21 Diesel

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History

Trade Theory

Rudolf Diesel1858 - 1913

Rudolf Diesel was an employee of the

Maschinenfabrik Augsburg Nuernberg (MAN).

In 1892 his engine priciple was patented.

Nobody knows how he was dying. On the way to

England by ship he most probably drowned.

Diesel Engine

First functioning Diesel engine in 1897

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Trade TheoryClassification of Engines

Engineaccording to

Duty cycleWorking

principle

Layout of

cylindersFuel

Engine

fillingCoolingIgnition

Mixure

formation

Four stroke

W

VR

Oposedcylinder

V

In-line

Two stroke

Turbine

Rotary

piston

Reciprocating

pistonPetrol

Diesel

Gas

Induction

system

Exterior

Mixture

formation

Compression

ignition

Spark

ignition

AirCharged

engine

WaterSuction

engine

Diesel Engine

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Trade Theory Diesel EngineOverview of the Bosch diesel fuel-injection systems

M, MW, A, P, ZWM, CW = In-line injection pumps in order of increasingsizePF = Single-plunger injection pumpsVE = Axial-piston distributor injection pumps

VR = Radial-piston distributor injection pumpsUPS = Unit pump systemUIS = Unit injector systemCR = Common rail system

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Diesel 4 Stroke Engine

Trade Theory Diesel Engine

TDC

BDC

Intake Valve

Intake Channel

Crankshaft

Connecting Rod

Piston Rings

Piston

Piston Pin

Cylinder

Crank Case

Exhaust Channel

Camshaft

Fuel injector

Stroke

Exhaust Valve

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Trade TheoryCompression Ratio

TDC 12

3

4

5

6

7

8BDC

Stroke

S

1

2

3

456

78

Compression Ratio : 14-22 : 1

Otto-Engine Diesel-Engine

Compression Ratio : 7-10 : 1

9

11

10

12

1314

15

Diesel Engine

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Trade TheoryDiesel combustion principle

PrincipleThe combustion

chamber is sub-

divided. The fuel

is injected through

a pintle nozzle into

the pre-combustion

chamber.

This pre-precombustion

chamber is connected

to the cylinder

combustion chamber

through a channel.

Glow plugs are

necessary for starting

the engine because

the cooling surface

is large.

Facts- Injection pressure

90-120 bar,

- Lower peak pressure

- Soft and silent running

of engine

- More uniform mixture

formation

- Smaller ignition lag

- Higher fuel consumtion

Diesel Engine

Pre-chamber processValve

Injection nozzle

Glow plug

Ball pin

Piston rings

Piston

Pre-combustion

chamber

Combustion

chamber

Channel

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Trade Theory

PrincipleThe combustion

chamber is

sub-divided.

The fuel is injected

into a mostly

sperical-shaped

whirl chamber

through a pintle

nozzle in a broad

spray.

The connecting

aperture to the

cylinder chamber

is wide, and runs

mostly tangential.

Good turbulence

of the fuel with air.

Glow plugs are

needed for starting.


100-125 bar

- Lower peak

pressures

and combustion

shocks.

- Soft and silent

running of engine

- Good mixture

formation

- Smaller ignition lag

- Higher fuel

consumtion

Diesel Engine

Whirl-chamber processValve

Injection

nozzle

Whirl chamber

Channel

Combustion

chamber

Piston rings

Piston

Diesel combustion principle

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Trade Theory

Direct injection process

PrincipleThe finaly atomized

fuel coming through

single or multi-hole

jets is directly injected

into the cylinder

chamber.

No Glow plugs are

required to start the

engine because the

cooling surface is

small.


200 bar

- Low heat loss

- Good starting

property

- Low fuel comsumtion

ca. 245 g/kWh

- Gretaer ignition lag

- Uniform mixture

formation more

difficult

- Harder running of

the engine

- Greater maximum

pressure

Diesel Engine


Valve

Injection

nozzle

Combustion

chamber

Integrated

combustionchamber

Piston

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Trade Theory

Principle of the M-System(Centre Sphere Method)Sub-divided combustion

chamber. Spherical shaped

combustion chamber in the

centre of the piston.

A twisted channel in the

suction line creates a

powerful turbulence.

The fuel is injected

almost without atomizing

through a single or double-

hole jet on the surface of

the combustion chamber.

The fuel film is vaporizedby the hot turbulent air.

The fuel-air mixture

burns layer-wise.


175 bar

- Lower prerssure

peaks

- Smaller ignition

lag

- Softer burning

- Elestic and silent

engine running

- Intensive to fuel

(multi fuel engine)

- Lower fuel

consumtion

(200-230 g/kWh)

Diesel Engine

M = MittenkugelbrennraumThis system was developed by the truck manufacturer MAN

MAN = Maschinenfabrik Augsburg Nuernberg


Combustion

chamber

M-SystemValve

Injection

nozzle

Pistion-

recess

Pistion

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Fuel tank

Fuel filter

Fuel heater

Fuel-injection pump

Heater for diesel-fuel

Electric line

Fuel adaptionFuel problems which normally

occur at low temperatures as

a result of precipitation of

parafin crystals can be avoided

by filter heating or direct fuel

heating.

Or, the flow properties can be

improved by a admixture of

petroleum or regular-grade

gasoline. Guide-value : 10 30 %

can be added, depending on the

temperature.

The instructions of the vehicle

manufacturer must be observed

here. Attention ! Never mixpetroleum or gasoline into diesel-

fuel on vehicles with common-rail

injection system.

Diesel fuel is offered regionally with

guarantees problem-free operation

down to 23 C

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Start-assist system for diesel-engines

Glow plug

Pre-heating with glow plug

Pre-heating for start periodIn direct-injection engines, pre-heating of the

intake air acts as a start-assyst measure.

In the case of pre-chamber engines, a glow plug

in the whirl chamber or pre-chamber acts as a

starting aid.

Modern glow plugs with a pre-heating time of

only a few seconds permit rapid starting.

Both measures serve to improve fuel vaporization

and mixture preparation and thus achieve reliable

ignition of the air-fuel mixture.

Injection

nozzle

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21 Diesel

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