A

Project Report

on

“Clean Diesel Technology”

Submitted in partial fulfillment of the requirement for the award of degree of

B.Tech in Mechanical Engineering.

By

SANJEET LIMBU

Roll.No.151/07.

Under the Supervision of

Prof. (Dr.). S. P. Sinha.

Visiting Faculty.

Department of Mechanical Engineering,

National Institute of Technology, Patna

Patna – 800005, Bihar (INDIA),

2011

CONTENTS

Certificate i

Candidate‟s Declaration ii

Acknowledgement iii

Abstract iv

Chapter 1. Introduction v

1.1 Diesel engines

1.2 Fuel delivery

Chapter 2 Major Advantages of Diesel Engines vi

2.1 Advantages versus spark-ignition engines

Chapter 3 Current and future developments vii

Chapter 4 The DSG Dual-Clutch Gearbox viii

Chapter 5 Turbocharged Direct Injection ix

Chapter 6 Common-Rail Diesel Technology x

Chapter 7 The Clean Diesel Team xi

Chapter 8 Jetta TDI Clean Diesel xii

Chapter 9 The 3.0l V6 TDI engine xiii

Chapter 10 Conclusion xiv

Chapter 11 Bibliography and list of sources xv

CERTIFICATE

This is to certify that project report entitled “Clean Diesel Technology”

submitted by us namely

SANJEET LIMBU.

Roll.No.151/07.

Students of VIII semester B. Tech (Mechanical Engineering) of NIT Patna have

completed the work under my supervision.

Dr. Sudarshan Singh, Dr. S. P. Sinha,

Professor & Head, Supervisor,

Mechanical Engg. Department, Visiting Faculty,

NIT Patna. Mechanical Engg. Deptt.

NIT Patna.

Examiner(s)

1.

2.

CANDIDATE DECLARATION

This is to certify that project report entitled “Clean Diesel Technology”

submitted by

SANJEET LIMBU.

Roll.No.151/07.

has been prepared by us under the supervision of Dr. S. P. Sinha, Designation of

Mechanical Engineering Department, NIT Patna and has not been submitted by us

elsewhere for award of any degree.

SANJEET LIMBU.

Roll.No.151/07.

ACKNOWLEDGEMENT

We wish to sincerely thank Prof. Sudarshan Singh, HOD – Mechanical engineering

Department, National Institute of Technology- Patna.

We would like to extend our heartiest thanks to our guide Prof. S.P. Sinha, for

enlightening us about the Major Project and giving us an opportunity to have a

unique and rewarding experience of undertaking the project.

Lastly, we would like to thank everyone who helped us from time to time during

this period of the Major project.

-SANJEET LIMBU.

Roll.No.151/07.

.

ABSTRACT

BlueMotion Technologies represent the cleanest, most energy-efficient cars in our range.

Innovative technologies such as TSI, TDI and DSG are major contributors to driving efficiency

and set a solid foundation to develop from. Advanced engines such high-torque diesel TDI,

ensure outstanding fuel consumption and fewer pollutants together with pure driving pleasure.

The impressive DSG Dual-Clutch gearbox offers greater fuel economy, convenience of an

automatic gearbox and the agility, dynamic performance and superior consumption figures of a

manual gearbox. So being efficient doesn't have to take the fun out of driving.

Diesel engines tend to have their torque peak quite low in their speed range (usually between

1600 and 2000 rpm for a small-capacity unit, lower for a larger engine used in a truck).This

characteristic is not so desirable in private cars, so most modern diesels used in such vehicles use

electronic control, variable geometry turbochargers and shorter piston strokes to achieve a wider

spread of torque over the engine's speed range, typically peaking at around 2500–3000 rpm.

TDI engines, millions of which have been produced, are examples of environmentally

compatible innovation. Powertrain and Fuel Strategy describes the technologies being pursued

by Volkswagen with a view to implementing a long-term changeover to sustainable fuels and

powertrains.

With acceleration from 0 to 60 mph in just 8.5 seconds the Volkswagen Jetta TDI and Touareg

V6 TDI, and the Audi Q7 TDI 3.0, offer the most affordable good clean fun on the road today.

Clean Diesel TDI engines provide 50 percent more torque at lower RPMs for superior

acceleration and propulsive power, three times the engine life and lower lifetime maintenance

costs

INTRODUCTION

Diesel engines

“A diesel engine (also known as a compression-ignition engine ) is an internal combustion

engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected

into the combustion chamber during the final stage of compression.”

Diesel engines are manufactured in two stroke and four stroke versions.

Fuel delivery

In diesel engines a mechanical or electronic governor regulates the idling speed and maximum

speed of the engine by controlling the rate of fuel delivery.

Modern diesel engines use an electronic control module (ECM) or electronic control unit (ECU).

Mechanical and electronic injection

Indirect injection

Direct injection

Unit direct injection

Common rail direct injection

MAJOR ADVANTAGES OF DIESEL ENGINES

Diesel engines have several advantages over other internal combustion engines:

They burn less fuel than a petrol engine performing the same work, due to the engine's higher

temperature of combustion and greater expansion ratio.

They have no high-tension electrical ignition system to attend to, resulting in high reliability

and easy adaptation to damp environments.

They can deliver much more of their rated power on a continuous basis than a petrol engine.

The life of a diesel engine is generally about twice as long as that of a petrol engine due to the

increased strength of parts used. Diesel fuel has better lubrication properties than petrol as well.

Diesel fuel is considered safer than petrol in many applications. The low vapor pressure of diesel

is especially advantageous in marine applications, where the accumulation of explosive fuel-air

mixtures is a particular hazard. For the same reason, diesel engines are immune to vapor lock.

For any given partial load the fuel efficiency (mass burned per energy produced) of a diesel

engine remains nearly constant, as opposed to petrol and turbine engines which use

proportionally more fuel with partial power outputs.

They generate less waste heat in cooling and exhaust.

Diesel engines can accept super- or turbo-charging pressure without any natural limit

unlike petrol engines, which inevitably suffer detonation at higher pressure.

The carbon monoxide content of the exhaust is minimal.

Biodiesel is an easily synthesized, non-petroleum-based fuel (transesterification) which can run

directly in many diesel engines.

Advantages versus spark-ignition engines

Power and fuel economy

Diesel engines are more efficient than gasoline engines of the same power rating. Gasoline

engines are 30 percent efficient while diesel engines can convert over 45 percent of the fuel

energy into mechanical energy.

However, diesel fuel is denser and contains about 15 percent more energy by volume.

The average diesel engine has a poorer power-to-weight ratio than the petrol engine.

Diesel fuel is injected just before the power stroke. Modern engines with electronic fuel delivery

can adjust the timing and amount of fuel delivery and so operate with less waste of fuel. In the

petrol engine, air and fuel are mixed for the entire compression stroke, ensuring complete mixing

even at higher engine speeds.

Diesel engines usually have longer stroke lengths in order to achieve the necessary

compression ratios.

The addition of turbocharger or supercharger to the engine greatly assists in increasing fuel

economy and power output, mitigating the fuel-air intake speed limit mentioned above for a

given engine displacement. Boost pressures can be higher on diesels than on petrol engines, due

to the latter's susceptibility to knock, and the higher compression ratio allows a diesel engine to

be more efficient than a comparable spark ignition engine.

The increased fuel economy of the diesel engine over the petrol engine means that the diesel

produces less carbon dioxide (CO2) per unit distance

Diesel engines have a lower rotational speed than an equivalent size petrol engine because the

diesel-air mixture burns slower than the petrol-air mixture. Poor power and narrow torque bands

have been addressed by superchargers, turbochargers, (especially variable geometry

turbochargers), intercoolers, and a large efficiency increase from about 35 percent for IDI to 45

percent for the latest engines in the last 15 years.

[3]Power and torque

Diesel engines have better torque characteristics. Diesel engines tend to have their torque peak

quite low in their speed range (usually between 1600 and 2000 rpm for a small-capacity unit,

lower for a larger engine used in a truck). This provides smoother control over heavy loads when

starting from rest, and, crucially, allows the diesel engine to be given higher loads at low speeds

than a petrol engine, making them much more economical for these applications. This

characteristic is not so desirable in private cars, so most modern diesels used in such vehicles use

electronic control, variable geometry turbochargers and shorter piston strokes to achieve a

wider spread of torque over the engine's speed range, typically peaking at around 2500–

3000 rpm.

While diesel engines tend to have more torque at lower engine speeds than petrol engines, diesel

engines tend to have a narrower power band than petrol engines. Naturally aspirated diesels tend

to lack power and torque at the top of their speed range. This narrow band is a reason why a

vehicle such as a truck may have a gearbox with as many as 18 or more gears, to allow the

engine's power to be used effectively at all speeds.

Turbochargers tend to improve power at high engine speeds; superchargers improve

power at lower speeds; and variable geometry turbochargers improve the engine's

performance equally by flattening the torque curve.

[4]Noise

Diesel clatter is caused by the combustion process, the sudden ignition of the diesel fuel when

injected into the combustion chamber causes a pressure wave. It can be reduced through: indirect

injection; pilot or pre-injection; injection timing; injection rate; compression ratio; turbo boost;

and exhaust gas recirculation (EGR). Common rail diesel injection systems permit multiple

injection events as an aid to noise reduction. Diesel fuels with a higher cetane rating modify

the combustion process and reduce diesel clatter.

[5]Reliability

The lack of an electrical ignition system greatly improves the reliability. The high durability of a

diesel engine is also due to its overbuilt nature , a benefit that is magnified by the lower rotating

speeds in diesels. Diesel fuel is a better lubricant than petrol so is less harmful to piston

rings and cylinder bores; it is routine for diesel engines to cover 400,000 km or more without a

rebuild.

[6]Quality and variety of fuels

Requirements for fuels in diesel engines are the ability of the fuel to flow along the fuel lines, the

ability to lubricate the injector pump and injectors adequately, and its ignition qualities (ignition

delay, cetane number). The forced vaporisation and higher cylinder temperatures means that

less-volatile fuels can be used.

[7]Fuel and fluid characteristics

The engines can work with the full spectrum of crude oil distillates, diesel fuel can be

synthesised from vegetable oil and alcohol, coal or other carbon base .

Fuel contaminants such as dirt and water are often more problematic in diesel engines . All diesel

engines will have a fuel filter and a water trap.

Current and future developments

As of 2008, many common rail and unit injection systems already employ new injectors using

stacked piezoelectric wafers in lieu of a solenoid, giving finer control of the injection event.

Variable geometry turbochargers have flexible vanes, which move and let more air into the

engine depending on load. This technology increases both performance and fuel economy. Boost

lag is reduced as turbo impeller inertia is compensated for. Turbo lag with the VW TDI engine is

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

The majority of our TDI engines are turbocharged using variable turbine geometry. An

intercooler is also incorporated into the system, lowering the temperature of the hot compressed

gas leaving the turbo and enhancing power and efficiency. The combination of TDI and common

rail technology is a major step forward in advancing our environmental and sustainability

strategy.

Accelerometer pilot control (APC) uses an accelerometer to provide feedback on the engine's

level of noise and vibration and thus instruct the ECU to inject the minimum amount of fuel that

will produce quiet combustion and still provide the required power (especially while idling).

The next generation of common rail diesels is expected to use variable injection geometry,

which allows the amount of fuel injected to be varied over a wider range, and variable valve

timing similar to that on petrol engines. Particularly in the United States, coming tougher

emissions regulations present a considerable challenge to diesel engine manufacturers.

TDI engines are one of the basic technologies that make a key contribution to the brand.

BlueMotionTechnologies stands for the interaction of a large number of innovations such as

TDI, TSI and DSG, which ensure mobility with lower fuel consumption and pollutant

emissions. The technical innovations that contribute to lower fuel consumption include start-stop

systems, regenerative braking and dual-clutch (DSG) transmissions.

Variable geometry turbocharger

Variable geometry turbochargers (VGTs) are a family of turbochargers, usually designed to

allow the effective aspect ratio of the turbo to be altered as conditions change. This is done

because optimum aspect ratio at low engine speeds is very different from that at high engine

speeds. If the aspect ratio is too large, the turbo will fail to create boost at low speeds; if the

aspect ratio is too small, the turbo will choke the engine at high speeds, leading to high exhaust

manifold pressures, high pumping losses, and ultimately lower power output. By altering the

geometry of the turbine housing as the engine accelerates, the turbo's aspect ratio can be

maintained at its optimum.

Most common designs

The common implementations include a ring of aerodynamically-shaped vanes in the turbine

housing at the turbine inlet.

Actuation

Electric servo actuation , Hydraulic actuators have been used

Other uses

In trucks, VG turbochargers are also used to promotes exhaust gas recirculation (EGR),

sufficient EGR rate even during transient events (e.g. gear changes) can be sufficient to reduce

nitrogen oxide emissions down to that required by emissions legislation. Another use is as

downstream engine exhaust brake, so that an extra exhaust throttle valve isn't needed.

Examples of use The 2007 Porsche 911 Turbo , 1.9L Volkswagen TDI Engine

The DSG Dual-Clutch Gearbox

Volkswagen develops environmentally friendly technologies that help reduce CO2 emissions.

The DSG intelligent automatic transmission developed by Volkswagen is also an integral part of

this strategy for the future.

The dualclutch principle ensures higher efficiency and lower fuel consumption than a

conventional automatic transmission. In addition, it also makes for greater comfort and driving

pleasure. In the meantime, Volkswagen has introduced a second dualclutch gearbox, the 7-speed

DSG, which is even more economical and will be used in the future on high-volume models with

power outputs up to 125 kW and torque values up to 250 Nm.

BorgWarner's dual-clutch DSG

Volkswagen offers the 6- and 7-speed DSG gearboxes for models with various different engines.

While the 6-speed DSG, introduced in 2002, is used for high-torque engines up to 350 Nm, the

7-speed DSG is available for engines with torque figures up to 250 Nm. The key innovation on

the 7-speed unit is its „dry“ dual clutch. In contrast to the six-speed DSG, the new transmission

does not have a „wet“ clutch with oil cooling. With the dual clutch, the efficiency of the DSG

gearbox is significantly higher than that of conventional automatic transmissions fitted with

hydraulic torque converters. Thanks to the DSG„s vehicles equipped with the 7-speed dual-clutch

gearbox may even present lower fuel consumption than comparable manual vehicles, depending

on the individual style of driving.

A dual clutch transmission, is a differing type of semi-automatic transmission. It utilises

two separate clutches for odd and even gear sets. It can fundamentally be described as two

separate manual transmissions contained within one housing, and working as one unit. They are

usually operated in a fully automatic mode, and many also have the ability to allow the driver to

manually shift gears, albeit still carried out by the transmission's electro-hydraulics.

A dual clutch transmission eliminates the torque converter as used in conventional epicyclic-

geared automatic transmissions.

Overview

In DCTs where the two clutches are arranged concentrically, the larger outer clutch drives the

odd numbered gears, whilst the smaller inner clutch drives the even numbered gears. Shifts can

be accomplished without interrupting torque distribution to the driven roadwheels, by applying

the engine's torque to one clutch at the same time as it is being disconnected from the other

clutch. Since alternate gear ratios can pre-select an odd gear on one gear shaft whilst the vehicle

is being driven in an even gear, (and vice versa), DCTs are able to shift more quickly than other

cars equipped with single-clutch automated-manual transmissions (AMTs), a.k.a. single-clutch

semi-automatics. Also, with a DCT, shifts can be made more smoothly than with an AMT,

making a DCT more suitable for conventional road cars.

Clutch types

There are two types of clutches utilised: two wet multi-plate clutches which are bathed in oil

(for cooling), or two dry single-plate clutches.

The wet clutch design is used for higher torque engines : 350 N·m and more (in the Bugatti

Veyron is designed to cope with 1,250 N·m ), whereas the dry clutch design is generally suitable

for smaller vehicles with lower torque outputs up to 250 N·m. However, the dry clutch variants

offer an increase in fuel efficiency, due to the lack of pumping losses of the transmission fluid in

the clutch housing.

Advantages

Better fuel economy (up to 15% improvement) than conventional planetary geared automatic

transmission and for some models with manual transmissions;

No loss of torque transmission from the engine to the driving wheels during gear shifts;

Extremely fast up-shift time of 8 milliseconds when shifting to a gear the alternate gear shaft

has preselected;

Very smooth gear-shift operations;

Consistent shift time of 600 milliseconds, regardless of throttle or operational mode;

TDI

TDI or Turbocharged Direct Injection is a design of turbodiesel engines, which feature

turbocharging and cylinder-direct fuel injection, developed and produced by Volkswagen

Group.

The TDI engine uses direct injection, where a fuel injector sprays atomised fuel directly into the

main combustion chamberof each cylinder. The engine also uses forced induction by way of

a turbocharger to increase the amount of air which is able to enter the engine cylinders, and most

TDI engines also feature an intercooler to lower the temperature (and therefore increase

the density) of the 'charged', or compressed air from the turbo, thereby increasing the amount of

fuel that can be injected and combusted.[1]

These, in combination, allow for greater engine efficiency, greater power outputs while also

decreasing emissions and providing more torque than its petrol engined counterpart.

The reduced material volume of the direct injection diesel engine reduces heat losses, at the

expense of slightly increased combustion noise. A direct injection engine is also easier to start

when cold, due to more efficient placing and usage of glowplugs.

Direct injection turbodiesel engines are frequent winners of various prizes in the International

Engine of the Year Awards. In 1999 in particular, six out of twelve categories were won by

direct injection engines: three were Volkswagen, two were BMW, and one Audi. Notably, the

Volkswagen Group 1.2 TDI 3L beat the Toyota Prius to win "Best Fuel Economy" in its class.

TDI engines operate on diesel fuel (also known as petrodiesel), or biodiesel subject to

manufacturers' prior approval.

VW to Switch to Common-Rail Diesel Technology

Performance has also improved, thanks to turbocharging and advanced gearboxes. In an effort to

improve efficiency and emissions, Volkswagen Auto Group recently announced that it would be

switching to common-rail turbo diesel technology, starting with a new wave of diesels beginning

in 2007 - perfectly timed to meet new tougher North American emissions regulations that will

also see cleaner diesel fuel introduced across the continent. Volkswagen, the industry leader in

diesel sales, not on the forefront of diesel technology?

Common rail technology differs in that fuel is delivered to all cylinders through a fuel rail that is

pressurized by one single pump, with highly precise computer-controlled injectors. Common

rail engines are capable of producing multi-phase injections (capable of injecting before and after

combustion) for even greater efficiency, performance, refinement and drastically reduced

emissions. Another factor involved in cutting emissions, particulate filters, can be fitted to

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

The reason, unsurprisingly, has to do with 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. Particle filters

are able to remove up to 80 percent of particulate emissions and would certainly help VW sneak

by lofty tailpipe regulations.

While VW has stuck it out with PD-injection, Audi, by comparison, offers common rail

technology on its luxury models. Combine this with the improved off-the-line performance of

torquey diesel engines, reduced fuel consumption and refinement thats on par with regular

gasoline engines, and there is no wonder why diesels are so popular in places where fuel quality

is clean enough to make use of them.

There is one more advantage of switching over to direct injection; price. PD-TDI motors require

one unit injector per cylinder, which quickly adds up on the bottom line. By switching to

common rail, prices should fall, helping ease the burden of opting for diesel at purchase.

The adaptation of the common rail fuel delivery system should solve the forthcoming issue of

meeting global emissions regulations. It should also help emissions pressure, allowing diesels to

be sold in North America.

MEET THE CLEAN DIESEL TEAM.

»» The Jetta TDI

Good clean diesel fun.

»» The Jetta SportWagen TDI

More power, more torque, lower emissions.

»» The Touareg 2 (V6) TDI

High excitement, low emission.

»» Audi A3 TDI 2.0

Highly efficient compact luxury.

»» Audi Q7 TDI 3.0

Power and efficiency.

»» Audi Q7 V12 TDI

Athleticism in its purest form.

Jetta TDI Clean Diesel

New Jetta TDI is the cleanest VW diesel ever

Volkswagen with their new Jetta TDI, which they're billing as the cleanest diesel VW has ever

sold in the U.S. The 50-state legal Jetta uses BlueTec urea injection to meet the low emissions

standards, with the "engine management system in the Jetta (changing) operating modes

periodically to treat the NOx that has been stored in the catalytic converter" along with a

particulate filter in the exhaust system.

This clean diesel Jetta meets the lowest emissions standards without the use of urea injection.

Instead, a nitrogen oxide storage catalyst reduces NOx emissions by up to 90 percent. The engine

management system in the Jetta changes operating modes periodically to treat the NOx that has

been stored in the catalytic converter. A particulate filter in the exhaust system further reduces

emissions.

The Jetta TDI is one of the first products of the BLUETEC offensive initiated jointly by Audi,

Mercedes-Benz, and Volkswagen. The goal of this partnership is to establish the concept of

BLUETEC as a uniform label for clean and highly fuel efficient diesel-powered cars and SUVs

with 50-state compliant engines. BLUETEC denotes diesel power plants that comply with the

strictest emissions regulations of the US market. The technologies individually developed by

each manufacturer serve to reduce NOx in particular – an exhaust element more prevalent in a

diesel engine.

Engines Specification:

2.0L, 16-valve, in-line 4-cylinder TDI® Clean Diesel engine, common rail direct injection; 140

hp, 236 lbs/ft of torque

Transmissions

6-speed manual transmission, 6-speed DSG®

Common rail direct injection

2.0L, 16-valve, in-line 4-cylinder TDI® Clean Diesel engine, common rail direct

Stroke 3.74 in

Displacement 120.1 cu. in.

Compression Ratio 16.5:1

Horsepower @ rpm 140hp @ 4,000 rpm

Maximum torque, lbs - ft @ rpm 236lb/ft @ 1,750-2,500 rpm

ENGINE DESIGN

Cooling System Water cooled, water pump, cross flow radiator, thermostatically controlled

3-speed radiator fan

Lubrication Rotary gear pump, intermediate shaft driven, oil cooler

Fuel / Air Supply Electronically controlled direct injection (EDC), turbocharger

FUEL CONSUMPTION City mpg 30

PERFORMANCE 0-60 mph 8.7 sec

Overall hybrid sales for the year 2010 were down 10% through September, while clean diesel

vehicles were up an astonishing 124.1% for the same time period over last year! Volkswagen

sold almost 5,000 of our Jetta TDI clean diesel vehicles in September alone!. More than

anything, this suggests that American consumers are starting to get the TDI clean diesel

message,the thrill of driving while still conserving fuel and reducing your carbon footprint. And

it‟s with good reason that the Jetta TDI sedan leads the pack. It boasts 42 highway mpg and

produces up to 90% fewer emissions than previous diesels.

Volkswagen TDI® Clean Diesel models are eligible for a tax credit of up to $1,700*, if the

model was purchased by December 31, 2010.

Diesel fuel is in demand worldwide. In the European Union and the United Kingdom, more than

half of all cars sold have a diesel engine. The reason is simple. A diesel-powered vehicle is easily

25-50% more efficient than one with a gasoline engine. In addition, diesel fuel in most E.U.

countries is taxed differently and it's less expensive than gasoline.

2008 VW Jetta Sedan 2.5 - 2009 VW Jetta Sedan TDI 2.0

The diesel (TDI) offers a 37% increase in fuel economy (using the combined estimates)

Volkswagen has another stealth offering that will likely show up in Europe before it makes its

way to North America. The VW Golf TDI Hybrid is equipped with a 74-horsepower three-

cylinder TDI engine - (probably the 1.4-liter used in the VW Polo BlueMotion) - mated to a 27-

horsepower electric motor and a seven-speed double-clutch DSG transmission.

The 3.0l V6 TDI engine

The range of engines fitted in the Phaeton and Touareg is being extended by a high-tech

turbodiesel engine. The 3.0l V6 TDI engine has been developed by Audi and is equipped with a

piezo-controlled common rail fuel injection system. This unifies power and smoothness in a

compact engine. The engine is combined with a diesel particulate filter and meets the EU 4

exhaust emission standard.

The 3.0l V6 TDI engine

The 3.0l V6 TDI engine is a new diesel engine developed from the Audi V engine family.

This engine family's special characteristic is its extremely short and compact design, which is

achieved by means of a chain drive. The engine additionally combines high output and ample

torque with smooth running characteristics and low exhaust emissions. A piezo-controlled

common rail fuel injection system ensures high injection pressure and a flexible injection

process. The engine is installed in the Volkswagen Phaeton and Touareg.

Technical engine features:

●High-strength, compacted graphite iron cylinder block

● 4-valve technology

● Intake manifolds with swirl flaps

● Chain drive for valve control system, balancer shaft

and oil pump

● Common rail fuel injection system

● Piezo-controlled injectors (piezo injectors)

● Diesel particulate filter

Design type 6-cylinder V engine (90° V angle)

Compression ratio 17 : 1

Valves per cylinder 4

Engine management system Bosch EDC 16 C common rail fuel injection system

Max. output 165 kW at 4000 rpm

Max. torque 450 Nm at 1400 to 3250 rpm 500 Nm at 1750 to 2750 rpm

Exhaust gas cleaning catalytic converter, exhaust gas recirculation, diesel particulate filter

Fuel Diesel, at least 51 CN

Engine mechanical system

Cylinder head

The 3.0l V6 TDI engine has two cylinder heads manufactured from aluminium alloy. Two intake

and two exhaust valves per cylinder are arranged according to the principle of cross- flow.

.

4-valve technology

Two intake and two exhaust valves per cylinder are arranged vertically in the cylinder head. The

vertically positioned, centrally located injection valve is positioned directly over the central

piston recess. This design leads to good mixture formation, resulting in low fuel consumption

and low exhaust emissions. The shape, size and layout of the intake and exhaust ports ensure

good volumetric efficiency and a favorable gas cycle in the combustion chamber. The intake

ports are designed as spiral and tangential ports. Thanks to the tangential port, the inflowing air

generates the desired, high degree of in-cylinder flow. Particularly at high speeds, the spiral port

leads to good combustion chamber filling.

4-valve technology

Air intake system

The intake manifolds of both cylinder banks are fitted with continuously variable swirl flaps.

Due to the position of the swirl flaps, the intaken air's swirl is adjusted depending on the engine

speed and load. The swirl flaps are moved by the intake manifold flap motor via a push rod. To

do this, the positioning motor is actuated by the engine control unit. An integrated sensor serves

to feed back the current position of the swirl flaps.

Function of the swirl flaps

Low engine speeds : The swirl flaps are closed when the engine is idling and at low engine

speeds. This causes a high level of swirling, good mixture formation.

Air intake system

High engine speeds

As of an engine speed of approx. 1250 rpm, the swirl flaps are open continuously. Good

combustion chamber filling is achieved thanks to the increased air throughput. As of an engine

speed of approx. 2750 rpm, the swirl flaps are opened completely.

Backlash compensation

The intake and exhaust camshafts are linked via spur gear toothing with integrated backlash

compansation. In this case, the exhaust camshaft's spur gear is driven by the intake camshaft's

spur gear. Backlash compensation ensures that the camshafts are driven with little noise.

Both spur gear parts are pushed axially together via the force exerted by a diaphragm spring.

Whilst this occurs, they are simultaneously caused to rotate via the lugs. This rotational

movement offsets the teeth of both spur gear parts and therefore leads to backlash compensation

between the intake and exhaust camshafts' gear wheels.

Chain drive

The camshafts, the balancer shaft and the oil pump are driven by the crankshaft via a chain drive.

This is located on the engine's gearbox side.

The chain drive makes the engine's compact design possible

The chain drive is comprised of:

● A central chain from the crankshaft to the intermediate gears (drive A),

● A chain from each of the intermediate gears to the intake camshafts (drives B and C),

● A chain from the crankshaft to the oil pump drive and to the balancershaft. The chains are

tensioned by sprung, hydraulic chain tensioners; this system is maintenance-free.

Ancillary component drive

The coolant pump, the power steering pump, the air

conditioner compressor and the alternator are driven

by the crankshaft via a poly V-belt.

Crankcase breather system

In combustion engines, pressure differences between the combustion chamber and crankcase

lead to air flows between the piston rings and cylinder contact surface; these are called blow-by

gases.

To prevent environmental pollution, these gases, which contain oil, are fed back to the intake

area via the crankcase breather system. A cyclonic oil separator separates the oil contained in the

gases from the air. This oil is returned to the oil pan via a port in the crankcase.

Crankcase breather system

Common rail fuel injection system

The common rail fuel injection system is a highpressure accumulator fuel injection system for

diesel engines.

The term "common rail" means that all of one cylinder bank's injectors have a common, high-

pressure fuel accumulator. In this system, pressure generation and fuel injection are separate. The

high pressure required for injection is generated by a separate high-pressure pump. This

fuel pressure is stored in a high-pressure accumulator (rail) and is made available to the injectors

via short injector pipes.

A detailed description of the common rail fuel injection system can be found in selfstudy

programme No. 351 "The common rail fuel injection system".

The main features of this fuel injection system are:

● The injection pressure can be selected almost

infinitely within the performance map.

● The availability of high injection pressure enables

optimal mixture formation.

● A flexible pilot, primary and secondary injection

process is achieved.

Common rail fuel injection system

Injectors (piezo injectors)

The 3.0l V6 TDI engine is fitted with piezo-controlled injectors. In comparison with solenoid

valve-controlled injectors, piezo technology has approximately 75 % less moved mass at the

injector needle.

This weight reduction offers the following advantages:

● Very short switching times

● Several injections per working cycle are possible

● Precisely apportionable injection quantities

Turbocharger

In the 3.0l V6 TDI engine, the charge pressure is generated by an adjustable turbocharger.

This is equipped with adjustable guide vanes, which enable the flow of exhaust gas onto the

turbine impeller to be influenced. The advantage of this is that optimal charge pressure and

therefore good combustion are achieved throughout the entire engine speed range. In the lower

engine speed range, the adjustable guide vanes offer high torque and good starting behaviour; in

the upper engine speed range, they enable low fuel consumption and low emission values.

The guide vanes are adjusted via an electric positioning motor. Electric initialisation makes fast

turbocharger response behaviour and precise regulation possible.

An exhaust gas temperature sender is located upstream of the turbocharger. The engine control

unit uses the exhaust gas temperature sender's signal to protect the turbocharger from

impermissibly high exhaust gas temperatures. In the event of excessive exhaust gas temperatures,

e.g. during full-throttle operation, the engine output is reduced.

CONCLUSION

The Volkswagen DSG dual-clutch gearbox not only meets the highest comfort and performance

requirements but also, as part of our Powertrain and Fuel Strategy, represents a key step towards

sustainable mobility. This environmental commendation documents the progress that has been

achieved in this area compared with a conventional torque converter automatic transmission.

The great advantage of TDI engines is that they are very powerful, even at low engine speeds,

and economical across the entire speed range. As they burn fuel more efficiently they produce

more power. What it means for you is much better performance, with more pulling power than

you would get from traditional fuel injection systems. This efficiency also means that you save

on fuel costs and emit less CO2, so helping to minimize your impact on the environment.

Compared with previous systems, diesel injection with piezo injectors offers the potential,

depending on the design, to reduce fuel consumption by roughly three per cent, to lower

emissions by up to 20 per cent, to increase the achievable engine power by up to five percent and

to approximately halve engine noise.

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

Diesel fuel is in demand worldwide. In the European Union and the United Kingdom, more than

half of all cars sold have a diesel engine. The reason is simple. A diesel-powered vehicle is easily

25-50% more efficient than one with a gasoline engine. In addition, diesel fuel in most E.U.

countries is taxed differently and it's less expensive than gasoline. Diesel also fuels construction

equipment, heavy trucks, freight trucks and cargo ships which are the economic engines of the

worldwide economy.

Blue Motion isn't just a single technology. It's a whole range of innovations and refinements that

help you save fuel and money, without taking the fun out of driving.

Bibliography and list of sources

Volkswagen AG Service Training VK-21 Brieffach 1995 D-38436 Wolfsburg

[Volkswagen AG 2007a] Volkswagen AG: The Passat – Environmental Commendation,

Wolfsburg:

Volkswagen AG. On the Internet at www.umweltpraedikat.de

[Volkswagen AG 2007b] Volkswagen AG: The Golf - Environmental Commendation,

Wolfsburg:

Volkswagen AG. On the Internet at www.umweltpraedikat.de

[Volkswagen AG 2008] Volkswagen AG: The Golf - Environmental Commendation, Wolfsburg:

Volkswagen AG. On the Internet at www.umweltpraedikat.de