Fuel consumption calculation unit, fuel consumption measuring apparatus, and exhaust gas measuring apparatus

• US 10,132,225 B2
• Filed: 08/11/2014
• Issued: 11/20/2018
• Est. Priority Date: 08/12/2013
• Status: Active Grant

• Current Assignee: Horiba Limited
• Original Assignee: Horiba Limited
• Inventors: Akita, Masanobu, Nakamura, Hiroshi, Asano, Ichiro, Adachi, Masayuki
• Primary Examiner(s): Evanisko, Leslie J
• Assistant Examiner(s): Hinze, Leo T
• Application Number:
  US14/456,668
• Publication Number:
  US 20150046101A1
• Time in Patent Office: 1,562 Days
• CPC Class Codes: F01N 13/008 Mounting or arrangement of exhaust sensors in or on exhaust apparatus sensor arrangements for engine control F02D41/1439
• CPC Class Codes: F02B 77/086 Sensor arrangements in the exhaust, e.g. for temperature, misfire, air/fuel ratio, oxygen sensors
• CPC Class Codes: F02D 2200/0614 Actual fuel mass or fuel injection amount
• CPC Class Codes: F02D 2200/0625 Fuel consumption, e.g. measured in fuel liters per 100 kms or miles per gallon
• CPC Class Codes: F02D 41/1445 the characteristics being related to the exhaust flow
• CPC Class Codes: F02D 41/1456 with sensor output signal being linear or quasi-linear with the concentration of oxygen
• CPC Class Codes: G01F 1/00 Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow measuring a proportion of the volume flow G01F5/00
• CPC Class Codes: G01F 1/66 by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
• CPC Class Codes: G01F 9/001 with electric, electro-mechanic or electronic means G01F9/008 and G01F9/02 take precedence
• CPC Class Codes: G01M 15/104 using oxygen or lambda-sensors testing catalytic converters F01N3/18, F01N11/007
• CPC Class Codes: G01N 33/0062 concerning the measuring method or the display, e.g. intermittent measurement or digital display
• CPC Class Codes: G01N 33/0068 using a computer specifically programmed
• CPC Class Codes: G01N 33/22 Fuels; Explosives
• CPC Class Codes: G01N 9/00 Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity

Abstract

The present invention is intended to, at the time of directly measuring a flow rate of exhaust gas flowing through an exhaust gas flow path and an air-fuel ratio of the exhaust gas, and on the basis of the flow rate and air-fuel ratio of the exhaust gas, calculating fuel consumption, reduce a measurement error of the fuel consumption. Also, the invention is a fuel consumption calculation unit that, with use of an exhaust gas flow rate obtained by a flow rate sensor provided in an exhaust gas flow path through which exhaust gas of an engine flows, and an air-fuel ratio obtained by an air-fuel ratio sensor provided in the exhaust gas flow path, calculates fuel consumption of the engine, and on the basis of the air-fuel ratio obtained by the air-fuel ratio sensor, changes a value of exhaust gas density used for the calculation of the fuel consumption.

Claims

1. A fuel consumption measuring apparatus that measures fuel consumption of an engine, the fuel consumption measuring apparatus comprising:

an exhaust gas flow path that is connected to a tail pipe of an exhaust pipe of the engine such that exhaust gas emitted from the tail pipe is introduced;

a flow rate sensor that is provided in the exhaust gas flow path and measures a flow rate of the exhaust gas flowing through the exhaust gas flow path;

an air-fuel ratio sensor that is provided downstream the tail pipe and a catalyst associated with the engine in the exhaust gas flow path and measures an air-fuel ratio;

a related data storage part that stores related data indicating a relationship between an air-fuel ratio and exhaust gas density; and

a calculation unit that changes exhaust gas density on a basis of the air-fuel ratio and the related data, and that calculates the fuel consumption of the engine with use of the flow rate of the exhaust gas, the air-fuel ratio, and the changed exhaust gas density.

2. The fuel consumption measuring apparatus according to claim 1, wherein the calculation unit, in a case where the air-fuel ratio is included in a rich region, changes the exhaust gas density, and in a case where the air-fuel ratio is included in a lean region, uses a predetermined constant value as the exhaust gas density.

3. The exhaust gas measuring apparatus according to claim 1, further comprising:

a flow conditioner that is provided on the upstream side of the flow rate sensor in the exhaust gas flow path.

4. An exhaust gas measuring apparatus comprising:

an air-fuel ratio sensor provided in an exhaust gas flow path that is connected to a tail pipe of an exhaust pipe of an engine such that the air-fuel ratio sensor is downstream the tail pipe and a catalyst associated with the engine;

a temperature sensor that measures temperature of the exhaust gas emitted from the tail pipe;

a related data storage part that stores related data that defines a relationship between concentration of each component contained in the exhaust gas and an air-fuel ratio;

a temporary concentration calculation part that refers to the related data storage part to calculate temporary H₂O concentration that is H₂O concentration corresponding to a measured air-fuel ratio obtained from the air-fuel ratio sensor; and

a lost H₂O calculation part that, on a basis of saturated water vapor concentration at the exhaust gas temperature measured by the temperature sensor and the temporary H₂O concentration, calculates a lost H₂O amount that is an amount of H₂O lost by condensation and the like in a path to a measuring point of the air-fuel ratio sensor to improve measurement accuracy of the air-fuel ratio sensor.

5. The exhaust gas measuring apparatus according to claim 4, further comprising

an air-fuel ratio amendment part that takes into account the lost H₂O amount to amend the measured air-fuel ratio.

6. The exhaust gas measuring apparatus according to claim 5, further comprising

a component concentration calculation part that refers to the related data storage part to calculate each component concentration corresponding to an amended air-fuel ratio that is the measured air-fuel ratio amended in the air-fuel ratio amendment part.

7. The exhaust gas measuring apparatus according to claim 6, further comprising:

a density calculation part that calculates exhaust gas density on a basis of the each component concentration calculated in the component concentration calculation part; and

a fuel consumption calculation part that calculates fuel consumption of the engine on a basis of the exhaust gas density and the amended air-fuel ratio.

8. The exhaust gas measuring apparatus according to claim 4, wherein

the temporary concentration calculation part refers to the related data storage part to calculate respective component concentrations corresponding to the measured air-fuel ratio obtained from the air-fuel ratio sensor, the exhaust gas measuring apparatus further comprising

a component concentration calculation part that takes into account the lost H₂O amount to amend one component concentration of the respective component concentrations calculated by the temporary concentration calculation part, and refers to the related data storage part to calculate the other component concentrations corresponding to the amended one component concentration.

9. The exhaust gas measuring apparatus according to claim 4, wherein the related data storage part stores the related data for each fuel type.

10. A fuel consumption measuring method for measuring fuel consumption of an engine with use of an exhaust gas flow rate, an air-fuel ratio and exhaust gas density, the fuel consumption measuring method comprising:

changing the exhaust gas density on a basis of the air-fuel ratio obtained by an air-fuel ratio sensor and related data indicating a relationship between an air-fuel ratio and exhaust gas density, wherein the air-fuel ratio sensor being is provided in an exhaust gas flow path that is connected to a tail pipe of an exhaust pipe of the engine such that the air-fuel ratio sensor is downstream the tail pipe and a catalyst associated with the engine, and measures a ratio of air to fuel of exhaust gas flowing through the exhaust gas flow path; and

calculating the fuel consumption, with use of the exhaust gas flow rate obtained by a flow rate sensor that is provided and measures a flow rate of the exhaust gas flowing through the exhaust gas flow path the air-fuel ratio obtained by the air-fuel ratio sensor and the changed exhaust gas density.