FIELD OF THE INVENTION
The present invention relates to estimating mass air flow through a throttle of a vehicle, and more particularly to estimating mass air flow based on manifold absolute pressure.
p>Several months ago I started to learn OBD-II programming and wrote a small utility to retrieve live data from my Scirocco’s OBD-II port. Since then I’ve improved my utility and made a graphic virtual dashboard on a tablet PC. Here is the video shot as a demo. The displayed data includes speed, RPM, engine load and throttle position. Of course a lot more data can be retrieved through OBD-II port and I planned to make several multiple screens showing different combinations of data to the virtual dashboard. Also I planned to add data logging and drag testing features.
The sheer http://www.bellayoscura.com/partir.html
amount of technology companies are willing to throw at your car’s dashboard is amazing (well, maybe not your car — after all, you’re still driving a ’76 Gremlin). Taking things up a notch, the folks at Fraunhofer have developed a dash that displays your location and the surrounding area in 3D, in real time. The system uses cameras to keep track of the location of your eyes, so the depth imaging effect can be achieved without using those funny glasses. In addition to the GPS, the dashboard only displays the information that is most relevant to the driver at any time — fuel gauge, tire pressure, route information or the title of the song can be displayed, depending on user preferences. It’s only a prototype at this point — be sure to check it out when you hit CeBIT in Hanover this March.
There are two types of LOAD specified in SAE J1979
One is CALCULATED LOAD VALUE and the other is ABSOLUTE LOAD VALUE.
Readily available ‘generic’ scan data provides an excellent foundation for OBD II diagnostics. Recent enhancements have increased the value of this information when servicing newer vehicles.
If you don’t have a good starting point, driveability diagnostics can be a frustrating experience. One of the best places to start is with a scan tool. The question asked by many is, “Which scan tool should I use?” In a perfect world with unlimited resources, the first choice would probably be the factory scan tool. › Continue reading
P-codes, or OBD-II PIDs On Board Diagnostics “Parameter IDs”, are codes used to request data from a vehicle, used as a diagnostic tool. These codes are part of SAE standard J/1979, required to be implemented in all cars sold in North America since 1996.
Typically, an automotive technician will use PIDs with a scan tool connected to the vehicle’s OBD-II connector.
- The technician enters the PID
- The scan tool sends to the vehicle’s bus (CAN, VPW, PWM, ISO, KWP. After 2008, CAN only)
- A device on the bus recognizes the PID as one it is responsible for, and reports the value for that PID to the bus
- The scan tool reads the response, and shows it to the technician
If your vehicle was manufactured after 1996, it contains an On Board Diagnostic (OBD) computer that captures information about how it’s running. OBD II is version 2.0 of the standard for communicating this information.
The data tracked by the OBD II system was originally intended to monitor the engine’s emissions and track down problems that caused cars to pollute more than normal. Today, however, manufacturers have extended the standard to contain a great deal of data about problems and performance. OBD II data is what causes your car’s “check engine” light to go on when there is a problem, and it is your mechanic’s tool of first recourse when you bring the car in with symptoms that have no obvious cause.
Since the data’s transmission format and content are standardized, a number of third parties have developed hardware to detect and display these codes. Some of these devices hook up to laptops, which means you can display and catpure this data.