OUTLINE OF DIESEL ENGINE II

(5) Classification by Cooling Method
1) Water Cooled type
This cooling method is used for ordinary automobile
2) Air-Cooled type
This cooling method is used for motor bicycles and some small cars.

(6) Classification by Valve Type
1) Side valve type (SV type)
The Valves are located on the side of cylinder. This design is not used for high speed diesel engines.
2) Overhead valve type (OHV type)
The valve are located on the top of the cyliner, that is, on the cylinder head. This design is used or high-speed diesel engines.
3) Overhead camshaft (OHC type)
Both the valve and the camshaft are located on the cylinder head.

(7) Classification by Number and Arrangement of Cylinders
Engines are classified both by number of cylinders and by the arrangement of cylinders :
1) In- Line (Straight) type
2) Horizontal type
3) Horizontal opposed type
4) V type
As the number of cylinders increases, the rotational force (torque) of the engines becomes more balanced, and the high and low limit on the speed of the engine are extended. As a result the range of the enginen speed can be enlarged. It is widely known that a multi engine cylinder generates less vibration than a single cylinder engine.

1) In-Line type
The cylinders are arranged in a straight line. This type of engine encounters dimensional limits when attempting to produce a large output by increasing the number of cylinders. However, these engines are easy to maintain and their production cost is relatively low.

2) Horizontal type
The cylinders are arranged horizontally in this kind of engine. The engine height can be decreased using this design. For example, the engine may be mounted under the floor of a bus to increase the passenger room area.

3) Horizontal opposed area

The cylinders are arranged so that they are opposed in the horizontal direction. This type o engine has a larger capacity and produces a higher output than the horizontal type. In Japan, these have been used as underfloor engines in high-speed buses. However, the engines is rarely manufactured now because of its high manufacturing cost and large weight. This type is superior to then in-line type and the horizontal type from the viewpoint of engine balance.

4) V type
As the capacity of an in-line engine is increased, physical restrictions (length and weight) arise. This is why V-type engine are used for large capacity engines. The boundary betwen the in-line type and the V-type seems to be a displacement of about 13 - 14 l. Selection betwen the two types is made based on consideration of their relative advantages and disadvantages.
Basically, a V-type engine is structurally the same as in-line type engine. However, the cylinder block manufacturing cost tends to be height.
V6, V8, V10 and V12 types are used. The V8 type is used most widely.
The angle of V shape is generally 90 degree V, which is the best angle for obtaining equal interval ignition.

OUTLINE OF DIESEL ENGINE

I. Engine Classifications
A diesel engine is a type of internal combustion engine, which is in turn a type of combustion engine. A combustion engine changes thermal energy generated by fuel combustion into mechanical work. Combustion engine can be classified into internal combustion engines and external combustion engines. Internal combustion engines can be classified into Reciprocating type (Diesel and Gasoline Engine) and Rotational Motion type (Gas Turbine and Rotary Engine).

II. Classification of Reciprocating Internal Combustion Engines

(1) Classification by Ignition Method
1) Spark ignition engine.
2) Compression ignition engine
Air is heated (450 - 550C) by compression and fuel injected into the compressed air in the form of high pressure atomized fuel. The atomized fuel is ignited and burnt by the compression heat of the air. Diesel engines belong this group.
3) Hot-bulb ignition engine.

(2) Classification by Combustion Method (Thermodynamic Classification)
1) Otto cycle (Constant volume cycle)
Combustion take place under constant volume. Gasoline engines belong this group.

2) Diesel cycle (Constant pressure cycle)
Combustion takes place under a constant pressure. This combustion method is called the diesel cycle because the first engine built by Rudolf Diesel, the inventor of the diesel engine, was an engine that operated by constant pressure combustion. However, current-day high-speed diesel engines (for automobiles) do not belong this category.

3) Sabathe cycle (Mixed cycle)
In the Sabathe cycle, the above two cycles are combined. In other words, combustion takes place under constant volume and constant pressure. Current high-speed diesel engines (for auto mobiles, general power units and small boats) belong this category.

(3) Classification by Fuel Type and Fuel Method

Fuels used for internal combustion engines can be broadly classified into the following types :
1) Gasoline, 2) Kerosene, 3) Light Oil, 4) Heavy Oil, 5) Liquefied-petroleum gas (LPG).
Fuel feed methods can be classified as follows :
1) Fuel is charged into the engine together with air, using carburetor.
2) Fuel is injected into the cylinder (combustion chamber) using an injection pump.
Note's : On current gasoline engine is now no longer use the carburetor, fuel and air mix using injection technology (Electronic Fuel Injection). The different between diesel and gasoline injection is : Gasoline engine injected a fuel into intake manifold (before intake valve) its still mean fuel is charged into the cylinder together with air.

(4) Classification by Operation Technique
1) 4-cycle engine
One cycle (suction, compression, combustion, and exhaust) of the engine requires two rotations of the crankshaft, that is, four strokes.
2) 2-cycle engine
One cycle of the engine requires one rotation of the crankshaft.

HISTORY OF DIESEL ENGINE

In 1892, Rudolf Diesel, a German engineer, announced a new type of engine which fuel is injected into compressed air and ignited. This engine came to be known as the diesel engine.
By 1897, diesel engine that used heavy oil as fuel had been developed for practical use in Germany. (Low speed diesel engine)
Betwen 1924 and 1926, the development of the injection pump by Robert Bosch (from Germany) led to the development of high-speed diesel engines.
In Japan, research and development into diesel engines started around in 1930. By 1936, 6-cylinder air-cooled diesel engine with a total displacement of 8l had been developed and put to use.
In 1939, 5.1l-6-cylinder water-cooled automotive diesel engine began to be utilized, and diesel engine research and improvements have been continually pursued since then.



The history of diesel engines was briefly explained above. Research and development on diesel engines has been promoted in two separate areas; low-speed diesel engines for boats using heavy oil as fuel and high-speed diesel engine for automobiles such us Truck using light oil as fuel. In Japan research and develpoment on low-speed diesel engine has a longer history than hig-speed diesel engines. Low speed diesel engines have been used for boats and agricultural machinery and as power sources in industry.