Vehicles in the upper-class range can obviously, no longer do without it. Electronics have also found their way into the cooling. They are necessary in too many components and sub-assemblies. Due to the power consumers used, the power demands grow, which makes the, nearly 3 kw, liquid-cooled generator necessary. A fundamental regulation is necessary, e.g., the subdivision into two cooling systems running at different temperature levels. In addition, two suitable radiators of differing sizes and all the other systems, deliver their heat to one of the two circulations.
How it works
There is already equipment without belt-driven waterpumps. In this case however, once again, a conventional set-up, with a high temperature circulation, which works quite normally together with the thermostat - an electronically regulated unit would be also possible. More interesting still, is the interior heating, which can be switched on- and off separately through the electronic pump (3). Thereby, also cooling the re-circulated exhaust gas (6). In addition, one also finds the electronic pump (2), which is only actuated if engine damage is threatened through residual heat after switching off the engine. It pumps in the opposite to normal direction of flow so long, until the engine has reached a safe temperature. With a running engine this control, through the check valve (7), plays no part.
The low temperature range is connected with the other only through the reservoir tank. Here the generator (4) and the fuel (5) are cooled. In this case, the electronics can can only rely on the generator and switch on the electronic pump (1) accordingly. A few degrees difference either way, makes no difference to the fuel. All together, a part of the engine control unit is of course, reserved here for the cooling. Some sensors, which are not shown here, also belong to this system, with the advantage that the systems interact with each other. Should e.g., the generator be overheated, the dash board control device can then reduce the power consumption.
Advantages of the electronic cooling system
No cooling effect after a cold start.
Power yield only when required.
Mostly low energy consumption.
Position independent from drive.
Residual heat exploitation possible.
Avoidance of Residual heat build-up.
To a large extent free from wear-and-tear.
Fully integrated in the engine management.
Disadvantages of the electronic cooling system
Expensive to manufacture.
There is a maximum performance limit.
At full capacity an unfavourable efficiency factor.
The massive amount of electronics installed, also in the cooling system, does have consequences. Then, how can one change the coolant or air-bleed the system, if one cannot be sure that all the electrically controlled valves are open? Consequence: Connection of testers/computers, and from the menu, selection of "coolant change". 09/09