Method for determining the air entering the cylinders of an internal combustion engine having a supercharger
First Claim
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1. A method of determining air entering cylinders of an internal combustion engine having a supercharger, comprising the steps of:
- using a suction equation to represent a first relationship between a relative filling per stroke and an intake manifold pressure;
using a first balancing equation for a filling in an intake manifold to represent a second relationship between the intake manifold pressure, a relative air mass per stroke through a throttle valve, and the relative filling per stroke;
using a flow rate equation at the throttle valve to represent a third relationship between the relative air mass per stroke through the throttle valve, a mass flow through the throttle valve, and an rpm of the internal combustion engine;
using a second balancing equation in a first volume between the throttle valve and the supercharger to represent a fourth relationship between an air mass entering the internal combustion engine, the relative air mass through the throttle valve, and one of a boost pressure and a pressure upstream from the throttle valve; and
determining the air using the suction equation, the first balancing equation, the flow rate equation, and the second balancing equation, the air being determined as a function of at least the rpm, an air throughput in the intake manifold, throttle valve position values and temperature, the suction equation, the first and second balancing equations, and the flow rate equation using values based on standard conditions for the equations.
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Abstract
A device for determining air entering cylinders of an internal combustion engine having a supercharger. The air is determined as a function of such quantities as rpm, air throughput in the intake manifold, throttle valve position values and temperature, characterized in that at least the following physical relationships are included in the determination:
suction equation of the engine
balancing equation for a filling in an intake manifold
flow rate equation at a throttle valve
balancing equation in a volume between the throttle valve and the supercharger.
32 Citations
19 Claims
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1. A method of determining air entering cylinders of an internal combustion engine having a supercharger, comprising the steps of:
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using a suction equation to represent a first relationship between a relative filling per stroke and an intake manifold pressure;
using a first balancing equation for a filling in an intake manifold to represent a second relationship between the intake manifold pressure, a relative air mass per stroke through a throttle valve, and the relative filling per stroke;
using a flow rate equation at the throttle valve to represent a third relationship between the relative air mass per stroke through the throttle valve, a mass flow through the throttle valve, and an rpm of the internal combustion engine;
using a second balancing equation in a first volume between the throttle valve and the supercharger to represent a fourth relationship between an air mass entering the internal combustion engine, the relative air mass through the throttle valve, and one of a boost pressure and a pressure upstream from the throttle valve; and
determining the air using the suction equation, the first balancing equation, the flow rate equation, and the second balancing equation, the air being determined as a function of at least the rpm, an air throughput in the intake manifold, throttle valve position values and temperature, the suction equation, the first and second balancing equations, and the flow rate equation using values based on standard conditions for the equations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
basing the suction equation, the first balancing equation, the flow rate equation, and the second balancing equation on a two-mass storage model;
forming a first mass using a first air mass in a volume upstream from the throttle valve; and
forming a second mass using a second air mass in a volume downstream from the throttle valve.
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3. The method according to claim 1, further comprising the step of:
performing individual calculations by iterative processes with assumptions for output data.
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4. The method according to claim 1, further comprising the step of:
calculating a throttle valve flow rate using the flow rate equation and two modeled pressure values, the two modeled pressure values being derived from the first balancing equation and the second balancing equation.
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5. The method of claim 1, wherein the suction equation is a function of the intake manifold pressure.
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6. The method of claim 5, wherein the suction equation is further a function of a partial pressure caused by residual gas in a combustion chamber.
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7. The method of claim 6, wherein the suction equation is further a function of the rpm.
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8. The method of claim 7, wherein the suction equation is further a function of a piston displacement.
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9. The method of claim 1, wherein the suction equation is defined by the equation ma_punkt=(ps−
- pirg)*n*(VH/2)/(R*Ts), in which ma_Punkt is an air flow rate sucked from a combustion chamber, ps is the intake manifold pressure, pirg is a partial pressure caused by residual gas in the combustion chamber, n is the rpm, VH is a piston displacement, and Ts is a gas temperature in the intake manifold.
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10. The method of claim 1, wherein the relationship defined by the suction equation is rl=(ps−
- pirg)*fupsrl, in which rl is the relative filling per stroke, ps is the intake manifold pressure, pirg is a partial pressure caused by residual gas in a combustion chamber, and fupsrl is a factor for converting the intake manifold pressure into the relative filling per stroke.
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11. The method of claim 1, wherein the first balancing equation is a function of an air flow rate sucked into a combustion chamber.
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12. The method of claim 1, wherein the first balancing equation is defined by the equation d(ms)/dt=mdk_Punkt−
- ma_Punkt, in which d(ms)/dt is a change in air mass with respect to time, mdk_Punkt is an air flow rate through the throttle valve, and ma_Punkt is an air flow rate sucked into a combustion chamber.
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13. The method of claim 1, wherein the relationship defined by the first balancing equation is ps=KIS*integral((rlroh−
- rl)*dt, in which ps is the intake manifold pressure, KIS is an integration constant, rlroh is the relative air mass per stroke, and rl is the relative filling per stroke.
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14. The method of claim 1, wherein the flow rate equation is a function of the mass flow through the throttle valve.
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15. The method of claim 14, wherein the flow rate equation is further a function of a pressure upstream from the throttle valve.
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16. The method of claim 1, wherein the flow rate equation is defined by the equation msdk(wdkba)=pvdk*(1/(R*Tvdk))**(1/2)*Adk(wdkba)*my*Xi(Ps/pvdk)*k, in which msdk is the mass flow through the throttle valve, wdkba is a throttle valve angle, pvdk is a pressure upstream from the throttle valve, Tvdk is a temperature upstream from the throttle valve, Adk is cross-section of an opening of the throttle valve, my is a coefficient of friction, and Xi is an outflow characteristic curve.
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17. The method of claim 1, wherein the relationship defined by the flow equation is rlroh=msdk/(n*KUMSRL), in which rlroh is the relative air mass per stroke through the throttle valve, msdk is the mass flow through the throttle valve, and KUMSRL is a conversion constant.
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18. The method of claim 1, wherein the second balancing equation is a function of an air flow rate through the throttle valve.
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19. The method of claim 1, wherein the relationship defined by the second balancing equation is pl=KIL*integral(rlhfm−
- rlroh)*dt, in which pl is the boost pressure, KIL is an integration constant, rlhfm is the air mass entering the internal combustion engine, and rlroh is the relative air mass through the throttle valve.
Specification