Robert Boschgmbh

Helmut Roth

Gerhard Sohner

Bernd Bodig

Peter Werner

Werner Jundt

Walter Ruf

Hartmut G Brammer

Richard Schleupen

Peter Jurgen Schmidt

Hartmut Michel

Herman Roozenbeek

Gerd Hohne

Gunther Berger

Dieter Neuhaus

Erich Jesse

Karl-Heinz Nubel

Hans Linstedt

Reinhold Herzog

Gert Strelow

Gotz Bundschuh

A protective case (13) for a vehicle ignition system covers both the ignition coil (5), an electronic control device (6), and the terminals (11) and connecting conductors (12) therebetween. The preferred material is plastic, with an electromagnetically conducting coating for screening against incoming and outing electromagnetic noise. Thus, protection is provided against mechanical, chemical, and electromagnetic environmental influences. The case is dimensioned to snap over and seal respective edges of the electronic control device (6), the ignition coil (5) and its core (8), the electrical terminals (11), and the interconnecting conductors (12). The case is bifurcated along an access slit (16) which is secured in a normally closed position by knob (15) which press-fits into a mating hole on the other side of the slit. Two sides of the case have curved ridges or dimples which provide flexibility to hinge the case open for insertion of the ignition coil (5) and electronic control device (6).

Protective case for combination ignition coil and electronic control

A safety device is included in a circuit comprising a power source and a user device. The power source has one terminal connected to ground, as does the user device, with the safety device connected in a conducting path leading to the ground in the user device. In the event of an incorrect polarity connection between the power source and user device, a current path through the safety device and to ground is established.

Safety device for a conducting path in a load device

A cutting tool arrangement for a nibbler, wherein a support shaft with a cutting head is arranged for reciprocating movement relatively to a die, has the support shaft including an elongated portion, a narrowing portion and an end portion. The cutting head formed as a sleeve-shaped element surrounds the end portion of the shaft and a lower part of the narrowing portion of the shaft and is soldered thereto to prevent fatigue concentration stresses in a transition zone between the narrowing portion of the shaft and the cutting head.

Cutting tool arrangement

A transistorized ignition system is protected against interruption of power supply by, for example, turn-off of the main or ignition switch while the transistor is in conductive condition so that, upon sudden interruption, an ignition event could be triggered at a time unsuitable for the remainder of the engine. A turn-off protection circuit is provided which includes a coupling resistor connected to the junction of the primary of the ignition coil and the main ignition current supply transistor thereto. The coupling resistor is connected in a circuit which holds the main current supply transistor in conductive condition, supplied from the energy stored in the ignition coil even after the main, ignition switch has been opened. A closed circuit for current flow due to this stored energy is provided within the overall ignition circuit. Preferably, the system includes a coupling transistor, connected across the power supply, which is blocked when the main transistor is conductive, so that the main transistor is controlled by power supply voltage appearing at the collector of the coupling transistor; the coupling resistor of the turn-off protected circuit then applies the inductive voltage from the coil to the collector terminal of the coupling transistor, and hence simulates continued power supply to the main current supply transistor to continue to hold it conductive and thus prevent abrupt turn-off and initiation of an undesired ignition event.

Turn-off protected ignition system for internal combustion engines

To provide for gradual turn-off of an ignition coil current control transistor, a control capacitor which provides turn-off current has its charge state changed gradually by means of an auxiliary transistor so connected to the capacitor that the conduction of the emitter-collector path of the auxiliary transistor is gradually changed, the main switching transistor being connected to and controlled by the auxiliary transistor and likewise changing gradually from conductive to blocking state in dependence on the gradual change in conduction of the emitter-collector path of the auxiliary transistor to prevent rapid turn-off of the main switching transistor and hence an undesired pulse at the secondary of the ignition coil which may induce continued operation of the internal combustion engine even though the ignition has been turned off.

Transistorized ignition system for internal combustion engines

Current flow to the ignition coil during low-speed operation of the engine, is controlled by an auxiliary control switch which is connected in shunt with the primary of the ignition coil. Serially connected with the primary is a main control switch which is controlled to close until current through the primary has reached a certain value, at which time the main switch opens and the shunt auxiliary switch is closed to permit continued inductive current flow through the coil and thus store ignition energy, the cycle repeating to maintain current flow through the primary at a level to store sufficient energy for the ignition spark which, at the ignition instant, effects opening of the shunt circuit by opening the auxiliary switch while also opening the circuit to the primary, thus providing a high-voltage pulse which provides for sparking of the spark plug. The sensor for current flow through the primary is preferably a resistor which, when the voltage drop thereacross exceeds a predetermined level, controls changeover of a transistor.

Ignition system for internal combustion engine

To prevent generation of a spurious spark at the spark plug if the distributor braker control assembly should have commanded an ignition control transistor to be conductive and when the ignition switch is disconnected under those conditions, thus cutting off power to the ignition control transistor rendering it non-conductive and causing spurious voltage pulses which results in a spark at the ignition, a control path is provided connected to a control transistor for the actual ignition transistor and connected in circuit with the current flow due to the energy stored in the ignition coil to control the emitter-collector path of the ignition switching transistor to continue to remain conductive for a short period of time to drain off the stored energy in the coil, although the main ignition switch has been opened.

Internal combustion engine semi-conductor ignition control system

To prevent a spurious inductive spark when the master ignition switch of the vehicle is opened with the breaker terminals closed, so that current stored in the ignition coil might cause a spurious inductive voltage pulse, a protective circuit branch is connected in parallel across the primary of the ignition coil and includes an auxiliary semiconductor short-circuiting switch, preferably a thyristor, the conduction of which is controlled to close by an auxiliary control circuit which senses opening of the master ignition switch and permits application of a portion of the inductive current flow to the gate of the thyristor to render it conductive, thus short-circuiting the primary of the ignition coil and preventing an inductive voltage kick which might cause a spurious spark.

Protective circuit for the ignition system of an internal combustion

To improve the operation of semiconductor control ignition systems under widely varying supply voltage conditions, a voltage divider having a division tap point is connected in parallel to the main switching part of the switching transistor of the ignition system, and a voltage breakdown element, typically a Zener diode is connected from the tap point to the control electrodes of the semiconductor switch to provide an additional control voltage thereto if the voltage at the tap point exceeds a value leading to breakdown of the breakdown device (Zener diode); the main control circuit for the main ignition transistor may be conventional.

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Stuttgart, Germany

Helmut Roth