FR2500183A1 - METHOD AND DEVICE FOR ADAPTING CHARACTERISTIC SIZES IN MEMORY, IN ELECTRONIC CONTROL EQUIPMENT, IN PARTICULAR FOR INTERNAL COMBUSTION ENGINES - Google Patents

Abstract

A method and a device for adapting stored characteristic variables in electronic control devices (13) for systems or machines (12), in particular internal combustion engines, are proposed. Characteristic operating points are successively approached by means of a control program of a control computer (10) and, in this process, operating variables are measured. These actual values are compared with associated set point operating variables of a set point operating variable generator (16). As a function of the deviation, the responsible characteristic values stored in the electronic control device (13) are stored until the actual values correspond to the set point values or until the actual values have reached, or are less than predetermined set point limit values. The new characteristic variables obtained in this way are permanently stored and now determine the further control behaviour.

Description

 The invention starts from a method for the adaptation of characteristic quantities stored in electronic control equipment for installations or machines, in particular for internal combustion engines.

The invention also relates to a device for implementing the method.

 Particularly in the case of an ignition control and an injection control of internal combustion engines by a microprocessor, the characteristic curves and the characteristic fields are usually adapted theoretically and finally empirically by measuring operating quantities on a internal combustion engine, until optimum operating characteristics with favorable values for exhaust gases and reduced consumption are achieved. The characteristic quantities thus obtained are then fixed in the form of characteristic fields in fixed-value memories (ROM) and determine the control mode in the same way for all the internal combustion engines of this type. In this case, it is necessary to ensure, because of the inevitable manufacturing tolerances of detectors and ancillary equipment, that a sufficient margin is maintained in relation to the critical limit values. Such critical values are, for example, constituted by the knock limit or the legal values concerning the exhaust gases. Although an evolution of the characteristic curves in the vicinity of these limit values is in principle desirable, a sufficient margin must be maintained because of these manufacturing tolerances. Other reasons that the maximum possible characteristic values are not used, are the risk of aging of various components as well as the influence of the environment. As usually internal combustion engines and otherinstsallations must function In different climatic conditions prevailing in the different countries, a compromise has to be found when choosing the characteristic quantities, this compromise naturally preventing an optimum choice for a certain combination of environmental conditions.

 Regardless of the environmental conditions or aging, the control systems for lighting or injection, operate as those for example known from DE-OS 27 39 508 and 30 09 046. These systems have the disadvantage that in each vehicle complex supplementary systems, such as superimposed control systems for starting and emergency operation, as well as expensive additional detectors are required.

 The aim of the invention is to overcome the drawbacks of the known solutions and to this end concerns a method characterized in that characteristic operating points are successively approached as a function of a control program, operating variables then being measured. and compared with the theoretical operating quantities assigned to these respective operating points, while depending on the observed discrepancies, the responsible characteristic quantities stored in the control electronics are modified.

 The process according to the invention defined above has the advantage over known solutions of the advantage that the characteristic quantities memorized and determining for the optimal operation can be subsequently optimized with respect to the manufacturing tolerances and adapted to specific conditions. 'environment. This can be achieved, for example, in that the installations concerned, after their finishing and their basic equipment with characteristic quantities, are exposed to the environmental conditions in which they will have to operate later. These characteristic quantities are then adapted from the process according to the invention. For example, in the case of an internal combustion engine, the vehicle as a whole can be exported to the country of use and adapted to it ( determined fuel quality, climatic conditions, exhaust regulations, etc.) to local environmental conditions. A control apparatus constituting a unit can thus function optimally under various conditions. This adaptation can also be repeated at specified time intervals (for example by the after-sales service) to also compensate for the drifts caused by aging. Contrary to known regulation systems, complex and expensive additional systems are not necessary in the vehicle itself. They are only needed in the finishing workshops and in the workshops where the adaptation has to be carried out. .

 Other features of the invention make it possible to envisage other advantageous forms and improvements of the process indicated above. The use for the adaptation of a central steering calculator which is associated with a plurality of terminals in the various adaptation locations including workshops, is particularly advantageous and only entails reduced investments. This calculator can for example be connected via telephone links with the terminals. In this way, it is possible to modify without additional expense, even a posteriori, for example in the case of a modification of the legal prescriptions, even the characteristic fields. of dog installations. It is sufficient for the director to modify the corresponding programs of the central computer.

 It is also particularly advantageous and economical in terms of time, in the case of characteristic quantities stored in the form of characteristic curves and characteristic fields, to adapt only a few typical operating points acting as points of reference. support, and then interpolate, based on this adaptation, all the characteristic curves and characteristic fields.

 The invention will be explained in more detail with reference to an exemplary embodiment shown in the accompanying single figure which is a block diagram of the device according to the invention.

 A control computer 10 for approaching the operating points is connected with appropriate control conductors 11 to an internal combustion engine 12 controlled by an electronic control apparatus 13.This control apparatus 13 may for example be a microcomputer for determining ignition and fuel injection processes. To the internal combustion engine is connected a plurality of detectors, not shown in more detail for operating quantities, detectors whose signals are applied to a preparation and selection circuit 14. The selection process is then determined by the calculator of control 10. The parameter dependent prepared signals are compared in a comparison device 15 with the output values of a generator 16-of theoretical operating gears. This generator ignores the theoretical values as a function of control of the control computer 10.

These theoretical quantities are then established by referring to legal requirements (eg for exhaust gases), consumption values and engine power. Such a theoretical value may for example also be a limit value, the actual value to be in this case modified until the intervention of a signal indicating the limit value. This is for example the case during the exploration of the knock limit. The difference between the real value and the theoretical value is applied to a circuit 17 for correcting the characteristic quantities, in which are stored any algorithms for the adjustment of the characteristic quantities, the characteristic curves and the characteristic fields as a function of the operating variables detected at the instant in question. The output of this characteristic value correction circuit 17 is applied, with the corrected characteristic quantities, to the electronic control equipment 13.

 In the figure below, the area 18 delimited by a dashed line represents the part of the series installation in which the data can be adapted in the control electronics. The other constituent groups represent the fixed installation for adaptation, which is located as a central investment, at the manufacturer or in the workshops.

 The mode of action of the present arrangement resides essentially in that, with the aid of a program which can be selected in any way from the control computer 10, various operating points that are characteristic of the installation to adapt, point successively first <s.

In the case of a motor vehicle, these characteristic points are, for example, different speed values, different acceleration and acceleration values, different temperature zones when the engine is running hot and possibly under a higher expenditure of different external temperatures, different external pressures, different compositions of the fuel-air mixture and different states of charge. The last points can be adjusted to the outputs 19 of the computer 10, which in the case of the load act for example on a roller control station or in the case of the outside temperature, on the heating of the room. operating point is adjusted different operating quantities, and different parameters P are measured on the machine or the installation 12 and are applied to the circuit 14 preparatio and selection. Such parameters include, for example, engine power, torque, emissions of harmful substances, power consumption, jogging, and the signals of a knock detector. Depending on the program thus adjusted in the control computers 10, different operating variables will then be compared successively or simultaneously with pre-adjusted theoretical values provided by the theoretical operating quantity generator. The difference is used in the circuit 17. correction of the characteristic quantities, within the framework of the algorithms that have been determined. These can be simple additions or multiplications, but also different more complex interpolation methods. The characteristic quantity thus modified is introduced into the electronic control apparatus 13 to base the subsequent operation. As the described arrangement constitutes a control circuit, the characteristic quantity is modified until the actual value is identical to the theoretical value or in the case of a given limit value in advance, this limit value has been This means, for example, in the case of the adjustment of the knock limit, that the characteristic quantity to be taken into consideration for the instant of ignition will be modified in the sense of a regulation.

early, until a knock signal occurs or is just about to occur. In a corsican way, for example for a too high content of CO, the characteristic quantity will be modified in the direction of a depletion of the mixture, until the desired or legal limit value is reached.

 The modification of the characteristic quantities for the electronic control device can then be carried out for example in intermediate memories, until a new characteristic field or new characteristic curves are established. In this case, of course, not all points need to be addressed. It suffices to establish a framework from several measured values and then to modify the characteristic curves or the characteristic fields as a whole by means of interpolation processes. Such an interpolation method is for example known from DE-OS 30 06 633. Finally, a fixed storage of the characteristic quantities must be carried out in the memory of the electronic control equipment 13.

This memory can be an EPROM or we can use a
ROM with basic data in which case the modification of these data is possible via welding bridges.

Claims (6)

 1. A process for the adaptation of characteristic quantities stored in electronic control devices for installations or machines, in particular for internal combustion engines, characterized in that characteristic operating points are successively discussed as a function of a control program, operating quantities are then measured and compared with the theoretical operating variables assigned to these respective operating points, whereas, depending on the deviations noted, the characteristic variables responsible, stored in memory in the control electronics, are modified.  2. Method according to claim 1, characterized in that the boarding of the operating points and the assignment of the theoretical operating variables are controlled by a central computer.  3. A process according to claim 2 applied to internal combustion engines, characterized in that a central computer is associated with several control terminals at adaptation locations.  4. Method according to any one of claims 1 to 3 for the adaptation of characteristic quantities stored in the form of characteristic curves or characteristic fields, characterized in that, after the measurement of several operating points serving as the characteristic curves or the characteristic field are modified as a whole by an interpolation method.  5.- Method according to any one of claims 1 to 4, characterized in that the crossing downwards or upwards of a limit value of an operating variable, is considered equivalent to the fact of reach a theoretical value.  6. Device for implementing the method according to any one of claims 1 to 5, characterized in that it comprises a control computer (10) for the boarding of the operating points, and a control circuit consisting of a preparation and selection connection (14) for the measured operating variables, a generator (16) of theoretical operating variables and a correction branch (17) of characteristic variables, which acts on the grandet's memory features of the electronic control equipment (13).