Small TBI

[xxalexx at ix.netcom.com]

> Date:          Sun, 08 Feb 1998 16:12:00 -0800
> From:          Ray Wasson <rwasson at cdsnet.net>
> To:            DIY_EFI at efi332.eng.ohio-state.edu
> Subject:       Small TBI
> Reply-to:      diy_efi at efi332.eng.ohio-state.edu

> I would like to know if it would be practical to pursue what I have in
> mind. My hobby & sport is designing, building & flying radio cont. model
> aircraft. I understand the mechanical aspect's but I know very little
> about electronics other than the basics. About 15 years ago I designed &
> built a carburetor for a 440cc ultralite airplane eng. It worked very
> well. In other words I know what I need as far as fuel curve etc., I
> just don't know how to do it or if it can be done electronically. What
> is needed is a reliable TBI system for 25 to 100cc 2 stroke engines. The
> requirements are as follows.
> Weight is critical. Desired weight under 8 oz. incl. batt..
> Reliability. Would be subject to a lot of vibration.
> Fully adjustable fuel curve. Be able to adapt to diffrent engines with
> diffrent requirements.
> The RPM range would be approximately 1000 to 10,000.
> The carburetors now used are just not sophisticated enough to run smooth
> at all throttle settings. Besides, in the future these small engines
> will be subject to emission standards.
> I have in mind a constant flow system with vane type air flow sensor &
> possibly a stepper motor working on a pressure regulator. It would be a
> low pressure system using crank case pressure to the fuel tank for fuel
> supply. Plenty of mixing takes place in the crank case of these engines.
> For starters, an acceleration & lean cruise circuit will not be needed
> unless it would be easy to include.
> Does any one think this is feasible and have any ideas?.
> Thanks for listening.
> Ray Wasson
> 
>
You might check the 125cc  motocross bikes for ideas.
Alex