Re: [alfa] Diesels and dollars

[bearbvd@xxxxxxxxxxxxxx (Greg Hermann)]

At 10:51 AM 5/26/04, Gwynne W. Spencer wrote:
>Even for mechanically injected engines, the limitations are not as severe
>as some think. My Volvo Penta KAD42 diesels in my boat turn 4000 rpm
>happily and they have the old fashioned mechanical fuel injection pumps.
>They are 219 cubic inch engines with magnetically clutched superchargers
>for the mid range and turbos for normal cruise and WOT producing 230 HP @
>3900 RPM  and 375 lb ft of torque at  2000 and 2500 RPM. The later versions
>of this same engine use common rail electronic injection and are giving in
>excess of 300 HP.
>
>Gwynne Spencer

Understood. And these engines are at the limit of the technology. Do you
have BSFC data for them when they are turning that fast ?? Compare this to
four cycle STREET (motorcycle) spark engines that routinely turn 11K
rpm--and engines at the limit of four cycle spark technology that turn 20K
rpm !!

Greg
>
>At 02:38 PM 5/26/2004 +0000, you wrote:
>> > engines act more like an Otto cycle engine--the higher the injection
>> > pressure, the FASTER they can get the fuel into the chamber, and the closer
>> > they can approach a constant volume burn, and therefore the higher
>> > efficiency of the idealized Otto cycle.
>>
>>This statement would only be true for mechanically injected engines.
>>
>>This is absolutely not true for electronic fuel injection.    It's not
>>that simple by any stretch.   Sequential vs. batch, PWM, opening times etc....
>>
>>-Peter
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