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Pulse-valve (distributor injection pump)
This is an example from the phase in which the automobile industry changed over from mechanical/hydraulic controlling, to electronic controlling. Solutions were found, which could be quickly intergrated into components, without having to completely reconstruct them.
The puzzle solution shows the lower part of a distributor injection pump, which has been cut away, so that the injection adjustment piston and the pulse-valve can be seen. The injection adjustment twists the roller-ring
of the axial piston pump, thus altering the injection timing (beginning of delivery) e.g., at higher RPMs, in the direction of 'advance'. Before the electronics came into play, this was done through the increasing internal
pressure in the pump moving the piston (see picture on the right) against a spring.
To adjust the piston through electronic control, the pulse-valve (see picture on the left) was afterwards built in. This now controlled the pressure, (through a so-called duty-cycle) by supplying it with tension at very short
time intervals (shorter than 100 ms) according to the desired flow rate. Because it was too inert to follow the respective impulse completely, it opened the flow-line according to the timing. The result was: One could
electronically influence an important parameter of the Diesel injection - namely the fuel injection timing - without having to produce a completely new construction. 01/11
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