Can direct injection engines start without a starter motor?

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?

On 09/08/2011 09:16 PM, 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?

won't work.

for diesels, it's not the pressure of the compression stroke that
ignites the fuel, it's the adiabatic heating the compression causes.
once an engine stops, the heat in any compressed air charge quickly
dissipates. once gone, nothing you inject will ignite.

for gasoline, while the adiabatic heating it not as extreme as diesel,
it's still present and very much crucial to vaporize the air/fuel mix
when charged, and to raise its temp to the point where the spark will
"tip it over the edge" and ignite.

for either engine, the crank never comes to rest at or near the very top
of the stroke on switch-off. the more pistons, the closer you might be
to having one of course, but for most common 4, 6 or 8 cylinder engines,
no cylinder will be compressed quite enough.

it's also hard to have the engine computer "choose" which piston to try
and fire - most systems only know one spot on the crank, and that's tdc
on #1 piston. and that's not known until the sensor is triggered, and
that requires rotation - iow, it's "blind" once the engine is turned
off. you could change the sensor system and keep info in non-volatile
memory, but given all the above, it's something of a pointless exercise,
both computationally and financially.


--
nomina rutrum rutrum

My 1914 Ford Model T doesn't have a starter motor, but soon as the
engine is warmed up, when I shut it off whichever cylinder has a charge
of gas in that cylinder the engine will usually start running when I
turn the ignition switch on.
cuhulin

On Sep 8, 9:16*pm, "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?

It is doable.
In the '80s Ford built an engine with no cam and computer controlled
solenoids to open and close the valves.It could start without a
starter motor.

One of the demonstrations I do for my students is to start an engine
with a soldering iron.It works great with GM Hei.
I set the motor up a bit past tdc on #1 and prime the cylinder with a
few drops of gas and leave the ignition on. When the students show up
I take a big transformer style soldering iron, hold it next to the
distributer. When I pull the trigger the hei makes a spark and (most
of the time) the engine fires up.
Makes a great discussion starter.
HTH,
Ben

On 09/09/2011 08:10 AM, ben91932 wrote:
> On Sep 8, 9:16�pm, "larry moe 'n >
> 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?
>
> It is doable.
> In the '80s Ford built an engine with no cam and computer controlled
> solenoids to open and close the valves.It could start without a
> starter motor.

did you personally see it run? because i think that's urban legend.
all the solenoid controlled cams do is allow reselection of which piston
to fire, they have no more bearing on the thermodynamics inside the
piston than cam controlled valves.


>
> One of the demonstrations I do for my students is to start an engine
> with a soldering iron.It works great with GM Hei.
> I set the motor up a bit past tdc on #1 and prime the cylinder with a
> few drops of gas and leave the ignition on. When the students show up
> I take a big transformer style soldering iron, hold it next to the
> distributer. When I pull the trigger the hei makes a spark and (most
> of the time) the engine fires up.

did you warm the engine up prior? otherwise you have a freshly primed
super-saturated fuel/air mix [in excess of what would normally be
possible - since condensation and run-down would prevent it], you have
an inductively triggered spark [again something not normally possible]
and you have a crank position never found on any normally stopped engine...

why not go for one of these?
http://en.wikipedia.org/wiki/Coffman_engine_starter
it'll definitely work...

note: it works by rotating the engine - something all other starters do.
you need rotation because you need the compression and adiabatic
heating to make this stuff work. that's why indirectly injected diesels
won't start without glow plugs - insufficient adiabatic heating on a
cold engine, so you have to heat something inside the chamber to get the
fuel to light.


> Makes a great discussion starter.
> HTH,
> Ben


--
nomina rutrum rutrum

On Thu, 08 Sep 2011 21:16:40 -0700, 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?

Interesting question Has this ever been implemented in any other engine?
If not, did you patent the idea before throwing it out here?

It certainly makes sense. If there is a cylinder loaded and compressed,
firing the spark off should start the motor. I'd be wondering, however, if
it might get the crank going in the wrong direction, hence the need for a
motor to ensure proper rotation.

There is a certain way/method (using the hand crank) to start a Model T
Ford (and similar cars of that vintage) and if you don't abide by that
certain way you could wind up with a busted wrist or thumb or knee.Those
old vehicles/engines can back fire and start runing in the wrong
direction.
cuhulin

On 09/09/2011 08:04 PM, hachiroku wrote:
<snip for clarity>

> I'd be wondering, however, if
> it might get the crank going in the wrong direction, hence the need for a
> motor to ensure proper rotation.

good point. this is likely because as an engine stops rotating on
shutdown, it "bumps" up against compressed mixture on whatever piston is
in the compression stroke, and stops /before/ tdc, not after. even if
the mixture could be ignited cold, the piston would have to be
positioned after tdc, not before.


--
nomina rutrum rutrum

jim beam wrote:
>
> On 09/09/2011 08:04 PM, hachiroku wrote:
> <snip for clarity>
>
> > I'd be wondering, however, if
> > it might get the crank going in the wrong direction, hence the need for a
> > motor to ensure proper rotation.
>
> good point. this is likely because as an engine stops rotating on
> shutdown, it "bumps" up against compressed mixture on whatever piston is
> in the compression stroke, and stops /before/ tdc, not after. even if
> the mixture could be ignited cold, the piston would have to be
> positioned after tdc, not before.


Actually that is not necessarily the case.

The one engine i have seen that would self start looked like it would run
backwards for something 90-140 degrees and then reverse and run forward.

If you turned the warmed-up engine off and waited about 2 seconds and
turned it on it would sometimes start right up. Sometimes it would kick
back and blow smoke out the air intake and sometimes it would kick-back
and then reverse and start running. And sometimes it would just do
nothing when you turned the key back to on.

This was an IH engine with carburetor and points.

-jim

On 09/10/2011 08:34 AM, jim wrote:
>
>
> jim beam wrote:
>>
>> On 09/09/2011 08:04 PM, hachiroku wrote:
>> <snip for clarity>
>>
>>> I'd be wondering, however, if
>>> it might get the crank going in the wrong direction, hence the need for a
>>> motor to ensure proper rotation.
>>
>> good point. this is likely because as an engine stops rotating on
>> shutdown, it "bumps" up against compressed mixture on whatever piston is
>> in the compression stroke, and stops /before/ tdc, not after. even if
>> the mixture could be ignited cold, the piston would have to be
>> positioned after tdc, not before.
>
>
> Actually that is not necessarily the case.
>
> The one engine i have seen that would self start looked like it would run
> backwards for something 90-140 degrees and then reverse and run forward.

then you had a serious carburetor problem dumping vast excess gas. the
only way a gasoline engine can "run backwards" is if it's getting fuel
from the exhaust. if you're dumping unmetered gas so it's accumulating
in the exhaust, it might run as long as that fuel vapor can exist in the
pipe, but beyond that, it's game over.


>
> If you turned the warmed-up engine off and waited about 2 seconds and
> turned it on it would sometimes start right up. Sometimes it would kick
> back and blow smoke out the air intake and sometimes it would kick-back
> and then reverse and start running. And sometimes it would just do
> nothing when you turned the key back to on.
>
> This was an IH engine with carburetor and points.
>
> -jim

historically, many [diesels - see above] engines have been able to "run
backwards". but since most of these engines have not been fitted to
italian tanks, this is considered a problem, and thus cams are usually
timed these days to prevent this from happening.

but you're not going to start a diesel without rotating the engine
[whichever direction] because you need the adiabatic heating to ignite
the fuel.


--
nomina rutrum rutrum