Conversion of the engine from diesel to gas (CNG LPG) Hướng dẫn chuyển đổi động cơ diesel sang CNG

Hướng dẫn chuyển đổi động cơ sử dụng nhiên liệu diesel sang sử dụng nhiên liệu CNG (Compressed Natural Gas) của hãng NGV Motori Italy. Động cơ chuyển đổi có công suất tương đương động cơ diesel, chất lượng khí thải được cải thiện, góp phần bảo vệ môi trường.

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NGV 2700 CONVERSION KIT

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I NDEX Pagina 1 di 4

Conversion of the engine – from Diesel to GAS (cng/lpg)

SECTION 01 – PRELIMINARIES CONTROLS ON THE ENGINE

SECTION 02 – WORKING ON THE ORIGINAL DIESEL

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06.02.06OPTION DEFAULT STUCK

06.02.07TYPE OF LAMBDA PROBE

06.02.08NUMBER OF LAMBDA PROBES

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SECTION 08 – ROAD TEST

10.03.02THE ENGINE SUPPLIES NOT ENOUGH POWER

10.03.03THE ENGINE RUNS UNEVENLY

SECTION A1 – STANDARD COMPONENTS

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A2 HARNESS

A2.01.01HARNESS DRAWING

A2.01.02FUNCTIONAL DRAWING

A2.01.03PIN –OUT

A2.02.03PIN –OUT

A2.03.03PIN –OUT

A2.04.03PIN –OUT

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T HE E NGINE Section 01

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01.01 D ISASSEMBLY O F T HE E NGINE

PHASE DESCRIPTION

01 Disassemble the original engine head

02 Disassemble the original valves

03 Disassemble the original camshaft

04 Disassemble the original crankshaft

05 Disassemble the original bearings

06 Disassemble the original pistons

07 Disassemble the original piston rings

08 Disassemble all the original diesel feeding system

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01.02 E NGINE C OMPONENTS C HECK

PHASE DESCRIPTION

01 Check the conditions of the valves

02 Check the conditions of the valve seats

03 Check the conditions of the camshaft

04 Check the conditions of the crankshaft

05 Check the conditions of the original block bearings

06 Check the conditions of the original connector rod bearings

07 Check the conditions of the original pistons

If the components previously checked are damaged, replace or repair them (the crankshaft and the camshaft can be refaced)

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02.01 C YLINDER H EAD Page 1 of 4

PHASE DESCRIPTION

The engine head modifications are necessary to be able to replace the original diesel injectors with the adequate spark plugs

01 Disassemble the original cylinder head

02 Measure the diameter of the original injector seat (D picture 01), in order to chose the type

of spark plug (the thread): if the original diameter is 9 mm or less, it is possible to use a

spark plug with the thread M10x1; if the diameter is bigger, until to 10,75 mm diameter, it

must be used a spark plug with the thread M12x1,25

03 Verify the length L (picture 01), in order to chose the type of spark plug (length of the

thread) Consider that when the spark plug is completely screwed in the seat, the only part

of it that must enter in the combustion chamber is the electrode, as shown in the picture 02

picture 01 – ORIGINAL ENGINE HEAD

picture 02 – ELECTRODE IN THE COMBUSTION CHAMBER

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PHASE DESCRIPTION

IMPORTANT: the workings that are following described ,must be coaxial with the original injectors seats; in case make an apposite tool to guarantee the coaxial

04 Verify that near the original injector seat there aren’t some oil or water conduits If there

are, check if machining the original seat to enlarge it (minimum 22 mm), in order to allow the passage of the spark plug wrench, the conduits aren’t broken The distance between the modified seat and the water or oil conduits must be not less than 4 mm If the distance is less than 4 mm is preferable use the adequate spark plug bushing (see the end of the

paragraph) See the picture 03 The water or oil conduits there could be in the position

shown by the arrows too

picture 03 – CONDUITS DISTANCE

05 After the choice of the type of the spark plug (thread diameter and thread length), enlarge

(if it is necessary) the hole indicated in the picture 04 Verify that the spark plug seat isn’t too near to the valves seats (see the picture 05)

picture 04 – MINOR THREAD DIAMETER picture 05–SPARK PLUG SEAT POSITION

water or oil conduits

Ø 9 for M10x1

Ø 10,75 for M12x1,25

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PHASE DESCRIPTION

06 Enlarge the diameter shown in the picture 05 in order to allow the passage of the spark

plug wrench If near the lower diameter there are no water or oil conduits, enlarge the

diameter of the picture 06 (minimum Ø 22 mm) until to the lower diameter length is the

same of the spark plug thread

picture 06 – SPARK PLUG WRENCH SEAT

07 If near the lower diameter there are water or oil conduits, it is necessary create the seat for

the spark plug seal washer, in order to the seat is smaller possible Remember that for a

spark plug M10x1 it must be created a seat of 16 mm diameter, 4 mm depth; for a spark plug M12x1,25 it must be created a seat of 17 mm diameter

picture 07 – SPARK PLUG WASHER SEAL SEAT

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PHASE DESCRIPTION

08 In relation to the type of SPARK PLUG chosen, execute the thread in the part of the spark

plug seat shown in the picture 08

picture 08 – THREAD EXECUTED

09 If in the original diesel engine there are original pre – heater plugs, they must be

disconnected from the original electric system; sometimes could be present an original air inlet heater; in this case disconnet and disassemble it, to avoid a wrong functioning of the engine

SPARK PLUG BUSHING

It is necessary execute a spark plug bushing when:

• during the working of the spark plug seat it is possible brake original water or oil conduits; to know this, is very important have an original head drawing or cut a cylinder head;

• it is present an original diesel injector bushing

The spark plug bushing:

• must allows the insertion and the fixing of the adequate spark plug (see the previously

instructions for the choice of the spark plug);

• the external part of the spark plug bushing has to join itself with the original engine head, in

order to avoid oil or water leakages;

• must be fixed using the original holes situated on the original engine head

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02.02 P ISTON Page 1 of 7

PHASE DESCRIPTION

The main function of the piston modifications is to reduce the compression ratio of the engine

Calculate the compression ratio for the gas converted engine, considering that the ideal compression

ratio must be:

- for N.A CNG engines: 12 ÷ 13

- for turbocharged CNG engines: ~ 11,5

- for N.A GPL engines: 9,5 ÷ 10

- for turbocharged GPL engines: 8,5 ÷ 9

The necessary data for the execution of the calculations of the new compression ratio are:

- original compression ratio of the engine

- displacement

- number of cylinders

- type of intake of air (turbo engine or N.A engine)

- original dimensions of the original piston (with an original drawing)

- verify that the disposition of possible oil conduits in the original piston allows the necessary workings (if it is possible, dissect an original piston)

COMPRESSION RATIO CALCULATION

01 Calculate the UNITARY DISPLACEMENT (U):

U= TOTAL DISPLACEMENT / NUMBER OF CYLINDERS

02 Calculate the VOLUME OF THE COMBUSTION CHAMBER when the piston is at the TDC (V2):

V2=UNITARY DISPLACEMENT /(ORIGINAL COMPRESSION RATIO –1)

03 Measure the volume of the original diesel bowl (Vbowl) filling it up with the water Measure

the quantity of water that enters in the original diesel bowl

picture 01 – ORIGINAL DIESEL PISTON BOWL MEASURING

Water

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PHASE DESCRIPTION

04 Subtract the volume of the ORIGINAL BOWL (Vbowl) to the VOLUME OF THE COMBUSTION

CHAMBER (V2), to find the volume included between the piston head and the engine head

when the piston is at the TDC:

Vt = V2 – Vbowl

picture 02 – VOLUME INCLUDED BETWEEN THE PISTON HEAD AND THE ENGINE HEAD

05 Take away 0,5 mm from the top of the piston and measure the new volume Vt:

Vt new = originalVt + (π * D2) / 4 * 0,5

picture 03 – WORKING ON THE PISTON HEAD

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PHASE DESCRIPTION

06 Calculate the volume of the bowl gas, working material until to the lateral (picture 04) and

inferior (picture 05) tangent of the original diesel bowl

Vgas bowl = (π * D2) / 4 * H

picture 04 – LATERAL TANGENT picture 05 – INFERIOR TANGENT

picture 06 – BOWL WORKING

07 Add the new volumes obtained:

V2 gas = Vt new +Vcng bowl

08 Calculate the new compression ratio with the formula:

ρ = U / (V2 gas) + 1 VERIFY IF THE NEW COMPRESSION RATIO IS ACCEPTABLE, LOOKING THE VALUES WRITTEN AT THE BEGINNING OF THE PARAGRAPH IF IT ISN’T

ACCEPTABLE, MODIFY THE VALUES OF D AND H (SEE THE PICTURE 06) IN

ORDER TO HAVE THE CORRECT VALUES TO OBTAIN A CORRECT COMPRESSION RATIO

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PHASE DESCRIPTION

WORKING ON THE PISTON

09 Disassemble the original pistons from the engine

picture 07 – ORIGINAL PISTON DISASSEMBLED

10 Fix the disassembled piston on the lathe machine, enveloping it in something that avoid

that the piston is damaged during its tightening in the lathe machine

picture 08 – POSITIONING PISTON

11 With the comparator verify if the piston is coaxial with the lathe machine

picture 09 – VERIFYING COAXIAL WITH THE LATHE

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PHASE DESCRIPTION

12 Work the top of the piston of 0,5 mm, as shown in the picture 10

picture 10 – PISTON HEAD WORKED

13 Work the original piston diameter of 0,2 mm Work it between the piston head and the

first piston ring seat, as shown in the picture 11

picture 11 – ORIGINAL DIAMETER WORKED

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PHASE DESCRIPTION

14 Work the original piston diameter of 0,2 mm Work it between the first piston ring seat

and the last piston ring seat, as shown in the picture 12

picture 12 – ORIGINAL DIAMETER WORKED

15 Work the original bowl, following the results of the calculations executed during the

COMPRESSION RATIO CALCULATION

picture 13 – BOWL WORKING

Working On Ring Seats

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PHASE DESCRIPTION

16 Execute the chamfers shown in the picture 14, in order to not leave sharp corners

picture 14 – CHAMFERS EXECUTED

17 With the grind paper smooth the surfaces worked (see the picture 15)

picture 15 – SURFACES SMOOTHED

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02.03 I NLET M ANIFOLD Page 1 of 3

PHASE DESCRIPTION

The inlet manifold modifications are necessary to be able to install and fix the NGV THROTTLE VALVE Verify that there is the necessary space on the vehicle to install the THROTTLE VALVE FLANGE, the

THROTTLE VALVE and the MIXER In case cut the inlet manifold (see the following instructions) in

order to connect the MIXER with the air filter

01 Disassemble the original inlet manifold from the engine

02 Cut at the adequate distance the original inlet manifold Remember that is better fix the

THROTTLE VALVE FLANGE more far possible from the inlet of the engine, in order to the

MIXER is able to mix good the mixture of air and combustible

picture 01 – DISTANCE

picture 02 – MANIFOLD CUT

03 Position and weld the THROTTLE VALVE FLANGE on the original inlet manifold See the

pictures 04 and 05 to see the correct position of the THROTTLE VALVE FLANGE

picture 03 – FLANGE WELDED

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PHASE DESCRIPTION

picture 04 – RIGHT POSITION

picture 05 – BAD POSITION

The conditions shown in the pictures 04 and 05 must be respected to allow the correct assemblage of the THROTTLE VALVE The position of the throttle valve flange depends from the position of the original accelerator pedal

parallel

Inlet Manifold Fixing Surface

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PHASE DESCRIPTION

It could be necessary add some ADEQUATE RUBBER MANIFOLDS to connect the MIXER to the original

air filter The external diameter of the mixer is 80 mm

In some engine there could be pipes for oil recovery connected with the original inlet manifold

These pipes must be positioned BEFORE (in relation to the flow of the air) the THROTTLE VALVE and the MIXER, in order to not modify the carburetion

Sometime there could be conduits of air compressor These conduits MUST BE connected to the

inlet manifold BEFORE (in relation to the flow of the air) the MIXER, in order to the mixture of gas

and air doesn’t flow into the compressor

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02.04 T EMPERATURE S ENSOR S EAT Page 1 of 2

PHASE DESCRIPTION

The temperature sensor seat must be created on the original cooling system in order to install and fix

the WATER TEMPERATURE SENSOR

01 Choose a water cooling system manifold where there is the flow of the cooling water and

disassemble an original water manifold and with a 4,2 mm diameter drilling tool execute

an hole on it

picture 01 – ORIGINAL WATER MANIFOLD DISASSEMBLED

02 Assemble the 4,2 mm diameter drilling tool on the drilling machine and execute a 4,2 mm

hole on the original water manifold disassembled in the phase 01

picture 02 – EXECUTING HOLE

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02.04 T EMPERATURE S ENSOR S EAT Page 2 of 2

PHASE DESCRIPTION

03 With the M5x0,8 tapper tool tap the hole executed in the phase 02

picture 03 – TAPPING HOLED

04 Reassemble the original water manifold in the original position

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02.05 L AMBDA S ENSOR S EAT Page 1 of 1

PHASE DESCRIPTION

The lambda sensor seat must be created on the exhaust pipe in order to install and fix the LAMBDA SENSOR

01 Execute a 23 mm diameter hole on the original exhaust manifold, at the distance shown in

the picture 01

picture 01 – HOLE POSITION ON THE INLET MANIFOLD

02 Position the LAMBDA SENSOR HOUSING in the hole previously executed and weld it on the

original exhaust manifold., verifying that there are any air leakages See the pictures 02

and 03

picture 02 – LAMBDA SENSOR POSITIONED picture 03 – LAMBDA SENSOR WELDED

300 ÷ 500 mm

Lambda Sensor Housing Hole

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02.06 O RIGINAL O IL P IPES Page 1 of 2

PHASE DESCRIPTION

Disassembling the original diesel components, it is necessary check the original oil pipes circuit, in order to the oil can’t come out from the oil circuit after the disassembling of the diesel pump

After the disassembly of the original diesel pump, check that the oil pipe that was connected to the

original diesel pump isn’t connected with other original components not disassembled If it is so,

close the oil pipe to avoid that the oil come out If the oil pipe is connected with other components, close only the inlet of the oil in the original diesel pump

FOLLOWING IS REPORTED AN EXAMPLE OF THIS TYPE OF WORKING

picture 01–OIL PIPE DISASSEMBLED

picture 02–OIL PIPE CUT

picture 03–OIL PIPE CLOSED

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02.06 O RIGINAL O IL P IPES Page 2 of 2

PHASE DESCRIPTION

Following is shown an example of the modification of the original oil pipes in order to bypass the diesel pump

picture 04 – ORIGINAL OIL PIPE DISPOSITION

picture 05 – OIL PIPES MODIFIED

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02.07 D IESEL P UMP S UPPORT

M ODIFICATION

Page 1 of 1

PHASE DESCRIPTION

This paragraph is related with the paragraph 05.01 T OOTHED W HEEL

When possible is better assemble the toothed wheel on the original diesel pump support; in these

cases, could be necessary modify this support Sometimes to assemble the TOOTHED WHEEL is

required the modification of the original diesel pump support or the assemblage of the adequate

TOOTHED WHEEL SUPPORT See the following pictures

picture 01 – WORKING DIESEL PUMP SUPPORT

picture 02–DIESEL PUMP SUPPORT WORKED

picture 03–POSITIONING FLANGE ON THE ORIGINAL SUPPORT

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02.08 R ADIATOR C AP Page 1 of 1

PHASE DESCRIPTION

Replace the original radiator cap with another cap that resists to a pressure of 1,2 bar, in order to the

cooling water has got a boiling point higher, so the radiator cans continue to exchange heater in high water temperature conditions too

ATTENTION:

converting the engine in CNG or LPG modes, the functioning temperature increases

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E NGINE R EASSEMBLY Section 03

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03.01 E NGINE R EASSEMBLY Page 1 of 1

PHASE DESCRIPTION

01 Elimination of all the original diesel feeding components

02 Replacement of all the engine gaskets

03 Assemblage of all the components modified as per instructions described in the section 02

W ORKING O N T HE O RIGINAL D IESEL C OMPONENTS

RESPECT THE ORIGINAL TIGHTENING TORQUES INDICATED IN THE ORIGINAL INSTALLATION MANUAL OF THE

ENGINE

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V ALVES G AP M ODIFICATIONS Section 04

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04.01 V ALVES G AP M ODIFICATIONS Page 1 of 4

PHASE DESCRIPTION

The valves gap must be modified in order to avoid that the mixture of gas and air unburned flows directly in the exhaust manifolds during the scavenging phase of the original diesel engine

This modification is necessary in order to:

• reduce the consumption;

• reduce the pollution;

• avoid exhaust backfires

In general in a CNG or LPG converted engine an optimal value of overlapping is included between 10° and 20°

The new maximum valves gap permitted for the CNG or LPG converted engine is 1 mm

ATTENTION ! THE NEW VALVES GAP MODIFIED AS PER INSTRUCTIONS PREVIOUSLY WRITTEN MAKES ENGINE MORE NOISY THAN THAT ORIGINAL DIESEL BUT IT NOT CREATES PROBLEMS OR DAMAGES.

To modify the valves gap is necessary a graded disk and place a needle reference (see the pictures 01 and 02)

picture 01 – NEEDLE picture 02 – GRADED DISK AND REFERENCE

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PHASE DESCRIPTION

01 Verify that the valves gap is the same of that written in the original diesel manual

02 Position the piston n°1 at the TDC

03 Fix the needle reference on the engine (see the picture 03)

04 Fix the graded disk on the pulley (situated on the crankshaft) (as shown in the picture 03)

in order to the reference is in corrispondence of the zero and of the indicator, in order to know when the engine is at the TDC

picture 03 – DISK +NEEDLE REFERENCE

ORIGINAL DIESEL OVERLAPPING MEASURING

05 Place the tickness of 0,05mm of the feeler between the compensator and the top of the

inlet valve, and verify (rotating manually the crankshaft) when the inlet valve starts to open (the feeler is blocked) Rotate the engine in its sense of revolution

picture 04 – PAPER BLOCKED

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PHASE DESCRIPTION

06 Check on the gradate disk the position (in degrees) when the inlet valve starts to open and

note it See the picture 05

picture 05 – POSITION ON GRADED DISK

07 Place the tickness of 0,05mm of the feeler between the compensator and the top of the

outlet valve, and verify (rotating manually the crankshaft) when the outlet valve starts to close (the feeler is unblocked) Rotate the engine in its sense of revolution

picture 06 – Measuring

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PHASE DESCRIPTION

08 Check on the gradate disk the position (in degrees) when the outlet valve starts to close

and note it See the picture 07

picture 07 – POSITION ON GRADED DISK

09 Add the value of the opening of inlet valve (obtained in the phase 05) to the value of the

closing of the exhaust valve (obtained in the phase 09), in order to obtain the original

diesel overlapping value

10 Compare the original diesel overlapping value with that required for the CNG or LPG

conversion (included between 10 and 20°)

11 Increase the valves gap and repeat the operations written from the phase 05 to the phase

10 until to the new overlapping value is acceptable, remembering that:

¾ the maximum acceptable valves gap is 1 mm;

¾ the inlet valve must open BEFORE the TDC;

¾ the exhaust valve must close AFTER the TDC

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05.01 T OOTHED W HEEL Page 1 of 2

PHASE DESCRIPTION

Before the choice of the type of TOOTHED WHEEL (there are three types of TOOTHED WHEEL: 36 teeth,

48 teeth and 60 teeth), choose the position where it has to be assembled Usually the TOOTHED WHEEL can be assembled:

¾ where there was the original diesel pump, before its disassembling;

¾ on an apposite support connected to the camshaft;

¾ on an apposite support connected to the crankshaft

The position of the TOOTHED WHEEL has to be chosen in order to it is easy reachable for do all the

necessary settings, so the better position is in the original position of the original diesel pump

Are following represented some examples of the possible installations of the TOOTHED WHEEL

picture 01 – ON THE DIESEL PUMP FLANGE picture 02 – ON THE CAMSHAFT

picture 03 – ON THE CRANKSHAFT

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05.01 T OOTHED W HEEL Page 2 of 2

PHASE DESCRIPTION

When the position of the TOOTHED WHEEL has been chosen, choose the type of TOOTHED WHEEL in relation the available space, remembering that is better choose the TOOTHED WHEEL with more teeth possible

After the choice of the type of TOOTHED WHEEL, create an adequate support for it, or modify an

original diesel pump flange in order to fix the chosen TOOTHED WHEEL

The support must guarantee:

¾ that the toothed wheel and the shaft are coaxial;

¾ the toothed wheel and the shaft rotate together

Fix the TOOTHED WHEEL previously chosen with the fixing holes of the TOOTHED WHEEL support situated in the centre of the slots of the TOOTHED WHEEL See the picture 01

picture 01 – HOLES IN THE CENTRE

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