JPH0652076B2 - Ignition measuring device - Google Patents

Description

FIELD OF THE INVENTION The invention relates to an internal combustion engine with a signal input, which is preferably connectable to a snail-shaped trigger device, and an evaluation circuit from which the trigger signal can be extracted. In the present invention, it relates to an ignition measuring device for detecting, for example, a rotational speed and an adjusting angle.

2. Description of the Related Art Ignition measuring devices for detecting the rotational speed and adjusting angle of an internal combustion engine are generally known. This type of ignition measuring device is usually connected to terminals 1 and 15 of the motor vehicle.
The terminal 1 then introduces a low voltage to the ignition coil and the terminal 15 is the output side of the travel switch. Furthermore, the trigger device is often connected to the ignition cable. The signal picked up in this way makes it possible to detect the engine speed and to generate the pulses used for the ignition of the stroboscopic lamp, so that the adjustment angle can be checked and Can be adjusted and set accordingly. Therefore, in order to carry out this type of measurement, the known ignition measuring device requires a large number of cable connections with the engine.

The problems known to be solved by the invention are that leakage coupling and other electrical and magnetic disturbances are often to be expected due to the high voltages that occur in the motor vehicle, especially in the area of the engine, but the known devices are especially triggered. Sensitive to inductive and capacitive disturbing pulses reaching the measuring device through the device. Therefore, in many cases the ignition measuring device is prone to erroneous measurements or is provided with a potentiometer whose sensitivity can be adjusted so that only the original trigger pulse reaches the measuring device. The known measuring device therefore requires an educated person to make the correct connections on the one hand and to operate the measuring device on the other hand in such a way that false measurements are avoided, in order to carry out the measurements.

Means for solving the problem and the effect of the invention In contrast, the ignition measuring device according to the invention starts from an ignition device of the type mentioned at the outset, in which the evaluation circuit determines and triggers a voltage corresponding to the ignition energy. The signal is intended to be evaluated only when the ignition energy exceeds a predetermined value determined from the preceding ignition pulse, while on the one hand a unique connection to the engine, for example via a trigger device. It is not necessary and the sensitivity of the measuring device has the advantage of adapting to the respective given conditions in the engine. The ignition measuring device therefore has the advantage that on the one hand it is easy to operate and, on the other hand, misconnections can be avoided without difficulty.

Further in accordance with the invention, the ignition measuring device is arranged so that the trigger signal is evaluated only when the ignition energy exceeds a predetermined value determined from the preceding ignition pulse, in addition to the ignition. When the cycle time determined from the signal time point and the preceding ignition signal time point is not below a predetermined leading value determined in one of the preceding cycle times, the rotational speed is detected from this cycle time. This configuration ensures that the fault pulse captured between the two ignition signals does not adversely affect the measurement result. This is because, in the engine, the change in the rotational speed moves only in a limited range even when acceleration and deceleration are significant between the two rotations. If this range is exceeded, a wrong rotation speed instruction is predicted, and the result is suppressed. The flash point is preferably determined from the ignition signal to which an adjusting time determined from the rotational speed of the preceding cycle and the input adjusting angle is added. This arrangement ensures that the last satisfactory rpm detection is used for the detection of the adjustment time, irrespective of whether a false measurement has occurred in the meantime. Therefore, the signal is particularly reliable.
The transmission of the flash pulse is suppressed when the predetermined flash time has not been exceeded since the last flash pulse. Therefore, unnecessary flashes are prevented, especially at high rotational speeds. Due to the low response sensitivity of the naked eye, a flash pulse train that the human eye cannot exactly follow is sufficient. Another flash pulse that would trigger the stroboscope flash would reduce the life of the stroboscope lamp on the one hand and on the other hand would require a large capacitor and a charging device for the preparation of flash energy, which in this respect is a simple matter of equipment. And considering its life, it is not desirable. It is also advantageous to form the next leading value from the last measured value and the old leading value, the two quantities being weighted differently.

Due to the high weighting of the measured values, a rapid adaptation characteristic is achieved, so that the number of false pulses reaching the evaluation point is very rapidly reduced, while on the other hand the high weighting of the preceding values increases the measurement sensitivity. It is quickly altered by some weak or strong pulses so that the following signal is not erroneously or imperfectly considered. In any case, by evaluating the ignition energy in the form of a measured value, it is possible to ensure that weak pulses reaching the input of the ignition measuring device due to a fault are not used for further data processing. it can.

Embodiments Next, the present invention will be described in detail with reference to the accompanying embodiments with reference to the drawings.

FIG. 1 schematically shows a trigger device 1 which is fastened to an ignition cable (for example, a trigger device which holds a current line in a pin-shaped manner and takes out a trigger signal). However, it is also possible to provide a plug instead of the trigger device for alternative embodiments. The trigger device 1 is connected to the evaluation circuit 2. A trigger signal is generated by this evaluation circuit when an ignition pulse occurs. The evaluation circuit is also provided with another device capable of detecting the ignition energy. To detect the ignition energy, for example, the ignition pulse should be rectified and the rectified voltage signal should be integrated, which in the simplest case is done with a capacitor. In order to carry out the digital data processing by the microprocessor 5, for example the capacitor signal should be converted into a digital word using an AD converter. Digital word is data line 4
Join in. The rising edge of the ignition pulse, which is picked up by a trigger device, is used as the trigger signal. The trigger signal is applied to line 3. An example of an input circuit that can be used is German Patent Application No. 324103.
No. 8 specification. The digitized ignition energy signal applied to line 4 as a digital 8 bit word is
It is led to the port P of the microprocessor 5. The trigger signal reaches the timer input T of the microprocessor 5 via the line 3. For example, model name HD6301 manufactured by Hitachi, Ltd. is suitable as a microprocessor. A keyboard device 6 is connected to the microprocessor 5 via a data line to another port. The microprocessor 5 has two outputs, one of which has an indicating unit 7
Is connected, and the stroboscope device 8 is connected to the other output side. The pointing device 7 is directly fed with the instruction in the form of a binary word on the data line, whereas the stroboscopic device 8 is sent a flash pulse from the microprocessor 3. The flash pulse is used to trigger the flash of the stroboscope lamp. The entire device is preferably housed in a casing, but it is also possible, for example, to arrange the stroboscopic device 8 at a distance from the ignition measuring device.

The operation of the ignition measuring device of the present invention will be described in detail with reference to the flow chart of FIG. The microprocessor 5 is in a state of waiting for a signal on the timer input side T at the start step 9. When the evaluation circuit 2 sends a trigger signal to the timer input T, the program sequence starts. At time t _n at which the ignition signal is input in step 10.
Is detected and stored. After a short, predetermined time, the energy content or component of the ignition pulse used for generating the trigger signal in the evaluation circuit is detected via the port P. This energy container or component M _{n, which} is applied digitally to the input side of the microprocessor, is detected and compared at decision point 12 with a first preceding value V _n-1 of the preceding measurement. If the relative value of the energy content or component present in the form of the measured value M _n is smaller than the first preceding value, it is considered as a fault pulse. This is because the energy content or composition of each ignition pulse is typically expected to be substantially the same. The measurement is then interrupted when a weak signal is generated, resulting in an immediate jump to program end 20. By this measure it is ensured that disturbing pulses with a weak energy content or component are not evaluated. In decision step 13, it is checked whether the predetermined flash waiting time BW has already been exceeded. It is based on the fact that the use of a flash frequency of 20 Hz or higher does not result in any optical result even if the flash frequency of 20 Hz or more is used because the response sensitivity of the naked eye is low in the examples. Therefore, the flash waiting time is 0.05 s. If the flash waiting time has not yet been reached, the flash pulse is prevented from being delivered in this measuring cycle.
This can greatly simplify the stroboscopic device. The capacitor for storing the ignition energy for the stroboscopic flash can be selected correspondingly to the previously selected maximum ignition pulse train and kept correspondingly small. Furthermore, by fixing the maximum number of flashes, the life of the stroboscope lamp is increased. When the flash was triggered because the waiting time was exceeded,
In step 14, the flash duration is calculated. The flash time t _B is the sum of the adjustment angle time T _VWn−1 calculated in the preceding pass cycle from the time of the input of the trigger signal t _n . After the arrival of the flash time t _B, the flash pulse is triggered. The cycle time ZZ _n is calculated in step 15. This time is the instant t when the ignition signal is input.
Input time t of the ignition signal of the preceding pass cycle from _n
Determined by subtracting _n-1 . At decision step 16, it is checked whether the cycle time roughly corresponds to the cycle time detected in the preceding program pass cycle. Even if the engine is significantly accelerated or braked, the cycle time will only change within a small range, so if the newly calculated cycle time does not reach the predetermined value, a sufficient measured value Regardless, it is presumed that the false pulse occurred. Then the program ends. If the cycle time is within the predetermined range, the advance value V _n is calculated in step 17. This new previous value V _n is determined from the preceding value V _n-1 detected in the instantaneous measurement value M _n and before that of the ignition energy. The coefficients a and b make it possible to weight the preceding value as well as the measured value M _n . By weighting the measured value M _n more heavily, the inner predecessor value V _n becomes very quickly adapted to the new measuring purpose. When the lead value is weighted more heavily, the measuring circuit has a stable sensitivity characteristic over a long period of time, so that an erroneous measurement does not occur due to a temporary slight deterioration of the measurement signal. Weighting can be performed between the two values depending on the desired characteristic. The preceding value V _n-1 is slightly lower in value than the expected measured value M _n for the energy component in the next program pass cycle.

Then, in step 18, the rotation speed is obtained from the cycle time of step 15. In this case, for example, whether the measurement target is a 2-cycle engine or a 4-cycle engine is considered. This can be entered via the keyboard device 6. From the desired adjustment angle for the entire 360 ° angle and the number of revolutions detected before it, the adjustment time required to determine the flash pulse timing in the subsequent cycle is also determined. After reaching the end of the program, the program returns to the program start step 9 again and waits for the next ignition signal.

Due to the adapted properties of the evaluation program, for example, adjacent ignition lines and faults due to misfiring can be detected and eliminated. Furthermore, the speed detection is also adapted to changes in the signal over time, which can be caused, for example, by slowly rising engine temperatures, extreme speeds or changing battery voltages in motor vehicles. The changes to be compensated for are also predicted during changes in the measurement object.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the ignition measuring device of the present invention, and FIG. 2 is a diagram showing a flow chart for explaining the operation of the microprocessor in FIG. 1 …… Head-to-shaped trigger device, 2 …… Evaluation circuit, 5 ……
Microprocessor, 6 ... Keyboard device, 7 ... Instruction unit, 8 ... Stroboscopic device

Claims (2)

[Claims] 1. An ignition measuring device comprising a signal input and an evaluation circuit from which a trigger signal can be taken out, said evaluation circuit (2) determining a voltage corresponding to ignition energy (M _n ) and said An ignition measuring device characterized in that the trigger signal is evaluated only when the ignition energy ( _Mn ) exceeds a predetermined value (Vn _-1 ) obtained from a preceding ignition pulse. 2. An ignition measuring device comprising a signal input and an evaluation circuit from which a trigger signal can be taken out, said evaluation circuit (2) determining a voltage corresponding to ignition energy (M _n ) and The trigger signal is evaluated only when the ignition energy (M _n ) exceeds a predetermined value (V _n-1 ) obtained from the preceding ignition pulse, and further the number of revolutions is the ignition timing at that time. (T _n ) and the cycle time (ZZ _n ) determined from the preceding ignition signal instant (t _n-1 ).
Is not less than a predetermined advance value (ZZ _n-1 ) determined in one of the preceding cycle times, the ignition measuring device is determined from the cycle time (ZZ _n ).