Hi Paul，

   The efficiency of internal combustion engines are not good as the exhaust gas is hot,
   especially on rotary engines.  If we inject small amount of water into the chamber
   just after ignition, and the water would evaporate and expand. Would this improve
   efficiency?  The water would take heat from the gas, thus make further use of the heat.
   I think this may increase gas mileage in cars significantly. How do you think?

   Best regards,

   Gordon Gao

   Of course it would work but there are all sorts of issues. Like rusting the end housings
   after you turn it off.  Two tanks to fill.  Water must be distilled.

   The six cycle engine does this. Google it.

   Paul Lamar

Some people are collecting water via condensation from the intercooler to use as water injection.  If you had some amount of cooled EGR, that would provide a lot of water to condense along with increasing the ratio of specific heats to reduce the peak compression temperature and thus heat transfer.  If Mazda goes with aluminum end housings, that would reduce the tendency for rust.

Once you add EGR, your burn rates will slow down so an aggressive ignition would be required such as Paul's capacitive discharge or SwRI's DCO system.  If you wanted to further increase burn rates, a dedicated EGR system could be employed which routes one exhaust straight to the intake so that rotor can run pig rich (30% to 50% additional fuel beyond stoichiometric) and make CO and H2, but that requires at least 4 rotors to get EGR rates to 25%.  It may also be possible to induce charge motion by having a tumble plate but then you trade VE for burn rate.

Aaron Buster


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