Broken car - what to do?

Dodane: 20-08-2016 11:13
Broken car - what to do? oil for Hummer

Why tuning a car is a good option for automotive fan?

Activities such as tuning cars is a real treat for those who know the automotive industry. Passionate about motorcycles or cars will not have any fun in connection with the exchange of automotive parts, which is not always as easy as it might seem. What's more, conducted in-house tuning of the car is even reason for pride for the majority of people who have taken such a project alone. One has to have special skills to create something truly beautiful, yet durable, the speed with which moves the car or motorcycle. The effect is sometimes surprising and worth spending even a lot of time over our vehicle, later to gain recognition.


Some SI engines are crankcase scavenged

Crankcase scavenged
Diagram of a crankcase scavenged 2-stroke engine in operation

Some SI engines are crankcase scavenged and do not use poppet valves. Instead the crankcase and the part of the cylinder below the piston is used as a pump. The intake port is connected to the crankcase through a reed valve or a rotary disk valve driven by the engine. For each cylinder a transfer port connects in one end to the crankcase and in the other end to the cylinder wall. The exhaust port is connected directly to the cylinder wall. The transfer and exhaust port are opened and closed by the piston. The reed valve opens when the crankcase pressure is slightly below intake pressure, to let it be filled with a new charge; this happens when the piston is moving upwards. When the piston is moving downwards the pressure in the crankcase increases and the reed valve closes promptly, then the charge in the crankcase is compressed. When the piston is moving upwards, it uncovers the exhaust port and the transfer port and the higher pressure of the charge in the crankcase makes it enter the cylinder through the transfer port, blowing the exhaust gases. Lubrication is accomplished by adding 2-stroke oil to the fuel in small ratios. Petroil refers to the mix of gasoline with the aforesaid oil. This kind of 2-stroke engines has a lower efficiency than comparable 4-strokes engines and release a more polluting exhaust gases for the following conditions:

They use a total-loss lubrication system: all the lubricating oil is eventually burned along with the fuel.
There are conflicting requirements for scavenging: On one side, enough fresh charge needs to be introduced in each cycle to displace almost all the combustion gases but introducing too much of it means that a part of it gets in the exhaust.
They must use the transfer port(s) as a carefully designed and placed nozzle so that a gas current is created in a way that it sweeps the whole cylinder before reaching the exhaust port so as to expel the combustion gases, but minimize the amount of charge exhausted. 4-stroke engines have the benefit of forcibly expelling almost all of the combustion gases because during exhaust the combustion chamber is reduced to its minimum volume. In crankcase scavenged 2-stroke engines, exhaust and intake are performed mostly simultaneously and with the combustion chamber at its maximum volume.

The main advantage of 2-stroke engines of this type is mechanical simplicity and a higher power-to-weight ratio than their 4-stroke counterparts. Despite having twice as many power strokes per cycle, less than twice the power of a comparable 4-stroke engine is attainable in practice.

In the USA two stroke motorcycle and automobile engines were banned due to the pollution, although many thousands of lawn maintenance engines are in use.citation needed

Źródło: https://en.wikipedia.org/wiki/Internal_combustion_engine


Cars for the rich

Luxury car brand virtually since their inception are surrounded with an aura of mystery for average earners. Although over the years the exclusive, global brand cars were beginning to reveal its secrets to the outside world and show their offer, however, to this day, some car models are intended only for the richest people in the world. Luxury cars are a sign of prestige and good luck, while allowing very stand out in the crowd. Most of them are made of special materials and to achieve a surprisingly high speed. Another advantage of these cars is equipped with many different, sometimes very expensive gadgets.