The object of the invention is a method of regulation parameters control in spark-ignition combustion -engine, in particular, the method of the ignition advance angle and the air excess ratio control, applicable to piston internal combustion engines fueled with waste energy products from technological processes, especially from chemical industry. In many industries waste energy products, coming from the applied technological processes, are created. From the. point of view of their management, waste products generated in chemical industry technological processes seem to be particularly interesting. Currently, they are partially used in heating processes as an additive to the primary fuels. In case of no demand for heat, the waste gaseous products are burned burdening the environment with heat emission and emission of combustion products, and waste liquid products undergo costly utilization. Some of those substances can be used as fuels in internal combustion piston-engines. This fits well the global trend of searching for and applying new fuels for powering internal combustion engines. It is also an important scientific and economic objective, leading to a more rational use of various energy sources. Due to the limited availability, chemical composition variability, and other reasons of logistic nature, fuels, constituting waste products of technological processes are not suitable for application in traction vehicles, but can be a successful power source for stationary engines propelling power generators or any other industrial machines. Here, the carrier of chemical energy in working processes of piston-engines can be fuel of variable fractional and group composition as well as of varied phase form. The main problem connected with the application of waste fuels for internal combustion engines feeding is the development of an appropriate fuel feeding system and the combustion system which will allow for their long lasting and reliable operation. It has to be noted that unlike standard engine fuels whose chemical composition and other properties are strictly defined by standards, waste fuels obtained from technological processes usually do not retain repeatable quality. The waste fuels often come from a number of technological processes, and changes in parameters concern not only the chemical composition, but the volume of the available fuel stream whose value can change with time. A very important aspect in case of recuperation of flammable gas components are their thermodynamic properties which usually depend on the technological processes in which those fuels are created. The most often, fuels resulting from various technological processes are available within one industrial ^' plant. Therefore, in order to use them rationally, they demand proper preparation, including drying and purification, and then mixing them in appropriate proportions and establishing desired thermodynamic properties. The above mentioned operations must be carried out with appropriate safety systems applied. All the above listed operations make using waste fuels in power engineering even more difficult. Therefore, the feeding system and the engine combustion system must be characterized, with a specified "flexibility" towards changing properties of the fuel, providing at the same time retaining the proper working parameters required by the propelled machine as well as ecological properties required by environment protection laws.

From PL136911 ^■ the ignition- advance angle regulation system in internal combustion engine is known, operating according to adaptive principle wherein the ignition advance angle is adjusted based on the information retrieved from the engine combustion chamber, i.e. based on the occurrence of maximum pressure of the gases burnt in the cylinder. The timing advance adjustment system applied provides for maximum efficiency of the engine based only on standard, normalized fuels. The presented system is not suitable for the management of combustion process in an engine based on low-energy, variable waste fuels obtained from technological processes in chemical industry. Additionally, controlling only the ignition advance angle does not ^' provide for maximum efficiency. On the other hand, PL2114378 discloses a method to manage, combustion process in a central heating boiler with automatic burner powered with solid fuel, wherein the fed fuel-air ratio is established based on the flue gas temperature. The presented method is not suitable for application in piston- engines, and the checking the exhaust temperature as such does not provide for reaching desired working conditions.

Methods of repeatable management of internal combustion engine operation are known, wherein the exhaust temperature value is used. Those methods, however, do not use the criterion of exhaust gas temperature as the main parameter determining the most preferable course of the combustion process, but the exhausts temperature value appears as the parameter reflecting the average level of that portion of the waste energy carried with the exhausts, exceeding of which determines the risk of engine failure. Therefore, it is used only its limiting function .

The conditions for controlling variable parameters determining the self-ignition and combustion processes in petrol fueled engine are known from Hunicz, Jacek: "Kontrolowany samozaplon w silniku benzynowym" [Controlled self-ignition in petrol fueled engine] , Lublin Technical University, 2011. In the publication referred to above, the energy state of the exhausts is used as the parameter determining ignition of the fuel-air charge, however, _UC i.cumiies the moment of self- ignition occurrence. Self-ignition in spark-ignition engines is treated as anomaly and should be eliminated completely. Therefore, the presented method to control variable parameters is not suitable for piston-engines with spark-ignition.

The technical problem faced by the present invention is to offer a method to control variable parameters in a piston, multi-cylinder, internal combustion, spark-ignition engine in such a way that it enables the most favorable run of the combustion process, individually in each cylinder, and allows obtaining the maximum power or the maximum efficiency, or meeting the condition to reach the predetermined exhausts temperature value, while dynamically adjusting the ignition advance angle and the fuel dose (and by the same the air excess ratio) for each cylinder separately, relatively to the change in component and energetic properties of low-energy waste fuel obtained in chemical industry technological processes. The proposed invention comprises a non-standard method which unexpectedly solved all the mentioned technical problems .

The object of the invention is a method to control variable parameters in internal ^' combustion engine with spark-ignition, comprising both ignition advance angle and fuel dose control, characterized in that the temperature of exhausts is measured in the exhaust duct of each cylinder individually, and basing on the temperature measurement, the ignition advance angle and fuel dose are adjusted individually for each cylinder, wherein the adjustment of the fuel dose is effected by selecting the injector opening time, and - the ^■ ignition advance angle adjustment is determined by the crankshaft rotation angle , wherein the value of the lyui un advance angle and the ^' injector opening time are selected adaptively, individually for each cylinder, based on the temperature of exhausts in each exhaust duct, and the adaptation is carried out until reaching uniform temperature value in each cylinder.

The key technical characteristic of the process is the possibility to select the ignition advance angle and fuel dose individually for each cylinder, particularly in multi-cylinder engine, due to the differences in fuel and air distribution for each cylinder relative to the change in load conditions and fuel properties. The adjustment of the fuel dose is effected by selecting the injector opening time, and the value of ignition advance angle is established by measuring the crankshaft rotation angle. The values of the ignition advance angle and the fuel dose can be selected individually for each cylinder collectively or separately, depending on the exhausts temperature measured individually in the exhaust duct of each cylinder, depending on the assumed criterion (e.g. power, efficiency, ecological requirements) . The value of ignition advance angle or injector opening time (fuel dose) are selected adaptively, individually for each cylinder, by a controller, based on the change in temperature of exhausts in each cylinder exhaust duct, depending on the assumed criterion. In the method herein, the adaptation consists in obtaining uniform exhausts temperature value in each cylinder, i.e. reaching a uniform working process in each cylinder, which results in reaching the predetermined criteria (e.g. power, efficiency, ecological requirements). The characteristic feature of the presented method is its effectiveness in relation to various types of gas and liquid fuels, which is not obvious for standard solutions. According to the invention, a method was achieved to control variable parameters in internal combustion engine with spark- ignition, comprising simultaneous control of the ignition advance angle and air excess ratio, wherein the temperature of exhaust gases is measured in the exhaust duct of each cylinder individually, and based on the temperature measurement, the ignition advance angle and the fuel dose are adjusted (thus affecting the air excess ratio) in order to maintain required working parameters of the engine, particularly on variation of energetic properties of the supplied waste fuel.

The proposed method enables obtaining the most favorable combustion process, individually in each cylinder in a multi- cylinder internal combustion engine. The most favorable means here the criterion of reaching the highest power or the highest efficiency, or meeting the condition of reaching the predetermined exhausts temperature value, or meeting ecological requirements. According to the assumptions, the criterion allows to select the appropriate air excess ratio in the fuel-air mix feeding the engine, and to select the appropriate value of the ignition advance angle. Individual exhaust temperature measurement enables, within the predetermined criterion: reaching the maximum power or the maximum efficiency or meeting the condition to reach the predetermined exhausts temperature value, selection of the appropriate air excess ratio for the fuel-air mixture, and selection of the appropriate ignition advance angle value, individually in each cylinder, according to the customized temperature value measurement.

Exemplary embodiments of the invention have been presented in the drawings, wherein Fig. 1 represents a block diagram illustrating the method to control variable parameters in an internal combustion engine with spark-ignition, Fig. 2 represents the properties of the mixture for a MAN engine fueled with natural gas or hydrogen, Fig. 3 represents exhaust temperature chart for a MAN engine fueled with natural gas or with hydrogen as the function of its power, Fig. 4 represents general efficiency of a MAN engine fueled with natural gas .or hydrogen, Fig. 5 represents the properties of the mixture for a bi-fuel MAN engine, Fig. 6 represents exhaust temperature chart for a bi-fuel MAN engine, and Fig. 7 represents general efficiency of the bi-fuel _. MAN engine.

Example The method to control variable parameters in an internal combustion engine with spark-ignition according to an embodiment of the present invention was applied for a 6- cylinder, charged engine of E2876 LE302 MAN type with the cylinder capacity of V _s = 12.82 dm ³ , which was factory configured with spark-ignition, was powered with natural gas via a mixer system and was designed to propel power generator. The basic technical characteristics of the engine are presented in Table 1.

Tab. 1. Technical characteristics of the tested engine

Engine type - MAN E2876 LE302

1. Ignition type spark, 4-stroke

2. Cylinder arrangement R, vertical

3. No. of cylinders 6

4. Piston diameter 128 mm

5. Piston stroke 166 mm

6. Capacity 12.82 dm ³

7. Geometric compression ratio 11

8. Rated power with natural gas 200 kW

9. Rated engine speed 1500 1/min

10. Maximum torque 1280 nm 11. Natural gas consumption (factory data) 58 Nm /h

The practical embodiment of powering the above described engine with waste fuels from chemical industry required construction of a special fuel installation, separate for liquid and gas phases, with configuration in both cases similar to the Common Rail fuel supply system. The gas fuel supply system consisted of six fuel rail segments, each of which was equipped with two electronically controlled injectors 3, which facilitated precise control of the fuel dose depending on the engine load. While supplying fuel from chemical industry, spark plugs of NGG BCRE527Y type were used, wherein the spark duct was projecting further into the combustion chamber, which was particularly significant during fueling the engine with very lean mixture. To control the engine's most important variable parameters, like: liquid and gas fuel dose value, ignition advance angle, throttle opening, and the combustion mixture composition (air excess ratio) , a programmable engine controller was used, equipped with four knock sensors, which unambiguously determined the knock limit for each cylinder in all analyzed engine operating conditions. Additionally, the combustion flow in each cylinder was managed by thermocouples placed in the exhaust duct of each cylinder, directly at the exhaust outlet from the head.

Working parameters were examined for constant engine speed of n = 1500 1/min, which resulted from the intended use of the engine for propelling power generator in a power station. Since the tested gas fuels - hydrogen and natural gas had properties different in relation to application as fuel in an internal combustion engine, a significant problem was the selection of the proper mixture composition (Fig. 2) . In this case, the criterion of engine operation while supplied with hydrogen was the knocking combustion limit, evaluated by means of the knock sensor and exhausts temperature, which could not exceed 700°C for the tested engine. The differences in the mixture composition supplied to the engine also caused differences in cylinder heat generation value and combustion process temperatures. While combustion of the natural gas and air mixture was limited by the maximum allowed exhausts temperature of 700°C, feeding the motor with lean air and hydrogen mixture, the exhausts temperature reached significantly lower values (Fig. 3) . Reaching so positive results would not be possible without control of the following variable parameters: ignition advance angle and air excess ratio for each cylinder in the internal combustion engine with spark ignition, based on the measurement of exhaust gas temperature. Next, the engine total efficiency was determined (Fig. 4) . The higher value of the overall efficiency for the engine fuelled with natural gas results mainly from the lower ratio of mechanical power loss in relation to achieved continuous output. Taking into account the constant value of engine mechanical resistance as well as lower indicated power achieved by the hydrogen fuelled engine, lower overall efficiency was achieved. However, in both examined cases the engine total efficiency is high, and while fuelled with natural gas it reaches ^' the maximum of ca . 42% and with hydrogen it is ca . 37%. Further on a research program was developed to carry out the strategy of differentiated chemical energy stream supply in connection with ^' current availability of both gas fuel and liguid phase fuel in order to execute bi-fuel motor power (Fig. 5) . In case labeled as H2 + mixl on the chart, the engine power of 100 kW was achieved fueling the engine solely with hydrogen. Further increase of the engine power, up to 140 kW was achieved by increasing the liquid phase dosage at constant hydrogen consumption. For H2 + mix2 case, the power of 130 kW was achieved while supplying the engine solely with hydrogen. - Only above that power level the engine was additionally supplied with liquid fuel. In both cases the liquid phase consisted of a mixture comprising 50% of n- butanol and 50% of isobutanol. The fuel was given a working name of MIX. With liquid phase being used only, the engine power was limited to 105 kW since during the engine operation in only liquid fuel mode, fuel permeated into the lubricating oil. It was connected mainly with imperfect vaporization of the liquid phase during fuel-air mixture creation. Dosing the liquid phase allowed extension of the available load range (from Ne = 150 kW by fueling with pure hydrogen) up to the engine stated ratings point (Ne = 190 kW with bi-fueling) , which was impossible to reach with pure hydrogen fueling since anomalies in combustion process occurred. The differences in the method of power engine, adjustment were also the cause for differences in cylinder heat emission value and combustion process temperature. While combustion of the liquid phase was limited with the maximum allowed exhausts temperature of 700°C, on fueling the engine with pure hydrogen and air lean mixture or lean bi-fuel mixture, the combustion temperature reached significantly lower values (Fig. 6) . Visualization of changes in total efficiency value depending on the load was presented in Fig. 7. For the above mentioned reasons, and due to the increased charge exchange work caused by quantitative power control, the total efficiency of the engine powered only with liquid phase did not exceed 27%. For bi-fuel powering, the results comparable to fueling with pure hydrogen were obtained (ca. 37%), with concurrent expansion of the load range. Reaching so positive results would not be possible without control of the following variable parameters : ignition advance angle and air excess ratio for each cylinder in the internal combustion engine with spark ignition, based on the measurement of exhaust gas temperature.