Can direct injection engines start without a starter motor?

On Monday, November 18, 2013 8:24:55 AM UTC-6, Nate Nagel wrote:
> On 11/18/2013 09:23 AM, Nate Nagel wrote:
>
> > On 11/15/2013 10:55 AM, money2noise wrote:
>
> >> On Thursday, September 8, 2011 10:16:40 PM UTC-6, larry moe 'n curly
>
> >> wrote:
>
> >>> Are any cars currently in production with direct injection designed
>
> >>> so
>
> >>>
>
> >>> they can be be started even if the starter motor doesn't work, at
>
> >>>
>
> >>> least in most cases, by having the computer choose a cylinder that
>
> >>> has
>
> >>>
>
> >>> its valves closed and its pistons in the power stroke position?
>
> >>> At
>
> >>>
>
> >>> least are direct injection cars designed to help the starter by
>
> >>> doing
>
> >>>
>
> >>> that?
>
> >>
>
> >> Not to mention aren't most modern fuel injected cars running between
>
> >> 50 and 70psi at the injectors anyways? That's a far cry from
>
> >> 2000psi. Maybe a diesel would be more interesting?
>
> >>
>
> >
>
> > He did specify *direct* injection; 2000 psi is about in the ballpark.
>
> >
>
> > Another thing I forgot in my previous post - at least for BMW, the high
>
> > pressure fuel pump is engine driven, not electric - if pressure has bled
>
> > down while the engine is off (not unusual; I've already replaced one
>
> > leaky injector) there will be no ability to inject fuel until the engine
>
> > turns over a few times.
>
> >
>
> > nate
>
> >
>
>
>
> Looks like Bosch has been working on this, but apparently it's only
>
> practical as a backup mechanism.
>
>
>
> http://www.etas.com/data/RealTimes_2...6_01_34_en.pdf
>
>
>
> nate
>
>
>
> --
>
> replace "roosters" with "cox" to reply.
>
> http://members.cox.net/njnagel

Google,,, American Car Prospector His name is John Hames. He drives around (mostly in Colorado) looking for certain cars to buy and then sell to buyers on a list he has. Not long ago he bought an old Corvette that has a weird looking mechanical fuel injection system on it. On my Comcast TV channels line up, his show is on the Velocity TV channel on Sundays.

On 11/14/2013 10:04 AM, Nate Nagel wrote:
> On 11/14/2013 10:31 AM, wrote:
>> Any direct injection gasoline engine can start without a starter
>> motor. They produce a high pressure(most injectors for GAS DIRECT
>> INJECTION/or SIDI for GM)between 500 to 2900 PSI depending on the
>> platform. The fuel injectors also run around 60 to 70 volts as
>> opposed to the traditional 12v injectors. They also have the ability
>> to fire one to three times per event and run on compression rations
>> of 11:1 to 13:1. They can run on multiple mods including stratified,
>> stratefied homogeneous, homogeneous anti knock, homogeneous lean, and
>> homogeneous.
>>
>> 2000(yes two thousand) psi is enough to turn a piston over.
>>
>
> I don't think that you'd want to spin the engine over by using fuel
> pressure... the compression stroke would hydrolock the engine, which
> tends to be detrimental to future functionality.
>
> However, you do raise an interesting point, that with modern engine
> controls, it might be possible for the engine computer to "know" which
> piston is just past TDC on its power stroke, inject a small fuel charge
> into that cylinder, then fire the plug, then proceed to the next
> cylinder etc. until the engine is running normally. Sort of analogous
> to an antique aircraft engine started with cartridges.
>
> There must be a reason this approach is found lacking however -
> immediate thoughts off the top of my head
>
> 1) there may not be enough oxygen in an uncompressed cylinder at TDC to
> burn enough fuel to reliably spin the engine to the "next" cylinder,
> especially if the engine is at operating temperature (e.g. after a short
> fuel stop) as the air in the engine would be considerably less dense
> than it would be at normal ambient temperatures.
>
> 2) Would rely on ECM memory to remember position of crankshaft and
> camshaft until next starting event. If your battery goes flat over a
> period of disuse, without a conventional starter motor it would be
> impossible to start the engine without either push-starting or cranking
> the engine by hand; not something I'd want to try with a high
> compression 6-cylinder by myself. Alternately, a new kind of sensor
> would have to be used which would allow the ECM to read cam position
> relatively precisely at zero RPM.
>
> To my knowledge nobody has implemented this approach yet; my
> direct-injected BMW engine still has a conventional electric starter, as
> does Hyundai's and every other mass produced DI engine.
>
> HOWEVER - I'm finding this line of thought interesting, and if it could
> work, would make an interesting ECM program addition for a backup
> starting method in the event of an electric starter motor failure; sadly
> not an uncommon issue with BMW N54/N55 engines from what I read on the
> forums. Rather than leaving one stranded, such a scheme would result in
> the engine starting but with an error message on the dashboard e.g.
> "Starter motor failed, repair at earliest convenience" or something like
> that.
>
> nate
>
Who needs a starter motor? I was able to push my 1994 Civic Si far
enough up a hill to bump start it with a nearly completely flat battery.

--
T0m $herm@n

On 11/14/2013 8:00 PM, Tegger wrote:
> Compressed-air starters were common on higher-end cars before electric
> starters becme practical. There's a reason why they're not around anymore.

And on some aircraft - hand-propping is scary.

--
T0m $herm@n