Method for controlling an internal combustion engine and ignition control device for such a method

Abstract

Described is a method for controlling an internal combustion engine, wherein an ignition control device is prompted by control signals of an engine control device to activate an ignition device by means of which an ignition of a fuel-air mixture in a cylinder of the internal combustion engine is affected. It is provided according to this disclosure, that the engine control device communicates a target ignition angle or information about an operating condition of the internal combustion engine to the ignition control device, and the ignition control device sets an operating parameter of the ignition device in dependence on the target ignition angle or the information about the operating condition of the internal combustion engine.

Claims

1. A method for controlling an internal combustion engine in which an engine control device communicates control signals to prompt an ignition control device to activate an ignition device, the activation of the ignition device effecting a fuel-air mixture in a cylinder of the internal combustion engine, the method comprising: the engine control device communicating a target ignition angle or information about an operating condition of the internal combustion engine to the ignition control device; the ignition control device setting an operating parameter of the ignition device as a function of the target ignition angle or as a function of the information about the operating condition of the internal combustion engine; and wherein the operating parameter of the ignition device is a variable non-zero magnitude of a primary voltage of the ignition device which is supplied to the ignition device from a voltage transformer.

2. The method according to claim 1, wherein the operating parameter is set by means of a characteristic curve or a characteristic map.

3. A method for controlling an internal combustion engine in which an engine control device communicates control signals to prompt an ignition control device to activate an ignition device, the activation of the ignition device effecting a fuel-air mixture in a cylinder of the internal combustion engine, the method comprising: the engine control device communicating a target ignition angle or information about an operating condition of the internal combustion engine to the ignition control device; the ignition control device setting an operating parameter of the ignition device as a function of the target ignition angle or as a function of the information about the operating condition of the internal combustion engine; and wherein the engine control device generates an edge of a pulse of the control signals in successive engine cycles at the same crankshaft angle, and the current crankshaft angle is communicated to the ignition control device through this edge.

4. A method for controlling an internal combustion engine in which an engine control device communicates control signals to prompt an ignition control device to activate an ignition device, the activation of the ignition device effecting a fuel-air mixture in a cylinder of the internal combustion engine, the method comprising: the engine control device communicating a target ignition angle or information about an operating condition of the internal combustion engine to the ignition control device; the ignition control device setting an operating parameter of the ignition device as a function of the target ignition angle or as a function of the information about the operating condition of the internal combustion engine; and wherein the control signals in an engine cycle are transmitted as a pulse sequence of at least two pulses including a first pulse and a second pulse wherein the first and second pulses each define a leading edge and a trailing edge with the leading edge of the first pulse defining a first edge, the trailing edge of the first pulse defining a second edge, the leading edge of the second pulse defining a third edge and the trailing edge of the second pulse defining a fourth edge; the third edge defining for how long the ignition device is to be activated.

5. The method according to claim 4, wherein a portion of the pulse sequence, in dependence of which the ignition control device sets the operating parameter of the ignition device, indicates a target ignition angle of the crankshaft or information on the operating condition of the internal combustion engine.

6. The method according to claim 4, wherein the ignition control device determines the current crankshaft angle from a portion of the pulse sequence.

7. The method according to claim 3 wherein the ignition control device determines a speed of the engine from control signals for different cylinders of the internal combustion engine by evaluating the time delay between the edges which correspond to a defined crankshaft angle for the different cylinders.

8. The method according to claim 1, wherein the fuel-air mixture is ignited by the ignition device by means of a corona discharge.

9. The method according to claim 1, wherein the ignition control device has a separate input for each cylinder of the internal combustion engine and receives control signals for the respective cylinder via this input.

10. The method of claim 4 wherein the fourth edge defines when the ignition device is triggered.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above-mentioned aspects of exemplary embodiments will become more apparent and will be better understood by reference to the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 shows a schematic illustration of a control system of an internal combustion engine; and

(3) FIG. 2 shows a sequence of control signals for different cylinders of an internal combustion engine.

DESCRIPTION

(4) The embodiments described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of this disclosure.

(5) FIG. 1 schematically illustrates a system for controlling the ignition activity of an internal combustion engine, which can be a gasoline engine, for example. This system includes an engine control device 1, an ignition control device 2 and an ignition device 3 for each cylinder of the internal combustion engine. The engine control device 1 transmits control signals to the ignition control device 2, which signals prompt the ignition control device 2 to activate the ignition devices 3.

(6) In such a system, a separate line 4 from the engine control device 1 to the ignition control device 2 can be provided for each cylinder of the internal combustion engine, as illustrated in FIG. 1. Each of the lines 4 between the engine control device 1 and the ignition control device 2 thus transmits only control signals for a single cylinder of the combustion engine which is associated with the respective line 4.

(7) FIG. 2 illustrates an example for control signals on the individual lines 4 between the engine control device 1 and the ignition control device 2. FIG. 2 shows the voltage level applied to the individual lines 4, in each case as a function of the crankshaft angle of the internal combustion engine. A binary signal is transmitted via the lines 4 so that a differentiation is made only between high and low voltage levels. The firing order of the example shown is 1-5-3-6-2-4, wherein the six illustrated signal paths belong consecutively from top to bottom to the first to the sixth cylinder.

(8) As shown in FIG. 2, the control signals transmitted on the lines 4 are pulse sequences, each of which consist of a plurality of pulses. In the example shown, each pulse sequence consists of two pulses. However, sequences having more than two pulses can also be used as control signals.

(9) The ignition control device 2 sets an operating parameter of the ignition device in dependence on a portion of the pulse sequence and determines the time of activation of the ignition device 3 from a further portion of the pulse sequence.

(10) In the example shown in FIG. 2, the first edge of the signal sequence lies at a crankshaft angle of 100° before the top dead center of the ignition. Thus, by evaluating the position of the first edge of the control signals for the different cylinders, the ignition control device 2 can calculate the current speed of the engine, for example from the time difference of the first edges of control signals for two cylinders which are in immediate succession in the firing order of the engine. However, any other edge of the control signal can be used instead of the first edge in order to mark a constant crankshaft angle.

(11) The second edge or a subsequent edge of the pulse sequence indicates the ignition angle at which an ignition is set to take place, thus communicates a target ignition angle to the ignition control device 2. The ignition control device 2 then sets, in dependence on the target ignition angle, one or more operating parameters of the respective ignition device 3, for example by means of a characteristic curve or a characteristic map. The ignition control device 2 can set, for example, a primary voltage of the ignition device 3, which is supplied to the ignition device 3. The primary voltage of an ignition device 3, for example of a corona ignition device, can be generated from an on-board voltage of the vehicle by means of a voltage transformer. Further operating parameters of a corona ignition device which can be set in dependence on the target ignition angle are frequency or impedance, for example.

(12) The third edge of the signal sequence can indicate, for example, for how long the ignition device is to be activated, thus, for example, for how long a corona discharge is to be generated with a corona ignition device or for how long an arc discharge is to be generated with a conventional spark plug. The fourth edge of the signal sequence can be used to trigger activation of the ignition device 3.

(13) The ignition control device 2 can be additionally connected to the engine control device 1 via a data line 5, for example via a CAN bus. Through this data line 5, the engine control device 1 can also communicate data on the current engine operating condition to the ignition control device 2. However, updating via a CAN bus is possible only in relatively large time intervals so that engine operating data transmitted at high speeds via the data line 5 are not always current, and transmission via the lines 4 is therefore advantageous. If the ignition control device 2 receives data form two transmission paths, error control is advantageously possible. Moreover, the ignition control device 2 can report any occurring malfunctions of the ignition devices 3 to the engine control device 3 via the data line 5. In such a case, the engine control device 1 can avoid certain engine operating conditions.

(14) While exemplary embodiments have been disclosed hereinabove, the present invention is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of this disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.