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Gasoline Engine (Petrol engines – Otto Motor)

  • What is a Gasoline Engine (Otto Motor)? How does it work?
  • Petrol engines are the most used engine types today and are still being used even at the 20% duty cycle. Although I advocate turning to electric motors, as long as the oil does not run out, there will be no history of internal combustion engines. Of course, automobiles using hydrogen also use the same type of internal combustion engine, but things are a bit different.


  • In 1876, gasoline engines from the German engineer Nikolaus Otto were reduced to 20% in the best Ferrari engine from the 3-5% of those days, but still about 10% of the power of the fuel was transferred to the transmissions, 5% to the inertia of the pistons, 5% to friction and 60% to heat and to waste completely. That is, the efficient power that can be transmitted to the wheels can be up to 20% of the energy generated by the spent fuel.
  • Petrol Engine

    Petrol Engine


  • Once we’ve had enough of the petrol engines, we will look at the working system a bit; We see injected engines as the most commonly used engine type. Injection engines are preferred because they can achieve a more homogeneous fuel + air mixture than carburettor engines. Today’s gasoline engines have been completely switched to injection system. We can express the operation of a petrol engine as simple as; Fresh air taken from the outside into the intake pipe of the motor is again taken as fuel + air mixture into the cylinder by injecting the fuel from the injection end at the end of the intake duct.


  • In the area of ​​the uppermost cylinder of the cylinder of the piston, which is called the combustion chamber, an air + fuel mixture close to homogeneity is compressed and ignited by the spark plug. Rapidly expanding cylinder volume due to the effect of the ignition and accordingly pushing the piston down, activates the crank-link mechanism connected to the pistol.


  • The connecting rod is the piston rod. The crank is a milder that provides the momentum necessary to move the vehicle. The plunger-connected rod mechanism transmits the linear motion from the piston to the circular motion on the crankshaft. The crankshaft is also connected to the transmission and the power to the wheels is adjusted. It is the working phase of a four-stroke engine seen in the flank. These;
  • Petrol Engine


  • 1. Intake: The fresh air + gasoline mixture is taken into the cylinder with the effect of vacuum created by opening the valve on the suction channel on the left side and moving the piston downward.


  • 2. Compression: The air + fuel mixture in the cylinder is compressed by the upward motion of the piston and the hen temperature and the pressure are increased and a very small volume is trapped. At this time, both valves are fully closed and insulation is provided.




  • 3. Combustion: The compressed gasoline + air mixture is ignited by the spark plug (spark generating element) located in the middle of the valves. The power to drive the vehicle is produced here.


  • 4. Exhaust: When the piston is coming back up after burning, the burned residual gases are thrown out by opening the exhaust valve on the upper right side. Then the 1st cycle, ie the suction phase, starts again when the piston comes down again.


  • The most important factor to keep the engine from shaking is the number of cylinders. For example, if you try to apply 5 cylinders on a V-type motor, there will be an incredible vibration and the engine will not work because there must be three cylinders on two sides on one side.


  • Commonly used cylinder arrangements are:


  • These engines with row cylinders are often used in front-wheel drive economy class vehicles. The use of this four-cylinder engine is very common. It does not take up much space, but it can withstand more than the desired power.
  • Petrol Engine


  • These engines, known as the V type, are made up of symmetrical and numbered cylinders, generally positioned 90 degrees to each other. For example, you can see a V6 engine above. This three-cylinder engine is widely used in sports or racing cars designed to produce high power. There are also more powerful versions like V8, V12 and V16. These engines are much smoother and run smoother than row-type engines. Because the centrifugal and inertial forces created by the motion of the pistons mutually dampen each other. This type of engine, which means that torque is strong and constant, remains fuel economy-class. For this reason, there is little use today.
  • Petrol Engine


  • The use of these types of engines where the cylinders are positioned horizontally is limited. It is used only by a few marginal auto companies (eg Subaru). These engines have the following advantage; As the piston moves in vertical cylinders, a large inertial force is generated which is caused by its own weight. When the pistons are horizontal, the piston weights, which are created under the effect of gravity, are not on the engine but on the cylinder surfaces. This reduces the inertia as well as the weight of the piston is working almost as if the piston is moved at a higher speed and can be moved easily.
Gasoline Engine (Petrol engines – Otto Motor)
Author: wik Date: 5:55 pm
Science and Mathematics, Technology

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