Method of modal mass analysis of exhaust gas from a motor vehicle

• US 4,727,746 A
• Filed: 12/31/1986
• Issued: 03/01/1988
• Est. Priority Date: 12/31/1985
• Status: Expired due to Fees

• Current Assignee: Horiba Limited
• Original Assignee: Horiba Limited
• Inventors: Mikasa, Hajime, Kitamura, Hideji
• Primary Examiner(s): Levy, Stewart J.
• Assistant Examiner(s): WILLIAMS, HEZRON
• Application Number:
  US06/948,037
• Time in Patent Office: 426 Days
• Field of Search: 73/23, 73/116, 73/117.3
• US Class Current: 73/23.31
• CPC Class Codes: G01M 15/102 by monitoring exhaust gases
• CPC Class Codes: G01N 1/38 Diluting, dispersing or mixing samples

Abstract

A method of measuring the quantity of an ingredient gas in the exhaust gas from a motor vehicle during each of a sequence of driving modes by measuring and storing in real time flow rate data Q_E (t) representative of the flow rate of the exhaust gas at a succession of times during a driving mode, measuring and storing concentration data representative of the concentration of the ingredient gas in the exhaust gas during a time period delayed with respect to the time period of the driving mode in order to compensate for a time delay in correspondence between changes in flow rate and performing an interpolation method and either a data-compression or data-expansion method on the concentration data in order to obtain corrected concentration values C_E (t) on a one-to-one basis in phase and magnitude to the flow rate data, and determining the quantity M(t) of the ingredient gas in the exhaust gas for each of the measurements of flow rate based on the operational equation M(t)=ρ×C_E (t)×Q_e (t), wherein ρ is the density of the ingredient gas.

Claims

1. A method of measuring the quantity of an ingredient gas in the exhaust gas from a motor vehicle during the time period of each of a sequence of driving modes, the time period of each driving mode having a starting time and an ending time, the ending time of the time period of each driving mode being the starting time of the time period of the next driving mode in the sequence, the method comprising for each driving mode in the sequence, the steps of:

measuring and storing data representative of the flow rate Q_E (t) of the exhaust gas at a succession of times, N_Q in number, including the starting time and the ending time, during the time period of the driving mode;

measuring and storing data C_ES (t) representative of the concentration of the ingredient gas in the exhaust gas at successive times, N_C in number, beginning at a time delayed relative to the starting time by a first predetermined amount of time dependent upon the change in driving mode at the starting time and the ingredient gas and ending at a time delayed relative to the ending time by a second predetermined amount of time dependent upon the change in driving mode at the ending time and the ingredient, such that the first measurement of concentration corresponds to the flow rate Q_E (t) at the starting time and the N_C th measurement of concentration corresponds to the flow rate Q_E (t) at the ending time;

performing an interpolation method on the stored data C_ES (t) to obtain, and then store, values C_E1 (t) representative of the concentration of the ingredient gas in the exhaust gas corresponding to, and at times in the same phase as, the stored data representative of the flow rate Q_E (t), and then correcting the values representative of the concentration C_E1 (t) to obtain corrected values C_E (t) representative on a one-to-one basis in phase and magnitude to the flow rate Q_E (t) by one of a data-compression method and a data-expansion method based on the operational equation C_E (t)=C_E1 (t)×

N_C /N_Q ; and

determining the quantity M(t) of the ingredient gas in the exhaust gas for each of the succession of times during the time period based on the operational equation M(t)=ρ

×

C_E (t)×

Q_E (t), where ρ

is the density of the ingredient.

2. A method of measuring the quantity of an ingredient gas in the exhaust gas from a motor vehicle during the time period of each of a sequence of driving modes, the time period of each driving mode, being of length T_M, having a starting time and an ending time, the ending time of the time period of each driving mode being the starting time of the time period of the next driving mode in the sequence, the method comprising for each driving mode in the sequence, the steps of:

measuring and storing data representative of the flow rate Q_E (t) of the exhaust gas at a succession of times during the time period of the driving mode;

measuring and storing data C_ES (t) representative of the concentration of the ingredient gas in the exhaust gas at successive times only during a period of time beginning at a time delayed relative to the starting time by a first predetermined amount of time τ

₁ dependent upon the change in driving mode at the starting time and the ingredient and ending at a time delayed relative to the ending time by a second predetermined amount of time τ

₂ dependent upon the change in driving mode at the ending time and the ingredient gas;

performing an interpolation method on the stored data C_ES (t) to obtain, and then store, values C_E1 (t) representative of the concentration of the ingredient in the exhaust gas corresponding to, and at times in the same phase as, the stored data representative of the flow rate Q_E (t), and then correcting the values representative of the concentration C_E1 (t) to obtain corrected values C_E (t) representative on a one-to-one basis in phase and magnitude to the flow rate Q_E (t) by one of a data-compression method and a data-expansion method based on the operational equation C_E (t)=C_E1 (t)×

(1+(τ

₂ -τ

₁)/T_M); and

determining the quantity M(t) of the ingredient gas in the exhaust gas for each of the succession of times during the time period of the driving mode based on the operational equation M(t)=ρ

×

C_E (t)×

Q_E (t), where ρ

is the density of the ingredient gas.