Self-Study Programme 439 2.0L TFSI flexible fuel engine.pdf

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Self-Study Programme 439
Audi
2.0l TFSI flexible fuel engine
Audi
Service Training
The 2.0l flexible fuel engine sees Audi making another contribu-
tion to environmental conservation. Audi has been offering this
ethanol-compatible flexible fuel engine with European Audi A4
models since the autumn of 2009. Today bioethanol is produced
via alcoholic fermentation of energy crops such as wheat, maize
and sugar cane. Thanks to the high renewable factor, the CO
2
balance of bioethanol in the vehicle as a whole is up to 75 % more
favourable than that of conventional petroleum-based fuel.
The advantage of the Audi concept is that the engine can be run on
fuel with any concentration of up to 85 % ethanol with no notice-
able differences in drivability or performance.
Political goals of the international community in marketing
bioethanol are:
• To drastically reduce greenhouse gas emissions.
• To reduce the dependency on imported fossil fuels.
• In terms of agricultural policy, it is envisaged that bioethanol
will provide alternative sources of income and development
opportunities for agriculture.
• In terms of trade policy, intensive production of biofuels will
help to curb agricultural overproduction and, thus, reduce
subsidy levels.
Objectives for the development of the 2.0l TFSI flexible fuel
engine are:
• To use an existing basic engine; 2.0l TFSI flexible fuel engine
designed to run on ethanol is based on the existing 2.0l TFSI
engine with
AVS*
and start-stop technology.
• From the start, the customer does not notice any drawbacks in
terms of driving comfort or driving pleasure.
• An engine running on bioethanol should start reliably at low
ambient temperatures without any need for pre-heating, which
is usually the case with competitor products today.
• The favourable properties of the bioethanol will be utilised to
optimise engine efficiency at all operating points.
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Learning objectives of this Self Study Programme are:
In this Self Study Programme you will learn about the technology
of the 2.0l TFSI flexible fuel engine and the differences between
this engine and the basic 2.0l TFSI engine.
If you have worked your way through this Self Study Programme,
you will be able to answer the following questions:
2
• What does the term "bioethanol" mean?
• What modifications does the 2.0l TFSI flexible fuel engine have
compared to the basic engine?
• What modifications have been made to the fuel system?
• What are the special features of the engine management
system?
• What are the points to note when servicing the vehicle?
Contents
Introduction
Brief technical description _________________________________________________________________________________________________________________________________ 4
Specifications ________________________________________________________________________________________________________________________________________________ 5
Bioethanol
Basic information ___________________________________________________________________________________________________________________________________________
Specifications for bioethanol ______________________________________________________________________________________________________________________________
Comparison of fuel properties _____________________________________________________________________________________________________________________________
Why E85, and not pure alcohol? ___________________________________________________________________________________________________________________________
Production process __________________________________________________________________________________________________________________________________________
6
7
7
7
9
Modifications to the basic engine
Development goals ________________________________________________________________________________________________________________________________________ 10
Cylinder liners ______________________________________________________________________________________________________________________________________________ 11
Cylinder head _______________________________________________________________________________________________________________________________________________ 11
Cranktrain ___________________________________________________________________________________________________________________________________________________ 12
Conrod _______________________________________________________________________________________________________________________________________________________ 12
Fuel system
Introduction ________________________________________________________________________________________________________________________________________________ 13
Fuel quality sender G446 __________________________________________________________________________________________________________________________________ 16
Engine management
Overview of the Bosch MED 17.1 system ________________________________________________________________________________________________________________ 20
Cold starting ________________________________________________________________________________________________________________________________________________ 22
Cold starting with ethanol ________________________________________________________________________________________________________________________________ 23
Fuel ingress into the engine oil and fuel extraction from the engine oil _____________________________________________________________________________ 26
Service
Scope of maintenance _____________________________________________________________________________________________________________________________________ 28
Control and auxiliary drive ________________________________________________________________________________________________________________________________ 28
Annex
Glossary _____________________________________________________________________________________________________________________________________________________ 29
Test your knowledge
Summary ____________________________________________________________________________________________________________________________________________________ 31
Self Study Programmes ___________________________________________________________________________________________________________________________________ 31
• The Self Study Programme explains the basics of the design and function of new models, new automotive
components or new technologies.
It is not a Repair Manual! Figures given are for explanatory purposes only and refer to the software version
valid at the time of preparation of the SSP.
For maintenance and repair work, always refer to the current technical literature. Terms shown in italics and
marked by an asterisk (*) are explained in the glossary at the back of this Self Study Programme.
!
Note
Reference
3
Introduction
Brief technical description
• Four-cylinder, four-valve turbocharged petrol engine
• Basic engine: grey cast iron cylinder block; balancer shafts in the
cylinder crankcase; steel crankcase; regulated oil pump sub-
merged in the sump and chain-driven by the crankshaft; timing
gear chain fitted at the engine front end; mass balancing with
chain drive fitted at the engine front end
• Cylinder head: four-valve cylinder head with a camshaft phaser
on the intake side and
AVS*
on the exhaust side
• Intake manifold with intake manifold flaps (tumble flap)
• Fuel supply: demand-controlled on the low pressure and high
pressure sides, multi-port high-pressure injectors; additional
cold start valve for ethanol operation
• Engine management: engine control unit MED 17.1
• Hot film air mass meter (digital) with integrated temperature
sensor, throttle valve with non-contact sensor
• Mapped ignition with cylinder-selective, digital knock control;
single spark plugs
• Turbocharging: integral exhaust turbocharger; charge air cooler,
charge air control with excess pressure; electrical divert air valve
• Exhaust system: single-chamber exhaust system with close-
coupled pre-catalyst
• Combustion process: homogeneous direct injection, intake
manifold injection during cold starting
439_003
Reference
For further information about the basic 2.0l TFSI engine, refer to Self Study Programmes 436 "Modifications to the chain-
driven 4-cylinder TFSI engine" and 384 "Audi chain-driven 1.8l 4V TFSI engine".
4
Specifications
Torque-power curve
Power in kW
Torque in Nm
Speed [rpm]
439_004
Engine code
Type
Displacement
in cm
3
Stroke
in mm
Bore
in mm
Cylinder spacing
in mm
Number of valves per cylinder
Firing order
Compression ratio
Power output
in kW at rpm
Torque
in Nm at rpm
Fuel
Engine management
CO
2
emission
in g/km
Carbon fibre composite
Four-cylinder inline engine
1984
92.8
82.5
88
4
1-3-4-2
9.6:1
132/4000 – 6000
320/1500 – 3900
95 RON petrol
1)
, ethanol (E85)
mixable in all ratios up to 85 %
Bosch MED 17.1
149
2)
Unleaded RON 91 petrol can also be used, but will result in a slight loss of power.
Value refers to an Audi A4 with front-wheel drive and 6-speed manual gearbox running on RON 95 premium unleaded petrol; the higher
the ethanol content, the lower the CO
2
emissions will be.
1)
2)
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