1.
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1. The two stroke engine is simple in construction but complex dynamics are employed in its operation.
a) Whats the peculiarity of the two stroke engine?
b) Are complex dynamics employed in the operation of most types of engines?
c) What affects the construction of the 2 stroke engine?
2. The air fuel mixture is forced into the cylinder through the transfer ports.
a) When is the air fuel mixture forced into the cylinder?
b) Why should the air fuel mixture be forced into the cylinder through the transfer ports?
c) What is the air fuel mixture forced into the cylinder through?
3. The 4 stroke cycle is more efficient than the 2 stroke cycle.
a) What type of engine is used to power tractors?
b) Is the 4 stroke or the 2 stroke cycle more efficient?
c) Why is the 4 stroke cycle more efficient?
4. Knock occurs when the fuel ignites at the wrong time.
a) When does knock occur?
b) When does the fuel usually ignite?
c) What is the proper time to ignite the fuel?
5. The Diesel can be run at much higher compression ratios.
a) Why is the Diesel compression ratio so high?
b) What compression ratios can the Diesel be run at?
c) How can compression ratios be increased?
2. ,
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1. The rising piston creates.......
a) a spark plug;
b) a partial vacuum in the crankcase;
c) the dreaded condition known as knock.
2. The inlet port is uncovered by the piston as it rises, and......
a) exhaust gases escape out to the atmosphere:
b) forces the piston downwards:
c) the air fuel mixture enters the crankcase.
3. In the diesel cycle the burning is triggered.........
a) by the time the combustion completes:
b) by heat generated in compressing fuel air mixture;
c) by the piston as it rises.
4. The 4 stroke cycle is used......
a) for industrial purposes today;
b) manufacturing expertise;
c) by the rapidly expanding gases of combustion.
5. The fuel isnt in the engine......
a) and requires considerably more moving parts;
b) although it is less stressful on the engine;
c) until the exact moment it is needed.
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UNIT 4
TEXT A
PLOUGH
The plough (American spelling plow) is an agricultural implement used to turn over the surface of the soil into ridges and furrows in order to cultivate crops.
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Ploughing has several advantages. The major reason for plowing is to incorporate the residue from the previous crop into the soil, reduce the prevalence of weeds in the fields, make the soil more porous,easing later planting.
The very earliest ploughs were simple scratch-ploughs and consisted of a frame holding a vertical wooden stick that was dragged through the topsoil.
The first iron plough was developed by Joseph Foljambe in Rotherham, England, in 1730. It was durable and light steel ploughwas lighter and more durable than ploughs made of iron or wood. It was designed by John Deere in 1830s. The first steel ploughs were walking ploughs, having two handles held by the ploughman to provide control over the depth and location of the furrow behind the draughting force. The ploughman was also controlling the draught animals. Riding ploughs with wheels and seat for the operator came later, and often had more than one share.
Much later they progressed info mould board plow which turn the soil in one run across the field. Modern mould board ploughs are powered by tractors.
WORD LIST
| turn over surface ridge furrow major reason incorporate residue previous reduce prevalence weed scratch consist of hold (held) wood stick drag durable steel location handle draughting force mould board run crop residues | , , |
1.
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| soil use crop iron | advantage porous easy wood | make later simple design | frame topsoil develop provide |
2. :
implement, surface, advantage, contain, supply, ground, tool, benefit, consist of, drag, pull, provide.
3. , .
| to plow to use to turn to cultivate | to incorporate to reduce to develop to design |
4. , . .
to turn over
in order to
to be dragged through
to provide control over
draught animals
to run across
5. , .
6. , . .
7. .
1. What is used to turn over the soil into ridges and furrows?
2. What is the major reason for ploughing?
3. When was the first iron plough developed?
4. Did the ploughman operate with handle to provide control over the depth and location of furrow?
5. Does the modern plough turn the soil in one run across the field?
TEXT B
MOLDBOARD PLOUGH
Moldboard ploughs are adapted for turning the furrow slices and breaking them up.
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Plough parts are: frame, frog, share, moldboard, landside, hitch, coulter; furrow, land and rear wheels.
The part of the plough that breaks the soil is called the bottom. The mouldboard is below the frame. It is tipped with a share, an asymmetric arrow shaped device designed to slice through the ground horizontally, as it moves forward. It also has a coulter, a sharpened blade or disk, attached to the frame of the plough. It cuts down through the ground ahead of the share and also cuts deep-set and tough roots. The landside serves to steady the plough while it is being operating. It slides along the face of the furrow exerting considerable part of side pressure created by rising furrow slices on the furrow wall. Shares and land sides are bolted to the frog of the bottom. The shin is the cutting edge of the moldboard. It is used to do a good cut of the soil.
On modern ploughs the mouldboard is separated from the shin and bottom, allowing these parts to be replaced without replacing the moldboard. Abrasion eventually destroys all parts of the plough that contact the soil. It is essential to follow a systematic plan in reconditioning the various parts of plough.
WORLD LIST
adapt
break up
frog ,
share
landside
moldboard plough
hitch ,
coulter
furrow wheel
land wheel
bottom
tip - .-.
arrow shaped device
slice through
sharpen
ahead
deep-set and tough roots
cut down through the ground
serve
steady
slide along
exert considerable part -
side pressure
shin
separate -
allow -
replace -
abrasion ,
destroy -
essential -
recondition
1. :
1. what plough parts are;
2. where the moldboard is located;
3. what the coulter fulfils;
4. what function of the coulter;
5. what the landside serves for;
6. why it is essential to follow a systematic plan in reconditioning the various parts of plough.
2.
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1. Moldboard ploughs are adapted for turning the furrow slices and harrowing.
2. Moldboards are tipped with shares.
3. A coulter cuts down through the ground behind the share and also cuts tough roots.
4. Moldboards, shares and landsides are bolted to the frog of the bottom.
5. A shin is the cutting edge of the moldboard.
3. 1,2, .
TEXT C
TYPES OF TRACTOR MOLDBOARD PLOWS
Modern moldboard ploughs are classified as follows:
a) According to utility all-purpose ploughs and specialized ploughs;
b) According to the number of bottoms one-, two-, three-, four-, five-, six-, eight bottom ploughs.
c) According to the way of joining to the tractor trailing, semi-mounted and integral mounted ploughs.
d) According to the shape of moldboards.
A trailing moldboard plough has from one to five bottoms. It is used for ploughing soils free from stones. The depth of ploughing is about 27cm.
Two way trailing plows plough the soil 25cm deep. They differ from one way trailing plough by there right and left hand bottoms. This type of plough can throw the furrow slices both to the right and to the left of the operator. It is used for ploughing irrigated lands or where it is desirable to break the land without a dead furrow.
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A trailing disk plough is pulled behind the tractor. It has three wheels: two furrow wheels and a land wheel. It can be attached to the tractor by a hitch either vertically or horizontally.
A two way mounted plough is made to perform the same functions as the trailing two way plough but it differs in construction. Different arrangements are provided to change from right to left hand bottom.
Disk ploughs are adapted to the conditions where the moldboard will not work, for example sticky soils, dry ground, stony ground, and deep ploughing.
WORD LIST
| according to utility the way of join semi-mounted integral mounted shape free from stones two-way trailing plough differ from throw desirable dead furrow behind either . or perform the same arrangement sticky to be familiar with | . - |
1. - .
) ;
) , , .
) .
2. : .
