Method and control device for determining a gas consumption of a gas-powered engine

Abstract

A method for determining a gas consumption of a gas-powered gas engine or a gas-powered dual-fuel engine. The engine is operated under actual operating conditions, and the actual gas consumption of the engine is acquired under the actual operating conditions. A target gas consumption of the engine to be anticipated under target operating conditions is calculated depending on the actual gas consumption and depending on discrepancies between the actual operating conditions and the target operating conditions.

Claims

1. A method for determining a gas consumption of a gas-powered engine, comprising: operating the gas-powered engine under actual operating conditions; acquiring an actual gas consumption of the gas-powered engine under the actual operating conditions; calculating a target gas consumption anticipated under target operating conditions depending on the actual gas consumption and discrepancies between the actual operating conditions and the target operating conditions; compensating the actual operating conditions based at least in part on the calculation; and operating the gas-powered engine under the compensated actual operating conditions, wherein the calculation of the target gas consumption is carried out according to the following equations:
V.sub.TARGET=V.sub.ACTUAL*KR1*KR2*KR3*KR4*KR5*KR6*KR7*KR8
KR1=1+k1*(T.sub.U-ACTUALT.sub.U-TARGET)
KR2=1k2*(p.sub.U-ACTUALp.sub.U-TARGET)
KR3=1+k3*(p.sub.AG-ACTUALp.sub.AG-TARGET)
KR4=1+k41*ML.sub.ACTUAL.sup.K42*(p.sub.LL-ACTUALp.sub.LL-TARGET)
KR5=1+k5*(MZ.sub.ACTUALMZ.sub.TARGET)
KR6=1+k61*(ZZP.sub.ACTUAL.sup.2ZZP.sub.TARGET.sup.2)K62*(ZZP.sub.ACTUALZZP.sub.TARGET)
KR7=1k7*(T.sub.LL-ACTUALT.sub.LL-TARGET)
KR8=1+k8*(H.sub.U-ACTUALH.sub.U-TARGET), wherein: V.sub.TARGET is one of the target gas consumption of the gas-powered engine and a reference gas consumption of the gas-powered engine, V.sub.ACTUAL is an actual gas consumption of the gas-powered engine, T.sub.U is an ambient air temperature, p.sub.U is an ambient air pressure, P.sub.AG is an exhaust gas backpressure, p.sub.LL is a charge pressure, MZ is a methane number of the gas, ZZP is an ignition timing of the gas-powered engine, T.sub.LL is a charge air temperature, H.sub.U is an ambient air humidity, ML is an engine load, and k1, k2, k3, k41, k42, k5, k61, k62, k7, k8 are engine-dependent constants.

2. The method according to claim 1, wherein the engine-dependent constants k1, k2, k3, k41, k42, k5, k61, k62, k7, k8 are based on a type of lambda control in the gas-powered engine.

3. The method according to claim 2, wherein with a lambda control via charge air discharge, k1, k2, k3 each equal 0, and k41, k42, k5, k61, k62, k7, k8 are each greater than 0 and less than 1.

4. The method according to claim 2, wherein with a lambda control via one of a wastegate and a variable turbine geometry, charge air discharge, k1, k2, k3, k41, k42, k5, k61, k62, k7, k8 are each greater than 0 and less than 1.

5. The method according to claim 1, wherein the gas-powered engine is one of a gas-powered gas engine and a gas-powered dual-fuel engine.

6. A control device of a gas-powered engine, having a processor and memory, the control device configured to: operate the gas-powered engine under actual operating conditions; acquire an actual gas consumption of the gas-powered engine under the actual operating conditions; calculate a target gas consumption anticipated under target operating conditions depending on the actual gas consumption and discrepancies between the actual operating conditions and the target operating conditions; compensating the actual operating conditions based at least in part on the calculation; and operating the gas-powered engine under the compensated actual operating conditions, wherein the calculation of the target gas consumption is carried out according to the following equations:
V.sub.TARGET=V.sub.ACTUAL*KR1*KR2*KR3*KR4*KR5*KR6*KR7*KR8
KR1=1+k1*(T.sub.U-ACTUALT.sub.U-TARGET)
KR2=1k2*(p.sub.U-ACTUALp.sub.U-TARGET)
KR3=1+k3*(p.sub.AG-ACTUALp.sub.AG-TARGET)
KR4=1+k41*ML.sub.ACTUAL.sup.K42*(p.sub.LL-ACTUALp.sub.LL-TARGET)
KR5=1+k5*(MZ.sub.ACTUALMZ.sub.TARGET)
KR6=1+k61*(ZZP.sub.ACTUAL.sup.2ZZP.sub.TARGET.sup.2)K62*(ZZP.sub.ACTUALZZP.sub.TARGET)
KR7=1k7*(T.sub.LL-ACTUALT.sub.LL-TARGET)
KR8=1+k8*(H.sub.U-ACTUALH.sub.U-TARGET), wherein: V.sub.TARGET is one of the target gas consumption of the gas-powered engine and a reference gas consumption of the gas-powered engine, V.sub.ACTUAL is an actual gas consumption of the gas-powered engine, T.sub.U is an ambient air temperature, p.sub.U is an ambient air pressure, P.sub.AG is an exhaust gas backpressure, p.sub.LL is a charge pressure, MZ is a methane number of the gas, ZZP is an ignition timing of the gas-powered engine, T.sub.LL is a charge air temperature, H.sub.U is an ambient air humidity, ML is an engine load, and k1, k2, k3, k41, k42, k5, k61, k62, k7, k8 are engine-dependent constants.

7. The method according to claim 6, wherein the engine-dependent constants k1, k2, k3, k41, k42, k5, k61, k62, k7, k8 are based on a type of lambda control in the gas-powered engine.

8. The method according to claim 7, wherein with a lambda control via charge air discharge, k1, k2, k3 each equal 0, and k41, k42, k5, k61, k62, k7, k8 are each greater than 0 and less than 1.

9. The method according to claim 7, wherein with a lambda control via one of a wastegate and a variable turbine geometry, charge air discharge, k1, k2, k3, k41, k42, k5, k61, k62, k7, k8 are each greater than 0 and less than 1.

10. The method according to claim 6, wherein the gas-powered engine is one of a gas-powered gas engine and a gas-powered dual-fuel engine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The drawings show:

(2) The only FIGURE is a block diagram of a gas-powered engine.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

(3) The invention is directed to a gas-powered engine 10, particularly a gas engine or a dual fuel engine. The gas-powered engine 10 comprises a plurality of cylinders 11 in which gas G is burned as fuel.

(4) Further, for combustion of the gas G in the cylinders 11 of the engine 11, charge air LL is fed to the cylinders 11. Exhaust gas AG is formed during the combustion of the gas G in the cylinders 11 of the engine 10.

(5) An exhaust gas turbocharger 12 cooperates with the engine 10. Exhaust gas AG which forms during the combustion of the gas G in the cylinders 11 of the engine 10 is fed to a turbine 13 of the exhaust gas turbocharger 12. Energy obtained in this way is utilized in a compressor 14 of the exhaust gas turbocharger 12 to compress the charge air LL to be fed to the cylinders 11 of the engine 10.

(6) It is an insight of the invention that the gas consumption of a gas-powered engine 10, namely, of a gas-powered gas engine or a gas-powered dual-fuel engine, is dependent on diverse ambient conditions or operating conditions, namely, on ambient air pressure and/or ambient air temperature and/or ambient air humidity and/or methane number of the gas and/or ignition timing of the engine and/or charge air temperature and/or charge air pressure and/or exhaust gas backpressure.

(7) Accordingly, it is suggested according to one aspect of the invention to convert an actual gas consumption acquired under prevailing actual operating conditions of the engine 10 to a target gas consumption to be anticipated under target operating conditions or reference operating conditions, namely, depending on discrepancies between the actual operating conditions under which the actual gas consumption was acquired and the target operating conditions or reference operating conditions for which the target gas consumption or reference gas consumption is to be calculated. For the sake of simplicity, only the expressions target gas consumption and target operating conditions will be used.

(8) The FIGURE shows a plurality of sensors 15, 16, 17, 18, 19, 20 and 21 by which the actual operating conditions can be acquired by measuring techniques. Accordingly, sensor 15 acquires an actual charge air pressure and sensor 16 acquires an actual charge air temperature. A sensor 17 acquires an actual methane number of the gas G. A sensor 18 acquires an actual exhaust gas backpressure downstream of the turbine 13 of the exhaust gas turbocharger 12. Sensors 19, 20 and 21 acquire an actual ambient air temperature, an actual ambient air pressure and an actual ambient air humidity. The actual operating conditions measured by sensors 15, 16, 17, 18, 19, 20 and 21 can be made available to a control device 22. The engine 10 further provides data about the actual ignition timing to the control device 22.

(9) Based on one or more of the actual operating conditions measured by sensors 15 to 21 and on the relevant target operating conditions, the control device 22 determines a target gas consumption under the target operating conditions from the actual gas consumption that was acquired under the actual operating conditions, namely, depending on discrepancies between the respective actual operating condition and the respective target operating condition.

(10) The calculation of the target gas consumption is preferably carried out using the following equations:
V.sub.TARGET=V.sub.ACTUAL*KR1*KR2*KR3*KR4*KR5*KR6*KR7*KR8
KR1=1+k1*(T.sub.U-ACTUALT.sub.U-TARGET)
KR2=1k2*(p.sub.U-ACTUALp.sub.U-TARGET)
KR3=1+k3*(p.sub.AG-ACTUALp.sub.AG-TARGET)
KR4=1+k41*ML.sub.ACTUAL.sup.K42*(p.sub.LL-ACTUALp.sub.LL-TARGET)
KR5=1+k5*(MZ.sub.ACTUALMZ.sub.TARGET)
KR6=1+k61*(ZZT.sub.ACTUAL.sup.2ZZP.sub.TARGET.sup.2)K62*(ZZT.sub.ACTUALZZP.sub.TARGET)
KR7=1k7*(T.sub.LL-ACTUALT.sub.LL-TARGET)
KR8=1+k8*(H.sub.U-ACTUALH.sub.U-TARGET),
where V.sub.TARGET is the target gas consumption of the engine, V.sub.ACTUAL is the actual gas consumption of the engine, T.sub.U-ACTUAL is the ambient air temperature, T.sub.U-TARGET is the target ambient air temperature, p.sub.U-ACTUAL is the actual ambient air pressure, p.sub.U-TARGET is the target ambient air pressure, p.sub.AG-ACTUAL is the actual exhaust gas backpressure, p.sub.AG-TARGET is the target exhaust gas backpressure, p.sub.LL-ACTUAL is the actual charge pressure, p.sub.LL-TARGET is the target charge pressure, MZ.sub.ACTUAL is the actual methane number, MZ.sub.TARGET is the target methane number, ZZP.sub.ACTUAL is the actual ignition timing, ZZP.sub.TARGET is the target ignition timing, T.sub.LL-ACTUAL is the actual charge air temperature, T.sub.LL-TARGET is the target charge air temperature, H.sub.U-ACTUAL is the actual ambient air humidity, H.sub.U-TARGET is the target ambient air humidity, and ML.sub.ACTUAL is the actual engine load, and where k1, k2, k3, k41, k42, k5, k61, k62, k7, k8 are engine-dependent constants.

(11) The constants k1, k2, k3, k41, k42, k5, k61, k62, k7, k8 depend in particular on the type of lambda control of the gas-powered engine 10.

(12) When a lambda control of the gas-powered engine 10 is carried out via charge air discharge, then: k1=0, k2=0, k3-0, 0<k41<1, 0<k42<1, 0<k5<1, 0<k61<1, 0<k62<1, 0<k7<1, 0<k8<1.

(13) When a lambda control of the gas-powered engine 10 is carried out via wastegate or via a variable turbine geometry, then: 0<k1<1, 0<k2<1, 0<k3<1, 0<k41<1, 0<k42<1, 0<k5<1, 0<k61<1, 0<k62<1, 0<k7<1, 0<k8<1.

(14) One aspect of the invention allows an actual gas consumption determined under actual operating conditions to be converted safely and reliably to a target gas consumption under target operating conditions.

(15) In particular, one aspect of the invention makes it possible to determine a reference gas consumption for an actual gas consumption determined on test blocks, namely, depending on the actual operating conditions prevailing on the test block and the corresponding reference operating conditions. Thus the actual operating conditions prevailing on different test blocks can be compensated, for example, different actual methane numbers and/or different actual ignition timings and/or different ambient air conditions and/or other operating conditions. In this way, the quality of series of test measurements determined on test blocks can be improved.

(16) The actual operating conditions taken into account are preferably operating conditions which are acquired through measuring techniques. In this way, an actual gas consumption can be converted to a target gas consumption or reference gas consumption in a simple and reliable manner.

(17) Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.