Commonrail Brochure MAN

7/29/2019 Commonrail Brochure MAN

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MAN Diesel

Common RailLess consumtion. Less soot. Less NO.


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MAN Diesel Common Rail

6L32/40CR

Cover: Detail of Common Rail pump valve carrier


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Large reductions in NOX, CO2 and soot emissions are a

strategic success factor for HFO diesel engines. Special

emphasis is placed on low load operation, where con-

ventional injection leaves little room for optimisation since

the injection process, controlled by the camshaft, is linked

to the engine speed. Thus, possibilities for designing a

load independent approach to the combustion process

are severely limited.

MAN Diesel Common Rail Technology (CR) severs this link in

medium-speed four-stroke engines. CR permits continuous

and load-independent control of injection timing, injection

pressure and injection volume. Thus, CR technology achieves

the highest levels of flexibility for all load ranges and yields

significantly better results than any conventional injection

system.

MAN Diesel now offers the industry two mature and field-tested injection systems that have been tailored to fit specific

engine characteristics: CR technology for medium-speed

four-stroke engines and ME technology for low-speed two-

stroke engines. ME technology is based on a Pressure

Boosted Common Rail System. It differs from the four-

stroke CR primarily in its servorail system that supplies

high pressure fuel to each cylinder via the pressure

booster and simultaneously activates the exhaust valve.

MAN Diesel injection systems: variable injection pressure

for reduced fuel consumption and lower emissions in all

engines from truck diesel engines in MAN commercial

vehicles to medium-speed and low-speed engines in

MAN Diesel.

The coming decades will see a sharp increase in the ecological and economic

demands placed on internal combustion engines. Evidence of this trend is

the yearly tightening of emissions standards worldwide, a development that

aims not only at improving fuel economy but above all at achieving clean

combustion that is low in emissions.

Injection technology formedium-seed four-stroke engines



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MAN Diesel Common Rail Technology lowers the emission

rate of soot and NOx at all possible engine operating points

even when using single injection only, i.e. without pilot or

post-injection.

The graph shown here compares conventional and CR

injection processes during generator operation over anengine load range of 0 to 00 % at an engine speed of

750 rpm.

Due to the flexibility of the injection process, NOx emission,

fuel consumption and exhaust opacity can be improved by

varying injection pressure and start of injection. Even in the

commonly problematic low load range, exhaust opacity can

be brought down below the visibility limit.

Smoke emission

(rel.)

NOx

SFOC

Max. cylinder

pressure (bar)

Engine Load (%)

0,9

0,6

0,3

0,0

1,25

1,00

0,75

0,50

1,1

1,0

0,9

0,8

200

150

100

050

CR

Conventional

MAN Diesel CR Technology Measurably friendly to the environment

0 25 50 75 100

0 25 50 75 100

0 25 50 75 100

0 25 50 75 100

Comparison of engine performance for different injection systems


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Higher efficiency with fleible injection

The old problem with the fixed link between injection

pressure and engine speed is well-known. In engines with

high effective mean pressure, there is a rapid decline in

injection pressure in the low load range, a phenomenon

that has a negative effect on the air-to-fuel ratio and on

spray atomisation that are key to combustion. Poor com-

bustion is the consequence.

The new MAN Diesel CR injection technology permits in-dependent and separate control of injection pressure and

timing. Fuel is fed into the rail (pressure accumulator) by an

electronically controlled high pressure pump and stored

there for each injection. The result is improved combustion

and lower emissions with the same or even better fuel

economy strong advantages, especially in the critical low

load range.

Doing more for the environment

The injection flexibility of MAN Diesel CR technology means

decidedly lower NOXand CO2 emissions thanks to highly

effective combustion.

Retrofit? Retrofit!

CR technology from MAN Diesel takes advantage of a

modular high pressure pump system with multiple lobes on

the camshaft. The camshaft drives the high pressure pumps,

which are equipped with solenoid operated suction throttle

valves for pressure control. This layout and the modular

structure of the units makes it possible to install MAN Diesel

CR technology retrospectively. Thus, many older diesel

engines can still benefit from the new technology: simple,

fast retrofitting and upgrading for lower emissions with no

loss in output.

injection valve

control valve

rail cover

rail unit

high pressure pump

camshaft

throttle valve

General benefits


Our CR technology is an ideal tool for lowering pollutant

emissions and fuel consumption while giving the user the

security that this system will continue to meet the demands

of the future: todays diesel engine designs at MAN Diesel

already include tomorrows requirements, such as multiple

injections.

pump accumulator


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MAN Diesel CR injection technology

is synonymous with reliability and

reliability begins at the development

process.

Enhancing reliability by thinking ahead

>> Should a high ressure um fail:

MAN Diesel CR systems are equipped with

at least two high pressure pumps and the

system can easily be operated with only one

high pressure pump.

>> Should the rail ressure controller fail:A safety valve with an additional mechanical

pressure control valve ensures the continued

operability of the system.

>> Should a rail ressure sensor or the seed/

to dead centre sensor malfunction:

Important sensors are redundant to ensure that

here, too, the system will continue to operate.

>> To rotect against fuel escaing from leaking

fuel ies:

All high pressure lines, rails and high pressure

connections are double wall insulated.

>> To rotect against uncontrolled injections:

Flow limitation valves at each cylinder prevent

unintended injection.

MAN Diesels experience in the development and production

of high pressure injection systems has been consistently

advanced and implemented in CR technology. In addition to

theoretical investigations of safety concept, test operations

with HFO on MAN Diesel system test rigs are of central im-

portance and make it possible to immediately define any

preventive measures required to guard against potential

technical problems. Consequently, CR technology from

MAN Diesel is able to offer excellent reliability in all operating

situations and, from the outset, brings with it a high degree

of maturity.

FOR ExAMpLE


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Detailed pre-tests using system test rigs with HFO in Augsburg

As a matter of principle, MAN Diesel has kept the basic

concept of its Common Rail Technology as simple

as possible and has integrated technically proven com-

ponents into the design. For example, in keeping with

this philosophy, the design does not use a separate

servo circuit for activating the injection valve. Less main-

tenance is one of the benefits. Also, integrated into the

CR technology are well-proven components with long

service experience, such as injection valves and nozzles.

The injection control valves are on the rail outside of the

cylinder head, resulting in greater system reliability.


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Modular um system for

greater reliability

MAN Diesel engines use either two or three high pressure

pumps, depending on the number of cylinders. The pumps

are capable of accumulating a pressure of up to 00 bar

in the rail system. This design offers added machine

reliability, because even if one pump should fail, the engine

will continue to be operable.

A high ressure rail segment

for control valves

In principle, there are several possible designs for the

fuel accumulator. For example:

>> one high pressure rail for the entire engine,

>> independent high pressure rail segments for two

or three cylinders,

>> individual accumulators for each cylinder.

MAN Diesel decided on one high pressure rail segment

for two cylinders, as with this design, medium-speed

four-stroke engines can achieve a maximum level of

pressure stability and operating reliability while at thesame time taking advantage of a simple and integral

structure.

The concept of modular elements has also been imple-

mented in the rail segment design. Types 2/0 and

/0B use the same base elements. Only the lengths

of the rail units were adjusted.

In addition, on both ends of the segment the patented

valve support integrates the control valves with solenoid,

flow limiter and connections for high pressure lines.

Introduction of the 32/40CR on the market was preceded by years of

intensive, practise oriented development at MAN Diesel using the

Augsburg test facilities. Subsequent tests performed in co-operation

with a customer yielded such positive results that today, MAN Diesel

is able to offer a mature technology that reliably guarantees an optimum

level of performance, environmental compatibility and economy.

Mature technology

Modular rail unit with integrated control valve for different engines

Type 32/40

Type 48/60B


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ECU The electronic heart of the MAN Diesel CR System

ECU

The heart of MAN Diesel CR injection technology is the

electronic control unit (ECU). It calculates pressure, injection

timing and injection volume on the basis of numerous

operational parameters recorded by sensors, such as

engine speed, cylinder top dead centre, load pressure andrail pressure. The calculated current pulses are then output

to the solenoids of the control valves (rail segment) and

suction throttle valve (high pressure pump).

At precisely the right time, the control valves receive a pulse

that causes the injection valves to open. As soon as enough

fuel has been injected, the valves close. The ECU is the key

to flexible combustion and thus to minimizing emissions at

a low level of fuel consumption.



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Ready for the future

MAN Diesel is working to adapt CR technology for fuel/water emulsions.

Furthermore, the combustion process is undergoing continuous development

with respect to CR technology.

A significant advantage in the trade off between NOx-soot emission and

fuel consumption was achieved on the single cylinder research engine

in Augsburg by means of an increased compression ratio and the so-called

Miller gas exchange valve timing in combination with pilot injections

that are feasible with our CR technology.


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MAN Diesel a member of the MAN Group

Copyright MAN Diesel SE

Subject to modification in the interest of technical progress.

D225EN-N2 Printed in Germany KW-070

MAN Diesel SEStadtbachstr.

22 Augsburg

Germany

Phone + 2 22-0

Fax + 2 22-2

[email protected]

www.manbw.com

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Commonrail Brochure MAN