 Physics - Hydraulics 3
It is extremely difficult to limit the application of hydraulics to the automotive sector only. In the chapter Hydraulics 1 we have assumed construction necessities after the war. Now we will look at where liquids are
everywhere in the vehicle and which are added.
This is important, for example, when scrapping a vehicle. The various oils from the engine, gearbox and axle drive are then drained and disposed of separately. In addition, other components may contain oil, e.g. the
steering system with hydraulic support (pictures above) and in any case the dampers (picture below).
The ways are quite long, after which in the meantime the coolant must be pursued (picture of a bus below). It may also have to be disposed of by adding antifreeze, sealing agents added later and those that make leaks
visible. This is certainly the case for refrigerants.
Then there is, of course, the tank and with it the injection system (picture below), where at least the fuel filter contains a larger quantity. We almost forgot the brake system, whose fluid has to be collected separately from
the oil in any case, because it is easy to recycle in this way.
We already mentioned the hydrodynamics of the engine oil (picture below) at the crankshaft. It occurs hydrostatically with clear control characteristics in the engine control system. Its separation from the combustion
pressure penetrating into the crankcase is also a challenge.
Oil in the automatic transmission is probably by far the most similar to a normal hydraulic system. There is a reservoir from which it is pumped, a lot of control valves (picture below), combined with clutches, which in the
meantime already produce a variable frictional connection. In the past, automatic transmissions even worked completely without electronics.
One should not forget to explain the torque converter (picture of the city bus below), which is rightly called 'hydrodynamic'. But also a lonely rear axle, highly loaded by enormous engine torque, can be interesting, if there
is an oil cooler above it, whose flow is not guaranteed by a pump, but by gear wheels, which spin oil under pressure into specially designed pockets.
The pictures at the top show important parts of the hydraulic power steering, where the control module at the entrance of the steering column and the pressure support for the respective steering direction really become
clear. The shock absorber is available for different deep hydraulics. In the simplest case it is its own pump due to the movements of the body, which e.g. ensures a changed spring height of the rear axle when loading.
And then it continues via a magnetizable liquid (picture above) or various valves. It is possible to harden such a damping even in the cycle of milliseconds. For some owners, it only becomes interesting when the vehicle
either squats close to the ground or begins a wild dance. These are the forerunners of the electric cars because of the high amount of energy required.
No, it is difficult to find an end here, as there are extendable supports (also in two directions) for crane vehicles and e.g. mobile homes. Then their owners don't need to find any extra horizontally aligned places
more to look for. Today, however, brake hydraulics are particularly close to every car, almost invisible, but with great effect, now also on the suspension. By the way, here the manufacturers are proud to become more
compact with almost every new generation.
| Rally cars save time with built-in jacks. |
Was that all to mention? Certainly not, although we are deliberately holding up an example from agriculture and one from the truck sector for later. In the meantime there have even been studies on the resistances with
which coolant flows through the engine, especially when pumps become electric and every kW counts.
| 
