Methods and system for determining consumption and fuel efficiency in vehicles
First Claim
1. A method of determining fuel consumption in a vehicle, comprising:
- (a) determining fuel consumption by using mass air flow (MAF) sensor data or manifold air pressure (MAP) sensor data, including obtaining MAF data or MAP data in the vehicle, comprising;
(b) obtaining long term and short term fuel trim values for the vehicle, which respectively characterize deviations of air-to-fuel stoichiometry in the vehicle due to aging and vehicle'"'"'s current operating conditions; and
(c) correcting the fuel consumption in the vehicle by applying said long term and short term fuel trim values to determine a corrected fuel consumption in the vehicle;
the obtaining comprising sensing data in the vehicle through a vehicle diagnostic bus; and
the sensing being performed in one or more of the following ways;
sensing data at respective frequencies, which are substantially inversely proportional to the rates change of respective data;
sensing data consecutively;
sensing data concurrently;
sensing data according to a random selection of their sampling order;
orsensing selected data at a sampling frequency, which is dependent on a value of another data.
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Abstract
A method of determining fuel consumption in a vehicle through the OBDII bus is described. The fuel consumption is determined by using mass air flow (MAF) sensor data or manifold air pressure (MAP) sensor data, and obtaining and applying long term and short term fuel trim values for the vehicle, which respectively characterize deviations of air-to-fuel stoichiometry in the vehicle due to aging and vehicle'"'"'s current operating conditions to determine the corrected fuel consumption in the vehicle. For MAP based method, an independent determining of Volumetric Efficiency of a vehicle'"'"'s engine is also provided. The method is further enhanced by providing various sensing patterns for various sensor data, which depend on the rate of change of the respective data.
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Citations
29 Claims
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1. A method of determining fuel consumption in a vehicle, comprising:
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(a) determining fuel consumption by using mass air flow (MAF) sensor data or manifold air pressure (MAP) sensor data, including obtaining MAF data or MAP data in the vehicle, comprising; (b) obtaining long term and short term fuel trim values for the vehicle, which respectively characterize deviations of air-to-fuel stoichiometry in the vehicle due to aging and vehicle'"'"'s current operating conditions; and (c) correcting the fuel consumption in the vehicle by applying said long term and short term fuel trim values to determine a corrected fuel consumption in the vehicle; the obtaining comprising sensing data in the vehicle through a vehicle diagnostic bus; and the sensing being performed in one or more of the following ways; sensing data at respective frequencies, which are substantially inversely proportional to the rates change of respective data; sensing data consecutively; sensing data concurrently; sensing data according to a random selection of their sampling order;
orsensing selected data at a sampling frequency, which is dependent on a value of another data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 26, 27, 28, 29)
determining fuel consumption by using manifold air pressure (MAP) sensor data, including obtaining MAP data in the vehicle through a vehicle diagnostic bus, comprising; determining volumetric efficiency (VE) of the vehicle as follows; (i) selecting time interval and setting VE=1; (ii) determining total fuel consumed by the vehicle during all selected time intervals according to an independent refuelling measurement (TFCM); (iii) determining total fuel consumed by the vehicle during all selected time intervals according to the method of claim 3 (TFCV) by using the current value of VE; (iv) updating the current value of VE=TFCM/TFCV; and (v) selecting another time interval and repeating the steps (ii) to (iv) a number of times to achieve a required accuracy for the current value of VE.
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27. The method as described in claim 26, the vehicle diagnostic bus being onboard diagnostic II (OBDII) bus, and the determining (ii) comprising manual or automatic refuelling measurement at a gas pump.
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28. A vehicle interface unit (VIU), comprising:
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a (VIU) computer having a CPU and non-volatile memory (NVM); the VIU computer is connected to the vehicle diagnostic bus providing access to sensors in the vehicle for collecting vehicle related data through the vehicle diagnostic bus; the NVM comprising a computer program code stored thereon for execution by the CPU, causing the computer to determine fuel consumption in the vehicle in accordance with the method of claim 26.
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29. A vehicle telemetric system, comprising:
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a central host connected to a communications network; one or more gateways connected to the communications network, the communications network enabling the transfer of data between the gateways and the central host; a vehicle interface unit (VIU) within a vehicle having access to sensors in the vehicle for collecting vehicle related data through a vehicle diagnostic bus, the VIU having means for communication over a wireless link with any of said gateways provided the vehicle is within a transmission range of one of said gateways; the VIU comprising a VIU computer having a CPU and non-volatile memory (NVM), the VIU being connected to the vehicle diagnostic bus; the NVM comprising computer readable instructions stored thereon for execution by the CPU, causing the VIU computer to determine fuel consumption in the vehicle in accordance with the method of claim 26.
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19. A method for determining fuel consumption in a vehicle, comprising:
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(a) determining fuel consumption by using mass air flow (MAF) sensor data or manifold air pressure (MAP) sensor data, including obtaining MAF data or MAP data in the vehicle, comprising; (b) obtaining long term and short term fuel trim values for the vehicle, which respectively characterize deviations of air-to-fuel stoichiometry in the vehicle due to aging and vehicle'"'"'s current operating conditions; and (c) correcting the fuel consumption in the vehicle by applying said long term and short term fuel trim values to determine a corrected fuel consumption in the vehicle; the obtaining comprising sensing data in the vehicle through a vehicle diagnostic bus; the obtaining, long term and short term fuel trim values comprising Obtaining a number of banks (pairs) of respective fuel trim values for each of the long term and short term fuel trim values, and determining average long term and short term fuel trim values over the respective number of banks; the determining (a) comprising one of the following; (i) determining fuel consumption in the vehicle by using MAF data for the time interval Δ
T=N·
Δ
ti as follows;AFratio is air-to-fuel stoichiometric ratio, ρ
fuel is fuel density in g/ml, MAF(ti),LONGFT i, andSHRTFT i are respectively MAF data, average long term, and average short term fuel trim data at time instance ti;
or(ii) determining fuel consumption in the vehicle by using MAP data for the time interval Δ
T=N·
Δ
ti, as follows;VE is Volumetric Efficiency for the vehicle (unitless), MAP is Manifold Air Pressure (kPa), ED is Engine Displacement (liters), R is ideal gas constant 8.314 kPa K−
1 mol−
1, and Mair is molar mass of air (g/mol)=28.97 g/mol;
RPMi, MAP(ti)LONGFT i,SHRTFT i and IATi are respectively Revolution Per Minute (min−
1) of an engine, Manifold Air Pressure sensor data, average long term, average short term fuel trim data, and Intake Air Temperature (degrees Celsius) at time instance ti,comprising sensing a revolution per minute (RPM), and intake air temperature (IAT) in the vehicle. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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Specification