lubrication in automotive engines

Lubrication

in Automotive Engines

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


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.


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


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


Working of a four-stroke engine


Working of 4-Stroke Petrol Engine


New Generation Petrol Engine


Direct Injection ( DI ) Petrol Engine


4 - Stroke Diesel Engine


4-Stroke Diesel Engine


Working Of Four-Stroke CI Engine (Dual Fuel)


Common Rail Turbo Diesel Engine


4-Stroke Diesel Engine


• Basic cycle

• Type of Fuel

• Introduction of fuel

• Ignition method

• Compression ratio

• Efficiency

• Weight

Comparison of Petrol and Diesel Engines


2 - Stroke Engine


• 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


• Power stroke / crankshaft revolution

• Weight of engine

• Moving Parts

• Initial cost

• Lubrication and cooling requirements

• Overall Efficiency

2 Stroke and 4 Stroke Engines - Comparison


2-Stroke SI Engine


Working Of 2 -Stroke SI Engine


2 - Stroke CI Engine


How Lubricants are applied ?


Major Parts lubricated

Journal Bearings

Piston rings - cylinder

Cams and followers

Diagram - 1

Parts of an Engine -

Diagram – 2

Diagram - 3 Diagram – 4


4 - Stroke Engine Lubrication

Splash Lubrication

Force Feed Lubrication

Combination Splash and Force Feed Lubrication


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


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


Automotive Trends


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


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


TYPICAL SOOT CONTENT

(Source : www. scientecmatrix.com)

Particulate Matter - Composition


Worldwide Diesel Emission Requirements


Low Emission Lubricants - Timeline

ACEA 2004

Indian Emission standards are for 11 major metropolitan cities


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


Reduced Emissions

New Engine Designs

New Engine Oil

Consequences of Lower Emissions

Improved

Fuel


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


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


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


Traditional design Low emission design

High top

ring location

Crevice Volume

Low Emission Piston Design Crevice Volume & Top Ring position


Hot Exhaust Gas

Exhaust

EGR

Control

Valve

EGR Duct

Intake

N

Fresh Intake Air

Exhaust Gas Recirculation

NOx Reduction Technologies EGR


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


VOLVO : SCR & Urea Tank Arrangement


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



• 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%



• 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

Thank You !

RAJIV RANJAN [email protected]

mailto:[email protected]


In-Line Type


V Type


Opposed Piston Type


Engine Parts & Oil Flow


Parts of an Engine


Splash Lubrication


Force Feed Lubrication System


Combination Splash and Force Feed Lubrication


Lubricant Flow Diagram

Thank You !

RAJIV RANJAN [email protected]

mailto:[email protected]