Methods and system for determining consumption and fuel efficiency in vehicles

• US 7,774,130 B2
• Filed: 03/31/2006
• Issued: 08/10/2010
• Est. Priority Date: 12/07/2005
• Status: Active Grant

• Current Assignee: GeoTab Incorporated
• Original Assignee: Netistix Technologies Corporation (GeoTab Incorporated)
• Inventors: Pepper, Gary Thomas
• Primary Examiner(s): ARTHUR JEANGLAUDE, GERTRUDE
• Application Number:
  US11/393,716
• Publication Number:
  US 20070129878A1
• Time in Patent Office: 1,593 Days
• Field of Search: 701/23, 701/24, 701/29, 701/35, 701/36, 701/33, 701/102, 701/103, 701/104, 701/123, 340/438, 340/439, 340/442, 340/450, 340/450.2
• US Class Current: 701/123
• CPC Class Codes: B60W 2530/209 Fuel quantity remaining in tank
• CPC Class Codes: B60W 40/12 related to parameters of the vehicle itself , e.g. tyre models
• CPC Class Codes: B60W 50/0098 Details of control systems ensuring comfort, safety or stability not otherwise provided for
• CPC Class Codes: B60W 50/14 Means for informing the driver, warning the driver or prompting a driver intervention
• CPC Class Codes: F02D 41/1402 Adaptive control

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.

Claims

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;

or

sensing selected data at a sampling frequency, which is dependent on a value of another data.

2. The method as described in claim 1, the vehicle diagnostic bus being onboard diagnostic II (OBDII) bus.

3. The method as described in claim 2, the step (a) comprising determining fuel consumption in the vehicle by using MAP data, only if MAF data is not available for the vehicle.

4. The method as described in claim 2, 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.

5. The method as described in claim 4, wherein the number of banks is less or equal to 4.

6. The method as described in claim 1, the obtaining comprising sensing various data in the vehicle at respective various frequencies, which are substantially inversely proportional to a rate change of the respective data.

7. The method as described in claim 3, the vehicle diagnostic bus being onboard diagnostic II (OBDII) bus.

8. The method as described in claim 1, the determining (a) and the obtaining (b) comprising sampling various vehicle'"'"'s data at respective various sampling frequencies, which are based on historic data for the respective vehicle'"'"'s data.

9. The method as described in claim 1, further comprising transmitting data obtained in any of the determining (a), obtaining (b) or correcting (c) from the vehicle to a central host for further processing and storage.

10. The method as described in claim 1, further comprising determining fuel efficiency, comprising obtaining an odometer reading for the vehicle, and relating the fuel consumed by the vehicle over the distance identified by the odometer reading for the corresponding time interval to determine fuel efficiency.

11. The method as described in claim 1, further comprising identifying a type of the vehicle, the type including a hybrid electric vehicle (HEV), and determining fuel consumption in the HEV in accordance with the method of claim 1 within time intervals, during which the HEV is free from operating under electric power.

12. A vehicle interface unit (VIU), comprising:

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 1.

13. The VIU as described in claim 12, further comprising a wireless modem connected to the VIU computer and providing communication over a wireless link with a gateway (wireless access point), which is connected to a communications network, the communications network providing transmission of data between the gateway and a central host.

14. A vehicle telemetric system, comprising:

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 1.

15. An access system for use in a vehicle telemetric system, the telemetric system comprising a central host connected to a communications network, the access system comprising:

one or more vehicle interface units (VIUs) and a gateway, the gateway being connected to the communications network,

each VIU being located in a different vehicle and having access to sensors in the vehicle for collecting vehicle related data through a vehicle diagnostic bus, each VIU having means for communication over a wireless link with the gateway, the wireless link being activated provided the vehicle is within a transmission range of the gateway;

each VIU comprising a VIU computer having a CPU and non-volatile memory (NVM), the VIU computer being connected to the vehicle diagnostic bus;

the NVM comprising a computer program code 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 1;

the gateway having another memory for storing the fuel consumption data received from the VIU, and a gateway means for forwarding the data to the central host.

16. A method for determining a fuel consumption of a vehicle in a vehicle telemetric system, the vehicle telemetric system comprising a central host connected to a communications network, one or more gateways connected to the communications network, each gateway having a wireless transmission range, a vehicle interface unit (VIU) within a vehicle having access to sensors in the vehicle for collecting vehicle related data through a vehicle'"'"'s bus, the VIU having means for wireless communication with any of said gateways, the method comprising:

(a) determining fuel consumption in the vehicle as described in claim 1;

(d) determining if the VIU is within the wireless transmission range of one of the gateways;

(e) forwarding some or all the fuel consumption data from the VIU to the one of said gateways over a wireless link;

(f) forwarding said some or all of the fuel consumption data received by the one of said gateways from the one of said gateways to the central host over the communications network; and

(g) notifying each gateway by the central host regarding said some or all fuel consumption data that have been already received at the central host.

17. A multi-user motor vehicle telemetric system, comprising:

(a) one or more central hosts connected to a communications network, each central host being associated with one or more users of the system;

(b) one or more gateways connected to the communications network, for transfer of data between the gateways and the central hosts;

(c) one or more vehicle interface units (VIUs), each VIU being placed within a respective vehicle and having access to sensors in the vehicle for collecting vehicle related data through a vehicle diagnostic bus in the vehicle, each VIU having a wireless modem for communication over a wireless link to gateways, which are designated to be accessed by said each VIU, each VIU being associated with one or more of said users;

(d) each central host having means for selecting gateways and collecting data from each VIU, which is associated with the users that the central host is associated with;

(e) each gateway having means for recognizing central hosts and VIUs belonging to the same user; and

(f) each VIU comprising a VIU computer having a CPU and non-volatile memory (NVM), the VIU being connected to a vehicle diagnostic bus in the vehicle; and

(g) the NVM comprising a computer program code 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 1.

18. A method for collecting vehicle performance data in a multi-user motor vehicle telemetric system, comprising one or more central hosts connected to a communications network, each central host being associated with one or more users of the system, one or more gateways connected to the communications network, the communications network enabling the transfer of data between the gateways and the central hosts, one or more vehicle interface units (VIUs), each VIU placed within a respective vehicle having access to sensors in the vehicle for collecting vehicle related data, each VIU having means for communication over a wireless link to gateways designated to be accessed by said each VIU provided the VIU of the vehicle is within a transmission range of one of said designated gateways, and each VIU is associated with one or more of the users, the method comprising:

(a) at each central host, selecting gateways for collecting data from each VIU which is associated with the users that the central host is associated with;

(b) at each central host specifying for each user the data to be collected from its associated VIUs through data collection profiles which are stored in the central host and the selected gateways;

(c) at each gateway determining the association between central hosts and VIUs belonging to the same user; and

(d) at each VIU, determining fuel consumption in the vehicle containing the VIU, in accordance with the method of claim 1.

26. A method for determining fuel consumption in a vehicle, comprising:

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 (TFC_M);

(iii) determining total fuel consumed by the vehicle during all selected time intervals according to the method of claim 3 (TFC_V) by using the current value of VE;

(iv) updating the current value of VE=TFC_M/TFC_V; 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.

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.

28. A vehicle interface unit (VIU), comprising:

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.

29. A vehicle telemetric system, comprising:

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.

19. 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 Δ

T=N·

Δ

t_i as follows;

$\frac{1}{{\mathrm{AF}}_{\mathrm{ratio}}\times <br><br>{\mathrm{\rho <br><br>}}_{\mathrm{fuel}}\times <br><br>1000<br><br><br><br>\text{ml/l}}<br><br>\underset{i=1}{\overset{N}{\sum <br><br>}}<br><br>\left(\mathrm{MAF}<br><br>\left(t_i\right)\times <br><br>\stackrel{\_}{{\mathrm{LONGFT}}_i}\times <br><br>\stackrel{\_}{{\mathrm{SHRTFT}}_i}\times <br><br>\mathrm{\Delta <br><br>}<br><br><br><br>t_i\right)$

AF_ratio is air-to-fuel stoichiometric ratio, ρ

_fuel is fuel density in g/ml, MAF(t_i), LONGFT_i, and SHRTFT_i are respectively MAF data, average long term, and average short term fuel trim data at time instance t_i;

or

(ii) determining fuel consumption in the vehicle by using MAP data for the time interval Δ

T=N·

Δ

t_i, as follows;

$\frac{\mathrm{VE}\times <br><br>\mathrm{ED}\times <br><br>M_{\mathrm{air}}}{120\times <br><br>R\times <br><br>{\mathrm{AF}}_{\mathrm{ratio}}\times <br><br>{\mathrm{\rho <br><br>}}_{\mathrm{fuel}}\times <br><br>1000<br><br><br><br>\mathrm{ml}<br><br>\text{/}<br><br>l}<br><br>\underset{i=1}{\overset{N}{\sum <br><br>}}<br><br>\frac{{\mathrm{RPM}}_i\times <br><br>{\mathrm{MAP}}_i\times <br><br>\stackrel{\_}{{\mathrm{LONGFT}}_i}\times <br><br>\stackrel{\_}{{\mathrm{SHRTFT}}_i}}{\left({\mathrm{IAT}}_i+273.12\right)}<br><br>\mathrm{\Delta <br><br>}<br><br><br><br>t_i$

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<sup>−

1</sup> mol<sup>−

1</sup>, and M_air is molar mass of air (g/mol)=28.97 g/mol;

RPM_i, MAP(t_i) LONGFT_i, SHRTFT_i and IAT_i are respectively Revolution Per Minute (min<sup>−

1</sup>) 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 t_i,

comprising sensing a revolution per minute (RPM), and intake air temperature (IAT) in the vehicle.

20. The method as described in claim 19, the fuel density ρ

_fuel being adjusted according to seasonal temperature variations.

21. The method as described in claim 20, the transmitting to the central host comprising

wirelessly transmitting the fuel consumption data from the vehicle to a gateway (wireless access point) connected to a communications network, the communications network enabling the transfer of data between the gateway and the central host.

22. The method as described in claim 20, the determining (a) and the correcting (c) comprising distributed determining of fuel consumption by using processing power of more than one computer, including initial processing of data in the vehicle, followed by final processing of data at the central host.

23. A vehicle interface unit (VIU) for a vehicle telemetric system, the vehicle telemetric system comprising a central host connected to a communications network and one or more gateways connected to the communications network enabling the transfer of data between the gateways and the central host, the VIU being located in a vehicle and 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, the wireless link being activated provided the vehicle is within a transmission range of the one of said gateways, and another wireless link being activated provided the vehicle is within a transmission range of another one of said gateways;

the VIU further comprising a VIU computer having a CPU and non-volatile memory (NVM), the VIU computer being connected to 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 19.

24. A vehicle telemetric system, comprising:

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 19.

25. An access system for use in a vehicle telemetric system, the telemetric system comprising a central host connected to a communications network, the access system comprising:

one or more vehicle interface units (VIUs) and a gateway, the gateway being connected to the communications network,

each VIU being located in a different vehicle and having access to sensors in the vehicle for collecting vehicle related data through a vehicle diagnostic bus, each VIU having means for communication over a wireless link with the gateway, the wireless link being activated provided the vehicle is within a transmission range of the gateway;

each VIU comprising a VIU computer having a CPU and non-volatile memory (NVM), the VIU computer being connected to the vehicle diagnostic bus;

the NVM comprising a computer program code 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 19;

the gateway having another memory for storing the fuel consumption data received from the VIU, and a gateway means for forwarding the data to the central host.