Transcript
Lubrication
in Automotive Engines
Presented by : RAJIV RANJAN
Presented by : RAJIV RANJAN
Device which transforms the chemical energy of a
fuel into thermal energy and uses it to produce
mechanical work.
What is a HEAT ENGINE ?
Chemical -> Thermal -> Mechanical Energy
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Types of Heat Engines
1. External Combustion (EC) Engines The products of combustion of air and fuel transfer heat to a second
fluid which is the working fluid of the cycle.
e.g. Steam engines.
2. Internal Combustion (IC) Engines The products of combustion are used as the working fluid of the
cycle.
e.g. Petrol/ Diesel engines.
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Theory of Internal Combustion (IC) Engines
- Types of IC engines
- Comparison of Petrol & Diesel Engines
- Comparison of 2 Stroke & 4 Stroke Engines
Internal Combustion Engines
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Types of Engines
Working Fuel • Engines working on Petrol /Gasoline Fuel (SI engines) • Engines working on Diesel Fuel (CI engines)
Number of strokes
• 4 - stroke engines / 4 Cycle Engines • 2 - stroke engines / 2 Cycle Engines
Cylinder Layout
• In-Line Type • V Type • Opposed Piston Type
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Working of a four-stroke engine
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Working of 4-Stroke Petrol Engine
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New Generation Petrol Engine
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Direct Injection ( DI ) Petrol Engine
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4 - Stroke Diesel Engine
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4-Stroke Diesel Engine
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Working Of Four-Stroke CI Engine (Dual Fuel)
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Common Rail Turbo Diesel Engine
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4-Stroke Diesel Engine
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• Basic cycle
• Type of Fuel
• Introduction of fuel
• Ignition method
• Compression ratio
• Efficiency
• Weight
Comparison of Petrol and Diesel Engines
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2 - Stroke Engine
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• Cycle of operation is completed in one revolution of the crankshaft i.e.
Only two piston strokes are required to complete the cycle
- one for compressing the fresh charge
- the other is the power stroke.
• The difference is the method of filling the cylinder with fresh charge
and removing the gases.
2-Stroke Engine
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• Power stroke / crankshaft revolution
• Weight of engine
• Moving Parts
• Initial cost
• Lubrication and cooling requirements
• Overall Efficiency
2 Stroke and 4 Stroke Engines - Comparison
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2-Stroke SI Engine
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Working Of 2 -Stroke SI Engine
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2 - Stroke CI Engine
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How Lubricants are applied ?
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Major Parts lubricated
Journal Bearings
Piston rings - cylinder
Cams and followers
Diagram - 1
Parts of an Engine -
Diagram – 2
Diagram - 3 Diagram – 4
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4 - Stroke Engine Lubrication
Splash Lubrication
Force Feed Lubrication
Combination Splash and Force Feed Lubrication
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Lubrication system
Oil is sucked into the pump, then forced through an oil filter and pressure fed to the main bearings.
From Main Bearings oil passes through feed-holes into drilled passages in the crankshaft to the big-end bearings of connecting rod.
The cylinder walls and piston-pin bearings are lubricated by oil splashed by the rotating crankshaft. The excess being scraped off by the lower ring in the piston.
A tributary from the main supply passage feeds each camshaft bearing. Another supplies the timing chain/gears on the camshaft drive.
The excess oil drains back to sump, where the heat is dispersed to the surrounding air.
1 Lubricants Flow Diagram 2 3 4
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2 Stroke Engine Lubrication
Petrol
Direct Injection
Problems Faced :
è Spark Plug Fouling
è Ring Sticking
è Combustion Chamber Deposits
è Port & Silencer Deposits
è Bearing Rusting
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Automotive Trends
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Emissions - Legislation - Timing
First started to appear in the 1950s 1957 California
Became widespread in the 1980s and 90s
Now covers USA, Europe, Japan, Australia, Argentina, Brazil, China, India, South
Korea, Thailand, Singapore
Others
Legislations in place till 2010 EU, Euro V 2008
USA, EPA 2007(Tier 3) Proposed limits for 2010
California Air Resource Board(CARB) Urban Bus Standard 2010
15% of new buses must be “zero” emission
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Legislated Emissions
NOx Nitrogen oxides NO and NO2 only
CO Carbon monoxide
HC Hydrocarbons Some times THC(Total HydroCarbons) Some times NMHC(Non Methane HydroCarbons)
PM Particulate Matter
Smoke Visible particulate matter
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TYPICAL SOOT CONTENT
(Source : www. scientecmatrix.com)
Particulate Matter - Composition
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Worldwide Diesel Emission Requirements
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Low Emission Lubricants - Timeline
ACEA 2004
Indian Emission standards are for 11 major metropolitan cities
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Emissions and Impact on Engine Technology
EURO 4
EURO I
EURO 2
EURO 3
Part
icula
tes
NOx
Turbochargers & Intercoolers
Fuel changes
Retarded injection, piston design changes
EGR
CRT
OXICAT
De-NOx CAT
SCR
ENGINE DESIGN
AFTERTREATMENT
SCR = Selective Catalytic Reduction, CRT = Continuously Regenerating Trap
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Reduced Emissions
New Engine Designs
New Engine Oil
Consequences of Lower Emissions
Improved
Fuel
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Diesel Engine Design Changes
• Two Categories of design changes
• Engine modifications affecting engine out
emissions
• Exhaust after treatment devices affecting
tail pipe emissions
• These are enabled with the development more sophisticated
• Engine management systems
• Hardware
• Fuels
• Lubricants
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Emission Reduction Techniques for Heavy Duty Diesel Vehicles
NOx Reduction PM Reduction
In-Cylinder In-Cylinder
• Retarded Timing • Improved Fuel Atomisation
• Charge Air Cooling • Central symmetric
• Rate Shaping Combustion chamber
• Dilution by EGR, Water • Lean A/F mixtures
After Treatment After Treatment
• SCR • DPFs
• NOx absorber • DOC
• Lean NOx catalyst
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Inter-
cooling
- High Pressure Fuel
Injection
- Retarded Timing
- Cooled EGR
Turbo-charging
- Common Rail
- Low S Diesel
• Central Injectors
• Piston Design
• Raised Top Ring
• Articulated Pistons
Engine Changes to Meet Emissions
High Quality Lubricants
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Traditional design Low emission design
High top
ring location
Crevice Volume
Low Emission Piston Design Crevice Volume & Top Ring position
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Hot Exhaust Gas
Exhaust
EGR
Control
Valve
EGR Duct
Intake
N
Fresh Intake Air
Exhaust Gas Recirculation
NOx Reduction Technologies EGR
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Exhaust After Treatment
• Selective Catalytic Reduction ( SCR )
• NOx is chemically reduced to Nitrogen by urea or
ammonia in the presence of catalyst
• Efficiency around 90%
• Needs source of reducer
• Diesel Particulate Filter ( DPF )
• Filters out particulates, predominantly carbon based
• Can be regenerated in situ by oxidising the carbon by
heat, sometimes in the presence of catalyst with oxygen
or even NO2
• Very good efficiency
• Already in widespread use
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VOLVO : SCR & Urea Tank Arrangement
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Heavy Duty Diesel DPF
DPF section shows Ash from Lube Oil after 50,000 km of urban bus operation DPFs need to be cleaned every 150,000 to 300,000 km
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Exhaust After Treatment
• Diesel Oxidation Catalyst (DOC)
• Lower HC and CO by oxidation
• Particulates are partly organic called soluble oil fraction(SOF)
• DOCs can lower the SOF part of particulates
• Lean NOx Catalyst
• Lowers NOx by reduction with HCs
• Present catalysts are not very active at typical Exhaust
temperatures
• Efficiency only about 40%
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Exhaust After Treatment
• NOx Absorbers
• Also called NOx traps
• NOx is chemically bound to the catalyst wash coat
• Once wash coat is saturated with NOx the engine runs
rich and it is reduced with HCs
• Favoured by EPA
• Appear to be very sulphur sensitive
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In-Line Type
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V Type
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Opposed Piston Type
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Engine Parts & Oil Flow
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Parts of an Engine
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Parts of an Engine
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Parts of an Engine
Presented by : RAJIV RANJAN
Parts of an Engine
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Splash Lubrication
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Force Feed Lubrication System
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Combination Splash and Force Feed Lubrication
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Lubricant Flow Diagram
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Lubricant Flow Diagram
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Lubricant Flow Diagram
Presented by : RAJIV RANJAN
Lubricant Flow Diagram
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