flyrotary@lancaironline.net Mailing List Archive

Monty,
Several items, first you are correct that the location shown might not require the max pressure. The systems for DI are mostly piezoelectric injector driven. These systems use the incredibly fast piezo injectors to inject from 3-5 pulses per firing event. Even in a low-pressure environment. There is another style of DI that uses air assist to push the charge into the combustion area. This system is limited to a max of about 4 bar. My guess is that Mazda would use the piezo system because they would have fewer restrictions during testing. There are a bunch of variables, but the DI system has several advantages, including stratified charge, super precise mixture control, and others. The 16X looks great though.
Bill Jepson

-----Original Message-----
From: M Roberts <montyr2157@alltel.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, 19 Nov 2007 10:43 am
Subject: [FlyRotary] Re: 16X Rotary Engine

Bill,

I'm not sure that a gasoline fueled 16X as pictured would need 18Kpsi of injection pressure. Where they have the injector located, it could inject before the majority of the compression takes place. Even if it were timed at the last second before the injection port was closed, it still isn't anywhere near TDC.

I do wonder about those other two bosses.......Common rail spark assisted turbocharged, heavy fuel????? If so a longer stroke would definitely be an advantage. Probably would need an electrically assisted turbo to get the thing to start. From the location of the bosses, timing would look to be very early on the injection. Then again, I have no experience with a spark assisted low compression diesel. To get any kind of efficiency you would have to have a turbo with a 2/1 pressure ratio to get the engine pressures high enough.

Monty

Bobby,

For gasoline N/A direct injection requires around 18K psi. Diesels use as high as 22K psi.

While this sounds scary, the equipment has been around for years and has proven reliability.

Bill Jepson

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