Unofficial FAQ: Ignition corrections

TeGGeR® wrote:
> jim beam > wrote in
> :
>
>
>>Jim Yanik wrote:
>>
>>>jim beam > wrote in news_-dnS91tZMHfzHfRVn-
:
>>>
>>>
>>>
wrote:
>>>>
>>>>
>>>>>TeGGeR® wrote:
>>>>>
>>>>>http://www.tegger.com/hondafaq/ignit...ion/index.html
>>>>>
>>>>>Hopefully this is correct now.
>>>>>
>>>>>Thanks to all for their help, especially Jim Yanik.
>>>>>
>>>>>--
>>>>>TeGGeR®
>>>>>
>>>>>The Unofficial Honda/Acura FAQ
>>>>>www.tegger.com/hondafaq/
>>>>>--------------------------------------
>>>>>I think in the 1990 Honda Civic, the igniter also provides
>>>>>for for some PWM control. It senses the back EMF and
>>>>>kills the coil drive at the correct momment to insure a
>>>>>hot spark. I played with an ignitor and couldn't get it
>>>>>to because correctly until I connected to to a Honda
>>>>>igntion coil. As I varied the frequency of the drive pulses,
>>>>>all the same width, the output created wider pulse at higher
>>>>>"RPM".
>>>>>
>>>>>Terry
>>>>>
>>>>
>>>>interesting! i'd read that they did that, but just haven't had the
>>>>time to sit down & test for it. thanks for the confirmation!
>>>>
>>>>
>>>
>>>
>>>That is probably what the IC in the igniter does.(control PW.)
>>>The ECU merely provides the trigger at the proper time.
>>>
>>
>>so where does it adjust pulse width - has to be on the front end,
>>right?
>> if it was on the rear, the timing would be off. or maybe the ecu
>>already knows what the igniter's timing characteristics are and
>>adjusts accordingly?...
>>
>>
>
>
>
> I think the ECU holds ground on Terminal 4 for the appropriate length of
> time, which keeps the igniter driving the coil until ground is removed.
> Once ground is removed from Pin 4, the IC switches off coil drive and the
> field collapses.
>
> The ECU decides when to apply ground and break it based on the inputs of
> various sensors, such as the Crank Angle Sensor. It needs to know current
> RPM, cylinder position and crank angle.
>
> Terry is also indicating that the coil is allowed to charge for a longer
> time at high RPMs to ensure a fatter spark under harsher conditions.
>
yes, but that longer time seems to be determined by the igniter, not the
ecu, if i understand jim yanik correctly. it kind of has to be because
only the igniter is set up to meter the actual flyback, and that is
itself a function of the health of the system.

"TeGGeR®" > wrote in
:

> jim beam > wrote in
> :
>
>> Jim Yanik wrote:
>>> jim beam > wrote in news_-dnS91tZMHfzHfRVn-
>>> :
>>>
>>>
wrote:
>>>>
>>>>>TeGGeR® wrote:
>>>>>
>>>>>http://www.tegger.com/hondafaq/ignit...ion/index.html
>>>>>
>>>>>Hopefully this is correct now.
>>>>>
>>>>>Thanks to all for their help, especially Jim Yanik.
>>>>>
>>>>>--
>>>>>TeGGeR®
>>>>>
>>>>>The Unofficial Honda/Acura FAQ
>>>>>www.tegger.com/hondafaq/
>>>>>--------------------------------------
>>>>>I think in the 1990 Honda Civic, the igniter also provides
>>>>>for for some PWM control. It senses the back EMF and
>>>>>kills the coil drive at the correct momment to insure a
>>>>>hot spark. I played with an ignitor and couldn't get it
>>>>>to because correctly until I connected to to a Honda
>>>>>igntion coil. As I varied the frequency of the drive pulses,
>>>>> all the same width, the output created wider pulse at higher
>>>>>"RPM".
>>>>>
>>>>>Terry
>>>>>
>>>>
>>>>interesting! i'd read that they did that, but just haven't had the
>>>>time to sit down & test for it. thanks for the confirmation!
>>>>
>>>>
>>>
>>>
>>> That is probably what the IC in the igniter does.(control PW.)
>>> The ECU merely provides the trigger at the proper time.
>>>
>> so where does it adjust pulse width - has to be on the front end,
>> right?
>> if it was on the rear, the timing would be off. or maybe the ecu
>> already knows what the igniter's timing characteristics are and
>> adjusts accordingly?...
>>
>>
>
>
> I think the ECU holds ground on Terminal 4 for the appropriate length
> of time, which keeps the igniter driving the coil until ground is
> removed. Once ground is removed from Pin 4, the IC switches off coil
> drive and the field collapses.

I do not believe this,as the IC inside the igniter monitors coil current.
>
> The ECU decides when to apply ground and break it based on the inputs
> of various sensors, such as the Crank Angle Sensor. It needs to know
> current RPM, cylinder position and crank angle.
>
> Terry is also indicating that the coil is allowed to charge for a
> longer time at high RPMs to ensure a fatter spark under harsher
> conditions.
>

Yes,coil current has to reach some preset point before the IC shuts off the
Darlington. That's the job of that IC.

The only way we will truly know for sure is to get a look at the IC's app
sheet,or scope the ECU signal to the igniter and see if it's pulse width
increases.If it does,then it controls the PW,not the IC.

--
Jim Yanik
jyanik
at
kua.net

Jim Yanik .> wrote in
:

> "TeGGeR®" > wrote in
> :
>
>> jim beam > wrote in
>> :
>>
>>> Jim Yanik wrote:
>>>> jim beam > wrote in news_-dnS91tZMHfzHfRVn-
>>>> :
>>>>
>>>>
wrote:
>>>>>
>>>>>>TeGGeR® wrote:
>>>>>>
>>>>>>http://www.tegger.com/hondafaq/ignit...ion/index.html
>>>>>>
>>>>>>Hopefully this is correct now.
>>>>>>
>>>>>>Thanks to all for their help, especially Jim Yanik.
>>>>>>
>>>>>>--
>>>>>>TeGGeR®
>>>>>>
>>>>>>The Unofficial Honda/Acura FAQ
>>>>>>www.tegger.com/hondafaq/
>>>>>>--------------------------------------
>>>>>>I think in the 1990 Honda Civic, the igniter also provides
>>>>>>for for some PWM control. It senses the back EMF and
>>>>>>kills the coil drive at the correct momment to insure a
>>>>>>hot spark. I played with an ignitor and couldn't get it
>>>>>>to because correctly until I connected to to a Honda
>>>>>>igntion coil. As I varied the frequency of the drive pulses,
>>>>>> all the same width, the output created wider pulse at higher
>>>>>>"RPM".
>>>>>>
>>>>>>Terry
>>>>>>
>>>>>
>>>>>interesting! i'd read that they did that, but just haven't had the
>>>>>time to sit down & test for it. thanks for the confirmation!
>>>>>
>>>>>
>>>>
>>>>
>>>> That is probably what the IC in the igniter does.(control PW.)
>>>> The ECU merely provides the trigger at the proper time.
>>>>
>>> so where does it adjust pulse width - has to be on the front end,
>>> right?
>>> if it was on the rear, the timing would be off. or maybe the ecu
>>> already knows what the igniter's timing characteristics are and
>>> adjusts accordingly?...
>>>
>>>
>>
>>
>> I think the ECU holds ground on Terminal 4 for the appropriate length
>> of time, which keeps the igniter driving the coil until ground is
>> removed. Once ground is removed from Pin 4, the IC switches off coil
>> drive and the field collapses.
>
> I do not believe this,as the IC inside the igniter monitors coil
> current.


So I've read.



>>
>> The ECU decides when to apply ground and break it based on the inputs
>> of various sensors, such as the Crank Angle Sensor. It needs to know
>> current RPM, cylinder position and crank angle.
>>
>> Terry is also indicating that the coil is allowed to charge for a
>> longer time at high RPMs to ensure a fatter spark under harsher
>> conditions.
>>
>
> Yes,coil current has to reach some preset point before the IC shuts
> off the Darlington. That's the job of that IC.
>
> The only way we will truly know for sure is to get a look at the IC's
> app sheet,or scope the ECU signal to the igniter and see if it's pulse
> width increases.If it does,then it controls the PW,not the IC.
>


Terry seems to have determined that there is evidence of this.

--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

One more update:
http://www.tegger.com/hondafaq/ignit...ion/index.html

This has been a most interesting thread, I must say.

--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

Jim Yanik wrote (in part):

Yes,coil current has to reach some preset point before the IC shuts off
the
Darlington. That's the job of that IC.

The only way we will truly know for sure is to get a look at the IC's
app
sheet,or scope the ECU signal to the igniter and see if it's pulse
width
increases.If it does,then it controls the PW,not the IC.

--
Jim Yanik
---------------------------

I have several "systems" pulled from cars to be crushed.
I rigged a 1990 ECM and sensors, with igniter to try
and figure out what was going on.

I am after a simple way to monitor the on time of the FIs.

I was kind of suprised to see the ignition pulse width
incrase with engine speed. I used a dual channel oscilloscope
and the output from the ECM stayed the same.

I experimented using a HP pulse generator to drive the igniter
by itself and found the same thing to be true. In my celica the PW
is directly controled by the ECM. I am asuming the IC monitors the
delta V, or rate of change and integrates the data to determine PW.

I will try to test my 1991 Civc this weekend. I have brought most of
the
ECM outputs and inputs via 1K isolation resistors to a breakout box
for testing.

I think it will be very usefull to measure on ratio of the FIs to
squeeze
every erg from the fuel for best MGP.

I can say that in many ways the ECM doesn't work the way I thought.
There are odd actions during the warm up period.

One important point is that it looks like Honda skimps on teh heat sink
compound. Of course the engine runs hotter then the igniter, so I am
not at all sure that adding more thermal coupling will help. I have
thought
of adding a "heat pipe" tp remove heat from the igniter. I now consider
the
igniter a subsystem that is doomed to failure. It simply operates too
hot
for prolonged life.

Having said that, a friend's 1990 Civic has ~200K and is still on the
original igniter. Somewhere I have a motorola "designing for long
life of Si devices"(something like that) that says that for every 3
degree
rise in temp over 20C, the life will be cut in half. But based on that
the
~90 degrees C engine temp the igniter ought to fail in the first 100
miles.
There are many things I just don't understand here.

But I now carry a spare ECM and igniter "just in case".

Terry

wrote in
oups.com:

> I now consider the igniter a subsystem that is doomed to failure. It
> simply operates too hot for prolonged life.
>
> Having said that, a friend's 1990 Civic has ~200K and is still on the
> original igniter.



My '91 Integra has 248K miles and the interior of the distributor is
entirely original, except for the rotor which I change every few years.


I wonder if maintenance might be a factor in igniter longevity the way it
is with coil longevity. Since the igniter is doing a lot of monitoring as
well as current carrying, might a large enough deviation from design spec
in ignition system characteristics overload the igniter?



--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

"TeGGeR®" > wrote in
:

> wrote in
> oups.com:
>
>> I now consider the igniter a subsystem that is doomed to failure. It
>> simply operates too hot for prolonged life.
>>
>> Having said that, a friend's 1990 Civic has ~200K and is still on the
>> original igniter.
>
>
>
> My '91 Integra has 248K miles and the interior of the distributor is
> entirely original, except for the rotor which I change every few
> years.
>
>
> I wonder if maintenance might be a factor in igniter longevity the way
> it is with coil longevity. Since the igniter is doing a lot of
> monitoring as well as current carrying, might a large enough deviation
> from design spec in ignition system characteristics overload the
> igniter?
>
>
>

It might be related to spark plug wire condition,and spark plug
condition;if your wires are breaking down,it would place a greater load on
the coil,and if the plugs were gummed up,slagged,or carboned,that would
affect the coil voltage.
IMO,igniters fail because of transients and migration of metals in the
Darlington and IC.

One could conceivably use an electron microscope and examine failed igniter
semiconductors and see why they failed,but it would be an expensive
undertaking,unless you're a college student with access to an e-
microscope,and doing a thesis or paper.

--
Jim Yanik
jyanik
at
kua.net

wrote:
> Jim Yanik wrote (in part):
>
> Yes,coil current has to reach some preset point before the IC shuts off
> the
> Darlington. That's the job of that IC.
>
> The only way we will truly know for sure is to get a look at the IC's
> app
> sheet,or scope the ECU signal to the igniter and see if it's pulse
> width
> increases.If it does,then it controls the PW,not the IC.
>
> --
> Jim Yanik
> ---------------------------
>
> I have several "systems" pulled from cars to be crushed.
> I rigged a 1990 ECM and sensors, with igniter to try
> and figure out what was going on.
>
> I am after a simple way to monitor the on time of the FIs.
>
> I was kind of suprised to see the ignition pulse width
> incrase with engine speed. I used a dual channel oscilloscope
> and the output from the ECM stayed the same.
>
> I experimented using a HP pulse generator to drive the igniter
> by itself and found the same thing to be true. In my celica the PW
> is directly controled by the ECM. I am asuming the IC monitors the
> delta V, or rate of change and integrates the data to determine PW.
>
> I will try to test my 1991 Civc this weekend. I have brought most of
> the
> ECM outputs and inputs via 1K isolation resistors to a breakout box
> for testing.

that would be most excellent!

>
> I think it will be very usefull to measure on ratio of the FIs to
> squeeze
> every erg from the fuel for best MGP.
>
> I can say that in many ways the ECM doesn't work the way I thought.
> There are odd actions during the warm up period.
>
> One important point is that it looks like Honda skimps on teh heat sink
> compound. Of course the engine runs hotter then the igniter, so I am
> not at all sure that adding more thermal coupling will help. I have
> thought
> of adding a "heat pipe" tp remove heat from the igniter. I now consider
> the
> igniter a subsystem that is doomed to failure. It simply operates too
> hot
> for prolonged life.
>
> Having said that, a friend's 1990 Civic has ~200K and is still on the
> original igniter. Somewhere I have a motorola "designing for long
> life of Si devices"(something like that) that says that for every 3
> degree
> rise in temp over 20C, the life will be cut in half. But based on that
> the
> ~90 degrees C engine temp the igniter ought to fail in the first 100
> miles.
> There are many things I just don't understand here.
>
> But I now carry a spare ECM and igniter "just in case".
>
> Terry
>

Jim Yanik wrote:
> "TeGGeR®" > wrote in
> :
>
>
wrote in
groups.com:
>>
>>
>>>I now consider the igniter a subsystem that is doomed to failure. It
>>>simply operates too hot for prolonged life.
>>>
>>>Having said that, a friend's 1990 Civic has ~200K and is still on the
>>>original igniter.
>>
>>
>>
>>My '91 Integra has 248K miles and the interior of the distributor is
>>entirely original, except for the rotor which I change every few
>>years.
>>
>>
>>I wonder if maintenance might be a factor in igniter longevity the way
>>it is with coil longevity. Since the igniter is doing a lot of
>>monitoring as well as current carrying, might a large enough deviation
>>from design spec in ignition system characteristics overload the
>>igniter?
>>
>>
>>
>
>
> It might be related to spark plug wire condition,and spark plug
> condition;if your wires are breaking down,it would place a greater load on
> the coil,and if the plugs were gummed up,slagged,or carboned,that would
> affect the coil voltage.
> IMO,igniters fail because of transients and migration of metals in the
> Darlington and IC.

there are two "migration" mechanisms - first is solid state diffusion.
that's where the bit about the life halving every 3 degrees comes in.

the other is a mass transportation effect at high current densities.

unfortunately, high current leads to heat, and semi conductors have high
current densities, so the only real way to know for sure about the
failure mechanism, as you say, is microscopy.

>
> One could conceivably use an electron microscope and examine failed igniter
> semiconductors and see why they failed,but it would be an expensive
> undertaking,unless you're a college student with access to an e-
> microscope,and doing a thesis or paper.
>
of the two igniter types tegger shows, the second is designed more for a
high temperature environment from what i can see. the small scale
circuitry in the components of the first igniter have much smaller
diffusion paths. the larger scale thick film device has, for
semiconductors at any rate, truly massive scale features. these are bad
for speed, but even at 10,000 rpm, that's only 166Hz, not exactly a high
frequency challenge.

> wrote in message
oups.com...
> One important point is that it looks like Honda skimps on teh heat sink
> compound. Of course the engine runs hotter then the igniter, so I am
> not at all sure that adding more thermal coupling will help. I have
> thought
> of adding a "heat pipe" tp remove heat from the igniter. I now consider
> the
> igniter a subsystem that is doomed to failure. It simply operates too
> hot
> for prolonged life.
>

I don't think the heat is too great for the ignitor. There apparently aren't
any electrolytic capacitors in it, and those are the big heat sensitive
worries.

The vulnerability of transistors to heat is related to junction temperature
and to collector voltage. When the collector junction gets hot enough, the
reverse voltage across it can make the dopants migrate and "blur" the
junction. That spot gets hotter and eventually melts, leading to the device
being shorted.

But the heat required to melt the junction without the voltage stress is
much higher than your engine compartment - the melting point of silicon is
over 2500 degrees F. The silicon chips are typically soldered to the heat
sink internally, and I have personally soldered a UHF power transistor to a
large copper heatsink with an acetylene torch.

Mike