Internal-combustion engines – High tension ignition system – Having dwell control
Reexamination Certificate
2002-01-18
2003-07-22
Solis, Erick (Department: 3747)
Internal-combustion engines
High tension ignition system
Having dwell control
C123S406580, C123S406600
Reexamination Certificate
active
06595192
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an ignition control device as well as to a corresponding ignition control method.
Although it is applicable to any ignition control system, the present invention is discussed with respect to an engine control unit that is located on board a motor vehicle.
BACKGROUND INFORMATION
Ignition control devices for controlling ignition events for coil ignition systems and devices have essentially two control functions: controlling a desired ignition power over the duration of connection, i.e., the duration of the charging of the ignition coil; and controlling an ignition pulse over the duration of disconnection, i.e., the termination of charging of the coil, using a correct angle.
The ignition power, which in coil ignition systems is metered over a charging time of the coil, is of varying magnitude in accordance with the vehicle system voltage applied to the electrical circuit of the coil and with the time constant of the electrical circuit.
Usually, the specific setpoint values are stored in the control unit as a characteristics field, as a function of the rotational speed and other possible engine parameters.
Conventional ignition control methods are designed for a specific control unit for a specific engine or a specific automobile manufacturer.
If an ignition control device is to be designed for a control unit platform that can be used in any SI engine in accordance with the control and regulation requirements of any customer, then new demands arise for the ignition control method in question.
Conventional ignition output has a substantially self-sufficient operation. An attempt is made to process as much information as possible in the ignition output in parallel and independently, so as to obtain the greatest possible degree of dynamic impact and output precision. For example, a separate rotational speed measurement for the ignition output is customary, being as close as possible, in terms of the angle, to the ignition event, in order to keep the error in the necessary prediction of the rotational angle curve in the dynamic as small as possible. In addition, an attempt is made to calculate the ignition events individually for each cylinder, to the greatest extent possible in parallel fashion.
For example, if it is detected that, due to the advances in the ignition events, the measuring location of the angular velocity must also be shifted, then this shift must be carried out only once and does not have an effect on the calculation of the ignition events for the other cylinders. If an engine control system cannot calculate all of the cylinders individually, for example due to lack of resources, then the attempt is made to form at least one group of cylinders that are similar within the engine.
For an ignition system that is designed for a platform, this method is very expensive, especially in terms of hardware resources. Ignition control systems that require reduced computing expense show that dynamic errors can be sufficiently compensated for by dynamic derivative actions with regard to the ignition angle or the dwell time.
Ignition methods having their own calculation chains avoid application expense, but use more hardware resources, and they also require, depending on the computing architecture, longer job execution times. A further point which characterizes many of the ignition outputs used today is that their output signals are usually fixedly assigned to specific hardware outputs. A method of this type makes project configuration cumbersome when the method is used in a control platform.
Furthermore, a very few ignition output methods check the mixture state of the cylinder that is to be fired. In the new generations of engines, which use plastic intake pipes, the problem of induction pipe explosions has arisen in various ways. This problem can be minimized by first igniting cylinders that are filled in a defined manner.
Therefore, an ignition method has heretofore been lacking that can service as many cylinders as possible using minimal hardware/controller resources, that can easily be configured in accordance with target hardware, and that can be controlled by the injection system.
For outputting angle signals, conventional control units use an angle transmitter wheel, which delivers to the ignition control device pulses that are equidistant in terms of angle. However, for reasons of computational job execution times, the calculation of the ignition events can only take place in most ignition control device architectures in segments, one segment being the angular interval of 720° of the crankshaft divided by the number of cylinders, i.e., in a four-cylinder engine, for example, 180°. Therefore, although the angular positions of the ignition events ascertained in the calculation are measured sufficiently precisely via the angle transmitter wheel and the timer/counter circuits that are customary in the ignition control devices, nevertheless the calculation itself proceeds on the basis of a measured rotational speed, which in a rotational speed dynamic is no longer present at the location of ignition.
SUMMARY OF THE INVENTION
Thus, it is desirable to design an ignition control device for the output of ignition events that is able to operate in overall engine control system, which can be used in the greatest possible number of system environments and under the most varied possible system conditions.
Because only a limited framework for control components is available at any one time (e.g., interrupt channels on a predefined controller) for reasons of cost optimization, the device and the method should be able to be realized at a minimal expense, above all with respect to hardware resources. The design of the ignition control method should be modular to the greatest extent possible in order to be able to adjust the ignition control method to various control variants as simply as possible.
The ignition control device according to the present invention has the advantage, with respect to the conventional approaches to the problem, that the design of the ignition control method incorporates the results of analysis of a multiplicity of engine variants. In comparison to the current ignition control methods, the designed ignition output is simpler, more capable of being configured, requires fewer resources, and has clearly defined interfaces, through which the other engine control functions can interact with the ignition output. In particular, the potential interaction with the injection output makes it possible to address the problem of induction pipe backfiring at 0 rotational speed and the problem of uneven starting.
In contrast to the technically current ignition output methods, the described ignition output interacts with other devices for the output of hardware events. In this case, one especially favorable interaction is, for example, querying the status of the injection. In this context, the injection system supplies to the ignition output the information that a defined filling of a cylinder with fuel has taken place. Subsequently, the ignition system will fire this cylinder as a first ignition.
Current ignition outputs begin with the ignition irrespective of the mixture state when the beginning of a 360 degree interval is detected or when simultaneous cylinder detection occurs. In this context, the ignition takes place in undefined mixture states. For example, if a too-lean mixture is ignited, this can result in delayed combustions and in the worst case, even in an explosion of the induction pipe. Furthermore, given a rich mixture, it is possible for the engine to run-up unevenly as a result of pronounced buildup of film on the walls in the induction pipe, which has a disturbing effect on the driving sensitivity, but also potentially on the introduction of exhaust gas reactions.
Conventional technical ignition output methods are not designed with a view to outputting different output patterns simultaneously. Usually, information as to which hardware channels are to be activated in an ignition is fixedly bound to the hardw
Friedmann Harry
Haussmann Martin
Kenyon & Kenyon
Robert & Bosch GmbH
Solis Erick
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