EP0000899A1 - Regelverfahren zum Betrieb eines Spaltgasgenerators und einer nachgeschalteten Brennkraftmaschine - Google Patents

Regelverfahren zum Betrieb eines Spaltgasgenerators und einer nachgeschalteten Brennkraftmaschine Download PDF

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Publication number
EP0000899A1
EP0000899A1 EP78100627A EP78100627A EP0000899A1 EP 0000899 A1 EP0000899 A1 EP 0000899A1 EP 78100627 A EP78100627 A EP 78100627A EP 78100627 A EP78100627 A EP 78100627A EP 0000899 A1 EP0000899 A1 EP 0000899A1
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EP
European Patent Office
Prior art keywords
air flow
primary air
fuel supply
secondary air
supply
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP78100627A
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German (de)
English (en)
French (fr)
Inventor
Bernt Dr. Paul
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Siemens Corp
Original Assignee
Siemens AG
Siemens Corp
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Publication date
Priority claimed from DE19772737072 external-priority patent/DE2737072A1/de
Priority claimed from DE19772737531 external-priority patent/DE2737531A1/de
Application filed by Siemens AG, Siemens Corp filed Critical Siemens AG
Publication of EP0000899A1 publication Critical patent/EP0000899A1/de
Withdrawn legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M27/00—Apparatus for treating combustion-air, fuel, or fuel-air mixture, by catalysts, electric means, magnetism, rays, sound waves, or the like
    • F02M27/02—Apparatus for treating combustion-air, fuel, or fuel-air mixture, by catalysts, electric means, magnetism, rays, sound waves, or the like by catalysts

Definitions

  • the invention relates to a control method for operating a cracked gas generator in which liquid fuel is converted to primary gas and possibly a gas containing bound oxygen to a cracked gas, and a downstream internal combustion engine in which the cracked gas is burned with secondary air.
  • a cracked gas generator in which liquid fuel is converted to primary gas and possibly a gas containing bound oxygen to a cracked gas, and a downstream internal combustion engine in which the cracked gas is burned with secondary air.
  • the supply of liquid fuel and total air and the ratio of primary air flow to secondary air flow are adjusted to values adapted to the stationary conditions.
  • Such a method as is known, for example, from German Offenlegungsschrift 23 06 026, has the advantage that low-pollutant fuels (for example "straight run” gasoline or other crude distillates which are obtained in refineries in the production of gasoline) have no additions of lead compounds or aromatics and are therefore not suitable for use in the operation of internal combustion engines because of their relatively low octane number for operating modern internal combustion engines (for example in motor vehicles).
  • Such liquid fuels are converted in the cracking gas generator by partial oxidation to a cracking gas which has a high octane number and which burns in the internal combustion engine with very little evolution of nitrogen oxides, partially burned hydrocarbons, aromatics and other pollutants.
  • the primary air number mentioned in the following 1 12 is therefore advantageously between 0.05 and 0.2.
  • the primary air ratio indicates the ratio of the amount of primary air supplied to the gas generator to the amount of air that would be required for the stoichiometric combustion of the converted liquid fuel.
  • the partial oxidation can also be carried out endothermally by means of a gas containing the oxygen in bound form.
  • the primary air number indicates how much air would have to be added to the fuel in order to obtain a cracked gas of the same gross composition.
  • the primary air flow, secondary air flow and possibly exhaust gas recirculation must be controlled in all operating conditions so that they are in certain proportions to the fuel supplied.
  • the fuel supply essentially as a function of the accelerator pedal position and the speed and, on the other hand, a throttle valve which is arranged in the intake line between the mouth of the fission gas line and the inlet of the internal combustion engine, corresponding to the Regulate accelerator pedal position.
  • the suction vacuum present upstream of the throttle valve serves firstly to suck in the secondary air through the suction line, secondly to suck primary air into the cracked gas generator and the cracked gas generated from the cracked gas generator into the suction line.
  • an automatic throttle valve which is adapted to the flow resistance of the cracked gas generator and ensures that primary air and secondary air are drawn in approximately in a constant ratio. If exhaust gas from the internal combustion engine is recirculated to the cracked gas generator, a suitable exhaust gas metering valve is used causes part of the primary air to be displaced by exhaust gas without changing the primary air ratio.
  • the invention is therefore based on the object of specifying an improved control system for the operation of the gas generator and the internal combustion engine, which in particular also relates to the respective operating states.
  • transient operating conditions can be adapted and rapid load changes, e.g. rapid increases in torque at constant speed, enables.
  • the ratio of the primary air flow to the secondary air flow is briefly increased in relation to the steady state with the increased fuel supply corresponding to the change in the fuel supply over time. It is advantageous if the temporarily increased secondary air flow only adjusts to the value of the secondary air flow that corresponds to the steady state of the increased fuel supply when the increase in fuel supply has already ended, i.e. when the time derivative of the fuel supply has disappeared.
  • the system In addition to the fuel supply, which can be controlled, for example, by a controllable fuel feed pump or by magnetically controlled injection valves, the system also regulates the flows of primary air, secondary air and fission gas / secondary air mixture, to which the flow of oxygen in bound form may also be required containing gas (e.g. exhaust gas or water vapor) can occur. Since the sum of primary air and secondary air is the total Air results, which is found in the mixture, even if it is partially bound in the cracked gas, it is generally sufficient to regulate two of the three specified gas flows.
  • gas e.g. exhaust gas or water vapor
  • the primary air flow can be controlled by means of a throttle device in the primary air supply.
  • the setpoint value of a quantity corresponding to the primary air flow can advantageously be calculated, the associated actual value measured, and the throttle device adjusted so that the control deviation (actual value / setpoint value difference) disappears.
  • the setpoint for the primary air flow is preferably increased briefly, which leads to an opening of the throttle device in the primary air supply that is disproportionate to the increase in the fuel supply.
  • primary air flow and secondary air flow can then be regulated separately so that the control deviation for the sum of the two flows disappears.
  • a throttle device in the mixture line of the internal combustion engine can also be regulated until the control deviation disappears.
  • the setpoint for the total air flow is advantageously formed from the position of the accelerator pedal or the fuel supply in accordance with a stationary operating state (i.e. without taking into account the time derivatives of the fuel supply, the speed or other parameters).
  • the actual value for the total flow can be composed of the measured actual values for the flows of secondary air and primary air.
  • a throttle device in the secondary air supply can be used to regulate the secondary air.
  • a variable corresponding to the primary air flow can advantageously be measured and calculated and the control deviation can be used to control the throttle device in the secondary air supply.
  • the secondary air flow can be determined by measuring the primary air flow. For example, From the position of the throttle valve which also regulates the total air flow via the mixture flow, it is easy to determine which setpoint for the pressure drop in the primary air supply is to be assigned to a specific setpoint of the secondary airflow. Therefore, not only the pressure drop in the secondary air feed, which can be measured by means of a manometer, but also the pressure drop in the primary air feed, can be used to form the control deviation when controlling the secondary air flow.
  • the secondary air flow is advantageously throttled briefly or increased less than the increase in the fuel supply corresponds.
  • the three volume flows for primary air, secondary air and total air are preferably controlled independently of one another.
  • target values for the primary air flow and the total air flow can advantageously be calculated, which are adapted to the respective operating states, in particular to the transient operating states during the load changes. If one measures the corresponding actual values of the air flows by means of flow rate measuring devices in the primary air supply and the secondary air supply, the primary air flow can be regulated by a throttle direction in the primary air supply is adjusted until the corresponding control deviation of the primary air flow disappears.
  • An actual value for the total air flow can be determined from the actual values for primary air flow and secondary air flow, and a throttle valve which is arranged in the mixture feed at the inlet of the internal combustion engine can be adjusted until the control deviation of the total air flow disappears.
  • the intake vacuum controlled by the throttle valve is only at the primary air valve with a certain delay; the primary air flow follows the corresponding control more slowly than the secondary air flow.
  • the secondary air flow rises rapidly, but the primary air flow rises more slowly, so that the secondary air flow increases at the expense of the primary air flow and the mixture becomes leaner.
  • the primary air flow is only about 10% of the total air flow and must be set precisely, the throttle device in the primary air supply would be overwhelmed if it took the total pressure drop in the intake system in the range of about 0.6 bar at idle and almost 0 at full load had to regulate. If one also tried - which is theoretically possible - to regulate the air flows only through the throttling devices in the secondary air supply and the mixture supply, the system tends to uncontrolled vibrations. With separate control and throttling of the three volume flows for primary air, secondary air and mixture at the inlet of the internal combustion engine, however, a fine control can be achieved that allows rapid load changes.
  • a flow resistance is preferably generated in the secondary air supply by an invariable throttle point, which causes a pressure drop in the secondary air supply comparable to the pressure drop in the primary air supply and the gas generator at medium load (average throughputs in the primary air supply and the secondary air supply).
  • the cracked gas can be generated not only by exothermic reaction of the liquid fuel with air (free oxygen), but also by endothermic reaction with bound oxygen, for example water vapor or exhaust gas.
  • Exhaust gas from the internal combustion engine can be returned to the cracked gas generator. Heat is converted into chemical energy, which leads to a higher efficiency of the system.
  • the reactor temperature can advantageously be regulated by changing the ratio of primary air flow to secondary air flow as a function of the reactor temperature.
  • the ratio is preferably regulated in accordance with the control deviation of the setpoint from the actual value of the reactor temperature.
  • An increase in the primary air flow leads to a more exothermic conversion and can be used to counteract a decrease in the reactor temperature.
  • the setpoint of the reactor temperature can advantageously be increased briefly. This leads to the desired temporary increase in the ratio of primary airflow to secondary airflow. It is particularly advantageous if the temperature setpoint is set to the temperature setpoint corresponding to this state only a short time after reaching a new steady state, which corresponds to the increased fuel supply.
  • the fuel supply can be regulated in direct dependence on the accelerator pedal position, the air flows in direct dependence on the changing fuel supply, i.e. as a function of the fuel supply. But you can also regulate the air flows in direct dependence on the accelerator pedal position, e.g. the accelerator pedal position can be used directly to control the throttle valve in the mixture line.
  • the fuel supply can also be regulated in direct dependence on the accelerator pedal position or also in direct dependence on the total air supply. This also ensures that the fuel supply, primary air flow and secondary air flow are always in a suitable relationship to one another.
  • a first electronic calculation stage it is also advantageous in a first electronic calculation stage to set the target values for the fuel supply and two of the three air ratios for the primary air ( ⁇ 12 ), the secondary air ( ⁇ 23 ) and the total air (113), taking into account the current operating state and to calculate the characteristics of internal combustion engines and fission gas generators. From these setpoints, the setpoints for at least two of the three volume flows of primary air L v , secondary air L m and total air L G are then calculated in a second electronic computing stage. The fuel supply B and the volume flows are then adjusted to the calculated target values.
  • the internal combustion engine and the fission gas generator can be matched.
  • the setpoints for these flows can be reduced to setpoints for the air numbers, the fuel supply B and the fraction b a of the fuel fraction to be converted by exhaust gas.
  • the setpoints for ⁇ 12 , ⁇ 13 or 2 23, b and B are calculated according to the functions of the measured values characterizing the operating state (e.g. the speed n, the accelerator pedal position ⁇ P and changes over time in these variables), these functions can be determined according to the map of the internal combustion engine.
  • This first stage can be designed in such a general way that the adaptation to the characteristic data of different types of internal combustion engines can be carried out by entering corresponding parameters in corresponding setpoint computers.
  • the second arithmetic stage which can be designed independently of the characteristics of the internal combustion engine and of the cracked gas generator, then according to the equations referred to the d i m ensionsrod target values ⁇ 12, ⁇ 23 and ⁇ 13 and b associated with target values for the volume flows L v , L M and / or L G and calculated for A R or a R.
  • a cracked gas generator is described, for example, in German Offenlegungsschrift 2,558,922 and German Patent Application 2,614,670 and usually consists of a reaction chamber 2 containing a catalyst and a heat exchanger 3 for the cracked gas to be cooled on the one hand and the liquid fuel to be evaporated and / or Primary air on the other hand.
  • Liquid fuel is introduced into the cracked gas generator via a fuel supply 5 and primary air via a primary air supply 6.
  • the fission gas generated is fed via a fission gas line 7 into the intake line of the internal combustion engine and mixed with the secondary air coming from the secondary air supply 8.
  • the mixture is burned in the internal combustion engine and the resulting exhaust gas can, if desired, be partially returned to the cracked gas generator via an exhaust gas recirculation 9.
  • the volume flows clearly emphasized in FIG. 1 become a controllable fuel by means of a throttle valve 11 in the intake line, a throttle device 12 in the primary air supply injector 13 in the fuel supply and optionally an exhaust gas metering valve 14 in the exhaust pipe.
  • An electronic control device is used to control the metering devices 11 to 14, which consists of two setpoint computer stages 20 and 21 and forms setpoints for the primary air flow L M , the secondary air flow L v , the exhaust gas component a R9 to be recycled, the fuel supply B and advantageously also for the ignition angle ⁇ z .
  • the setpoints for B and ⁇ z can be used directly to control the fuel delivery pump and the ignition angle at the ignition distributor of the internal combustion engine, while the setpoints for L v , L m and a R are entered together with the actual values of these variables in closed control loops that the metering devices 11 to 14 control so that the control deviations formed in the difference formers 22 of the control loops disappear.
  • Known flow rate measuring devices 23, 24, 32 can be used to record the actual values for the volume flows.
  • such devices are commercially available and are already used in the gasoline injection control for motor vehicles known under the name "L-Jetronik".
  • the primary air flow e.g. a flow meter with a magnetic field dependent resistor arrangement suitable, as described in German Offenlegungsschrift 24 34 864.
  • These flow meters are designed so that they deliver output signals that are proportional to the amount of gas passing through the measuring point per unit of time.
  • Signals for the rotational speed n and position ⁇ P of the accelerator pedal present in the respective operating state are required as input variables of the electronic control devices.
  • a sensor 25 is used on the internal combustion engine, for example on the interrupter, and a transducer 26 which converts the accelerator pedal position into a corresponding electrical signal, for example a potentiometer, the tap of which is mechanically coupled to the accelerator pedal. Since an increase in the exhaust gas recirculation can bring about a drop in the reactor temperature of the cracked gas generator, it is also advantageous to use a temperature sensor 27 to record the reactor temperature T R and to enter it in the first stage 20 to calculate the setpoint for b a .
  • the exhaust gas temperature which fluctuates greatly in accordance with the load state of the internal combustion engine, is also advantageously detected by means of a temperature sensor 28 and likewise entered in the first stage. From these variables, the setpoints for B, ⁇ 12 , ⁇ 23 and b a are calculated in the first stage according to functions that are selected in accordance with the characteristic diagram of the internal combustion engine. Deviations in time of these variables, for example the change in speed and / or the fuel supply over time, are also taken into account when determining the functions corresponding to the characteristic diagram.
  • the setpoints for a R , L V and L M are formed from the stoichiometric relationships described above, which are independent of the characteristic diagram.
  • the second stage can be used for many types of fuel machines are manufactured as an unchangeable building block.
  • the conversion of the dimensionless numbers ⁇ 12 , ⁇ 23 and b a into the associated setpoints for the volume flows only the specific weight and "air fuel ratio" of the liquid fuel used in stoichiometric operation and the temperature and pressure of the intake air, ie the outside atmosphere, are included.
  • a temperature sensor 30 and a pressure measuring device 31 can be arranged in the line for the intake air.
  • the target value for the secondary air ratio ( ⁇ 23 ) instead of the target value for the secondary air ratio ( ⁇ 23 ), the target value for the total air ratio ( ⁇ 13 ) is calculated, from which In the second stage 51, the target values for the volume flows L G and L v are formed.
  • the target value for the primary volume flow L v is compared in a corresponding differential element of the difference generator 53 with the actual value for L v in order to control the throttle device 12 of the primary air supply with the control deviation.
  • the position ⁇ D of the throttle valve 55 is controlled with the control deviation obtained.
  • this throttle valve is not arranged in the part of the intake line (secondary air supply) that conducts the secondary air, but in the part that conducts the fission gas / secondary air mixture. Since with knowledge of L M and L v also the total air flow and the mixture flow clearly be are correct, the secondary air flow is indirectly regulated solely by controlling the throttle valve 55 and the throttle device 12.
  • a separate regulation of the secondary air flow is provided in this embodiment by means of a second throttle device 56 arranged in the secondary air supply.
  • a setpoint value adapted to the characteristic diagram of the internal combustion engine is formed in the intake line for the vacuum generated by the suction of the internal combustion engine .
  • This setpoint value is compared in a further differential element 57 with the corresponding actual value, the control deviation being used to control the throttle device 56.
  • the throttle device 56 could also be regulated in accordance with the setpoint value for L M formed in the second stage, as a result of which fine regulation of the volume flows L v , L M and L G would be achieved, but the embodiment proposed here in particular enables rapid load changes.
  • the pressure drop can be measured by measuring the pressure difference upstream and downstream of the throttle device 56 in the secondary air line. But you can also advantageously control the throttle device 56 by measuring the pressure drop in the primary air line.
  • a differential manometer 58 bridging the throttle device 12 is provided.
  • This arrangement also has the advantage that changes (eg contamination) in the cracked gas generator, which would lead to an increase in flow resistance in the cracked gas generator during use and would reduce the primary air flow, are compensated for by themselves.
  • the pressure drop across the throttle decreases device 12, which leads to the fact that the second throttle device 56 is closed in the secondary air line to the same extent, so that the desired ratio of primary air to secondary air is maintained.
  • the throttle valve 55 at the inlet of the internal combustion engine could be dispensed with in such an arrangement. Then, however, the entire range of the intake vacuum between about 0.6 bar at idle and approximately 0 at full load would have to be regulated by the two throttle devices 12 and 56, which, above all, makes fine regulation of the primary air difficult.
  • the first stage 50 is constructed from four computing modules 60 to 63 and a dynamic element 64, which will be explained in more detail below.
  • FIG. 3 We start with block 60 for calculating the target value for fuel supply B, the structure of which is shown in FIG. 3.
  • the accelerator pedal is used to control the machine output, the position of which is detected and entered by a voltage signal ⁇ p of the measuring transducer 26 which is proportional to the desired load.
  • ⁇ p the voltage signal generated by the transmitter 26 and proportional to the speed n is fed into a multiplier 101 together with ⁇ p .
  • An amplifier 102 with an adjustable amplification factor for realizing the proportionality factor e 0 is provided in the line for ⁇ p .
  • the setpoint for the pressure drop ⁇ p v in the primary air line is composed of a constant base value g o , which takes into account, for example, the pressure drop in the cracked gas generator, and a link that is proportional to the suction in the intake line. It becomes the functional dependency chosen.
  • B is a voltage signal obtained by differentiating the target value B in the dynamic element 64 for the temporal change in the fuel supply.
  • the size B is taken into account with regard to load changes and has the effect that, in the event of a sudden load change, which is accompanied by a sudden change in the fuel supply, the setpoint value for the pressure drop is changed briefly and the secondary air is thus controlled in such a way that the secondary air flow compared to the primary air flow at a Performance increase temporarily throttled and the mixture is enriched.
  • g 1 and g 2 are proportionality factors which can be specified in accordance with the system characteristic map and are taken into account by corresponding amplifiers 103 and 104 which are connected to the inputs for ⁇ p and B.
  • a setpoint T S for the reactor temperature is calculated in the computing module 60.
  • the function chosen which is required to calculate b a and ⁇ 2 and thus to regulate the reactor temperature.
  • B S prevails, where d 0 , d 1 and B S are adjustable constants adapted to the characteristics of the cracked gas generator. If the fuel throughput increases rapidly, the reactor temperature is increased, and if the fuel throughput decreases.
  • -B S can again be set and tapped on a potentiometer 109, d 1 and d 2 are generated by corresponding variable amplifiers 110.
  • the exhaust gas recirculation can be used to effectively regulate the reactor temperature. This is particularly advantageous if the reactor contains temperature-sensitive catalysts.
  • the computing module 61 (FIG. 2) is provided, which calculates the target value for the fraction b a of the primary air to be replaced by exhaust gas as a function of the measured value T R of the reactor temperature.
  • this module has, in addition to the input for T R , an input for the reactor target temperature T S and the target value of the fuel supply B, which are connected to the corresponding outputs of the module 61, and for the measured value of the exhaust gas temperature sensor 28 on.
  • b a is calculated in proportion to the difference T R - T S.
  • the exhaust gas recirculation can be increased if the exhaust gas is at a high temperature and carries with it part of the necessary conversion heat.
  • c 0 , c 1 , c 2 , T Ao and B o are parameters which are selected in accordance with the characteristics of the fission gas generator.
  • FIG. 4 schematically shows the circuit diagram of such a module, which has inputs for the voltage signals T R and T A formed in the temperature sensor sensors 27 and 28 and for the target values T S and B calculated in the module 60.
  • B o and T Ao are tapped as variable voltages at potentiometers 120, 121.
  • 122 denotes a logic switch that connects one of the two inputs 123, 124 to output 125. If the signal (T R- T S ) at input 126 is positive, input 123 is connected to the output in the manner shown in the symbol.
  • Another computer module 62 is used to calculate the setpoint for ⁇ 13 stipulated that the exhaust gas composition with regard to its content of nitrogen oxides, partially burned hydrocarbons and other pollutants is as optimal as possible.
  • the exact setpoint must be calculated taking into account the combustion properties of the internal combustion engine.
  • the stationary behavior of the internal combustion engine can be sufficiently taken into account if 113 is selected as a function of the gasoline supply and the speed, proportional to a polynomial, into which these quantities are included up to the third power.
  • This polynomial can be written in general terms. with 16 parameters b 00 , b 01 ' b 10' ... b 33 ' which can be specified to adapt to the characteristic field of the internal combustion engine.
  • the function for the setpoint of the air ratio ⁇ 13 becomes Proposed, b 17 and b 18 are also selectable to adapt to the map of the internal combustion engine.
  • the circuit diagram of the arithmetic module 62 is shown in FIG. 5.
  • Inputs 150 and 151 for the time derivatives of n and B, which are formed by differentiation in the dynamic element 64, are respectively given to the one input of a divider 154 and 155 via corresponding variable amplifiers 152 and 153.
  • the other inputs of these dividers are connected to inputs 156 and 157 for the voltage signals of n and B.
  • the output signals of these dividers are added to a constant voltage taken from the supply voltage network by means of the amplifier 159.
  • the inputs 156 and 157 are applied to a multiplier system 160, which can consist of amplifiers and multipliers and allows the setting of the 16 freely definable parameters b 00 and b 33 as multipliers.
  • a voltage signal corresponding to the desired value is then formed from the signals obtained in the multiplier 161.
  • the exhaust gas composition and the engine power are also essentially determined by the ignition angle ⁇ z , which can also be optimized depending on the map of the internal combustion engine, for which the functional relationship is analogous is chosen.
  • a circuit can be used which is connected to the inputs 150, 151, 156 and 157 and is constructed analogously to the arrangement according to FIG. 5.
  • the appropriate setpoint for the primary air i12 must be calculated for each load state (ie for each B value).
  • ⁇ 12 is a function of a temporal mean B that is formed in the dynamic element. If the fuel supply is in the middle range, ie between two predeterminable fuel supplies B 1 and B 2 , so ⁇ 12 can be selected independently of the fuel supply. With smaller conversions, however, the air ratio must be increased, ie the reaction must be steered more exothermically in order to compensate for heat losses in the reactor and to avoid soot formation. Further, it may be advantageous for large 'fuel, the air ratio throughputs increase to raise by increasing the reaction heat, the heat of vaporization for the increased fuel supply. The air number 1 12 is therefore calculated proportionally to a quantity h 0 for which the following applies
  • the temperature T E of the mixture of primary air and vaporized fuel is measured by means of the temperature sensor 29 at the inlet of the internal combustion engine, ie after leaving the heat exchanger 3 (FIG. 1).
  • T E the temperature of the mixture of primary air and vaporized fuel
  • a lower heat shade of the reaction ie a lower primary air ratio, is necessary in order to maintain the operating temperature of the reactor.
  • the operating temperature of the cracked gas generator can be regulated via the exhaust gas recirculation. Often, however, it will not be advantageous for the catalytic conversion in the reactor to replace too much of the primary air with exhaust gas.
  • a limit transmitter which, when a maximum is reached or exceeded values a Rmax for exhaust gas recirculation gives a signal GW in the first stage:
  • GW> 0 means that a further increase in exhaust gas recirculation is not possible.
  • ⁇ 12 therefore becomes proportional to a quantity h chosen so that it results
  • Fig. 6 shows how the module, which has inputs for B, T E , T R and T S , from potentiometers 170, amplifiers 171 and 172, amplifiers with adjustable gain factor 174, an amplifier 176 connected as an inverter, resistors 177, one Multiplier 178 and the mentioned logic switches 179 according to DIN 40 700-18-34 can be built.
  • a dynamic module is required in order to supply the arithmetic modules 60, 62 and 63 with the voltage signals corresponding to the quantities n, B and B.
  • this module contains an amplifier 200 which is connected in a conventional manner and which is additionally bridged as an integrator with a capacitor and whose input is connected to the output of the first setpoint computer 60 which carries the signal for the setpoint B. At the output of the amplifier arises then a voltage signal which has a smoothed course of the desired fuel supply curve.
  • the measured value sensor 25 for the speed and the input for the setpoint B are each connected to the input of a differentiating element 203 or 204. Voltage signals corresponding to the values h and B are then present at the outputs.
  • the air quantity L required for the stoichiometric combustion of the fuel quantity B to be supplied must first be calculated. Taking into account the measured values for the pressure P L and the temperature T L of the intake air, it is possible to write approximately for "straight run" gasoline
  • a calculation module 220 (FIG. 8) with inputs for T Lt P L and B is used for the calculation, the output of which leads to a multiplier 221 in which the signal for L is multiplied by the setpoint value ⁇ 13 taken from module 62.
  • a computing block 222 is used with inputs for the setpoints ⁇ 12 and b a taken from the first stage and the value L calculated in the block 220.
  • the corresponding size and the desired value b a calculated in the first stage are given in a computing module 224 in which the recirculated exhaust gas fraction a R is calculated.
  • the signal GW must still be generated in the limit transmitter 65.
  • the setpoint a R and the adjustable limit a Rmax are entered into the limit transmitter .
  • the two values are compared and a constant positive voltage is generated at output 226 for a R > aRmax. For aR ⁇ 0, output 226 is grounded.
  • Fig. 9 shows the structure of the second stage, which is designed for internal combustion engines with a maximum throughput of 24 liters of gasoline per hour. Since the characteristics of the internal combustion engine have no further influence on the processes of the second stage, the stage can be designed the same for all internal combustion engines of this size.
  • the first stage is designed so that it can be adapted to very different maps. This variability is particularly advantageous when the final optimization of the volume flows to be controlled has not yet been determined.
  • the device is suitable for Changing the individual variable parameters to determine the adaptation to the map of certain internal combustion engines experimentally. Once the functional relationships to be taken into account in the first stage for an internal combustion engine type have been determined, the many adjustment options and intervention options in the first stage can of course be dispensed with.
  • the individual parameters can then be built into the circuit as fixed quantities, which can be manufactured using integrated technology, for example.
  • the circuit proposed here in analog logic can also be constructed in digital logic. Microprocessors can also be used advantageously.
  • the device according to FIG. 2 can also be modified such that the line 70 coming from the difference generator 54 is not connected to the throttle valve 55 but to the input 71 for ⁇ p of the first setpoint computer 60.
  • the line 72 coming from the accelerator pedal sensor 26 is not connected to the input 71 but to the throttle valve 55.
  • the accelerator pedal directly controls the throttle valve 55 here.
  • the setpoint computer 60 forms a setpoint for the fuel supply, which, as before, is used on the one hand Control of the fuel feed pump 13, on the other hand to form a new "setpoint" for the total airflow and thus to form a new control deviation, which is returned to the setpoint computer 60.
  • the same process variant can also be carried out if (for example in the device according to FIG. 1) the secondary air flow takes the place of the total air flow.
  • the term -g 2 .B acts in the same way when calculating the setpoint for ⁇ p v , that in the event of a sudden increase in the fuel supply a lower setpoint for the pressure drop of the primary air line is calculated.
  • the second throttle device 56 is throttled in the secondary air line, which would lead to a reduction in the secondary air flow. This would initially reduce the total air flow, which, however, is regulated by a setpoint that is independent of B. Consequently, the throttle valve 55 is opened at the same time and thus the suction in the cracked gas line is increased. Overall, primary air flow and secondary air flow are increased, but the ratio of the two flows is temporarily shifted in favor of the primary air flow.
  • FIGS. 2 to 9 can be simplified.
  • Such a simplified device is shown in FIGS. 10 and 11.
  • 253 and 252 denote the transducers for the accelerator pedal position and the engine speed, from whose signals in the first setpoint computer 260 of the first computer stage 250 the setpoint for the gasoline supply is formed.
  • the fuel flow is regulated by the fuel metering device 254 in proportion to the setpoint signal for B.
  • the setpoint signal for B is fed into a second setpoint computer 261.
  • This second setpoint calculator (FIG. 11) is constructed in such a way that the voltage signal present at input 301 and proportional to B is converted into one with RC elements amplifier 302 connected as a differentiator is given to form B.
  • the temperature setpoint T S (o) for steady-state operating states is therefore predetermined by the position of the tap of a potentiometer 303 connected to a constant voltage.
  • the tapped voltage is passed via an amplifier 304 (impedance converter) together with the output of the amplifier 302 to the one input of an amplifier 305, whereby to form the sum T S (o) + ⁇ (with ⁇ as a specifiable, the characteristic data of the internal combustion engine adjustable parameters), the signal B via a resistor 306 and the signal T S (o) via an adjustable resistor 307.
  • a temperature setpoint is now formed, which is changed in accordance with the time derivative B of the fuel supply when the fuel supply changes compared to the temperature setpoint T S (o) adapted to the stationary operating states.
  • the setpoint is now calculated for temperature control in such a way that a decrease in the reactor temperature is counteracted by an increase in the air ratio, but ⁇ 12 is otherwise kept at a constant value ⁇ 12 (o) .
  • the predeterminable value ⁇ 12 (o) is again tapped at a potentiometer 308, while the actual value T R of the reactor temperature can be entered, for example, as a negative voltage drop tapped at a resistance thermometer.
  • Lines 310, 311, 312 for ⁇ 12 (o) , T S (o) + ⁇ B and -T R are connected to the input an adder consisting of the resistors 313 and the amplifier 314.
  • the adder output is given via a resistor 315 to the input of a further amplifier 316, the input being grounded via a capacitor 317 and the resistor 315 being bridged by a diode 318.
  • the forward direction of the diode is from amplifier 315 to amplifier 316 when the output signal of amplifier 313 is positive for growing B. Then namely the input of the amplifier 316 is put through the diode 318 to the output potential of the amplifier 315 and it becomes the setpoint calculated.
  • the voltage at the capacitance 317 at the input of the amplifier 316 decays with the time constant RC and the setpoint becomes
  • the output signal of the setpoint computer 261 is now input into the second computer stage 251, which is also input with a constant setpoint for the total air, which is adapted to the stationary operating conditions.
  • the setpoints are then entered into difference formers 264 and 265 in order to add the corresponding actual values for the primary air and the total air, which are additive from the measured actual values for the primary air and the secondary air is formed to be compared.
  • the control deviations serve to adjust a throttle device 255 in the primary air supply and a throttle valve 256 at the inlet of the internal combustion engine until the control deviation disappears.
  • No controllable throttle device is provided in the secondary air supply 257. Rather, it only contains a constant throttle point 258, which ensures that a pressure drop comparable to the pressure drop in the primary air feed and the cracked gas generator occurs in the secondary air supply when the internal combustion engine is under load.
  • the throttle valve 256 is not fully open and the throttle device 255 is half open, the flow resistance in the secondary air supply should be so great that the division of the total air flow into primary air flow and secondary air flow, which is inversely related to the flow resistances, just requires that for this medium load condition Corresponds to air flows.
  • the throttle valve 256 By changing the throttle valve 256, the two flows can be regulated simultaneously and practically without changing in relation to one another, while the ratio of the two flows can be finely regulated by changing the throttle device 254 in the primary air supply.
  • the calculation of the primary air ratio proposed here has the effect that, when the fuel supply increases, the setpoint for the reactor temperature and thus the primary air ratio and (at the expense of the secondary air flow) the primary air flow is increased without significant delay.
  • Such enrichment can be achieved in the method according to the invention if the control (eg the throttle valve) for the total air flow or the secondary air flow responds with a time delay compared to the fuel supply and the primary air control when the accelerator pedal is depressed.
  • the control eg the throttle valve
  • the secondary air flow responds with a time delay compared to the fuel supply and the primary air control when the accelerator pedal is depressed.
  • FIG. 12 shows with curve 260 the torque M d measured when the fuel throughput increased from 4 to 6.5 liters of "straight run" gasoline per hour on a commercially available 2 1 engine and a device according to FIGS. 10 and 11.
  • the curve 261 shows the pressure drop at the primary air valve 255, which is half open when the load is low.
  • the fuel supply and at the same time the throttle valve 256 at the inlet of the engine are opened. This would lead to a slow increase in the primary air flow (slow increase in pressure drop), while the almost instantaneously responsive secondary air flow would increase disproportionately. However, this is prevented by fully opening the primary air valve 255, which. is recognizable by the disappearance of the pressure drop.
  • the primary air valve closes only gradually and the primary air flow is adjusted to the new steady state corresponding values.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
EP78100627A 1977-08-17 1978-08-08 Regelverfahren zum Betrieb eines Spaltgasgenerators und einer nachgeschalteten Brennkraftmaschine Withdrawn EP0000899A1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE19772737072 DE2737072A1 (de) 1977-08-17 1977-08-17 Regelverfahren zum betrieb eines spaltgasgenerators und einer nachgeschalteten brennkraftmaschine
DE2737072 1977-08-17
DE19772737531 DE2737531A1 (de) 1977-08-19 1977-08-19 Regelungsverfahren zum betrieb eines spaltgasgenerators und einer nachgeschalteten brennkraftmaschine
DE2737531 1977-08-19

Publications (1)

Publication Number Publication Date
EP0000899A1 true EP0000899A1 (de) 1979-03-07

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EP78100627A Withdrawn EP0000899A1 (de) 1977-08-17 1978-08-08 Regelverfahren zum Betrieb eines Spaltgasgenerators und einer nachgeschalteten Brennkraftmaschine

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US (1) US4421071A (it)
EP (1) EP0000899A1 (it)
JP (1) JPS5445416A (it)
IT (1) IT1098085B (it)

Cited By (1)

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Publication number Priority date Publication date Assignee Title
US20240084755A1 (en) * 2021-01-29 2024-03-14 Bayerische Motoren Werke Aktiengesellschaft Real-Time Determination of a Fresh-Air Mass in a Cylinder

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US5697346A (en) * 1993-05-28 1997-12-16 Servojet Products International Method for using sonic gas-fueled internal combustion engine control system
DE19727539C1 (de) * 1997-06-28 1998-06-10 Draegerwerk Ag Vorrichtung zur Erzeugung von Sauerstoff
DE10148649C1 (de) * 2001-10-02 2003-08-07 Bosch Gmbh Robert Verfahren sowie Steuer und/oder Regelgerät zum Betreiben einer Brennkraftmaschine, sowie Brennkraftmaschine

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DE2306026A1 (de) * 1973-02-07 1974-08-22 Siemens Ag Verfahren und vorrichtung zum betrieb einer brennkraftmaschine, insbesondere eines otto-motors, mit einem spaltgasgenerator
US3915125A (en) * 1971-07-16 1975-10-28 Siemens Ag Method for the operation of internal-combustion engines and gas reformer for implementing the method
DE2607573A1 (de) * 1975-02-25 1976-09-02 Cav Ltd Regelsystem fuer kraftstoffversorgungssystem eines brennkraftmotors
DE2649407A1 (de) * 1975-11-25 1977-06-02 Toyota Motor Co Ltd Verfahren und vorrichtung zur steuerung einer zur vorbehandlung des einer brennkraftmaschine zugefuehrten treibstoffs vorgesehenen einrichtung
DE2558922A1 (de) * 1975-12-29 1977-07-07 Siemens Ag Gasgenerator zur umsetzung eines reaktionsgemisches aus kohlenwasserstoffhaltigem brennstoff und einem sauerstoffhaltigen gas in ein brenngas

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JPS50116823A (it) * 1974-02-26 1975-09-12
US4131086A (en) * 1974-07-20 1978-12-26 Nippon Soken, Inc. Fuel reforming apparatus for use with internal combustion engine
US4147136A (en) * 1974-12-06 1979-04-03 Nippon Soken, Inc. Fuel reforming system for an internal combustion engine

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Publication number Priority date Publication date Assignee Title
US3915125A (en) * 1971-07-16 1975-10-28 Siemens Ag Method for the operation of internal-combustion engines and gas reformer for implementing the method
DE2306026A1 (de) * 1973-02-07 1974-08-22 Siemens Ag Verfahren und vorrichtung zum betrieb einer brennkraftmaschine, insbesondere eines otto-motors, mit einem spaltgasgenerator
DE2607573A1 (de) * 1975-02-25 1976-09-02 Cav Ltd Regelsystem fuer kraftstoffversorgungssystem eines brennkraftmotors
DE2649407A1 (de) * 1975-11-25 1977-06-02 Toyota Motor Co Ltd Verfahren und vorrichtung zur steuerung einer zur vorbehandlung des einer brennkraftmaschine zugefuehrten treibstoffs vorgesehenen einrichtung
DE2558922A1 (de) * 1975-12-29 1977-07-07 Siemens Ag Gasgenerator zur umsetzung eines reaktionsgemisches aus kohlenwasserstoffhaltigem brennstoff und einem sauerstoffhaltigen gas in ein brenngas

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20240084755A1 (en) * 2021-01-29 2024-03-14 Bayerische Motoren Werke Aktiengesellschaft Real-Time Determination of a Fresh-Air Mass in a Cylinder
US12215645B2 (en) * 2021-01-29 2025-02-04 Bayerische Motoren Werke Aktiengesellschaft Real-time determination of a fresh-air mass in a cylinder

Also Published As

Publication number Publication date
JPS5445416A (en) 1979-04-10
US4421071A (en) 1983-12-20
IT1098085B (it) 1985-08-31
IT7826713A0 (it) 1978-08-11

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