DE3923487A1 - METHOD FOR CONTROLLING ACTUATORS - Google Patents

Description

The invention relates to a method for controlling Actuators in displacement machines, in particular from A injection pumps, valves or flat slides in internal combustion engines that sequence through electromagnetic excitation or de-excitation be operated.

In the case of displacement machines, an adaptable control system is required Inflow and outflow of the working medium required to the Ar processing process according to the respectively required criteria to be able to influence optimally. The control sequence has great influence on various parameters, for example the conditions of the working medium before, in and after the work area, the working frequency and the processes in the work area. The need adaptability of the control is particularly important for Internal combustion engines given that they are very different Operating states work transiently and one accordingly variable positive control of the gas exchange valves is advantageous.

To control the gas exchange valves in internal combustion engines previously mainly used camshafts. A variable Control is only possible with very high technical effort Lich. In addition there are electromagnetic controls of gas exchange valves on internal combustion engines have become known, in which the Closing force applied to the gas exchange valve by a spring while the opening forces are actuated accordingly erten electromagnets are generated, such as in DE-OS 20 63 158 is described.

In the case of machines of this type, circuit arrangements are to be controlled necessary from several similar actuators, the  one after the other in time with the combustion cycles of the individual cylinders which are controlled. In conventional circuits, Sig nale at most on the small signal side with the help of the multiplex technology passed on; For each actuator, a demul tiplex process uses a separate power amplifier. At expensive built output stages with current control devices, clocking However, the lungs and impact detection of magnetic armatures increase Effort in the order of magnitude, with a larger number of Actuators is no longer economical.

Each of these actuators is usually replaced by a separate one Circuit controlled. However, once it is ensured that from not more than one actuator at the same time is controlled, a common connection can be made for these actuators control circuit can be used. This is desirable because of this the total amount of components can be significantly reduced.

The object of the invention is a method for controlling actuating divide into displacement machines to create that despite spending energy-optimal power amplifiers with less equipment wall gets along and is therefore also inexpensive.

This is because of a method of the type described in the introduction achieved by each actuator that the excitation current of one Power amplifier is supplied via a switching element, which each selects the actuator to be operated.

This means that the problem of controlling the rich term actuator is solved in that each actuator Switch element is assigned, via which the selection of a certain th actuator is possible.

According to a preferred embodiment it is provided that the Supply of current to the actuators via each one Actuator assigned thyristor is provided, provided can be that only one thyristor is switched through.  

According to a further preferred embodiment, that in the presence of several amplifiers and several Schaltele If one output stage fails, control by another right output stage is also taken over.

Embodiments of the invention are based on the drawings explained in more detail.

Fig. 1 shows in the diagram the current profile for four actuators as a function of time.

Fig. 2 shows a circuit for performing the method according to the invention.

Fig. 3 shows a circuit arrangement which enables redundancy in the control of the actuators.

In Fig. 1 it is shown how four actuators are sequentially controlled or acted upon depending on the time t with the currents I 1 , I 2 , I 3 and I 4 , I 5 representing the total current over time.

In Fig. 2, a circuit is shown in the four electromagnetic consumers 1 , 2 , 3 and 4 , for example switching magnets for each actuator, via a common, the current flow influencing circuit 12 , hereinafter referred to as the final stage, offset in time can be controlled. The type of circuit is symbolically indicated by a transistor 5 . The regulation of the current flowing to the consumers 1-4 takes place in the final stage 12 , the type of regulation being irrelevant.

The distribution of the current flow to the consumers 1-4 takes place in a multiplexer 11 , which has switching elements 6 , 7 , 8 and 9 , which are controlled by a control circuit 10 according to the working cycle of the internal combustion engine. It goes without saying that the arrangement of transistor and Thy ristor with actuator can also be interchanged.

If several of the circuits shown in FIG. 2 are present, redundancy can also be achieved by means of a suitable combination, so that if one of the transistors fails, the other transistor or transistors take over its task.

A circuit arrangement of this type is shown in FIG. 3. There are two output stages 31 and 32 , to which multiplexers 33 , 34 , 35 and 36 are assigned. In the normal case, output stage 31 controls consumer group 37 via multiplexer 33 , while output stage 32 controls consumer group 38 via multiplexer 36 .

In the event of a fault in output stage 31 , output stage 32 takes over the function of output stage 31 via multiplexer 34 and, in addition to consumer group 37, also controls consumer group 38 . There is a shorter period of time available for every consumer. However, this is unproblematic in most cases, since unrestricted operation is no longer possible, but e.g. B. in the case of the control of injection valves of motor vehicle engines still good emergency running properties who achieved the.

Even with circuit arrangements of the type shown in Fig. 3, there is a significant cost advantage over the use of eight separate power amplifiers that would be required to achieve redundancy in a conventional manner.

Claims (4)

1. A method for actuating actuators in Verdrängungsma machines, in particular injection pumps, valves or flat valves in internal combustion engines, which are actuated sequentially by electromagnetic excitation or de-excitation, characterized in that each actuator is supplied with the excitation current from a common output stage via a switching element , which ches the actuator to be selected in each case. 2. The method according to claim 1, characterized in that the zu routing the current to the actuators via each Actuator assigned thyristor takes place. 3. The method according to claim 2, characterized in that in each case only one thyristor is switched through. 4. The method according to any one of claims 1-3, characterized net that in the presence of several amplifiers and several Switching elements in the event of a power stage failure another power amplifier is also taken over.