 Working procedures
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There are repeated attempts to convert the conventional piston engine into one with external combustion. One such possibility exists with the Stirling engine, although it also exists with internal combustion.
This process has been brought back into use due to its higher efficiency. It uses the difference between heated and cooled space to extract kinetic energy.
As mentioned, the two chambers can be arranged side by side or one inside the other. The former arrangement requires two cylinders, the latter a more complex crankshaft. However, this engine design has
not yet been able to establish itself in motor vehicles, either due to high costs and low performance or poor control characteristics.
Engines could initially be classified according to their working procesdure. If we define the cycle as half a crankshaft revolution, a working cycle can occur in two or four strokes and repeat cyclically. A working
cycle is the complete process, including the exchange of old gas for fresh gas, compression, ignition, and the particularly important expansion of the latter.
The fuel required for operation is also important for a piston engine. Here, a distinction must be made between the fundamentally possible fuel types with which a particular engine can operate, with or without
major modifications. The former are divided into gaseous and liquid fuels, although every fuel must, of course, be in a gaseous state immediately before combustion.
From now on, the order of the categories becomes rather random. If we next consider the type of control of the incoming and outgoing gases, this can be achieved by valves, slides, slots, or diaphragms. The
sliders can release openings by turning or lifting. Valves don't necessarily have to be opened by cams; slots are more likely to be opened by the piston, rotary/longitudinal slides, and diaphragms. The latter act
like air nonreturn valves (two-stroke engines).
If we now focus briefly on the reciprocating piston engine, the design is of course interesting. In addition to the inline, boxer, and V-engines, the VR or W engines must be mentioned. But don't forget other
designs, where, for example, two crankshafts move pistons in the same cylinder toward and away from each other. In this way, even three crankshafts are possible.
And even if it's a radial engine, where an odd number of pistons and their connecting rods access a rotating crankshaft. Here, too, a second star can be placed on gap behind the first one. Or consider an air conditioning
compressor, whose pistons move up and down in a rotating drum.
If you think a reciprocating piston engine fundamentally requires a crank drive, we regret to disappoint you. It can do without one if it generates pressure at its bottom or at a second piston connected to it. This also makes it
possible to power a vehicle. Instead of hydraulic or pneumatic pressure, it could also be powered by electricity.
Turbocharging distinguishes it from naturally aspirated engines. Turbocharging itself is divided into mechanical and exhaust-driven engines, perhaps combined with an electric motor/generator. Of course, there are many
combinations of both, but the Comprex turbocharger, powered directly by exhaust gases and with almost no loss of efficiency, is also worth mentioning here.
Turbocharging distinguishes them from naturally aspirated engines. Turbocharging itself is divided into mechanical and exhaust-driven, perhaps combined with an electric motor/generator. Of course, there are many
combinations of both, but the Comprex turbocharger, powered directly by exhaust gases and with almost no loss of efficiency, is also worth mentioning here.
Even distinguishing between diesel and gasoline engines isn't quite so simple anymore. If you refer to the presence of an externally-supplied ignition, you're on the safe side. In testing, there are gasoline engines that
operate with self-ignition in certain operating ranges. And direct injection has long since ceased to be the domain of diesel engines.
In the past, diesel engines were clearly quality-controlled, meaning fuel injection was intensified when accelerating. Gasoline engines were accordingly regulated by quantity, meaning they received more air and the
corresponding amount of fuel. But who knows about the crude characteristics of an engine management system, especially when it comes to stratified charge?
In the past, diesel engines were clearly quality-controlled, meaning fuel injection was intensified when accelerating. Gasoline engines were accordingly regulated by quantity, meaning they received more air and the
corresponding amount of fuel. But who knows about the crude characteristics of an engine management system, especially when it comes to stratified charge?
Oh yes, we almost forgot about cooling. Of course, you're familiar with air and liquid cooling, and you even know that both are thermostatically adjustable. With the former, the fan can be replaced by airflow. But are you
familiar with pure oil cooling? Here, engine oil handles all the heat transfer. Of course, as with liquid cooling, there's always a bit of air cooling involved.
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