Process for model-assisted determination of the fresh-air mass flowing into the cylinders of an internal combustion engine with external exhaust-gas recycling
First Claim
1. In a process for determining a quantity of fresh-air mass flowing into a cylinder of an internal combustion engine, the internal combustion engine having an inlet pipe, a throttle valve, a first sensor device for detecting a degree of opening of the throttle valve, an exhaust-gas recycling device with an exhaust-gas recycling valve, a second sensor device for detecting a degree of opening of the exhaust-gas recycling valve, a load sensor producing a load signal, and an electronic control device calculating a basic injection time on a basis of the load signal and a speed of the internal combustion engine, the improvement which comprises:
- reproducing conditions in the inlet pipe using an inlet pipe flow model, and using the degree of opening of the throttle valve, the degree of opening of the exhaust-gas recycling valve, an ambient pressure, an exhaust-gas temperature, a temperature in the inlet pipe and parameters representing a valve setting as input variables of the inlet pipe flow model;
forming a model variable for an air mass flow at the throttle valve and for a residual-gas mass flow at the exhaust-gas recycling valve;
forming a model variable for an air mass flow into the cylinder as a function of an inlet pipe pressure;
forming a model variable for a residual-gas mass flow into the cylinder as a function of a residual-gas partial pressure;
calculating the inlet pipe pressure as a decisive variable for determining an actual load of the internal combustion engine from the model variables of air mass flow at the throttle valve, the residual-gas mass flow at the exhaust-gas recycling valve and the air mass flow into the cylinder;
calculating the residual-gas partial pressure in the inlet pipe from the model variables of the residual-gas mass flow at the exhaust-gas recycling valve and the residual-gas mass flow into the cylinder;
determining a fresh-gas partial pressure from the inlet pipe pressure and the residual gas partial pressure; and
deriving a total air mass flowing into the cylinder by integrating a relationship between the fresh-gas partial pressure and a fresh-air mass flow into the cylinder.
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Accused Products
Abstract
A method for calculating an actual fresh-air mass flowing into a cylinder with the aid of an inlet pipe flow model. The description of the flow model is based on a nonlinear differential equation. The chosen model approach contains modeling of an external exhaust-gas recycling system, variable inlet systems and systems with variable control valves. The model-assisted load detection method can be used in engine control systems based on air mass flow and on inlet pipe pressure. A correction algorithm, in the form of a model control loop allows permanent improvement of accuracy when the model parameters are inexact. That is to say model balancing is provided in steady and unsteady operational states.
96 Citations
19 Claims
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1. In a process for determining a quantity of fresh-air mass flowing into a cylinder of an internal combustion engine, the internal combustion engine having an inlet pipe, a throttle valve, a first sensor device for detecting a degree of opening of the throttle valve, an exhaust-gas recycling device with an exhaust-gas recycling valve, a second sensor device for detecting a degree of opening of the exhaust-gas recycling valve, a load sensor producing a load signal, and an electronic control device calculating a basic injection time on a basis of the load signal and a speed of the internal combustion engine, the improvement which comprises:
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reproducing conditions in the inlet pipe using an inlet pipe flow model, and using the degree of opening of the throttle valve, the degree of opening of the exhaust-gas recycling valve, an ambient pressure, an exhaust-gas temperature, a temperature in the inlet pipe and parameters representing a valve setting as input variables of the inlet pipe flow model; forming a model variable for an air mass flow at the throttle valve and for a residual-gas mass flow at the exhaust-gas recycling valve; forming a model variable for an air mass flow into the cylinder as a function of an inlet pipe pressure; forming a model variable for a residual-gas mass flow into the cylinder as a function of a residual-gas partial pressure; calculating the inlet pipe pressure as a decisive variable for determining an actual load of the internal combustion engine from the model variables of air mass flow at the throttle valve, the residual-gas mass flow at the exhaust-gas recycling valve and the air mass flow into the cylinder; calculating the residual-gas partial pressure in the inlet pipe from the model variables of the residual-gas mass flow at the exhaust-gas recycling valve and the residual-gas mass flow into the cylinder; determining a fresh-gas partial pressure from the inlet pipe pressure and the residual gas partial pressure; and deriving a total air mass flowing into the cylinder by integrating a relationship between the fresh-gas partial pressure and a fresh-air mass flow into the cylinder. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification