Diesel Basic

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Centre

Diesel Engine

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Division : MICO/PDT(BTC) Division : MICO/PDT(BTC)

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Centre

1 1

Principle of the reciprocating engine

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Centre

Principle of the reciprocating engine

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Division : MICO/PDT(BTC) Division : MICO/PDT(BTC)

Bosch Traini

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Centre

1 1

4 stroke cycle diesel engine

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Centre

Fuel layout on a diesel engine(o/f valve on FIP)

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Division : MICO/PDT(BTC)

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Sectional view of the

injection pump PE .. A

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Common Rail System

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The basic VE Pump contains the following functional

groups:

Vane type supply pump

Distributor Head (High Pressure Pump)

Mechanical Governor

Hydraulic Timer

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Bosch Training Centre

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1

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Emission Legislation

Higher Power and Torque

Fuel Efficient

Smoother drivability

Cost effective

Injection Quantity

Injection Begin

Injection Pressure

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1

Degrees of Freedom in Common Rail :

•

Injection Pressure

•

Injection Quantity

•

Injection Begin

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What is Common Rail?

Common Rail is a

Modular ,

Diesel Fuel Injection System.

Electronic Controlled,

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Special Characteristics :

•

Injection Pressure is produced and governed relatively independent of

the Engine Speed and can be selected freely within a wide range.

•

Injection begin and Injection Quantity can be freely selected

(EDC function)

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How are the main characteristics of CR system

achieved ?

•

CR uses an intermediate High Pressure Accumulator (Rail)

•

Uses Electronic Control of Injectors (use of Electro-magnetic valves)

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1 1400 1200 1000 800 600 400 200

Injection pressure [bar]

1000 2000 3000 4000 5000 Engine speed [RPM] Common Rail other port-controlled systems 1600 1800 Common Rail

Other port controlled Systems (Conventional)

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Driver demand

CP3 MPROP

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Common Rail System

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High Pressure Pump CP1 - Standard

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Common Rail System

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High Pressure Pump CP1 - Standard

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1

High Pressure Pump CP1 - Standard

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Common Rail System

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Common Rail System

Maximum

delivery

Maximum delivery

Q [l/h]

I [A]

Zero delivery

Zero

delivery

Fuel Fuel

Detail A

A

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DRV

_–

Pressure Regulator Valve

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Common Rail System

DRV

_–

Pressure Regulator Valve

F M a g n e t F M a g n e t H i g h p r e s s u r e F S p r i n g F

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Common Rail System

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1

Factors determining the Rail Volume :

Rail Volume is a compromise based on the following two factors

Volume to be kept as small as possible to keep the response time

of the system short (i.e., the setpoint pressures to be achieved in as

short a time as possible)

Volume should be as large as possible to keep the Pressure oscillation

to minimum possible value.

Common Rail System

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Pressure Limiter Valve

0 500 1000 1500 2000 0 4 time p r e s s u r e [ b a r ]

Low Pressure Fuel High Pressure Fuel

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Injector

Principle

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F

0

F

0

p

₂ 

0 Closed

Open

p

₁

p

₁

Control

volume V

st

p

₂ 

0 p

_st 

p

₁

_p

st 1   2

Inlet

Orifice

Outlet

Orifice

U I F_V V a l v e L i f t

Injector 2/2 Valve

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Common Rail System

Injector

Control Chamber Pressure Nozzle end

Pressure Armature Lift Current

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1 0 10 20 30 40 50 60 70 80 90 100 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1600bar 1500bar 950bar 600bar 300bar 250bar Full Load Area

Low Idle Area Emission area

Pilot Injection Area

Energizing Time (ms)

Q u a n t i t y ( m m 3 / s t r . )

Injector Characteristics

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Input circuits (1) analog signals digital signals sign. process. unit _Signal processing (3) D A Interfaces (5): communication diagnosis Output circuits (2) A D digital correcting and output signals steady correcting varaibles sign. process. unit

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