View Single Post
Old 03-11-2011, 05:52 PM   #29 (permalink)
nemo
Master EcoModder
 
nemo's Avatar
 
Join Date: Nov 2010
Location: US
Posts: 1,016

Chief - '06 Pontiac Grand Prix
90 day: 26.7 mpg (US)

SF1 - '12 Ford Fiesta S
90 day: 30.95 mpg (US)
Thanks: 195
Thanked 247 Times in 190 Posts
Why a camshaft?

Quote:
Originally Posted by Christ View Post
One way to make a multi fuel engine would utilize multiple cam profiles to effectively lower the dynamic compression characteristics of the engine in use. Example: an engine which is built with a simple CR of 14:1, with the gasoline cam profile being one which limits air intake such that the cylinder is not completely filled, similar to an "atkins"cam. The resultant smaller air/fuel charge will not detonate as readily due to compression.

Alternatively, the second, or E85 profile would be that of a standard camshaft, designed for a high compression, E85 only application.

With regard to fueling, the most compatible system would include two sets of injectors, each with an independent fuel system, the only common structures being electronics and intake manifold.
Why use a cam at all? Would it not be more efficient to use a solenoid or a stepper motor to control the opening and closing of the valves, which then could be computer controlled. Not only could the valve timing, duration and lift be fully adjustable, but then in essence have a variable displacement engine by selecting not to use cylinders at the when not needed.
  Reply With Quote