Method and apparatus for performing modal mass analysis of exhaust gas from motor vehicle
First Claim
1. A method of determining flow rate of exhaust gas from a motor vehicle with a known engine displacement, the method comprising the steps of:
- measuring and storing the engine speed;
calculating a theoretical exhaust flow rate value QEi, representative of the theoretical flow rate of the exhaust gas, based on the known engine displacement and the measured engine speed; and
calculating an approximate actual exhaust flow rate value QEa on the basis of a polynomial curve expression relating to the calculated theoretical flow rate value QEi.
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Accused Products
Abstract
A method and apparatus for measuring the quantity of an ingredient gas in the exhaust gas from a motor vehicle with a known engine displacement during a time period in which the vehicle is driven over varying driving modes (modal mass analysis). The resultant measurement is achieved without use of a constant volume sampling device by first measuring and storing data CE (t) representative of the concentration of the ingredient gas in the exhaust gas at successive time intervals during the period. The vehicle speed during each successive time interval is measured and stored, followed by calculating theoretical exhaust flow rate values QEi (t), representative of the flow rate of the exhaust gas for each of the succession of time intervals, based on the known engine displacement and the measured engine speed. Then approximate actual exhaust flow rate values QEa (t) are calculated using a polynomial curve fit method on the calculated theoretical flow rate values QEi (t). Lastly, the quantity M(t) of the ingredient gas in the exhaust gas for each of the succession of time intervals is determined on the basis of the operational equation
M(t)=ρ×C.sub.E (t)×Q.sub.Ea (t),
where ρ is the density of the ingredient gas.
39 Citations
14 Claims
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1. A method of determining flow rate of exhaust gas from a motor vehicle with a known engine displacement, the method comprising the steps of:
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measuring and storing the engine speed; calculating a theoretical exhaust flow rate value QEi, representative of the theoretical flow rate of the exhaust gas, based on the known engine displacement and the measured engine speed; and calculating an approximate actual exhaust flow rate value QEa on the basis of a polynomial curve expression relating to the calculated theoretical flow rate value QEi. - View Dependent Claims (2, 3, 4)
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5. A method of measuring the quantity of an ingredient gas in the exhaust gas from a motor vehicle with a known engine displacement during a time period in which the vehicle is driven over varying driving modes, the method comprising the steps of:
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measuring and storing data CE (t) representative of the concentration of the ingredient gas in the exhaust gas at successive time intervals during said period; measuring and storing the vehicle engine speed during each said successive time interval; calculating theoretical exhaust flow rate values QEi (t), representative of the flow rate of the exhaust gas for each of the succession of time intervals, based on the known engine displacement and the measured engine speed; calculating approximate actual exhaust flow rate values QEi (t) using a polynomial curve fit method on the calculated theoretical flow rate values QEi (t); and determining the quantity M(t) of the ingredient gas in the exhaust gas for each of the succession of time intervals on the basis of the operational equation
space="preserve" listing-type="equation">M(t)=ρ
×
C.sub.E (t)×
Q.sub.Ea (t),where ρ
is the density of the ingredient gas. - View Dependent Claims (6, 7, 8)
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9. An apparatus for determining a flow rate of exhaust gas from a motor vehicle with a known engine displacement, the apparatus comprising:
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means for measuring and storing the engine speed; means for calculating a theoretical exhaust flow rate value QEi, representative of the theoretical flow rate of the exhaust gas, based on the known engine displacement and the measured engine speed; and means for calculating an approximate actual exhaust flow rate value QEa on the basis of a polynomial curve expression relating to the calculated theoretical flow rate value QEi. - View Dependent Claims (10, 11)
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12. An apparatus for determining a quantity of an ingredient gas in the exhaust gas from a motor vehicle with a known engine displacement during a time period in which the vehicle is driven over varying driving modes, the method comprising the steps of:
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means for measuring and storing data CE (t) representative of the concentration of the ingredient gas in the exhaust gas at successive time intervals during said period; means for measuring and storing the vehicle speed during each said successive time interval; means for calculating theoretical exhaust flow rate values QEi (t), representative of the flow rate of the exhaust gas for each of the succession of time intervals, based on the known engine displacement and the measured engine speed; means for calculating approximate actual exhaust flow rate values QEa (t) on the basis of a polynomial curve expression relating to the calculated theoretical flow rate values QEi (t); and means for determining a quantity M(t) of the ingredient gas in the exhaust gas for each of the succession of time intervals on the basis of the operational equation
space="preserve" listing-type="equation">M(t)=ρ
×
C.sub.E (t)×
Q.sub.Ea (t),where ρ
is the density of the ingredient gas. - View Dependent Claims (13, 14)
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Specification