DYNAMIC MODELING OF AN INTERNAL COMBUSTION ENGINE OPERATING WITH MULTIPLE COMBUSTION MODES
First Claim
1. A method of modeling a diesel engine operable for multiple combustion modes, the engine having an EGR throttle, HP throttle, and compressor turbine, comprising:
- expressing the following engine condition values as mathematical functions;
the pressure at the intake manifold of the engine;
the pressure between the compressor and the HP throttle;
the pressure at the exhaust manifold of the engine;
the compressor power; and
the fresh air fraction at the intake manifold;
storing the mathematical functions in a computer readable medium;
substituting engine condition values into the mathematical functions; and
using the mathematical functions to calculate input values that will produce the engine condition values;
wherein the input values include the flow rates through the EGR throttle, HP throttle, and compressor turbine.
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Abstract
A method of modeling a diesel engine that is capable of multiple combustion modes and equipped with a turbocharger and EGR loop. The model comprises a set of equations, each equation representing one of the following as a time derivative: pressure at the intake manifold, pressure between the turbine and an intake manifold throttle, pressure at the exhaust manifold, the compressor power, and the fresh air fraction (the ratio of fresh air to EGR). The model is used to determine what engine conditions (such as throttle positions and turbocharger output) will result in desired pressures and fresh air fraction.
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Citations
12 Claims
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1. A method of modeling a diesel engine operable for multiple combustion modes, the engine having an EGR throttle, HP throttle, and compressor turbine, comprising:
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expressing the following engine condition values as mathematical functions;
the pressure at the intake manifold of the engine;
the pressure between the compressor and the HP throttle;
the pressure at the exhaust manifold of the engine;
the compressor power; and
the fresh air fraction at the intake manifold;
storing the mathematical functions in a computer readable medium;
substituting engine condition values into the mathematical functions; and
using the mathematical functions to calculate input values that will produce the engine condition values;
wherein the input values include the flow rates through the EGR throttle, HP throttle, and compressor turbine. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of modeling a diesel engine operable for multiple combustion modes, the engine having an EGR throttle, HP throttle, and compressor turbine, comprising:
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expressing the following engine conditions as mathematical functions;
the pressure at the intake manifold of the engine;
the pressure between the compressor and the HP throttle;
the pressure at the exhaust manifold of the engine;
the compressor power; and
the fresh air fraction at the intake manifold;
storing the mathematical functions in a computer readable medium;
substituting input values into the mathematical functions;
wherein the input values include the flow rates through the EGR throttle, HP throttle, and compressor turbine; and
using the mathematical functions to calculate engine condition values for the input values. - View Dependent Claims (11)
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12. A method of modeling a diesel engine operable for multiple combustion modes, the engine having an EGR throttle, HP throttle, and compressor turbine, comprising:
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expressing the following engine condition values as mathematical functions;
the pressure at the intake manifold of the engine;
the pressure between the compressor and the HP throttle;
the pressure at the exhaust manifold of the engine;
the compressor power; and
the fresh air fraction at the intake manifold;
wherein the mathematical functions are in terms of time derivatives of the engine conditions;
wherein the mathematical function representing pressure at the intake manifold is derived from expressions representing conservation of mass at the intake manifold;
wherein the mathematical function representing pressure between the compressor and HP throttle is derived from expressions representing conservation of mass between the compressor and the HP throttle;
wherein the mathematical function representing pressure at the exhaust manifold is derived from expressions representing conservation of mass at the exhaust manifold;
wherein the mathematical function representing compressor power is derived from expressions representing thermodynamics of the flow through the compressor;
wherein the mathematical function representing the fresh air fraction is derived from the fresh air fraction at the exhaust manifold and the flow rates through the HP throttle and the EGR throttle; and
storing the mathematical functions in a computer readable medium.
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Specification