Power or working stroke
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.
News for motorists
Despite the fact that people interested in the automotive industry very keen viewing messages associated with handwritten carrying out repairs in the car or parts replacement, however, a large part of radio listeners or people viewing web pages are waiting for a completely different type of information. This is important especially when we are on the way. Well, very important are the current traffic information. More than one radio provides such information, which is certainly often awaited by drivers standing in unexpected traffic jams and so on. Thanks to that we will hear information about the accident or other traffic problems well in advance, we can even change your route so you can avoid traffic problems.
Employment opportunities in the automotive industry
While working in the garage is the most common employment opportunities for people fascinated with the automotive industry, it is certainly not the only option that we can choose where we want to take up employment in this industry. Very interesting, though perhaps sometimes quite tedious task for people interested in the subject is the position of consultant in showrooms respective car brands. You have to admit, however, that in order to obtain employment in a place like this should have appropriate knowledge and skills, especially in dealing with customers. Many options of employment also provides production vehicles of different types or auto parts. Employment in this place very often involves simple tasks.