Abstract: A multi-user vehicle telemetric system comprises vehicle interface units (VIUs), wireless gateways, and one or more central hosts. The VIU in a vehicle collects data over the OBD-II bus and stores the data in the form of DataPoint Records (DPRs) in an on-board non-volatile (e.g. flash) memory. When the VIU is within wireless range of a gateway, it establishes a WiFi (802.11b) connection with the gateway, and submits stored DPRs to the gateway, to be stored in permanent storage at the gateway. Although the DPRs are stored in permanent storage on the gateway, they are deleted from permanent storage on the gateway after they are successfully uploaded to the central hosts. The gateways are shared, and communicate with the central hosts over a wide area network (WAN). When a gateway has gathered new DPRs from a VIU, it submits these to selected central hosts.

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.

Abstract: A vehicle telemetric system comprises vehicle interface units (VIUs), wireless gateways, and a central host. The VIU in a vehicle collects data over the OBD-II bus and stores the data in the form of Data Point Records (DPRs) in an on-board flash memory. When the VIU is within wireless range of a gateway, it establishes a WiFi (802.11b) connection with the gateway, and submits stored DPRs to the gateway, to be stored in permanent storage at the gateway. The gateways communicate with the central host over a wide area network (WAN). When a gateway has gathered new DPRs from a VIU, it submits these to the central host. Databases in the gateways as well as in the central host are maintained and synchronized to track received DPRs by sequence number and originating VIU. In conjunction with specific protocols, all DPRs are thus collected reliably, even though communication with a vehicle may be intermittent. Efficient use of WiFi bandwidth is made by avoiding the unnecessary collection of duplicate DPRs.