WO2013026517A1

WO2013026517A1 - Method and measuring arrangement for determining specific and/or absolute emissions values for nox and/or co2 in an internal combustion engine

Info

Publication number: WO2013026517A1
Application number: PCT/EP2012/003218
Authority: WO
Inventors: Knut Hoyer; Dimitrios T. HOUNTALAS
Original assignee: Testo Ag
Priority date: 2011-08-19
Filing date: 2012-07-28
Publication date: 2013-02-28
Also published as: DE102011110669A1; DE102011110669B4; CN103748340B; CN103748340A

Abstract

In a measurement arrangement for determining specific and/or absolute emissions values for NOx and/or CO2 (19) in an internal combustion engine (3), it is proposed that the profile with respect to time (5) of the cylinder pressure (1) at at least one cylinder (2) be measured and, from this, without direct measurement of a rotational angle of a crankshaft (7), a cylinder pressure curve (10) be derived which represents the relationship between the cylinder pressure (1) and a rotational angle of a crankshaft (7) of the internal combustion engine (3). It is furthermore proposed that, from said cylinder pressure curve (10) in combination with a CO2 - and/or O2 - concentration measurement, an output power (11) and an exhaust-gas mass flow rate (12) be determined, which are combined with a measured NOx concentration (17) in the exhaust gas (15) of the internal combustion engine (3) to give the specific and/or absolute emissions values for NOx and/or CO2 of the internal combustion engine (3).

Description

Method and measuring arrangement for determining specific and / or absolute emission values for NOx and / or C02 in an internal combustion engine

The invention relates to a method for determining specific and / or absolute emission values for NO _x and / or C0 ₂ in an internal combustion engine. The invention further relates to a measuring arrangement for determining specific and / or absolute

Emission values for NO _x and / or C0 ₂ in an internal combustion engine. Here, the absolute emission value indicates the emitted mass per unit time, for example in kilograms per hour, while the specific emission value indicates the emitted mass per unit time in relation to the power, for example in grams per kilowatt hour.

It is known to measure such values in order to control, for example, compliance with legal requirements in an internal combustion engine or to compare the emission of internal combustion engines.

In order to come to the results mentioned, the exhaust gas mass flow must be known or determined. Alternatively, these results can also be calculated from the power and the fuel consumption. The direct measurement of these quantities, however, proves to be difficult in practice. Often, such measurements are only on special test benches, but not in normal operation of the combustion engine. machine in the installed position possible. This is particularly disadvantageous when internal combustion engines or in the field, for example marine diesel engines on ships, are to be measured or monitored. It has been found that the power measurement, especially the mass flow measurement of the known type requires a comprehensive apparatus that can be subject to high measurement errors. The equipment is also expensive and often time-consuming to use. As a further disadvantage of the known methods, it has been found that the internal combustion engines each have to be out of operation in order to install the measuring technology.

The invention has for its object to provide an alternative, easy to handle way to obtain the relative or absolute emission levels for NO _x and / or C0 ₂ in an internal combustion engine.

To achieve the object is inventively provided in a method of the type mentioned that the time course of a cylinder pressure measured at least one cylinder of the internal combustion engine and from a cylinder pressure curve of the cylinder pressure in dependence on a rotational angle of a crankshaft is determined that from the Zy - Linder pressure curve then on the one hand an output of the internal combustion engine and on the other hand an exhaust gas mass flow is determined and that the determined exhaust gas mass flow with a measured NO _x concentration in the exhaust gas of the internal combustion engine, in particular of the cylinder, and with the specific output power to the specific and / or absolute emission values for NO _x and / or C0 _{2 is} combined. The invention has the advantage over the known methods that the angle of rotation of the crankshaft does not have to be measured directly. Rather, the associated rotation angle is derived from the time course of the cylinder pressure without a frequently erroneous synchronization between a measurement of the rotation angle and a measurement of the cylinder pressure is required. The cylinder pressure curve is thus derived from the time profile of the cylinder pressure, without a measurement of a rotation angle of a crankshaft is required. This has the further advantage that the crankshaft does not have to be accessible for a rotation angle measurement. The combustion engine can therefore be measured in built-in position and during operation without modifications. The measurement of the NO _x - Concentration ion in the exhaust gas can be carried out together and performed separately for all cylinders or for the individual cylinders.

In one embodiment of the invention can be provided that for each cylinder of the internal combustion engine measured in each case a time course of a cylinder pressure and from a cylinder pressure curve of the cylinder pressure in dependence on one or the rotation angle of one or the crankshaft is determined. The advantage here is that estimates of a time course of a cylinder pressure on unmated cylinders can be avoided. Another advantage is that accurate measurement results are available for all cylinders in order to be able to determine the emission values with high accuracy. In one embodiment of the invention it can be provided that the output power is determined from an indicated power, wherein a predetermined mechanical efficiency of the internal combustion engine is used. In this case, the indicated power designates the theoretical power of the combustion engine on the assumption that the expansion work of the combustion gas is converted completely friction-free into the stroke movement of the piston. The mechanical efficiency in particular compensates for the friction losses occurring in the real combustion engine. For example, it can be provided that the mechanical efficiency is measured in advance on a test bench or a correlation is used for a mechanical efficiency. This can preferably be done by factory tests or by tests on a test bench. The mechanical efficiency measured in this way can then be stored in a storage means and kept ready for use in the method according to the invention. It can also be provided that the mechanical efficiency is estimated based on stored correlations. These correlations can take into account, for example, the friction effects in a manner known per se. The consideration of the friction losses and the estimation of the (actual) power output are known, for example, in methods in which the power is determined by the instantaneous measurement of the cylinder pressure. For this purpose, in the known methods, a rotational angle sensor has hitherto been used on the crankshaft in order to determine the current working position of the cylinder. However, this requires a conversion of existing combustion engines and far-reaching intervention in these before the measurement and thus an undesirable interruption of the operation.

In one embodiment of the invention, it may be provided that a rotation angle required for determining the indicated power or the power output is determined based on an upper reversal point or dead center of the cylinder. For example, this can be done by evaluating the cylinder pressure curve. For this purpose, for example, a reference pressure can be defined, which characterizes the upper reversal point or dead center. The advantage here is that the reversal point of the cylinder a comparatively accurate inference to the current angle of rotation of the crankshaft allowed.

The determination of the upper reversal point from the cylinder pressure curve is known per se and can be used to advantage here to replace the angular measurement on the crankshaft.

The direct measurement of the exhaust gas mass flow is particularly difficult in internal combustion engines, which are to be measured in the installed working position, as difficult, since the exhaust duct is usually not accessible without extensive work and in the known measurement method large measurement error probabilities are present. In one embodiment of the invention can therefore be provided that the cylinder pressure curve is evaluated by a computer program to determine the exhaust gas mass flow, wherein the computer program includes a motor model. The advantage here is that measurements of flow rates or flow rates are dispensable.

In one embodiment of the invention can be provided that a measurement of C0 ₂ -Konzentrat ion is carried out in the exhaust gas to determine the exhaust gas mass flow. This can be done, for example, by calculating a carbon balance. The advantage here is that the CO ₂ concentration can be measured comparatively easily by taking a sample from the exhaust gas.

It can also be provided that a measurement of the O ₂ concentration in the exhaust gas is carried out to determine the exhaust gas mass flow. This determination can preferably be carried out by calculating an oxygen balance. Again, it is advantageous that concentration measurements are easy to carry out. It is advantageous if the exhaust gas mass flow is determined using a motor model. It can be provided that the engine model simulates an open thermodynamic cycle of the internal combustion engine and thus a gas exchange at the internal combustion engine. Thus, an easily manageable and implementable means for determining the exhaust gas mass flow is provided.

Alternatively or additionally, it may be provided that an intake and exhaust system of the internal combustion engine is simulated with the engine model to the time course of pressure and temperature in the intake and exhaust system and / or in the at least one cylinder, in particular in all cylinders determine. The advantage here is that with known thermodynamic equations the exhaust gas mass flow can be calculated.

It can therefore be provided that the cylinder pressure curve is processed to determine the exhaust gas mass flow, the principles of energy and mass conservation being taken into account by a motor model which models a gas exchange process of the internal combustion engines. Preferably, the engine model models the mass exchange between the intake system, combustion chamber and exhaust system.

It can be provided, for example, that a mass flow of unburned intake air through the cylinder is taken into account with the engine model. The advantage here is that the accuracy in the determination or calculation of the exhaust gas mass flow can be improved even further.

It can also be provided that a combustion rate is derived from the cylinder pressure curve and from this a fuel consumption is derived. It can be provided that a heat release rate analysis is carried out to determine the fuel consumption. Such heat release rate analyzes are known per se by the term "heat release rate analysis" for various purposes in the pertinent technical literature.Figure may be provided that the heat release rate analysis is carried out by analyzing the cylinder pressure curve additional input variables are largely dispensable.

Often the literature on heat release rate analysis considers net heat release, heat losses, and total heat release. This can be used with advantage here.

It can be provided that the measurements of the time profile of the cylinder pressure for each cylinder are carried out in succession. The advantage here is that the equipment required to carry out the process is minimized. It can also be provided that the measurements of the time profile of the cylinder pressure for the cylinders are carried out simultaneously. The advantage here is that the time required to carry out the method according to the invention is as minimal as possible.

In one embodiment of the invention can be provided that the internal combustion engine is a diesel engine. The internal combustion engine may be, for example, a marine diesel engine or a stationary diesel engine. Thus, the method can be used in particular for monitoring limit values even in comparatively large internal combustion engines, in which the measurement variables otherwise required for measuring emission values are difficult or only accessible with considerable modifications. For example, it can be provided that the time profile of the cylinder pressure is measured or tapped via an indexing cock of the cylinder. The advantage here is that the indicator tap provides a measuring access, which is just as standard in marine diesel engines or stationary diesel engines designed and available. The use of the indicator tap makes it possible to carry out the method according to the invention on an internal combustion engine without requiring conversions on the internal combustion engine or requiring it to be stopped separately.

For measuring the time profile of the cylinder pressure according to the invention, it can be provided that the cylinder pressure is measured at predetermined times. It is particularly favorable if these times are regularly spaced from one another. For example, the times may be evenly spaced from one another, or a rule may be defined with which the time interval is determined as a function of the measured variable or of its change. Thus, the times at which the cylinder pressure is measured, can be optimally adjusted to the measured time course.

To achieve the object mentioned, it is provided according to the invention in a measuring arrangement of the type mentioned in the introduction that at least one pressure sensor for measuring a chronological progression of the cylinder pressure is connected or connectable to at least one cylinder, preferably to several or all cylinders of the internal combustion engine Signal output of the pressure sensor is connected to a data processing unit or can be connected, that the data processing unit is set to determine a cylinder pressure curve, which represents the dependence of the cylinder pressure of a rotation angle of a crankshaft, from the time course of the cylinder pressure, that the data Processing unit for determining an output of the internal combustion engine from the cylinder pressure curve and for determining an exhaust gas mass flow from the cylinder pressure curve is arranged that an exhaust NO _x - esseinheit for measuring the NO _x concentration in the exhaust gas of the internal combustion engine, in particular of the at least one cylinder to the internal combustion engine connected or connectable that a signal output of the exhaust gas NO _x measuring unit is connected to the data processing unit and that the Datenverar- processing unit for calculating the specific and / or absolute emission values for NO _x and / or C0 ₂ from the determined exhaust gas mass flow and the measured NOx concentration is set up. The advantage here is that an easily manageable measuring arrangement is provided with which the method according to the invention can be carried out without intervention in the workflow of the internal combustion engine are required. The data processing unit is preferably set up for calculating the specific and / or absolute emission values from the output power, the exhaust gas mass flow and the NO _x concentration.

In one embodiment of the invention it can be provided that a pressure sensor for measuring the time profile of the cylinder pressure is connected or connectable to each cylinder of the internal combustion engine, that a signal output of one or each pressure sensor is connected to a data processing unit or connectable. The advantage here is that the cylinders of the internal combustion engine are individually dimensioned. Thus, accurate measurement data can be provided.

It can be provided that the data processing unit is set up to determine an upper reversal point of the cylinder from the cylinder pressure curve. The advantage here is that a reference measurement for determining the angular Position of the crankshaft is not required. Rather, a reference pressure can be defined, and the upper reversal point can be characterized in that the cylinder pressure reaches or exceeds this reference pressure. Accordingly, a lower reversal point can be characterized by reaching or falling below a (further) reference pressure. This is particularly beneficial when the crankshaft is not accessible from the outside. It can be provided that at least one piece of information, in particular a correlation, is stored in a storage means via a mechanical efficiency of the internal combustion engine. Thus, the output of the engine of an indicated power can be determined.

In an embodiment of the invention, it may be provided that the data processing unit has a time-measuring means for measuring the time profile of the cylinder pressure.

In one embodiment of the invention can be provided that the internal combustion engine is connected to an exhaust C0 ₂ -Messeinheit with which the C0 ₂ concentration in the exhaust gas can be determined. This can be used for example for the determination of the exhaust gas mass flow and / or the fuel consumption and can be used for this purpose.

Alternatively or additionally, it can be provided that the internal combustion engine is connected to an exhaust gas 0 ₂ measuring unit with which the 0 ₂ concentration in the exhaust gas can be determined. This can be used for example for the determination of the exhaust gas mass flow and / or the fuel consumption and can be used for this purpose. Another advantage is that concentration measurements on the exhaust gas are relatively easy to carry out. It can be provided that in the data processing unit, an engine model of the internal combustion engine is realized with which the exhaust gas mass flow from the cylinder pressure curve can be calculated. Thus, additional measuring points on the internal combustion engine for determining the exhaust gas mass flow can be dispensed with.

It can be provided that the engine model depicts a carbon mass balance and / or an oxygen balance of the internal combustion engine. The advantage here is that the exhaust gas mass flow can be calculated from known thermodynamic and / or chemical relationships. It can also be provided that in the data processing unit a means for heat release rate analysis (heat release rate analysis) is formed, which is set up to calculate the fuel consumption from the cylinder pressure curve. The advantage here is that additional measuring means for the direct measurement of fuel consumption are dispensable.

It is particularly favorable if the internal combustion engine is a diesel engine, in particular a marine diesel engine or stationary diesel engine. The advantage here is that thus legal requirements that apply to diesel engines, in a simple manner when operating the internal combustion engine in working position are verifiable.

It can be provided that the pressure sensor is connected to the indicator tap of the cylinder or can be connected. The advantage here is that an already existing measurement access for connection of the measuring arrangement is available.

It may be provided in an embodiment of the invention that the exhaust NO _x measurement unit in or on an exhaust the combustion engine is arranged or can be arranged. The advantage here is that the exhaust forms an easily accessible from the outside measuring point, which is accessible without structural modifications of the internal combustion engine. Alternatively or additionally, it can be provided that the exhaust gas C0 ₂ - measuring unit is arranged or can be arranged in or on or an exhaust of the internal combustion engine. It can also be provided that the exhaust gas 0 ₂ measuring unit is arranged or can be arranged in or on or an exhaust of the internal combustion engine. Embodiments in which these features are present in combination are particularly favorable.

A particularly easy-to-handle measuring arrangement results when the exhaust NO _x measuring unit is integrated into a portable measuring device. Additionally or alternatively, it may also be provided that the exhaust gas C0 ₂ measuring unit is integrated in a transportable measuring unit. Additionally or alternatively, it may also be provided that the exhaust gas 0 ₂ measuring unit is integrated into a transportable measuring unit.

The exhaust gas NO _x measuring unit, the exhaust gas CO ₂ metering unit and the exhaust gas metering unit _{2 are} preferably integrated in the same transportable measuring unit, which can be connected or connectable to the data processing unit.

The data processing unit can be designed as a portable computer, for example as a laptop, netbook or the like.

The measuring arrangement can also be designed as a stationary or permanently installed device with which the method according to the invention can be carried out and executed continuously, for example continuously or cyclically recurring. In this case, each cylinder of the combustion engine be associated with an individual pressure sensor. The cycles can have lengths of a few seconds to a few hours or days. The measuring arrangement may have a control unit which is mounted on a ship's bridge or a driver's cab. Thus, a direct remote monitoring during operation is possible.

The measuring arrangement may be provided with a position measuring system, for example a GPS measuring device, and / or with further measuring devices of a vehicle, in particular a ship, such as e.g. a speedometer, be connected. Thus, the emission data can be linked with position data of the internal combustion engine and / or with vehicle data, in particular ship data. Thus, the emission data can be related to specific emission protection areas in which the emission took place.

The emissions data and / or the data associated therewith may be communicated via GSM, Internet or other wireless or wired communication means and channels to a remote control or remote maintenance system, for example a technical office. In addition, measurements or sensors for the charge air temperature and / or the charge air pressure can be provided. The advantage here is that the accuracy of the performance determination and the fuel consumption determination can be improved, since in addition fluctuations in the temperature and / or the pressure of the charge air can be taken into account in the process.

A particularly compact embodiment of the measuring arrangement provides that all components except for the pressure sensor and a sampling probe or line to the exhaust or fuel Ent- are integrated into a preferably portable device. The advantage here is that the Zyl inderdruck; and the exhaust gas with only one device, eg designed as a hand-held device, and can be analyzed by the method according to the invention. The necessary measurements of the method are thus feasible with only one device, and also the subsequent data processing is integrated and executed in the device.

The invention will now be described in more detail with reference to an exemplary embodiment, but is not limited to this exemplary embodiment. Further exemplary embodiments result from combination of one or more features of the protection claims with one another and / or with one or more features of the exemplary embodiment. It shows:

1 shows a flowchart of the method according to the invention in a highly simplified representation and FIG. 2 shows a schematic diagram of a measuring arrangement according to the invention in a highly schematic representation.

Fig. 1 shows in a block diagram important steps in the course of a method according to the invention.

FIG. 2 shows in a greatly simplified schematic diagram for explaining the invention important components of a measuring arrangement according to the invention. Both figures will be described together below.

In the flowchart of FIG. 1 it can be seen that a cylinder pressure 1, which prevails in a cylinder 2 of an internal combustion engine 3 shown in FIG. 2, is detected as an input variable. The measuring arrangement in FIG. 2 denoted as a whole by 4 measures the time profile 5 of this cylinder pressure 1 and supplies the information about the time profile 5 to a data processing unit 6.

In the data processing unit 6, a cylinder pressure curve of the cylinder pressure is determined from the time profile of the cylinder pressure, ie a time-dependent curve, which reproduces the dependence of the cylinder pressure on the rotational angle of the crankshaft.

For measuring the cylinder pressure 1, the measuring arrangement 4 has a pressure sensor 8 whose signal output 9 is connected to the data processing unit 6.

The data processing unit 6 or the pressure sensor 8 are equipped with a timing means 23, not shown, with which the time course 5 of the cylinder pressure 1 can be detected.

The time measuring means 23 in the data processing unit 6 in this case predetermines a clock with which the measured values of the cylinder pressure 1 are to be measured.

In order to determine the cylinder pressure curve 10 already mentioned, the data processing unit 6 evaluates the shape of the time curve 5 of the cylinder pressure, in particular the position and width of the maxima and minima, preferably over a period corresponding to several cycles of operation of the internal combustion engine 3.

From this cylinder pressure curve 10, the data processing unit 6, in cooperation with the other components of the measuring arrangement 4, determines an output power 11 of the measuring system. Combustion engine 3 and in particular of the currently connected to the pressure sensor 8 cylinder. 2

From the cylinder pressure curve, the data processing unit 6 can also determine, in interaction with the other components of the measuring arrangement 4, an exhaust gas mass flow 12 which characterizes the mass flow of the exhaust gas at the cylinder 2 being examined. The measuring arrangement 4 further has an exhaust gas NO _x measuring unit 13 which can be connected to the internal combustion engine 3 and in particular to an outlet connection (not shown) of a currently measured cylinder 2 or to the exhaust 31, and whose signal output 14 is connected to the data processing unit 6 is.

Thus, the exhaust gas NO _x measuring unit 13 is supplied with exhaust gas 15 of the internal combustion engine 3 with a probe 16, and the exhaust gas NOx measuring unit 13 measures the NO _x concentration 17 in the exhaust gas 15.

In a further calculation step 18, the data processing unit 6 combines the provided values of the output 11, the exhaust gas mass flow 12 and the NOx concentration 17 into a numerical value 19 for the specific and / or absolute emission values for NO _x and / or CO ₂ , preferably for NO _x and particularly preferably for NO _x and C0 ₂ .

For the evaluation of the exhaust gas measurement, the cylinder pressure measurement is synchronized in time with the exhaust gas measurement. For this purpose, the time measuring means 23 can be used.

To determine the output power 11, the indexed power of the cylinder 2 is considered which represents the ideal, loss-free, theoretical ratios in the combustion process. Machine 3 describes. To calculate the real output power 11, the indicated power is calculated with a mechanical efficiency of the internal combustion engine 3, which describes the losses occurring at the real combustion engine 3. This mechanical efficiency was previously determined or measured at the factory or on a test bench for the internal combustion engine 3 and stored and provided in a storage means 20 of the measuring arrangement 4. Alternatively, the mechanical efficiency may be derived with the data processing unit 6 using a general correlation from a reference measurement.

The measurement of the mechanical efficiency was therefore in the described embodiment not in the working position in the installed state of the internal combustion engine 3, but before installation of the internal combustion engine 3 or during maintenance of the internal combustion engine 3 on a special test in a conventional manner.

To determine the indicated power, in particular in the data processing unit 6, an upper reversal point of the cylinder 2 is determined by evaluating the cylinder pressure curve 10 and in particular its shape.

The determination of the exhaust gas mass flow 12 can be carried out with the measuring arrangement 4 according to the invention in different ways. In the data processing unit 6 for this purpose, a computer program 21 is deposited, which images a motor model 22 of the internal combustion engine 3.

This engine model 22 simulates the open thermodynamic cycle of the internal combustion engine 3 and thus forms the gas exchange at the internal combustion engine 3 from.

The engine model 22 further simulates the intake and exhaust system, indicated by an exhaust 31, the combustion engine 3. With this simulation, the time course of pressure and temperature in the cylinders 2, in particular in the respective combustion chamber determinable.

In addition, the engine model 22 takes into consideration a mass flow of the unburned intake air through the cylinder 2.

The measuring arrangement 4 further comprises an exhaust gas C0 ₂ measuring unit 24, which is arranged in a conventional manner for measuring the C0 ₂ concentration 25 in the exhaust gas 15 and which also to the probe 16 for removing a portion of the exhaust gas 15 of Combustion engine 3 is connected.

The measuring arrangement 4 furthermore has an exhaust gas 0 ₂ measuring unit 26, with which the 0 ₂ concentration 27 in the exhaust gas 15 can be measured in a manner known per se.

The exhaust gas 0 ₂ measuring unit 26 is also connected to the probe 16 for removing the exhaust gas 15. With the probe 16, the measuring arrangement 4 can thus be connected to the exhaust 31 of the internal combustion engine 4 for carrying out the method according to the invention.

FIG. 2 shows that the exhaust gas NO _x measuring unit 13, the exhaust gas CO ₂ measuring unit 24 and the exhaust gas 0 ₂ measuring unit 26 are integrated in a gas analyzer 28, wherein the measuring signals of the measuring units 13, 24, 26 exceed the common signal output 14 are guided to the data processing unit 6. In further embodiments, the measuring units 13, 24, 26 also formed separately from each other and connected to the data processing unit 6. All components can also be integrated in one device. From the measurement results for the C0 ₂ concentration 25 and for the 0 ₂ concentration 27, the data processing unit 6 calculates the exhaust gas mass flow 12 in a calculation step 29 with the likewise determined fuel consumption 30 of the internal combustion engine 3 or of the cylinder 2.

This can be done alternatively or in addition to the calculation with the engine model 22.

In the calculation step 29, the carbon balance and the oxygen balance of the combustion process in the cylinder 2 are calculated and evaluated for this purpose.

Here, the determination of the specific and / or absolute emission values for NO _x and / or C0 ₂ for all cylinders 2 in a collective exhaust not shown or otherwise carried out simultaneously or simultaneously in time. Alternatively, when the determination of the specific and / or absolute NO _x and / or CO ₂ emission levels for one cylinder 2 is completed, the pressure sensor 8 and the probe 16 may be connected to the next cylinder 2 of the internal combustion engine 3 so as to obtain the same as that shown in FIG 1. Repeat procedures for the new or next cylinder. For this purpose, in each case the pressure sensor 8 is connected to the respective indexing cock of the cylinder 2 in order to measure the time profile 5 of the cylinder pressure 1 at this cylinder 2. The already mentioned fuel consumption 30 is calculated from the low pressure curve 10 by means of heat release rate analysis, heat release rate analysis determined. It is possible in further embodiments, a direct measurement of fuel consumption.

It should be noted that the internal combustion engine 3 in FIG. 2 is a marine diesel engine. In further fields of application of the invention, the internal combustion engine 3 can also be designed as another diesel engine, for example as a stationary diesel engine for generators and the like, or else in a wide variety of vehicles. However, the internal combustion engine 3 is preferably a diesel engine which has an indicator tap on one or each cylinder 2, which can be used to connect the pressure sensor 8.

The components of the measuring arrangement 4 shown individually in FIG. 2 are integrated in a transportable measuring unit. The measuring arrangement 4 furthermore has a display unit (not shown further) with which the invoice results, in particular the specific and / or absolute emission values for NO _x and / or CO ₂ , can be displayed. In the measuring arrangement for determining specific and / or absolute emission values for NO _x and / or CO ₂ 19 in an internal combustion engine 3, it is proposed to record the time profile 5 of the cylinder pressure 1 at at least one cylinder 2 and from this without direct measurement of a rotation angle Crankshaft 7 to derive a cylinder pressure curve 10, which maps the relationship of the cylinder pressure 1 with a rotation angle of a crankshaft 7 of the internal combustion engine 3. It is further proposed from this cylinder pressure curve 10 or from all measured cylinder pressure curves 10 in combination with a C0 ₂ - and / or 0 ₂ concentration measurement to determine an output 11 and a Ab ^¬ gas mass flow 12, which with a measured NO _x concentration 17 in the exhaust gas 15 of the internal combustion engine 3 to the specific and / or absolute emission values for NO _x and / or C0 _{2 of} the internal combustion engine. 3 be combined .

Claims

claims

A method for the determination of specific and / or abso ^¬ Luten emission values for NO _x and / or C0 ₂ (19) in an internal combustion engine (3), characterized in that a time profile (5) (a cylinder pressure (1) at least one cylinder 2) of the internal combustion engine (3) is measured and from this a cylinder pressure curve (10) of the cylinder pressure (1) is determined as a function of a rotational angle of a crankshaft (7) that from the cylinder pressure curve (10) then on the one hand an output power (11) of the internal combustion engine ( 3) and on the other hand, an exhaust gas mass flow (12) is determined and that the determined exhaust gas mass flow (12) with a measured NO _x - concentrate ion (17) in the exhaust gas (15) of the internal combustion engine (3), in particular of the cylinder (2), and the specific output power (11) is combined to the specific and / or absolute emission values for NO _x and / or C0 ₂ (19).

A method according to claim 1, characterized in that for each cylinder (2) of the internal combustion engine (3) in each case a time course (5) of a cylinder pressure measured and therefrom a cylinder pressure curve (10) of the cylinder pressure (1) in dependence on or the rotation angle of a or the crankshaft (7) is determined.

A method according to claim 1 or 2, characterized in that the output power (12) is measured from an indicated power, wherein a predetermined mechanical efficiency of the

Combustion engine (3) is used, and / or that the mechanical efficiency in advance on a test bench or a correlation is used for a mechanical efficiency, in particular by factory tests or by experiments.

Method according to one of claims 1 to 3, characterized in that for determining the indicated power an upper reversal point of the cylinder (2) is determined, in particular from the cylinder pressure curve (10), and / or that for determining the

Exhaust gas mass flow (12) the cylinder pressure curve (10) is evaluated by a computer program (21), wherein the computer program (21) includes a motor model (22).

Method according to one of claims 1 to 4, characterized in that for the determination of the exhaust gas mass flow (12) a measurement of the C0 ₂ -Konzentrat ion (25) in the exhaust gas (15) is performed, in particular under calculation of a carbon balance, and / or that Determining the exhaust gas mass flow (12) a measurement of 0 ₂ -Concentration (27) in the exhaust gas (15) is performed, in particular under calculation of an oxygen balance.

Method according to one of claims 1 to 5, characterized in that the exhaust gas mass flow (12) using an engine model (22) is determined, in particular wherein the engine model (22) an open thermodynamic cycle of the internal combustion engine (3) and thus a gas exchange is simulated on the internal combustion engine (3) and / or that with the engine model (22) an intake and exhaust system (31) of the internal combustion engine is simulated to determine the time course of pressure and temperature in the at least one cylinder (2).

Method according to one of claims 1 to 6, characterized indicates that the motor model (22) a mass ^¬ stream of unburned intake air through the cylinder (2) is taken into account and / or that is derived from the cylinder pressure curve (10) a combustion rate and out of a fuel consumption (30), in particular wherein from the fuel consumption and the or an air mass flow the exhaust gas mass flow (12) is determined, and / or that for determining the fuel consumption (30) a heat release rate analysis (heat release rate analysis), in particular by analysis of the cylinder pressure curve (10), is carried out.

Method according to one of claims 1 to 7, characterized ge ^¬ indicates that the measurements of the time course (5) of the cylinder pressure (1) for each cylinder (2) are performed sequentially or simultaneously and / or that the internal combustion engine (3) is a diesel engine , in particular a marine diesel engine or a stationary diesel engine, and / or that the time profile (5) of the cylinder pressure (1) via an indicator tap of the cylinder (2) is measured or tapped.

Method according to one of claims 1 to 8, characterized in that for measuring the time profile (5) of the cylinder pressure (1) the cylinder pressure (1) is measured at predetermined, in particular regularly spaced from each other, times and / or that additionally the charge air temperature and / or the charge air pressure are measured.

0. Measuring arrangement (4) for determining specific and / or absolute emission values for NO _x and / or CO ₂ (19) in an internal combustion engine (3), characterized in that at least one pressure sensor (8) for measuring the time profile (5 ) of the cylinder pressure (1) to at least one cylinder (2) of the internal combustion engine (3) is connected or connectable that a signal output (9) of the pressure sensor (8) to a data processing unit (6) is connected or connectable, that the data processing unit (6) for determining a cylinder pressure curve (10), which reproduces the dependence of the cylinder pressure (1) of a rotation angle of a crankshaft (7), from the time course

(5) of the cylinder pressure (1) is set up, that the data processing unit (6) for determining an output power (11) of the internal combustion engine (3) from the cylinder pressure curve (10) and for determining an exhaust gas mass flow (12) from the cylinder pressure curve (10) in that an exhaust gas NO _x measuring unit (13) for measuring the NO _x concentration (17) in the exhaust gas (15) of the internal combustion engine (3), in particular of the at least one cylinder (2), is connected to the internal combustion engine (3) or that it is possible to connect a signal output (14) of the exhaust NO _x measuring unit (13) to the data processing unit (6) and that the data processing unit (6) calculates the specific and / or absolute NO _x and / or emission values C0 ₂ (19) from the determined exhaust gas mass flow

(12) and the measured NO _x -Konzentrat ion (17) is set up.

Measuring arrangement (4) according to claim 10, characterized in that at each cylinder (2) of the internal combustion engine (3) a pressure sensor (8) for measuring the time course (5) of the cylinder pressure (1) is connected or connectable, that a signal output ( 9) of the or each pressure sensor (8) to a data processing unit

(6) is connected or connectable.

Measuring arrangement (4) according to claim 10 or 11, characterized indicates that the data processing unit (6) for determining an upper reversal point of the cylinder (2) from the cylinder pressure curve (10) is arranged and / or that in a memory means (20) at least one information, in particular a correlation, on a mechanical efficiency of the internal combustion engine

(3) is deposited and / or that the

Data processing unit (6) for measuring the time course (5) of the cylinder pressure (1) a time measuring means

(23).

Measuring arrangement (4) according to one of claims 10 to 12, characterized in that the internal combustion engine

(3) is connected to an exhaust C0 ₂ measuring unit (24), with which the C0 ₂ concentration (25) in the exhaust gas

(15) is determinable and / or that the

Combustion engine (3) to an exhaust gas 0 ₂ measuring unit

(26) is connected, with which the 0 ₂ concentration

(27) in the exhaust gas (15) can be determined.

Measuring arrangement (4) according to one of claims 10 to 13, characterized in that in the data processing unit (6) an engine model (22) of the internal combustion engine (3) is realized, with which the exhaust gas mass flow (12) from the cylinder pressure curve (10) is calculable, and / or that the engine model (22) maps a carbon balance and / or an oxygen balance of the internal combustion engine (3) and / or that in the data processing unit (6) a means for heat release rate analysis (heat release rate analysis) is formed, which is set up to calculate the fuel consumption (30) from the cylinder pressure curve (10).

Measuring arrangement (4) according to one of claims 10 to 14, characterized in that the internal combustion engine (3) is a diesel engine, in particular a marine diesel engine or stationary diesel engine, and / or that the pressure sensor (8) to the indexing cock of the cylinder (2) is connected or connectable.

Measuring arrangement (4) according to one of Claims 10 to 15, characterized in that the exhaust gas NO _x measuring unit (13) and / or the exhaust gas CO ₂ measuring unit (24) and / or the exhaust gas 0 ₂ measuring unit ( 26) is arranged or can be arranged in or on an exhaust pipe (31) of the internal combustion engine (3) and / or that the exhaust gas NO _x measuring unit (13) and / or the exhaust gas CO ₂ measuring unit (24) and / or the exhaust gas O ₂ measuring unit (26) is / are integrated in a transportable measuring unit.

Measuring arrangement (4) according to one of claims 10 to 16, characterized in that the measuring arrangement (4) is designed as a stationary or permanently installed device and / or that sensors for the charge air temperature and / or the charge air pressure are provided and designed.