1 DIESEL ENGINE Teknik Kendaraan Ringan Semester 5 th Class XII Kompetensi Kejuruan SK-KD 5 TH

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DIESEL ENGINE

Teknik Kendaraan RinganSemester 5 th Class XII

Kompetensi Kejuruan

SK-KD 5TH

DIAGRAM ALUR PENCAPAIAN KOMPETENSI

Teknologi dan Rekayasa

DIESEL ENGINE

In 1894, German inventor Rudolph Diesel developed the first single-cylinder diesel engine.

He signed a multi-million dollar deal with Adolphus Busch, head of brewery empire, to manufacture the diesel engine.

However, he lost his fortune, and in 1913, mysteriously was found dead after going overboard a boat. Suicide was one speculation, but also assassination by Kaiser Wilhelm’s agents, fearing that Diesel, with WW I looming, would sell the engine to England

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The Combustion Cycle

The four-stroke combustion cycle of the diesel engine is composed of the intake stroke, compression stroke, power stroke, and the exhaust stroke.

The diesel engine operates through the motion of compression pistons in inside the cylinders of the engine.

Pistons inside the cylinders are connected by rods to a crankshaft. As the pistons move up and down in their cylinders, they cause the crankshaft to rotate.

The crankshaft’s rotational force is carried by a transmission to a drive shaft, which turns axles, causing the wheels to rotate.

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The Intake Stroke

During the intake stroke, the intake valve opens as the piston moves down to allow air into the cylinder.

The air is pushed by atmospheric pressure into the cylinder through the intake valve port.

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The Compression Stroke

After the piston reaches its lower limit, it begins to move upward and as the piston moves up, the intake valve closes.

The exhaust valve is also closed, so that at this point in the cycle, the cylinder is sealed.

As the piston moves upward, the air is compressed and the compression of the air causes the pressure and the temperature of the cylinder to increase.

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The Power Stroke

As the piston reaches maximum compression of the air, diesel fuel is injected to the combustion chamber filled with compressed air.

The heat of the compressed air ignites the fuel spontaneously at the self-ignition temperature of the fuel.

As the cylinder pressure increases, the piston is forced down into the cylinder.

The power impulse is transmitted down through the piston, through the connecting rod, and to the crankshaft, which is rotated due to the force.

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The Exhaust Stroke

As the piston reaches the bottom of its stroke, the exhaust valve opens.

As the piston moves up on the exhaust stroke, it forces the burned gases out of the cylinder through the exhaust port.

Then as the piston reaches the top of its stroke, the exhaust valve closes, and the intake valve opens.

The cycle repeats again with the intake stroke.

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Teknologi dan Rekayasa9


Efficiency

One positive aspect of the diesel engine is that they are thermally efficient.

The improved efficiency is caused by the relatively high compression ratios

The diesel engine is 54% thermally efficient, while gasoline engines are only 34%.

As a result of diesel engines thermally efficiency, they are able to achieve better gas mileage because they produce greater horsepower output for fuel intake.

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Fuel Economy

One main reason for the diesel engine’s excellent fuel economy is that it burns far more air than fuel.

In a gasoline engine, it’s air intake is carefully restricted and controlled by the carburetor for a 15:1 air to fuel ratio.

However, in the diesel engine, the air intake is unrestricted.

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Durability

Diesel engines are also capable of running high miles without major engine work.

Truck diesel engines can run 250,000 or even 500,000 miles without major engine work.

In 1978, Mercedes-Benz launched a “Great Diesel Search” to find the highest mileage diesel in the United States.

Robert O’Reilly drove his 1957 Mercedes-Benz 180D 1,184,000 miles, 750,000 on its original engine.

Another owner drove his 1968 Mercedes-Benz 220 D 912,000 miles, 902,000 miles on its original engine.

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Compression Ratio

The diesel engine compresses at a very high ration of 14:1 to 25:1.

The higher the compression ratio, the more power is generated.

The main limiting factor to compression ratio is based on the knock limits of the fuel.

Knock is the term used to describe the auto ignition that occurs when a fuel ignites because the pressure in the cylinder is such that combustion occurs.

The knock limit of the fuel is determined by the point at which the engine begins to shake.

The higher the knock limit, the higher the compression ratio, the more power is generated.

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Advantages of a Diesel Engine

Low maintenance, greater efficiency, high power output, and better fuel economy under all types of loads.

Does not require a spark plug to ignite fuel, it relies on the spontaneous combustion through the heat of compression to ignite the diesel fuel.

Because of this type of combustion, a diesel engine are built more ruggedly and heavily built than the gas engine.

The ruggedness of the diesel engine gives a two to three times longer life than the gas engine, which has a life of around 100,000 miles.

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Disadvantages Components of diesel engines are usually heavier that

those of gasoline engines because of the additional structural strength needed to obtain the higher compression ratio and power output.

They can emit large amounts of ozone-forming constituents and particulates.

Because of diesel engines’ weight and compression ratio, they tend to have lower maximum RPMs than gasoline engines. This makes diesel engines has high torque rather than high horsepower,

and this tends to make cars with diesel engines slow in terms of acceleration.

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Diesel fuel is not as readily available at all locations as gasoline tends to be.

Diesel engines are harder to start in cold weather conditions, because it is difficult to get the temperature inside the cylinder up to the self-ignition temperature of the diesel fuel.


Emissions

The most harmful emission from diesel engines are the nitrogen oxides.

The problem of nitrogen oxide (NO) production in diesel engines comes from the early rapid burning, which produces very high-temperature products.

As a result of the pollutants from diesel engines, they are subject to increasingly stringent regulations that require continual improvements in the combustion process.

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Main Differences of Gas and Diesel

The main difference between a gasoline engine and a diesel engine is that in a diesel engine, there is no spark plug to ignite the fuel.

Diesel fuel is injected into the cylinder, and it ignites spontaneously as the heat and pressure of the compression stroke cause the temperature inside the cylinder to increase.

The other major difference between the two types of engines is in the gas mileage. As a result of diesel fuel having a higher energy

density than gasoline, diesel engines get higher gas mileage.

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DIESEL COMPONENTS

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COMBUSTION CHAMBER TYPE( DIRECT INJECTION )


Semi Spherical TypeSpherical Type

Multi Spherical Type

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SWIRL CHAMBER TYPE PRECOMBUSTION CHAMBER TYPE ( AIR CELL )

Glow Plug

Nozzle

Piston

INDIRECT INJECTION TYPE

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IN – LINE INJECTION PUMP

FeedHole

Control groove

Driving face

IN – LINE INJECTION PUMP

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VE : “ VERTEILER EINSPRITZ )

DISTRIBUTOR INJECTION PUMP ( VE )

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DISTRIBUTOR INJECTION PUMP ( VE ) ( SCEMATIC )

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From Fuel Tank

To Injection Pump

FUEL FILTER PARTS

1. Priming Pump

2. Filter

3. Water Sendimeter

FUEL FILTER

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NOZZLE PARTS

1.Pressure spring2.Nozzle Needle3.Nozzle Body4.Adjusting Shim

NOZZLE

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PRE HEATING SYSTEM

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Bibliography:

Bosch Injection Pump Repair BookToyota Technician, Toyota Astra Motor

Presented by Anang WaskitoSMK Negeri 1 Magelang

Documents

1 DIESEL ENGINE Teknik Kendaraan Ringan Semester 5 th Class XII Kompetensi Kejuruan SK-KD 5 TH