Posted by Michelle Steiner on May 8, 2009, 11:22 pm
> >> I don't know how you do it, but I come to a complete stop before
> >> shifting from forward to reverse and visa versa.
> >
> > That has nothing to do with reversing the direction that the ICE
> > turns.
> >
> >> I'll bet a four cycle engine could be designed to run either way.
> >
> > Then why hasn't anyone done so yet?
> >
> I didn't say it would be practical, only possible. Why don't they
> sell passenger cars with 12 wheels? Oh hell, you win Michelle.
I didn't realize that this was a contest.
--
It's now time for healing, and for fixing the damage the GOP did to America.
Posted by Steve Giannoni on May 8, 2009, 7:39 pm
Either 2 or 4 stroke engines will have the axis of the crankshaft
displaced to accommodate more efficient coupling during the power
stroke. Can only run in one direction ...
On Thu, 07 May 2009 15:35:49 -0700, "David T. Johnson"
>Tom Cole wrote:
>>
>> I agree that it seems illogical that the ICE should be needed when
>> reversing under full power, yet the ICE *does* start under these
>> conditions on my 05 Prius and also on my wife's 03 Prius, even when they
>> are in EV mode. We reverse into our garages and if the approach is
>> misjudged such that the front wheels are stopped at the kerb, applying
>> full accelerator to get over the steep bump will cause the car to come
>> out of EV mode and the ICE to start.
>>
>> I have also experienced this when reversing up steep driveways in EV
>> mode.
>The MG2 electric motor is the only device that powers the wheels when
>reversing. If the ICE starts, it is doing so to charge the battery but
>it cannot directly supply to the wheels in reverse but it CAN do that in
>the forward direction, as long as MG2 is also turning. If your
>reversing requires more power than is available in the battery, the ICE
>will start to charge the battery which then supplies battery current to
>MG2 to maintain the reversing. The ICE can't directly power the wheels
>in reverse because the ICE (like every ICE) only rotates in one
>direction. It would take a 'reverse' gear box to translate the ICE
>'forward' rotational direction into the reverse direction...and such a
>gearbox does not exist on the Prius...which also does not have a
>'transmission' to power the vehicle forward with different 'gears' since
>the MG2 can supply the necessary torque for slower speeds without the
>need for gears.
Posted by Peter Granzeau on May 10, 2009, 7:13 pm
On Fri, 08 May 2009 15:39:38 -0400, Steve Giannoni
>Either 2 or 4 stroke engines will have the axis of the crankshaft
>displaced to accommodate more efficient coupling during the power
>stroke. Can only run in one direction ...
Actually, I have seen large marine Diesel engines which could run in
either direction. They were brought to a complete stop, the intake and
exhaust were switched, then the engines were restarted going the other
direction. You design engines correctly, that's possible.
Posted by Steve Giannoni on May 17, 2009, 3:54 pm
Your exception doesn't really break the rule. There are several design
features of normal engines optimized for rotation in only one
direction. eg - intake vs. exhaust : valves, ports, open/close
positions, etc. ..., connecting rod bearings, ...
wrote:
>On Fri, 08 May 2009 15:39:38 -0400, Steve Giannoni
>>Either 2 or 4 stroke engines will have the axis of the crankshaft
>>displaced to accommodate more efficient coupling during the power
>>stroke. Can only run in one direction ...
>Actually, I have seen large marine Diesel engines which could run in
>either direction. They were brought to a complete stop, the intake and
>exhaust were switched, then the engines were restarted going the other
>direction. You design engines correctly, that's possible.
Posted by Steve Giannoni on May 17, 2009, 9:09 pm
My mistake - NOT the connecting rod bearings.
On Sun, 17 May 2009 11:54:51 -0400, Steve Giannoni
>Your exception doesn't really break the rule. There are several design
>features of normal engines optimized for rotation in only one
>direction. eg - intake vs. exhaust : valves, ports, open/close
>positions, etc. ..., connecting rod bearings, ...
>wrote:
>>On Fri, 08 May 2009 15:39:38 -0400, Steve Giannoni
>>
>>>Either 2 or 4 stroke engines will have the axis of the crankshaft
>>>displaced to accommodate more efficient coupling during the power
>>>stroke. Can only run in one direction ...
>>
>>Actually, I have seen large marine Diesel engines which could run in
>>either direction. They were brought to a complete stop, the intake and
>>exhaust were switched, then the engines were restarted going the other
>>direction. You design engines correctly, that's possible.
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> >> shifting from forward to reverse and visa versa.
> >
> > That has nothing to do with reversing the direction that the ICE
> > turns.
> >
> >> I'll bet a four cycle engine could be designed to run either way.
> >
> > Then why hasn't anyone done so yet?
> >
> I didn't say it would be practical, only possible. Why don't they
> sell passenger cars with 12 wheels? Oh hell, you win Michelle.