01 Engine System LG956L

(1)

(2)

Section 1 overview of engine

1 Model meaning

2.Characteristic of engine

Section 2 Crank-link mechanism

1.Engine block group

2.Crankshaft flywheel group

3.Piston rod group

Section 3 Valve mechanism

1.Overview

Section5 Lubrication system

1.Function

2.Method of lubrication

3.Main spare part

Section 6 Cooling system

1.Function of cooling system

2.Main spare part of cooling system

Section 7 Air intake and exhaust system

1.Function of air intake and exhaust system

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第&页总共205页

1.Overview

2.Main composition of valve

mechanism

Section 4 Fuel supply system

1.Overview

2.Fuel injection pump

3.Regulator

4.Fuel delivery pump

5.Fuel injection

6. 燃油水寒宝

7.Fuel filter

1.Function of air intake and exhaust system

2.Working principle of air intake and exhaust system

3.Parts of air intake and exhaust system

Section 8 Common failures

1.Start unsuccessfully engine

2.Underpower of engine

3.Exhaust black smoke

4.Exhaust white and blue smoke

5.Low lubricating oil pressure

6.High lubricating oil pressure

7.High lubricating oil consumption

8.High coolant temperature

(3)

1 、

、

Introduction of the meaning

LG956L is equiped with Weichai

engine which is in-line,

four-stroke, water-cooled, turbocharged

six-cylinder diesel engine, the

engien model number is

WD10G220E23, the meanings of

the words and numbers see the

WD10G220E23

WD

Water Diesel

10 Displacement Code

(Displacement is 10L.)

G

Construction machinery

220 Power(220ps)

the words and numbers see the

right table.

G

Construction machinery

220 Power(220ps)

E2

State three emission

(4)

2 、

Characteristics of the Weichai

engine

（

WD10G220E23

）：

1 、

High reliability, long life

Using the tunnel structure, the

crankcase and the seven main bearing

cap are forged as one piece by

high-quality alloy steel, nitrided

crankshaft and connecting rod, and

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strength bolts with flexible design, to

ensure the high reliability of the engine

moving parts. Reasonable design of the

high power function of the camshaft

profile can make the engine distribution

system has higher reliability and lower

mechanical vibration noise.

Characteristics of the use of construction

machinery are fully considered,

(5)

2 、

、

Powerful engine

、

large torque reserve

Using the imported Ps3000, Ps7100 fuel

injection pump with low inertia porous injector,

through fuel supply characteristics correcting

and efficiency turbocharger proper matching can

achieve a good dynamic and make the torque

reserves reach more than 20%, to provide strong

horsepower for all kinds of engineering

machinery.

3 、

、

Good economy

Three new structures of piston rings, best

matching cylinder clearance, equiped with new

type of combustion chamber and the best swirl

ratio, overlapping curve is honed on the cylinder

plate form to aviod leakage, ensure a more

perfect geometry of cylinder bore, and reduce

the consumption of fuel and oil, the lowest fuel

consumption of the turbocharged engine reaches

194g/kW.h, , oil consumption less than

(6)

4 、

、

Powerful engine

、

High

torque reserve

The exhaust can meet the Euro II

emission standard, which are well suited

for working in limited space such as

tunnels, warehouse, cabins, etc.

5 、

、

Good ability to adopt the

plateau

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The new type of turbocharger has a

function of air intake reflow, which can

broaden the scope of the diesel engine

high effiency workspace, compensate for

the power loss in plateau, and can

provide good adaptability in plateau.

6 、

、

Good low temperature start

The cold starting device is added to

ensure the engine can start smoothly at

-40

℃

.

(7)

Crank and connecting rod

mechanism

1 、

、

Basic components

The crank and connecting rod

mechanism mainly consists of

three parts: the body assembly,

crankshaft flywheel assembly,

piston and connecting rod

Piston rod assembly

piston and connecting rod

assembly.

Engine body assembly

(8)

Crank and connecting rod

mechanism

2 、

、

Main function

The crank and connecting rod

mechanism is the main parts of the

reciprocating piston engine to transfer

the heat energy into mechanical energy,

which function is to transfer the pressure

on the piston crown acted by the gas to

the rotational torque of the crankshaft,

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the rotational torque of the crankshaft,

and output to the external.

Most of the power is tranmitted to the

outside through the flywheel, another

portion is through the gear and idler gear

of the front end of the crankshaft to drive

other mechanisms and systems of itself,

primarily to withstand high temperature,

high pressure, chemical corrosion and

the impact of inertia force.

(9)

1 、

、

The cylinder block assembly

It is mainly composed of the cylinder

block, cylinder liner, cylinder head,

cylinder gasket, oil sump, engine mounts

and other mechanical components.

（

1 ）

）

Cylinder block

①

Function The cylinder block is a

basic installation for each mechanisms

and systems, which is used to maintain

the precise positional relationship

between each moving parts of the

engine. The cylinder block is usually

forged together with crankcase as one

piece, so called cylinder-crankcase.

②

Structure According to the

different position of the installation

planes between the cylinder block and

the oil pan, the cylinder block is usually

divided into three types: general

FORM

characteristic

Application

General

The lower surface of the cylinder block

and the axis of the crankshaft are on the

same plane, the stiffness is small

Cars, small trucks

Gantry

The lower surface of the cylinder block

is below the axis of the crankshaft, the

stiffness is larger

Medium and heavy trucks

Tunnel

Main bearings are not separated

(equipped with modular crankshafts),

large mechanical

loadload of diesel engine

General form

Gantry form

_{Tunnel form}

General type

(10)

（

1 ）

）

Cylinder block

③

The structural style of the

LG956L Weichai engine

The cylinder block of the Weichai

WD10G220E23 engine is the tunnel

structure, the main bearing cover and the

crankcase forged toghther in one

piece,the crankcase and the cylinder

block are separated by the centerline of

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the crankshaft, the upper part is the

cylinder block, the lower part is the

crankcase, the crankcase and the seven

main bearings together form a integrated

framework with good stiffness.

This tunnel structure not only has a

good stiffness, and can use the sliding

bearings to reduce the noise and improve

the service life.

(11)

（

1) Cylinder block

④

Precautions for the installtion of

the Cylinder block and crankcase

The WD10G220E23 engine has no

gasket between the crankcase and

cylinder, the bottom of the cylinder

block should be coated smoothly with

510 sealant, which will lower the oil

pressure, the sealant does not need too

much, and installation should be

implemented immediately after the

coating finished.

Notice: The cylinder block and

crankcase are required to be installed in

pairs, which are not interchangeable.

When one of the parts is damaged, both

parts should be replaced, optional

installation is not allowed.

(12)

（

2 ）

）

Cylinder liner

①

Function

The main function of the cylinder liner

is to guide the piston direction and seal

the gas inside the cylinder.

②

Classification of cylinder

sleeve

There are two types of cylinder liners:

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There are two types of cylinder liners:

Dry cylinder liner and wet cylinder liner,

the dry cylinder liner is not directly in

contact with the cooling liquid, but the

wet cylinder is just the opposite.

Weichai WD10G220E23 diesel engine

uses the thin-walled dry cylinder liner.

Form

Characteristic

Advantage

Aisadvantage

Demand

Wet

cylinder

sleeve

The outer surface

is in direct contact

with the cooling

Cooling effect,

casting

convenient,

easy

disassembly

Poor rigidity,

easy

leakage(water

and gas)

With upper and

lower positioning

belt and lower

bearing seal tape

Dry

cylinder

sleeve

The outer surface

is not in direct

contact with the

cooling water

（

Contrary to the above

）

With upper and

lower positioning

belt

(13)

（

2 ）

）

Cylinder sleeve

③

Precautions for the installtion of

Weichai WD10G220E23 diesel engine

cylinder liner

Use alcohol or Loctite 755 to wash the

grease off the cylinder hole and the

cylinder liner external surface before

installation, then apply a thin layer of

molybdenum disulfide powder on the

surface of the cylinder liner external

surface, and finally, use hands or tools to

pressure the cylinder liner into the

cylinder block.

Check the cylinder liner is

0.02-0.07mm above the upper surface of the

cylinder block after the cylinder liner

pressed into the cylnder block.

(14)

（

3 ）

）

Cylinder head

①

Function

The main function of the

cylinder head is to seal the upper

part of the cylinder, and form a

combustion chamber with piston

crown and cylinder wall.

②

Type of cylinder head

Double-cylinder

split type

Single-cylinder

split type

Integral-type

Cylinder head

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②

Type of cylinder head

The cylinder head has common

types of integral-type,

single-cylinder split type and double

cylinder split type.

form

characteristic

application

integral

Poor rigidity, easily deformed by

heat or pressure, which will

influence the seal, the whole block

must be replaced when damaged.

old-fashioned

engine

split

one cylinder per

block

easy to be made or repaired, good

rigidity

_{wide application}

two cylinder per

block

three cylinder

(15)

（

3 ）

）

Cylinder block

③

The cylinder head of Weichai

WD10G220E23 engine adopts the

structure with one cylinder and one

cover, good manufacture technics,

and easily disassembled and

transported.

Each cylinder is fixed by four

M16 bolt, and two adjacent

cylinder head simultaneously

pressed together by three M12 stud

with a clamping block, which

increases the engine rigidity.

(16)

2 、

、

The piston and connecting rod

assembly

The Piston and connecting rod

assembly is mainly composed of piston,

piston ring, connecting rod, piston pin and

other mechanical components.

1-piston

2-Spiral spring-loaded oil ring

（

oil ring

）

3-cone ring

（

Compression ring

）

4-ladder ring

（

Compression ring

）

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4-ladder ring

（

Compression ring

）

5-connecting rod sleeve

6-connecting rod

7-connecting rod cover

8-connecting rod bolt

9-connecting rod bush

10 、

11connecting rod bush

12-retaining ring

(17)

（

1 ）

）

Piston

①

Function of piston

The main function of the piston is

designed to withstand the pressure from

buring air, and transmit the force through the

piston pin to the connecting rod to push the

crankshaft rotate. The piston head forms a

combustion chamber with cylinder head and

cylinder wall.

②

Structure of piston

②

Structure of piston

The basic structure of the piston can be

divided into three parts: the crown, the head

and the skirt.

The piston head forms a combustion

chamber with cylinder head and cylinder

block, bear force generated by the air

pressure in the cylinder, and transmit the

force through the piston pin to the

connecting rod to push the crankshaft rotate.

1 －

－

top

；

2 －

－

head

；

3 －

－

skirt

；

4 －

－

land

；

5 －

－

ring groove

；

6 －

－

pin boss

；

7 －

－

reinforcing rib

；

8 －

－

Snap ring groove

；

9 －

－

(18)

The piston head is the upper part

above the piston ring groove,

which function is as follows:

A: Withstand the air force and transmit it

to the connecting rod.

B: Working together with the piston

rings to realize the cylinder cealing.

C: Transmit the heat absorbed from the

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piston head to the cylinder wall by

passing throught the piston ring.

The piston skirt is the lower part of the

engine from the oil ring groove down to

the bottom, which function is to guide

the piston reciprocated in the cylinder

and withstand side pressure.

1 －

－

top

；

2 －

－

head

；

3 －

－

skirt

；

4 －

－

land

；

5 －

－

ring groove

；

6 －

－

pin boss

；

7 －

－

reinforcing rib

；

8 －

－

Snap ring groove

；

9 －

－

(19)

③ The structure and characteristics of the Weichai WD10G220E23 engine piston

A：The piston is made of aluminum alloy, the specific weight is small, and the thermal conductivity is very good.

B：The top of the piston has a S - shaped combustion chamber, and a pit which can avoid the valve, in additional, combustion chamber and avoid the valve pit, while the product code is on the piston top.

C: Piston top shore (also known as fire shore) processes a thin annular groove, called back slot, processes a thin annular groove, called back slot, which has the function of collecting dirt and proventing occlusion, and can improve the running state between the top of the piston and the cylinder.

D：

The piston can be grouped by weight, the

difference between each group is not more than 10g, the marks of these groups are G1、 G2、 G3、G4、G5. When replacing the piston, the weight of the pistons on the same machine should be the same.

(20)

(2) Piston ring

①

Classification

Piston ring is a resilient split ring,

which can be divided into compression

ring and oil ring.

②

Function of compression ring

The first and second rings are called

compression ring, which function is to

Compression ring

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ensure the seal between the cylinder and

the piston, prevent the gas leakage, and

transmit most of the heat absorbed from

the piston crown to the cylinder wall.

③

Function of oil ring

The third ring is oil ring, which

function is to distribute oil, scrape oil,

reduce the friction resistance and assist

the sealing.

(21)

(2) Piston

④

Sealing principle of

Gas ring has a slot, and is flexible, which

outer diameter is greater than the cylinder

diameter in free state, when installed into the

cylinder together with the piston, the outer

surface set close to the cylinder wall to form

the first sealing surface, the sealed gas can

not get throught the space between gas ring

and the cylinder, but enter the space between

ring and ring groove, on one hand, it can

press the ring to the surface of the groove to

form the second sealing surface, on the other

hand, the pressure acting on the back of the

ring can greatly enhance the sealing effect of

the first sealing surface.The gas ring sealing

effect is generally related to the number of

the gas ring, WeiChai diesel engine has 2 gas

rings.

second sealing face

First sealing face

(22)

(2) Piston ring

⑤ ⑤ ⑤

⑤ Type of the compression ring section

Rectangular ring：：Simple technical process,：：

good thermal conductivity, but the oil pumping phenomenon is easy to occur, which will cause the carbon deposition.

Twist ring：：：：The torque M is generated by the

left-right asymmetry, which can make the edge of the rings to contact with the upper and lower surface of the groove, prevent oil pumping, and increase seal.

Rectangular ring

Taper face ring

Twist ring

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Taper face ring：：：：Scrap the oil downward, and

float on the oil film when slide upward,which can reduce the mechanical wear, but the cone angle is hard to be made.

Keystone ring：：：：The ring side clearance is

changed according to the changes of the direction of the side pressure, which can squeeze the carbon deposition out of the ring groove, but the technical process of the upper and lower surfaces are more complicated.

Barrell face ring：：Good contact can increase：：

sealing, but the convex surface is hard to be made.

Twist ring

(23)

(2) Piston ring

⑥

Compression ring pump oil

Function

：

Good for cylinder

lubrication.

Harm

：

Large lubricating oil

consumption, easy to form carbon

deposition in the ring groove,

which will caused ring stuck in the

piston

Cylinder

which will caused ring stuck in the

groove and lose the sealing effect,

scratch the cylinder wall, and even

break the ring.

Measure

：

Reduce the ring

quality, change the shape of the

ring section, and use the

(24)

(2) Piston ring ⑦ Oil ring

Function：：：：The main function of the engine oil

ring is is to distribute oil, scrape oil, and play an assistant role to sealing the gas, which can be divided into two types, common oil ring and combination oil ring.

A: General oil ring

The general oil ring is also called integral oil ring, with a groove machined in the middle of the outer cylindrical surface of the ring, and a hold or a slot drilled in the groove, when the piston

General oil ring

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or a slot drilled in the groove, when the piston

moves downward, the excess oil will be scraped off the cylinder wall and flow back to the crankcase through the small hole or slot.

B：：combination oil ring：：

The combination oil ring is composed of a pair of upper and lower side rail rings and a middle dilator, the side rail ring is made of chrome-plated steel, the perimeter of the dilator is slightly larger than the internal circumference of the cylinder, which can tightly press the side rail ring against the cylinder wall, and the scraping effect is obvious.

Function of oil

scraper ring

(25)

（

2 ）

piston ring

⑧ The structure and characteristics of Weichai WD10G220E23 engine piston rings

First ring：：：：The surface of the double sided

trapezoid tubbish ring is treated by means of phosphating treatment, with a notch and an installation marking "TOP"on the upper part; The work surface is sprayed with molybdenum layer, which will help to increase the effect of wearing resistance and anti galling.

Second ring：：Cone ring, the cone angle of the ：：

torus is 90 ° ± 5 ', the surface is treated by means of oxidation treatment, the work surface is sprayed with chromium layer, and the upper part of the ring has a installation marking "TOP"

Third ring：：：：The internal expanding circle

combined oil ring is made of cast iron, has 12 blades, double-edged surface chrome plated, lined with spiral springs, which has the characteristics of small abrasion, good oil seal and scraping effect, stable performance, durable and so on.

(26)

（

3 ）

）

piston pin

① ①① ① Function ：：：：

Connecting the piston and connecting rod, transfering the force between the two parts. ② ②② ② Structure ：：：： Hollow cylinder. ③ ③③ ③ Material：：：：

Alloy surface carburization (surface hardness increased)

④ ④④

④ Assembly

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Full floating—The pin rotates freely and wear

evenly in the pin hole and connecting rod bushing, the inner of both ends of the pin seat has clip rings.

Half floating—The the floats in the pin seat,

which is connected with the small end of the connecting rod by bolts.

Notice：：Heat the aluminum pistons in the 70～：：

90℃ water or oil before installing the pin into the piston to ensure the combination between the pin and the pin seat hole in the cold state is a transition fit .

Full floating assembly

Half floating assembly

Snap

ring

Connecting rod head Connecting rod head Connecting rod head Connecting rod head Connecting rod sleeve Connecting rod sleeve Connecting rod sleeve Connecting rod sleeve

Piston pin Piston pin Piston pin Piston pin Piston pin seat Piston pin seat Piston pin seat Piston pin seat

(27)

（

4 ）

）

Connecting rod

①

Composition

T h e c o n n e c t i n g r o d i s c o mp o s e d o f connecting rod small end, shaft, connecting rod big end, screw and connecting rod cap,etc.

②

Function

Connect the piston with the crankshaft, transfer the force from piston to crankshaft, and transfer the reciprocating movement of the piston

Connecting rod

small end

Connecting rod

shank

into the rotary movement of the crankshaft.

③

Classification

Generally, the engine connecting rod can be divided into two types, the equal type and the oblique fractional type.

Weichai WD10G220E23 engine adopts the oblique fractional rod.

Connecting rod

large end

Inclined cut

(28)

（

4 ）

）

Connecting rod

⑤

Connecting rod of weichai

engine(WD10G220E23)

A: Weichai WD10G220E23 engine connecting rod big end is the oblique incision type,split by 45°oblique, using the 60°teeth to locate the combined surface, with characteristics of positioning accuracy, combined tightly, etc. B：The weight of the connecting rod is divided into 9 groups which are respectively marked by C, D, E, F, G, H, J, K, I, the quality of each level

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第&页总共205页

C, D, E, F, G, H, J, K, I, the quality of each level is no more than 29g, when replacing the connecting rod, make sure the marked letter is the same, otherwise it will cause the diesel engine to produce abnormal vibration.

C：The connecting rod and connecting rod cover must be processed as a whole set, marked the same number, and are not interchangeable.

The connecting rod bolts can only be used once.

(29)

（

5 ）

）

Bearing shell

A tile form of sliding bearing is

mounted in the connecting rod big end

hole to reduce friction and the wear of

connecting rod journal of the crankshaft,

which is called connecting rod bearing.

The bearing shell is divided into

upper and lower shell, which is currently

use the thin-walled rigid bearing, with

wear-resistant alloy layer casted on the

internal surface.

Function of the connecting rod

bearing shell

：

Bearing, heat conduction, protecting the

big end connecting rod and reduce the

wear.

1-steel backing

2-oil groove

(30)

3 、

、

Crankshaft flywheel

assembly

Mainly consists of crankshaft,

flywheel and other accessories.

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第&页总共205页

(31)

（

1 ）

）

Crankshaft

①

Composition

The crankshaft is composed of main

journal, connecting rod shaft neck,

crank, counterbalance, front-end and

back-end, etc.

A connecting rod shaft neck and a

crankshaft constitute a crank.

②

Function

②

Function

The crankshaft interacts closely with

the connecting rod to change the gas

pressure into rotation power, transfer the

force to the transmission mechanism,

and drive the valve mechanism and other

auxiliary devices.

Main journal

crankshaft

Connecting rod

journal

collar

(32)

（

2 ）

）

Flywheel

Function: Depending on the flywheel

inertia to keep the engine running

balance, and help engine to overcome

short time overloading.

Material: High strength, wear-resistant

material (Grey cast iron)

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1 －

－

flywheel

；

3 －

－

bush

；

4 －

－

bolt

；

5 －

support

；

7 －

gear ring

；

(33)

（

3 ）

）

Absorber

In the process of engine working, each cylinder has its own working stroke, the magnitude and direction of the force transfered from the connecting rod to the crank pin are changed periodically, the exciting force caused by the periodic variation acts on the crankshaft to cause the the instantaneous angular velocity of the crank is also changed periodically. But the flywheel fixed on the crankshaft has a big rotary inertia, which can be regarded to do uniform rotation, so at one moment the crank speed is faster than the flywheel and the next the crank speed is slower than the flywheel, which can form a torsional oscillation against the flywheel, such is the crankshaft torsional vibration. When the ratio of the excitation frequency to the natural frequency of the crankshaft is an integer, the crankshaft will produce resonance.

Function：：：：Reduce the vibration, avoid

resonance

Principle：：Friction in the damper gradually ：：

(34)

（

4 ）

）

Six cylinder engine crank layout

Principle

：

1.The firing interval should be uniform

to ensure that the engine is running

smoothly.

2.The two continuous working cylinders

should be as far as possible

（

To reduce

the load of the main journal, and avoid

1-6

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the load of the main journal, and avoid

the overlap of the air influences the air

intake.

）

(35)

（

5 ）

Firing order of six-stroke engine

The four stroke inline six cylinder

engine firing angle is 720/6=120

°

, six

cranks are respectively arranged on the

three planes, the firing order is

1-5-3-6-2-4.

T h e c y l i n d e r o f t h e We i c h a i

WD10G220E23 engine, near the fan, is

the first cylinder.

Crank

corner

（

（°

°

°）

°

）

Cylinder

1 Cylinder

2 Cylinder

3 Cylinder

4 Cylinder

5 Cylinder

6 0~60

power

exhaust

intake

power

compre

ssion

_intake

60~120

compre

ssion

exhaust

120~180

intake

power

180~240

exhaust

compres

240~300

the first cylinder.

sion

240~300

power

intake

300~360

compre

ssion

exhaust

360~420

intake

power

420~480

exhaust

compre

ssion

480~540

power

intake

540~600

compre

ssion

exhaust

600~660

intake

power

660~72

0 exhaus

t

compr

ession

(36)

1 、

、

Overview

The function of valve mechanism is to control the air inlet and outlet, which regularly controls the opening and closing of the intake and exhaust valve, supply mixture fresh air to the cylinder and timely draw used air out according to the requirement of the cylinder working order and working process. In addition, when the inlet and outlet valve closed, it can ensure the cylinder seal.

When the engine works, the camshaft is

7

6

5 RELIABILITY IN ACTION

driven by the crankshaft through the timing gear,

the cams push the tappet and rod and pass the action to the rocker arm which rotate around an axis to overcome the spring force to push the valve moves down and be opened. When the camshaft continue to rotate and cross the maximum pushing process, the valves will return to the original position and be closed.

1-pushrod 2-tappet 3-camshaft 4-valve 5-valve spring 6-locking plate 7-rocher arm

1

2

3

(37)

2、、Main composition of valve mechanism、、

The valve mechanism is maily composed of Va lve as s e mb l y a nd val ve tr ans mis sio n assembly.

1、、、、Valve group

The valve assembly includes valves, valve seats, valve guides, valve springs, locking plate and retainer.

(1) Valve

The function of the valve is to control the opening and closing of the inlet and outlet valve, resist high temperature, high pressure and

Snap ring

Locking plate

Valve spring retainer

resist high temperature, high pressure and impact, require the valve to have the following characteristic: sufficient stiffness, strength, wear resistance, high temperature resistance, corrosion resistance, impact resistance.

(2) Valve guide

It's function is to guide the valve, ensure the valves do straight reciprocating motion. In adition, it has the function of heat transfer, pass heat from the valve head to the rod shaft, and spread out through the cylinder head.

Valve cone angle

valve

Valve spring

(38)

（

3 ）

）

valve seat

The valve seat interacts closely with the valve head sealing conical surface to seal the cylinder, and the heat from the valve head can be

transmitted to the outside through the valve seat.

（

4 ）

）

valve spring

The function of the valve spring is to ensure the valve's return, prevent the transmission parts detachment during movement. When the valve closed, the valve spring should ensure the seal

Snap ring

Locking plate

Valve spring retainer

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closed, the valve spring should ensure the seal

between valve and valve seat. when the valve opened, it should ensure the valve can't be separated from the cam by the inertial force created during the movement. The valve spring is a cylindrical spiral spring, one end is supported on the cylinder head and the other end is pressed against the spring seat which is at the end of the valve rod, the spring seat is fixed to the end of the valve rod with a locking plate.

Valve cone angle

valve

Valve spring

(39)

2 、

、

Valve transmission assembly

The valve transmission assembly transfers movement between camshaft and valve, which includes camshaft, tappet, push rod, rocker arm, valve clearance adjusting screw and other components.

（

1 ）

）

Camshaft

The camshaft controls the opening and closing of the valve, each intake valve and exhaust valve respectively has corresponding

Air intake (exhaust) cam angle

Cam shape

exhaust valve respectively has corresponding intake cam and exhaust cam, the valve opening and closing time and height can be influenced by the rotation of the cam, the cam arrangement influences the opening and closing time of the valve and working order.

The cam has two types, the inlet cam and outlet cam, the number of cams is the same as the number of inlet and outlet valves. For each working cycle, the crankshaf will turn two cycles, and the camshaft will turn one cycle. 360/60=60°。

Six

Six-

-

-stroke

stroke

engine camshaft

Push rod

tappet

Rocker arm

(40)

（

2 ）

）

Tappet

The function of the cam tappet is to

transmit the thrust from the cam to the

push rod, and bear the lateral force

exerted by the rotation of the camshaft.

（

3 ）

）

Pushrod

The function of the push rod is

to

transmit the thrust from the camshaft to

the rocker arm, which is the most easily

Air intake (exhaust) cam angle

Cam shape

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the rocker arm, which is the most easily

flexible parts of the gas distribution

mechanism

（

4 ）

）

rocker arm and seat

The function is to transmit the thrust

from the tappet and push rod to the

rocker arm to push the rocker arm swing

to open and close the valve.

Six

Six-

-

-stroke

stroke

engine camshaft

Push rod

tappet

Rocker arm

(41)

3 、

、

valve clearance

①

definition

Valve clearance means the clearance

between the end of the valve rod and

rocker arm or tappet when the valve is

completely closed under the cold

condition.

②

function

：

The function is to compensate for the

amount of expansion after the valve is

heated. Different models have different

size of valve clearance, the exhaust valve

clearance is larger than the inlet valve

(42)

3、、、、valve clearance

③ ③③

③ Valve clearance is too large or too small

will cause certain harms:

If the valve clearance is too large, which will cause the the open of the inlet and exhaust valve delayed, the exhaust time shortened , the valve opening height reduced, and the normal gas distribution phase changed , result in insufficient air intake and incompletely air exhaust, parts of the gas distribution mechanism impact increased

WD10G220E23 engine intake and exhaust valve clearance

（

（cool state

cool state

cool state）

）

Intake valve

Exhaust valve

RELIABILITY IN ACTION

and wear accelerated. If the valve clearance is

too small, when the parts heated and expanded, which will push the valve open, cause the valve can not be tightly closed to prevent the gas to be released, reduce the engine power, result in serious carbon deposition or burn, and even the valve strike the piston.

The Weichai WD10G220E23 engine air intake valve clearance(cold machine) is 0.3mm and the exhaust valve clearance is 0.40mm

。

Intake valve

Exhaust valve

(43)

3 、

、

valve clearance

④

adjustment and inspection of valve

clearance

1 ）

Using the 13mm socket wrench to

remove the 6 cylinder head cover.

2 ）

Use the 32mm Crank Wrench to

slowly rotate the diesel engine, adjust the

tick mark on the flywheel house point to

the OT mark and the piston of the first

cylinder point to the compression top

dead center(The inlet and exhaust valves

of the first cylinder are closed.)

(44)

3 、

、

Valve clearance

④

Adjustment and inspection of valve

clearance

5 ）Take the intake and exhaust valve

clearance

with

a

feeler

Intake valve clearance: 0.3mm

Exhaust valve clearance:0.4mm

Notice: When measuring the valve clearance,

the accurate value is taken under the

condition that the diesel engine should be in

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a cold state(lower 60

℃), and there should be

a obstacles sticky feeling as the feeler slides

between the valve lifter and the rocker.

6 ）When adjusting the valve clearance,

first unscrew loosen the locknut and the

adjusting bolt, and then place the required

thickness feeler between the rocker arm and

the valve, tighten the adjusting bolts, and

then tighten the lock nut.

(45)

3 、

、

valve clearance

④

adjustment and inspection of valve

clearance

7 ）Rotate the engine until the first cylinder

to the compression top dead center, adjust

the clearance of the intake and exhaust valve

of the first cylinder, the intake valve of the

second cylinder, the exhaust valve of the

third cylinder, the intake valve of the fourth

cylinder, the exhaust valve of the fifth

cylinder, the sixth cylinder should not be

adjusted. See right picture(I means the air

intake, E means the air exhaust).

8 ）Keep on rotating the engine until the

sixth cylinder to the compression top dead

center, then adjust the other valve clearance

which have not been adjusted in the seventh

adjusting step.

(46)

4 、

、

valve phase

（（（

（1））））Intake valve early opening and late

closing：：：：

Enlarge the valve opening height at the beginning of the air intake stroke, reduce the air intake resistance, and increase the air intake quantity.

Intake valve late closing：：：：

Delaying the intake time, and increasing the air int a ke q ua ntit y und er t he e ffe c t o f t he atmospheric pressure and the gas inertia force.

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atmospheric pressure and the gas inertia force.

Exhaust valve open early ：：：：

The cylinder can exhaust the gas by itself with the help of the high pressure in the cylinder, which can reduce the exhaust resistance,and ensure the gas discharged cleanly.

Exhaust valve close late ：：：：

Extending the air exhaust time, and ensure the air completely discharged the pressure and inertia force of the exhaust air.

(47)

4 、

、

valve phase

（

2 ）

）

valve overlap

As the inlet valve opens early, the exhaust valve closes late, the inlet valve opened before the upper dead point, while the exhaust valve closed after the upper dead point, which inevitably cause the phenomenon of two valves opened at the same time, in this case the valve angle will be overlapped, when two valves opened at the same time, the corresponding crank

Valve phase

Working process

Compression

process

opened at the same time, the corresponding crank angle is called the valve overlap angle.

（3）Air actual intake and exhaust valve opening, closing and duration time.

The actual air intake and duration time: At the end of the air exhaust stroke, the piston reaches the upper dead point, when the crankshaft turned to a position where the angle between the crankshaft and the upper dead point is a, the inlet valve begin to open, and will be closed until the piston accross the bottom dead point.

Exhaust process

(48)

4 、

、

valve phase

（

3 ）

）

Air actual intake and exhaust

valve opening, closing and duration

time.

The actual time and duration of the air

intake.

The duration of the entire intake

process is equivalent to the crank

rotation angle: 180

°

+ α + β.

α: Intake advance angle, generally α =

Valve phase

Working process

Compression

process

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α: Intake advance angle, generally α =

10-30

β: Intake lag angle

，

generallyβ=40-80

°

Weichai WD10G220E23 engine:

Exhaust advance angle α =34

°～

39 °

Exhaust lag angle β =61

°～

67 °

Exhaust process

(49)

4 、

、

、valve phase

（

（3）

）

）Intake and exhaust valve opening

）

and closing time and duration.

The actual time and duration of the air

intake.

When the working process is closing to the

end, and the piston angle before the bottom

dead point is γ, the exhaust valve opens.

When the piston passes the up dead point,

and the after angle is δ, the exhaust valve is

Valve phase

Working process

Compression

process

and the after angle is δ, the exhaust valve is

closed. The crankshaft rotates 180

°+ γ+ δ

during the whole process.

γ:exhaust advance angle

，generally γ

=40-80

°

δ:Intake lag angle

，generally:δ =10-30°

Weichai WD10G220E23 engine:

exhaust advance angle γ =76

°～ 81°

Intake lag angleδ =26

°～ 34°

Exhaust process

(50)

1.overview

(1) composition of fuel supply system

The fuel supply system consists of injection

pump, fuel supply pump, fuel filter, injector,

high pressure oil pipe, low pressure oil pipe

and other accessories.

（

（2）

）

）function of fuel supply system

）

The main function of the fuel supply

system is to continuously feed the engine

with filtrated clean fuel, and inject certain

Oil injector

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with filtrated clean fuel, and inject certain

amount of diesel into combustion chamber as

certain pressure and

quality according to

different engine performance requirements,

which will mix and burn with the air rapidly

.

Fuel supply system consists of fuel

injection pump, fuel delivery pump, fuel

filter, fuel injector, high pressure oil pipe,

low pressure oil pipe and accessories.

High pressure

pump

Fuel filter

Low

pressure

pipe

(51)

1.overview

（（（

（3））））working process of fuel supply system The engine rotation is transfered from the coupling or drive gear to the injection pump camshaft through the advance device. The camshaft rotation drives the fule delievery pump suck oil from the fuel tank, the filter clean oil will be delivered to the plunger through fuel channel in the fuel injection pump, the plunger will move upward through the cam shaft rotation, the piston, the fuel pressure will increased to a high pressure, and the fuel oil will flow into the high pressure, and the fuel oil will flow into the injector nozzle through the high pressure oil pipe and the injector.

When the pressure of the fuel oil delivered to the injector nozzle reaches above the specified starting injection pressure of the injector, the oil will be sprayed into the engine combustion chamber in the form of mist.

The overflowed or left fuel oil of the fuel injector and fuel injection pump will flow back to the fuel tank through their respective fuel pipe.

(52)

2.Oil injection pump

（（（

（1））））function of injection pump

The main function of the fuel injection pump is to supply certain amount of high pressure fuel to the injector in regulation time，while at the same time accomplishing the engine rotary speed control.

（（（

（2））））basic demand of injection pump

① The fuel pressure should ensure the requirement o f t h e injection pressure and atomization quality.

② The fuel supply should meet the exact

Injection pump

high pressure fuel pump

RELIABILITY IN ACTION

② The fuel supply should meet the exact

amount of fuel required by the diesel engine. ③ Ensure the diesel engine working order and accurate fuel supply within the given time.

④ The amount of fuel supply and fuel injection timing could be adjusted to ensure each cylinder oil supply evenly.

⑤ The fuel supply regulation should ensure the diesel fuel burned completely.

⑥ The beginning and ending of the oil supply must act quickly, the oil cut off must act swiftly to avoide oil drip.

Injector assembly

connector

(53)

(3)working principle of injection pump

①

oil intake process

The plunger will move downward under

the force of spring after the cam convex

portion turned over the highest position

，

which will creat vacuum in the plunger

upper space (called the pump oil chamber),

when the hole on the plunger sleeve

opened by the plunger upper end, the

diesel fuel in the oil channel of the pump

upper space will enter the the pump oil

chamber through the oil inlet, when the

plunger moves to the bottom dead center,

(54)

（

（3）

）

）working principle of injection pump

）

②

②oil supply process

When the camshaft turned to the cam convex portion and lift up the roller body, the plunger will move upward under the force of the spring, the diesel oil will be compressed, and part of the fuel will return to the upper oil chamber of the injection pump through the oil hole. When the plunger upper end cover the upper edge of the inlet hold on the sleeve, the pump oil chamber

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inlet hold on the sleeve, the pump oil chamber

will become a sealed oil chamber at the top of the plunger, the p lunger continues to move upward, the pressure in the pump oil chamber will rapidly increased, when the pump oil pressure > the spring force of the oil outlet valve + the residual pressure of the high pressure pipe, the oil outlet valve will be pushed open, the high pressure oil will enter the high pressure pipe through the oil outlet valve, and sprayed into the combustion chamber through the injector.

(55)

（

（3）

）

）working principle of injection pump

）

③

③oil return process

The plunger supply oil upward, when the plunger moves to a position where the chute connected to the oil return hole on the sleeve, the low pressure oil channel of the pump oil chamber will be connected with

the mid level outlet, radial hole and the chute, the oil pressure will be lowered, the oil outlet valve will rapidly closed under the spring force, and the oil supply will be stopped. Then the plunger will still move upward, when the cam convex portion turned over the highest position，the plunger will move downward under the spring force, and the next cycle is begin.

(56)

3.governor

（

1 ）

）

working principle

The fuel injection volume can be

changed by the governor by controlling

the movement of the governor rake.

When the engine load increased and

the rotation speed decreased, the

governor will automatically increase the

amount of fuel injection to prevent

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amount of fuel injection to prevent

engine power off.

When the engine load decreased and

the rotation speed increased, the

governor will automatically reduce the

amount of fuel injection to prevent the

engine speed is too high.

Right picture shows the basic structure

of the RAD type speed governor.

1－pull-rod；2－speed adjusting bolt；3－guide rod；4－floating lever；5－

high speed limit screw；6－control handle；7－idle screw；

8－shift yoke rod；9－idle spring；10－stroke adjusting screw；

11－speed adjusting sleeve；12－flyweight；13－roller；14－camshaft；15－