Abstract
Complicated in terms of algorithms and architecture of modern gasoline-injection systems must be subjected to thorough verification of the prototype stage. Commonly used for this purpose is a computer simulation. The purpose of this simulation is to verify the correctness of the algorithm, in particular the assessment of precision injection pulse generation. The measure of accuracy is the accuracy of the duration (length) of impulse, which is measured as a deviation of measured duration (length) of impulse from duration (length) of impulse which is expected (value of it is designated in the synthesis of control).
This paper presents a modern system simulation, in which the actual control object, it is naturally aspirated injection petrol engine is replaced by the set of dynamic (time dependent) selected runs of values. The examples presented in the publication of the control the injection are the essence of a new method of simulation and its main properties. The main advantage of this method is the high reliability of the results obtained, not because it applies a mathematical model of the engine but because it uses the actual values used in the control process and engages the elaborated controller. Simulator is built on the basis of measurement and control card Control Desk DS 1104 produced by dSPACE. It works in a closed loop, which means that the 2-second runs which represent static stage of engine run, the simulator provides on a continuous basis in real time. In the same way are the simulated transient stages. If in the process of static computer simulation will be determined the best control sets of signals (it is not included in the publication), it can be compared with the results obtained from the dynamic simulation. This allows for a quantitative assessment of the quality of the controller. The method of dynamic simulation study was verified by examination of microprocessor injection controller which sets the mixture composition according to the formula “Cycle by Cycle” in five static states as well as acceleration and slowing down of the engine. This method of control is based on the forecasting - including measurement of cyclic air flow (with the use of thermo anemometer) as well as measurement of required quantity of gasoline in the cycle. Presented results show the high usefulness of the simulation methods developed in the process of synthesis and elaboration of control systems, and also verify the validity of the developed control algorithm C/C v.3 and its examples.
Keywords: SI engine, air-fuel mixture ratio control, simulation