VEMS is a DIY fuel injection system for automobiles, motorcycles,
boats or other gasoline driven applications.
Former, simpler featureset version (from mostly the same authors) was MegaSquirtAVR.
MegaSquirtAVR was an implementation with
similar basic featureset (though extended in significant ways) as the
B&G MegaSquirt design (or any other injection controller, like the GM design that
gave the idea to B&G),
- but complete new, from scratch hardware implementation with a different, more advanced microcontroller,
- and complete new, from scratch firmware implementation in a different, more advanced language (C).
No parts of the MegaSquirt firmware were used (obviously, since the MegaSquirt assembly code does not run on the more advanced processor), and no parts of the MegaSquirt PCB were used.
It was decided that one of the configuration interfaces is made
compatible with MegaTune, with a customized profile. MegaTune is
an easy to use windows, GUI based tuning-software
(released under GNU General Public Licence), by no accident the same is used by MegaSquirt.
Stepper motor or PWM solenoid based idle air control was a basic feature from the start, as well as directly attached PS2 keyboard and LCD interface.
8 channel Ignition and embedded wideband oxygen sensor controller was added in 2003, along with knock sensing, multiple versatile configurable outputs, and other advanced improvements that were not available in the MegaSquirtAVR.
Interestingly, MegaSquirt advocates spread false claims that VEMS "stole MegaSquirt". This has no basis: not a single line was used (it would be impossible, because the more advanced microcontroller does not run MegaSquirt assembly language!), and not a square-cm of PCB was copied either: a from scratch hardware and from scratch firmware.
Actually, MegaSquirt only had a very small subset of the functionality of the 2003 VEMS design (some of VEMS extra functions were added later, and some are not available in megasquirt, even today).
(instead of competing in functionality) killed and continuously keep killing
any reference to VEMS
(eg. when mentioned by a helpful user) in their user forums to prevent users from discovering (and migration to) the more advanced system.
The opensource MegaTune tuningsoftware is used, and the documention is also opensource. Consult the licence of each part to find out details.
The power of the VEMS design partly comes from the
- powerful Atmega128 processor from atmel.com
- avr-gcc compiler (thanx, GNU folks).
- careful HW and software design, and efficient event-management
(by use of timers)
- many different trigger arrangements, including some that uses 3 trigger sensors (vs. the common setup that uses 1 or 2 sensors)
- implementing user wishes
Fetures under construction
Even more versatile configuration
Ion-sense feedback based closed-loop ignition control for knock avoidance and optimal power.