Methods and system for determining consumption and fuel efficiency in vehicles
OwnerGary Thomas Pepperinventor
Life of this patent
Estimating the term…
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.
Claims29
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;
- or
- sensing selected data at a sampling frequency, which is dependent on a value of another data.
A method for 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:
- 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 ΔT=N·Δti as follows:
- 1
- AF
- ratio
- ×
- ρ
- fuel
- ×
- 1000
-
-
- ml/l
-
- ∑
- i
- =
- 1
- N
-
- (
- MAF
-
- (
- t
- i
- )
- ×
- LONGFT
- i
- _
- ×
- SHRTFT
- i
- _
- ×
- Δ
-
-
- t
- i
- )
- AFratio is air-to-fuel stoichiometric ratio, ρfuel is fuel density in g/ml, MAF(ti), LONGFTi, and SHRTFTi 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 ΔT=N·Δti, as follows:
- VE
- ×
- ED
- ×
- M
- air
- 120
- ×
- R
- ×
- AF
- ratio
- ×
- ρ
- fuel
- ×
- 1000
-
-
- ml
-
- /
-
- l
-
- ∑
- i
- =
- 1
- N
-
- RPM
- i
- ×
- MAP
- i
- ×
- LONGFT
- i
- _
- ×
- SHRTFT
- i
- _
- (
- IAT
- i
- +
- 273.12
- )
-
- Δ
-
-
- t
- i
- 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) LONGFTi, SHRTFTi 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.
Dependencies are inferred from the claim text.