Physics of Automobile Engines
...ylinder. The force applied to the brake pedal produces a proportional force on each of the output pistons, which in turn apply the brake shoes frictionally to the turning wheels to slow rotation. The hydraulic brake system on most automobiles operates in a similar way. The direct injection 3-cylinder cdi ream mounted engine with turbocharger and charge air cooler weights just 69 kg. Average consumption over 100 km is just 4.2 L (combined). The smart fortwo coupe cdi has low consumption and low emissions: 90g of Carbon dioxide per kilometer. Cdi stands for central rail direction injection. In expert circles, it is synonymous with a quantum leap in engine technology: A central high-pressure pump that generates pressure of 1350 bar in the common fuel line and injection nozzles. The high pressure and electronic control allow exact injection doses and fine atomization of the fuel. The advantages are clean, and maximum efficiency combustion. The turbo diesel engine with common-rail direct injection generates high torque even at low revs. At 1800-2800 rpm a maximum torque of no less than 73.8 lb-ft is attainable. You’ll soon notice the difference on steep hills. To understand the basic idea behind how a reciprocating internal combustion engine works, it is helpful to have a good mental image of how "internal combustion" works. One good example is an old Revolutionary War cannon. You have probably seen these in movies, where the soldiers load the cannon with gun powder and a cannon ball and light it. That is internal combustion, but it is hard to imagine that having anything to do with engines. more relevant example might be this: Say that you took a big piece of plastic sewer pipe, maybe 3 inches in diameter and 3 feet long, and you put a cap on one end of it. Then say that you sprayed a little WD-40 into the pipe, or put in a tiny drop of gasoline. Then say that you stuffed a potato down the pipe. I am not recommending that you do this! But say you did... What we have here is a device commonly known as a potato cannon. When you introduce a spark, you can ignite the fuel. What is interesting, and the reason we are talking about such a device, is that a potato cannon can launch a potato about 500 feet through the air! There is a huge amount of energy in a tiny drop of gasoline. The potato cannon uses the basic principle behind any reciprocating internal combustion engine: If you put a tiny amount of high-energy fuel (like gasoline) in a small, enclosed space and ignite it, an incredible amount of energy is released in the form of expanding gas. You can use that energy to propel a potato 500 feet. In this case, the energy is translated into potato motion. You can also use it for more interesting purposes. For example, if you can create a cycle that allows you to set off explosions like this hundreds of times per minute, and if you can harness that energy in a useful way, what you have is the core of a car engine! Almost all cars currently use what is called a four-stroke combustion cycle to convert gasoline into motion. The four-stroke approach is also known as the Otto cycle, in honor of Nikolaus Otto, who invented it in 1867. A device called a piston replaces the potato in the potato c...