converter, where NOx is

then converted into nitrogen and water. The new TDI Common Rail will instead use a NOx-

storage catalyst, which is basically a reservoir that temporarily holds the noxious emissions, like

a particulate filter, until they can be burned off during one of the engine cycles. To conclude, it

seems that TDI engines have always been ahead in terms of performance and fuel consumption

compared to the CRDI engines. However to meet the stricter emission norms the TDI engines

fall short, which are fulfilled by the CRDI engines. The best option to achieve optimal of the two

engine technologies was to combine them, which leads us to the Common Rail TDI engines. So

we can now achieve greater fuel efficiency along with meeting the highest emission standards.

REFRENCES

1) Bernard Challen, Rodica Baranescu, Diesel Engine Reference Book, Butterworth-Heinemann, 2

edition (May 1999)

2) Self-Study Program, Course Number 841303, Service Training, Volkswagen of America, Inc.

3) Robert Bosch, Electronic Diesel Control EDC: Bosch Technical Instruction, Robert Bosch GmbH

4) http://www.myturbodiesel.com/buyersguide.htm

5) www.tdiclub.com

http://tdiclub.com/TDIFAQ/tdifaq.pdf

6) http://www.tdicurious.ca/

7) www.volkswagen.de

http://www.volkswagen.de/vwcms/master_public/virtualmaster/en2/experience/innovation/powertrain/sta

rt/common_rail.html

http://www.volkswagen.de/vwcms/master_public/virtualmaster/en2/experience/innovation/powertrain/sta

rt.html

8) http://en.wikipedia.org/wiki/Unit_Injector



9) http://rb-kwin.bosch.com

Documents

Final Tdi Diesel 01