Intake, induction or suction
Intake, induction or suction: The intake valves are open as a result of the cam lobe pressing down on the valve stem. The piston moves downward increasing the volume of the combustion chamber and allowing air to enter in the case of a CI engine or an air fuel mix in the case of SI engines that do not use direct injection. The air or air-fuel mixture is called the charge in any case.
Compression: In this stroke, both valves are closed and the piston moves upward reducing the combustion chamber volume which reaches its minimum when the piston is at TDC. The piston performs work on the charge as it is being compressed; as a result its pressure, temperature and density increase; an approximation to this behavior is provided by the ideal gas law. Just before the piston reaches TDC, ignition begins. In the case of a SI engine, the spark plug receives a high voltage pulse that generates the spark which gives it its name and ignites the charge. In the case of a CI engine the fuel injector quickly injects fuel into the combustion chamber as a spray; the fuel ignites due to the high temperature.
Power or working stroke: The pressure of the combustion gases pushes the piston downward, generating more work than it required to compress the charge. Complementary to the compression stroke, the combustion gases expand and as a result their temperature, pressure and density decreases. When the piston is near to BDC the exhaust valve opens. The combustion gases expand irreversibly due to the leftover pressure?in excess of back pressure, the gauge pressure on the exhaust port?; this is called the blowdown.
Exhaust: The exhaust valve remains open while the piston moves upward expelling the combustion gases. For naturally aspirated engines a small part of the combustion gases may remain in the cylinder during normal operation because the piston does not close the combustion chamber completely; these gases dissolve in the next charge. At the end of this stroke, the exhaust valve closes, the intake valve opens, and the sequence repeats in the next cycle. The intake valve may open before the exhaust valve closes to allow better scavenging.
What problems must cope owner of the vehicle?
One of the most common problems, which has to face many a owner of such a vehicle such as a car or a motorcycle, a scratch on the car paint. We can scratch the car in just a few moments, without using even this sharp tool. Many scratches formed, for example, the inability of parking or reversing. Unfortunately, many of them are also the result of actions of hooligans, we leave the car, for example, in the wrong neighborhood. How to deal with such a problem? Of course, in many cases it is necessary to visit the factory paint. In smaller straches it may be useful to also use, for example, with a special pen that allows at least a little to mask the resulting defects.
How to check the car before you buy?
Used cars are much less expensive than acquiring your dream vehicle straight from the showroom. Not surprisingly, it is a very popular way to quickly obtain necessary sometimes the vehicle. What can you do to buy certainly a good car? Very often it is recommended to select a proposed us a car to the garage. The perfect solution would be that if we had a friendly workshop where our friend after a review by a special software this car could tell us a lot about him. Experienced car mechanics unhindered see if the car has already passed through some accident or has other hidden defects, which would like to avoid a potential car owner.