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Liquid-cooled four-stroke engine ignition engine with carburetor

Topic: Technology
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Otto stands for the designer name, an Otto engine is an engine with pistons that go up and down either gasoline or diesel. There are other types of engines, for example. Wankel engine with rotating pistons, the Stirling engine with external combustion gas turbine with internal combustion.
How the engine works. Gasoline drawn using the petrol pump driven by the camshaft until gasoline to the carburetor. Petrol comes first to float the house in the carburetor. There in is the float that determines whether it will get into more gasoline in the carburetor.

The float floats on the fuel and adjust the float valve so that it comes in just enough fuel to make the fuel to keep a constant level. Then, the fuel to the diffuser inserted in the air wedge. The diffuser makes about / spreads out the fuel into fine particles, the fuel is gasified. The cone mixed fuel and air. The most common mixing ratio is 15:1, which means that it takes 15 kg of air during combustion of 1 kg of fuel. In cold starts and accelerations, there is often a richer mixture that you have greater% fuel in the mixture. The air, you want as cold as possible. Because then it can expand more when the fuel mixture is ignited inside the engine and makes you get a higher pressure inside the engine. So on some carburetors is cooling water past the gasifier and cools the air in it. One can also see that it says intercooler on some cars, which means that it has a special system for cooling air to the engine.

Then continue the fuel mixture to the cylinders. The fuel mixture enters the cylinder through the inlet valve / valves while the piston is moving downward. When the piston moves down, a negative pressure in the cylinder which means that the fuel suction. This is called the induction stroke (intake rate).

The next line is called the compression stroke. Now, all valves closed. The piston moves upwards and compresses the fuel mixture to about 1/10 of its former volume. If an engine a compression ratio of 10:1, it means that the fuel mixture is compressed to 1/10 of its original volume.

Third rate called the work rate or the rate of expansion. Even now, all valves are closed. The beginning of this line, the piston is at the top and now ignites the compressed fuel of the spark from the spark plug. When the expanding / explode the fuel and the temperature is raised to 2000 - 2500 ° C. And the pressure increases to about 30-40 bar. The pressure pushes the piston downward in the cylinder and the engine may work impulse that provides engine power. The piston is pushed down and makes the crankshaft to rotate. The crankshaft power leads to the flywheel resulting force to the gear which in turn drives the wheels of the vehicle. The flywheel has to get a smooth flow of power. Since the crankshaft to increase and decrease the rotational speed when the different cylinders "teeth" have to have the flywheel which equalizes the unequal power flow by spinning the whole time the engine is running. The flywheel stores energy. The rhythm is the so much faster than the other bars, causing an uneven flow of power to the crankshaft. So goes engines quieter and smoother the more cylinders they have. If we had no flywheel would get a jerky once the vehicle. Engines that are not laps as much as diesel engines must have a heavy flywheel to have a quiet time. Engines with few cylinders have also a heavier flywheel. However, a scooter has a lightweight flywheel but instead more laps to get a smooth ride.
Fourth and last bar called the outlet or exhaust stroke. Now the outlet valve / valves open / open. The piston moves upward and pushes the hot exhaust gases. When the piston is at the top of this rate are the four strokes completed and now it is about the rate one. All four strokes are called together for a process, and then spin the crankshaft two turns. Of the four strokes, just as three that will be effective the other bars have consumed power. The motor still spins depends on the flywheel as in step one, two and four relinquished stored energy
Unlike tvåtktsmotorn works as follows.

When the engine compresses the fuel mixture in a two stroke engine sucked while new fuel mixture into the crankcase (below the piston) in which a vacuum had when the piston was up. The fuel mixture must be mixed with oil to lubricate the engine (bearings). In a four-stroke engine is the fuel mixture in above the piston and which lubricates rather than pure oil that is always down in the crankcase. This oil can not be elsewhere, and not above the piston. At the same rate ignite the fuel mixture, and the piston is pushed down by the pressure.

As the two pushed the fuel mixture above the piston goes down. Simultaneously the exhaust gases out, this makes it impossible to prevent some fuel mixture supplied with the exhaust gases out. This results in higher operating costs and more environmentally destructive. Add Brand to two-stroke engine has no valves.

But now Jaguar claims that they have constructed a two-stroke engine with four-valve technology, they also claim that this engine would be cleaner than a four-stroke. It sounds incredible but will apparently be true.

The cooling system

The most common cooling system today is water, but there are some cars with air cooling. Approximately 1/3 of the fuel's energy is removed for engine cooling.

A cooling system consists of cooling channels inside the engine where water circulates (this is also called the cooling jacket) and a cooler in front of the cooling fan that is either belt or electric. The electric fan is turned on when needed (modern cars). The coolant in the cooling system consists of water mixed with glycol. In the summer, raise the glycol boiling point of the water and prevents the cooling system corrosion. In winter, the same as in summer, but also prevents the water from freezing.

The actual cooler consists of many small flat tubes. Around these tubes are the closely spaced fins which conduct heat and spread it out over a larger area so that cooling is more efficient.

Nowadays, almost all the cooling systems of övertryckstyp. This is controlled by the radiator cap that doubles as filling and inspection cover. Radiator cap usually have both over and under-pressure valve. By means of the relief valve, the pressure in the cooling system increased to between 20 and 100 kPa (0.2-1.0 bar) depending on the radiator cover to use. The opening pressure is indicated by a code on the radiator cap. The overpressure means that you can raise the boiling point of the coolant to 110 ° C if the pressure relief valve has an opening pressure of 30 KPa. This means that you can have higher opening temperature of the thermostat, resulting in higher operating temperature of the engine. The result is: cold engine wear decreases, the cooling effect increases and the cabin heater is improved. Therefore, change is often thermostat on old cars between winter and summer, for the engine to quickly warm up and to get good heat in the cabin in the winter.

To add is that the nonprofit engine temperature is 112 ° C. But in a normal car is located coolant at between 80-90 ° C when the engine is warm.

Radiator cap is usually also equipped with a pressure valve that lets air when the coolant cools. This prevents the tubes from contracting.

How it works. It works like a paddle wheel or rather a coolant pump is driven by the fan belt and pumps around the water only inside the engine when the coolant temperature is below 80 ° C depending on the thermostat you have. If it's cold enough out there may be enough coolant circulating inside the engine. However, when the temperature rises above 80 ° C the thermostat opens and lets the water can now go through the cooler and to cool. The thermostat does not open until a certain temperature makes the engine gets hot faster and reduces the cold wear.
There are two types of thermostats. One is called bälgtermostat. It operates as a bellows is partially filled with ether or alcohol having a low boiling point. At one end of the bellows is a valve attached. When the liquid in the bellows is formed is heated steam opens the valve.

The second type of thermostat works so that it is wax expands when it gets hot, pushing a plunger which in turn opens up a rubber membrane.

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One Response to "Liquid-cooled four-stroke engine ignition engine with carburetor"

  1. Wankel on January 2, 2009 at 5:28 pm #

    "Otto is the designer's name, an Otto engine is an engine with pistons that go up and down either gasoline or diesel."

    Otto principle requires spark plugs which you do not use of the Diesel just called diesel engine and no ignition otherwise it was an ok ascribed.


Comment Liquid-cooled four-stroke spark ignition engine of the carburetor

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