In an age where we have begun to embrace the electric car as the new future of transportation, I think it's important to remember that most of the population will continue to drive Internal Combustion Engine (ICE) vehicles for quite some time. I love the new all electric car technology, but I think that a lot of respect is still due for the brilliant engineering and science that has brought the automobile to the place it is today. I'm going to discuss in a series of articles the wonder of the ICE vehicle that most of us enjoy driving.
In essence, the start of the vehicle is the idea of making fire. The key is turned, and BOOM...you have fire! (Hopefully! If you don't, call us). The key thing about it though, is that it is a series of very controlled fires created in rapid succession. In short, explosions. However, purists refer to it as a 'burn'.This is because the compressed mix is lit by a spark on one end and the flame travels through the space creating rapid expansion. Granted, I'm not telling you anything you don't know, but bear with me, I promise it will get better.
The first steps of the technology was to harness this into a power that can be used. First, the engine has to take in a measured amount of fuel and air, momentarily seal it up in a can, compress it, then light it in a matter of milliseconds. Then, it must get rid of the burnt soot and do it again. There are a lot of other factors that come into play to keep an engine running properly, but the combustion part is the key to the energy that is used to drive the wheels. This is the part that is being replaced by electric motors that drive the wheels in electric cars. Therefore, to truly respect the technology that has come into play, we should compare the source of power and how it's used.
Early engines began the process in the carburetor. It's honestly been so long since I've used that word that I had to spellcheck it! Anyhow, the simplified explanation of it's mechanical function is this:
a circular hole with little spray nozzles for fuel and a flap mechanically opened and closed by a lever. The lever is controlled by the throttle pedal through a linked mechanical cable. Fuel lines attach to the nozzles. Air is drawn in by vacuum created by a piston drawn down inside a cylinder. (Think syringe). In the early Ford Model A, the draw down was done by a crank that you would stick in the front to turn the shaft that the piston is attached to. The first advancement there was a electric starter that gave it a turn. Inspite of many modifications, that starter design is still in use today.
Just past the carburetor, is the intake manifold. This is a hallway to 4, 6 or 8 doors depending on the number of cylinders. The doorways are opened and closed by valves. The intake manifold also determines the volume of air being mixed with the fuel going into the cylinder. In early vehicles, this was a less than specific calclulation. Today, it's very precisely measured.
Once the fuel/air mix passes through the door into the room, (the cylinder), the valve closes the door behind it. Then the piston inside the cylinder rises up and tightly compresses the mix. At the top of the cylinder, is the spark plug tip. Once the air/fuel mix is tightly compressed, the spark plug ...sparks. The flame passes through and expands, pushing the piston back down the cylinder. This is the power that drives a shaft that the piston is attached to. That shaft connects to a shaft in the transmission. That connects to the driveshaft, and that connects to axles that drive the wheels. Power from a spark, fuel/air mix and compression.
Back inside the cylinder, the burnt leftovers from the mix are still hanging out. Since the other cylinders are going through the same process in a timed succession, and are attached to the same shaft, the piston is rising back up the cylinder. Since we need to get rid of that stuff, a back door is there with a valve to open it and let the burnt stuff out. Exhaust. When the piston reaches the top, the door closes and the piston begins to draw down again. The intake valve opens it's door and the process begins again.
Due to the non-specific calculations on early engines, quite a bit of material remained in the burnt air that went out the exhaust. The tailpipes blew out plumes of black smoke because the fuel was only partially burnt. In most cases, less that 50% of the fuel that went into the engine actually burned and created power. The rest was charred and spit out the tail pipe as a carbon cloud. Very inefficient and extremely bad for the environment.
Unfortunately, the early car manufacturers weren't really aware of this. Once science stepped in and revealed this, the race to both reduce the emissions (exhaust) and increase fuel efficiency began. Once mankind realized that this engine was wasting fossil fuels, polluting the environment and not really working efficiently, the drive to create the technology began. Believe it or not, it is a cooler journey than even the evolution of the phone. We are so fascinated by the tech in our hands that we often give little thought to the amazing technology that carries us around everyday.
Stay tuned for the next part where we will begin to break down where the tech in engines began, what it does, and why it makes a difference.
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Erik and Jennifer are the owner/operators of Mobile Service Pros. We enjoy working with our customers and community.