Maker Pro
Maker Pro

Please view this spice file.. (fuel injector driver amp)

J

Jamie

Jan 1, 1970
0
I did up a driver amp for an injector and first I need some opinions
if the think the valve is going to drop out between pulses. I am at home
at the moment and did not bring with me any injectors to work with.

I have the amp absorbing the wheeling voltage instead of using a
diode, would like some feed back on that.

P.S.
THis amp is design the drive the coil low or high, only one side does
the work depending on how the coil is connected on the other side, (+)
or common.

Version 4
SHEET 1 880 680
WIRE 320 -192 -272 -192
WIRE 592 -192 320 -192
WIRE 608 -192 592 -192
WIRE -272 -144 -272 -192
WIRE 320 -96 320 -192
WIRE 320 -96 240 -96
WIRE -272 -48 -272 -64
WIRE 176 -48 144 -48
WIRE 320 -48 320 -96
WIRE 144 -32 144 -48
WIRE 256 0 240 0
WIRE 32 16 -144 16
WIRE 80 16 32 16
WIRE -144 32 -144 16
WIRE -144 32 -176 32
WIRE 592 32 592 -192
WIRE 144 80 144 64
WIRE 320 80 320 48
WIRE 320 80 144 80
WIRE 320 192 320 80
WIRE 352 192 320 192
WIRE 592 192 592 112
WIRE 592 192 352 192
WIRE 656 288 528 288
WIRE 528 320 528 288
WIRE 320 336 320 192
WIRE 320 336 224 336
WIRE 656 336 656 288
WIRE 32 384 32 16
WIRE 160 384 112 384
WIRE 320 384 320 336
WIRE -176 432 -176 32
WIRE -176 432 -304 432
WIRE 256 432 224 432
WIRE 528 432 528 400
WIRE 656 432 656 416
WIRE 320 512 320 480
FLAG 320 512 0
FLAG -272 -48 0
FLAG -304 512 0
FLAG 352 192 MIN
FLAG 528 432 0
FLAG 656 432 0
FLAG 672 16 Injector_coil
SYMBOL voltage -272 -160 R0
WINDOW 123 0 0 Left 2
WINDOW 39 24 44 Left 2
SYMATTR InstName V1
SYMATTR Value 12
SYMBOL Misc\\signal -304 416 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value PULSE(0 10 0 100u 100u 8ms 10ms 1000)
SYMBOL npn 256 384 R0
SYMATTR InstName Q3
SYMATTR Value FZT849
SYMBOL npn 256 -48 R0
SYMATTR InstName Q1
SYMATTR Value FZT849
SYMBOL pnp 176 0 M180
SYMATTR InstName Q2
SYMATTR Value 2N2907
SYMBOL pnp 160 432 M180
SYMATTR InstName Q4
SYMATTR Value 2N2907
SYMBOL npn 80 -32 R0
SYMATTR InstName Q5
SYMBOL res 16 400 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R1
SYMATTR Value 5k
SYMBOL ind2 576 16 R0
SYMATTR InstName L1
SYMATTR Value 10mh
SYMATTR Type ind
SYMATTR SpiceLine Rser=2
SYMBOL ind2 512 304 R0
SYMATTR InstName L2
SYMATTR Value 100mh
SYMATTR Type ind
SYMBOL res 640 320 R0
SYMATTR InstName R2
SYMATTR Value 1k
TEXT -328 -216 Left 2 !.tran 0 .100 0 startup
TEXT -408 -176 Left 2 !K1 L1 L2 .9

jamie
 
L

legg

Jan 1, 1970
0
I did up a driver amp for an injector and first I need some opinions
if the think the valve is going to drop out between pulses. I am at home
at the moment and did not bring with me any injectors to work with.

I have the amp absorbing the wheeling voltage instead of using a
diode, would like some feed back on that.

Compare the current flow and power losses, as presented. Why are the
top drive components even present?

You can't model a electromotive element as a simple inductor or
transformer. During the initial or final periods of energisation the
magnetic structure changes.

If you've got to dump energy somewhere, use a resistor if you can't
clamp and recycle it. They're cheaper and can be more reliable.

RL
 
J

Jamie

Jan 1, 1970
0
snip

where is it going to be used? it is far too slow to work in a car
engine

do you have the option of driving both ends of the injector or are you
limited to
the low side, with the high side connected to the battery?

-Lassee

Slow? how so? I was doing 1khz with no problems, I 'll try a faster
test later.

I am not limited to how the coil is connected, I am going to connect
the other end to a bridge so that I can switch the poles on coil collapse.

jamie
 
J

John S

Jan 1, 1970
0
I did up a driver amp for an injector and first I need some opinions
if the think the valve is going to drop out between pulses. I am at home
at the moment and did not bring with me any injectors to work with.

I have the amp absorbing the wheeling voltage instead of using a diode,
would like some feed back on that.

P.S.
THis amp is design the drive the coil low or high, only one side does
the work depending on how the coil is connected on the other side, (+)
or common.


Here ya go:

Version 4
SHEET 1 880 680
WIRE 320 -192 -272 -192
WIRE 592 -192 320 -192
WIRE 608 -192 592 -192
WIRE -272 -144 -272 -192
WIRE 320 -96 320 -192
WIRE -272 -48 -272 -64
WIRE 32 16 -144 16
WIRE 320 16 320 -32
WIRE -144 32 -144 16
WIRE -144 32 -176 32
WIRE 592 32 592 -192
WIRE 320 192 320 80
WIRE 352 192 320 192
WIRE 592 192 592 112
WIRE 592 192 352 192
WIRE 656 288 528 288
WIRE 528 320 528 288
WIRE 656 336 656 288
WIRE 32 384 32 16
WIRE 160 384 112 384
WIRE 320 384 320 192
WIRE -176 432 -176 32
WIRE -176 432 -304 432
WIRE 160 432 160 384
WIRE 256 432 160 432
WIRE 528 432 528 400
WIRE 656 432 656 416
WIRE 320 512 320 480
FLAG 320 512 0
FLAG -272 -48 0
FLAG -304 512 0
FLAG 352 192 MIN
FLAG 528 432 0
FLAG 656 432 0
FLAG 672 16 Injector_coil
SYMBOL voltage -272 -160 R0
WINDOW 123 0 0 Left 2
WINDOW 39 24 44 Left 2
SYMATTR InstName V1
SYMATTR Value 12
SYMBOL Misc\\signal -304 416 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value PULSE(0 10 0 100u 100u 8ms 10ms 1000)
SYMBOL npn 256 384 R0
SYMATTR InstName Q3
SYMATTR Value FZT849
SYMBOL res 16 400 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R1
SYMATTR Value 500
SYMBOL ind2 576 16 R0
SYMATTR InstName L1
SYMATTR Value 10mh
SYMATTR Type ind
SYMATTR SpiceLine Rser=2
SYMBOL ind2 512 304 R0
SYMATTR InstName L2
SYMATTR Value 100mh
SYMATTR Type ind
SYMBOL res 640 320 R0
SYMATTR InstName R2
SYMATTR Value 1k
SYMBOL zener 304 -96 R0
SYMATTR InstName D1
SYMATTR Value 1N5378B
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL diode 336 80 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D2
SYMATTR Value MUR460
TEXT -328 -216 Left 2 !.tran 0 .100 0 startup
TEXT -408 -176 Left 2 !K1 L1 L2 .9
 
J

Jamie

Jan 1, 1970
0
legg said:
Compare the current flow and power losses, as presented. Why are the
top drive components even present?

You can't model a electromotive element as a simple inductor or
transformer. During the initial or final periods of energisation the
magnetic structure changes.

If you've got to dump energy somewhere, use a resistor if you can't
clamp and recycle it. They're cheaper and can be more reliable.

RL
The energy is being clamped through the amp output when attempts to
exceed input bias reference exist.

I have both poles designed in the circuit so the coil can be
connected either way and also by doing so, any unexpected voltage on the
output is going to force either the top or bottom to clamp as required
to maintain it.

For example.
If I have a reference of 5 volts on the input and lets say the
output device or anything attached attempts to be higher than 5 volts
it'll force the bottom pole on to drain it off. If the output was lower
than 5 Volts, the top pole(rail) components will then turn on to make up
for loss.

So as far as magnetic collapse energy coming back, if it does not
match with the input reference it will be corrected.

I've already examine some type EV6 and throttle body injectors with a
scope to monitor current and kick back using a basic MOSFET low side
drive with and with out diode clamp. What I saw with both was a slight
current curve ripple with initial first cycle pulse and I can only
assume this is due to the inner components interacting with the magnetic
core material as it moved in place. The only useful information that
lead to this was the possibility of detecting pintle movements which for
now is not at the top of the list.

What I saw with the scope and a basic equivalent inductor was close
enough to be used as a model in a basic sketch.

We will be metering Xylene through the injectors. It looks like a
throttle body type may work the best. With that I can simple do the
initial open and then meter it with PWM to maintain it. The test we
did with Kerosene seems to confirm that we should be doing a first full
open and then following pulses are current monitor and can be regulated
via PWM.

The final circuit is going to be monitoring current for max magnetic
current peak. This is going to allow a automatic parameter to indicate
what the base frequency of the inject should be and once that is
calculated the PWM will be a window of that range for a variable
maintainable control. This will be done on the start of each initial use
of the injector. I did this to help in the event when the inject gets
warm the variation of core material and pull in time will auto adjust,
hopefully.

I most likely will have a small uC behind this all.

Jamie
 
J

Jamie

Jan 1, 1970
0
John said:
The usual problem driving fast solenoids is dumping the stored energy;
for that, you need a high reverse/flyback voltage. One complication is
that most solenoids change their magnetic path when the armature is
seated, making the closed solenoid have a lot more inductance than the
un-energized one. You could test for that. For serious speed, you need
to take that into account.

You can dump the stored energy into a dissipative element, a resistor
or a zener, or you can recover it somehow, like using a full bridge
driver.

Why not just use a power fet and a zener clamp, or buy a full-bridge
driver chip?

John
The problem is current, while a chip driver can handle the small ones we
have a throttle body type that seems to require a lot more current and
the energy store is massive compared to the Bosch EV6 manifold types

Our first test model on the bench does use a MOSFET on the low side
with a wheeling diode on the coil. It works fine but I found the diode
getting rather hot with the throttle body type, due to the very
inductive core it has..

With the design of that amp I did, it does drain off the energy very
nicely. I picked an inductor that matches closely what the injector
does. If you watch the analysis of the circuit and view the current,
you'll see the amp soaking up the back current and I don't need a wheeling
diode.. The reason I went this way is I may decide to have a long decay
on the pulse so to let the inductor collapse slowly.

We'll be metering xylene and the reference for each cycle of spray
will be coming from an encoder pulse as a one shot, in case the machine
stops on a tooth and from there, it's going to be a time period of
injection depending on the LBS/Ph demand.

I am at home for the time being and I didn't bring any injectors
home with me for electrical testing so I am relying on the measurements
I took of the coil at work and using a inductor with the series R that
matches it.

Jamie
 
J

Jamie

Jan 1, 1970
0
John said:
Here ya go:

Version 4
SHEET 1 880 680
WIRE 320 -192 -272 -192
WIRE 592 -192 320 -192
WIRE 608 -192 592 -192
WIRE -272 -144 -272 -192
WIRE 320 -96 320 -192
WIRE -272 -48 -272 -64
WIRE 32 16 -144 16
WIRE 320 16 320 -32
WIRE -144 32 -144 16
WIRE -144 32 -176 32
WIRE 592 32 592 -192
WIRE 320 192 320 80
WIRE 352 192 320 192
WIRE 592 192 592 112
WIRE 592 192 352 192
WIRE 656 288 528 288
WIRE 528 320 528 288
WIRE 656 336 656 288
WIRE 32 384 32 16
WIRE 160 384 112 384
WIRE 320 384 320 192
WIRE -176 432 -176 32
WIRE -176 432 -304 432
WIRE 160 432 160 384
WIRE 256 432 160 432
WIRE 528 432 528 400
WIRE 656 432 656 416
WIRE 320 512 320 480
FLAG 320 512 0
FLAG -272 -48 0
FLAG -304 512 0
FLAG 352 192 MIN
FLAG 528 432 0
FLAG 656 432 0
FLAG 672 16 Injector_coil
SYMBOL voltage -272 -160 R0
WINDOW 123 0 0 Left 2
WINDOW 39 24 44 Left 2
SYMATTR InstName V1
SYMATTR Value 12
SYMBOL Misc\\signal -304 416 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value PULSE(0 10 0 100u 100u 8ms 10ms 1000)
SYMBOL npn 256 384 R0
SYMATTR InstName Q3
SYMATTR Value FZT849
SYMBOL res 16 400 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R1
SYMATTR Value 500
SYMBOL ind2 576 16 R0
SYMATTR InstName L1
SYMATTR Value 10mh
SYMATTR Type ind
SYMATTR SpiceLine Rser=2
SYMBOL ind2 512 304 R0
SYMATTR InstName L2
SYMATTR Value 100mh
SYMATTR Type ind
SYMBOL res 640 320 R0
SYMATTR InstName R2
SYMATTR Value 1k
SYMBOL zener 304 -96 R0
SYMATTR InstName D1
SYMATTR Value 1N5378B
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL diode 336 80 R180
WINDOW 0 24 64 Left 2
WINDOW 3 24 0 Left 2
SYMATTR InstName D2
SYMATTR Value MUR460
TEXT -328 -216 Left 2 !.tran 0 .100 0 startup
TEXT -408 -176 Left 2 !K1 L1 L2 .9
I think you better go back to the drawing board on that one? did you see
the analysis on that?

The back energy is up to 120V, the low side sink transistor is
only rated for 30V.

If I go in there with the proper clamp, the coil then looks like my
amp analysis except its being handled in the amp and not a wheeling diode.

Jamie
 
J

John S

Jan 1, 1970
0
I think you better go back to the drawing board on that one? did you see
the analysis on that?

Is that supposed to be a trick question?
The back energy is up to 120V, the low side sink transistor is
only rated for 30V.

I know. I was not trying to do your design for you. Just give you some
direction.
If I go in there with the proper clamp, the coil then looks like my amp
analysis except its being handled in the amp and not a wheeling diode.

Jamie

So, are you telling me that you want the *average* current through the
coil to be 1.5 amps with the peak at 2.4 amps and the valley to be .95
amps? If so, then you're there.

Note that Q1, Q2, and Q5 are doing absolutely nothing. You can take them
out and not change the circuit operation. I think RL pointed this out
earlier.

Note that you are dissipating 13W in Q3.

That make you happy?
 
J

John S

Jan 1, 1970
0
The back energy is up to 120V, the low side sink transistor is
only rated for 30V.

Energy is in joules (or ft-lbs, or some such) but not in volts.

Some transistors are rated for more than 30V. You don't have any that
can take more than that?
If I go in there with the proper clamp, the coil then looks like my amp
analysis except its being handled in the amp and not a wheeling diode.

Jamie

I have no idea what you are trying to convey in your last sentence.

Are you trying to do the saturation or the peak-and-hold? Either way,
your circuit sucks big time.
 
J

Jamie

Jan 1, 1970
0
John said:
Is that supposed to be a trick question?



I know. I was not trying to do your design for you. Just give you some
direction.


So, are you telling me that you want the *average* current through the
coil to be 1.5 amps with the peak at 2.4 amps and the valley to be .95
amps? If so, then you're there.

Note that Q1, Q2, and Q5 are doing absolutely nothing. You can take them
out and not change the circuit operation. I think RL pointed this out
earlier.

Note that you are dissipating 13W in Q3.

That make you happy?
Sure, but I wasn't planning on using those any way. Just the first thing
in the list that look good.. I still may end up going the MOSFET and
large clamp diode way, but we'll see. We do have a large count of
TIP3055 that will do the job just fine.

We have been thinking of generating a half trapezoid wave on the
decay side for the input reference, one that we can adjust.

Jamie
 
J

Jamie

Jan 1, 1970
0
John said:
Energy is in joules (or ft-lbs, or some such) but not in volts.

Some transistors are rated for more than 30V. You don't have any that
can take more than that?


I have no idea what you are trying to convey in your last sentence.

Are you trying to do the saturation or the peak-and-hold? Either way,
your circuit sucks big time.
if you say so, it does work. I manage to find some parts at home base
here to load test it using a DC solenoid coil. The coil isn't an
injector but a spring loaded unit actuator so I can experiment a bit. I
am getting ready to set up the AB-GEN for a experimental wave form I
have in mind.

Have a good day. As always.

Jamie
 
J

John S

Jan 1, 1970
0
if you say so, it does work. I manage to find some parts at home base
here to load test it using a DC solenoid coil. The coil isn't an
injector but a spring loaded unit actuator so I can experiment a bit. I
am getting ready to set up the AB-GEN for a experimental wave form I
have in mind.

Have a good day. As always.

Jamie

Oh, okay. So it works. Then why have you asked for a review? Did you
just want approval for your crap? Don't expect it here. Go away.
 
J

Jamie

Jan 1, 1970
0
John said:
You're so funny, we've already been to whole crap load of sites
on this subject, but thanks any way.

Btw, if you read that page you so posted, you'll find that I've been
telling you about what we had to do with our project as far as doing the
Peak+Hold or just high-Z units, also if you remember, I did talk about
the affects being shown in the wave forms as the mechanics inside move
into place.

We are most like going to use a throttle body type which is a Peak
and hold, this means I either need to use that amp circuit so I can drop
the
output voltage at the initial open or use PWM and have a long start
pulse followed by short ones to maintain hold, that I could do with the
MOSFET if I go PWM. Either way, dealing with the energy is hump I am
getting over with.

Have a good day.

Jamie
 
J

Jamie

Jan 1, 1970
0
the point is that with that very slow rate of decay you have no
dynamic range
on the pulswidth, and on top of that it will be variable with pressure
and
everything else at exactly what current it closes





try something like this: (the highside driver is a bit slow but it
gets the point across)

Version 4
SHEET 1 2440 680
WIRE 1536 -496 1120 -496
WIRE 1296 -224 1040 -224
WIRE 1536 -224 1536 -496
WIRE 1536 -224 1376 -224
WIRE 1536 -144 1536 -224
WIRE 1808 -144 1536 -144
WIRE 1536 -128 1536 -144
WIRE 1536 -128 1440 -128
WIRE 1040 -48 1040 -224
WIRE 1184 -48 1040 -48
WIRE 1808 -48 1808 -64
WIRE 1808 -48 1440 -48
WIRE 1808 -32 1808 -48
WIRE 1040 32 1040 -48
WIRE 1184 32 1104 32
WIRE 1584 32 1440 32
WIRE 1584 48 1584 32
WIRE 1760 48 1584 48
WIRE 1808 112 1808 64
WIRE 2048 112 1808 112
WIRE 1040 128 1040 96
WIRE 1104 128 1104 96
WIRE 1312 128 1312 80
WIRE 1808 208 1808 112
WIRE 1808 400 1808 288
WIRE 1456 480 1248 480
WIRE 1760 480 1536 480
WIRE 1248 512 1248 480
WIRE 1248 608 1248 592
WIRE 1808 608 1808 496
FLAG 1120 -416 0
FLAG 1312 128 0
FLAG 1808 608 0
FLAG 1248 608 0
FLAG 2048 176 0
FLAG 1104 128 0
FLAG 1040 128 0
SYMBOL PowerProducts\\LT1910 1312 -48 R0
SYMATTR InstName U1
SYMBOL voltage 1120 -512 R0
WINDOW 123 0 0 Left 0
WINDOW 39 24 44 Left 0
SYMATTR InstName V3
SYMATTR Value 12
SYMBOL nmos 1760 -32 R0
SYMATTR InstName M2
SYMATTR Value IRL3915
SYMBOL res 1792 -160 R0
SYMATTR InstName R3
SYMATTR Value .025
SYMBOL voltage 1248 496 R0
WINDOW 123 0 0 Left 0
WINDOW 39 24 44 Left 0
SYMATTR InstName V4
SYMATTR Value PULSE(0 12 1m 1u 1u 50m 200m 1)
SYMBOL ind2 1792 192 R0
SYMATTR InstName L3
SYMATTR Value 10mh
SYMATTR Type ind
SYMATTR SpiceLine Rser=2
SYMBOL schottky 2064 176 R180
WINDOW 0 24 72 Left 0
WINDOW 3 24 0 Left 0
SYMATTR InstName D1
SYMATTR Value MBRS360
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL nmos 1760 400 R0
SYMATTR InstName M1
SYMATTR Value irl3915mod
SYMBOL cap 1088 32 R0
SYMATTR InstName C1
SYMATTR Value 5n
SYMBOL res 1392 -240 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R4
SYMATTR Value 10k
SYMBOL zener 1056 96 R180
WINDOW 0 24 72 Left 0
WINDOW 3 24 0 Left 0
SYMATTR InstName D2
SYMATTR Value BZX84C6V2L
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res 1552 464 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R1
SYMATTR Value 1k
TEXT 1632 -560 Left 0 !.tran 0 .100 0 startup
TEXT 1984 504 Left 0 !.model irl3915mod ako: irl3915 bv=55


-Lasse
That is an interesting idea, I can do that with antique parts using a
dual timer. one for the holding pulse stream and the other a one-shot
for volume measuring that needs to be adjusted of course.

We will be using an encoder that can ramp the volume as the pulse rate
increases. I think I can then adjust the one shot as the ratio mix.

I will be fully clamping the back voltage. It will actually be an aid
to hold the valve in a steady position at lower current rather than a
problem. Injector to be used needs a high current pulse then it idles
back to about 1.5 amps or so. That is where I need the pulse if I go
the full switching way :)


Lots interesting. Thanks.

Thanks,.
 
J

Jamie

Jan 1, 1970
0
John said:
Oh, okay. So it works. Then why have you asked for a review? Did you
just want approval for your crap? Don't expect it here. Go away.
I was only interested in the opinion of how I decided to handle the back
energy which I can meter that way. For example, Lets say I will allow it
to ramp back up to like 30 volts. I can use a voltage divider network in
the off stroke to set the clamp level with that circuit..



Have a nice day,.
 
J

Joerg

Jan 1, 1970
0
the stroke on an in jector is very small so I don't think it changes
that
much, though on some you can see see a small wiggle in the waveforms
when it
opens and closes

On the ones I designed controls for the effect was very pronounced.

to get any kind of accurate metering of fuel it needs to dump the
current
fast so the closing time it repeatable

Yup. Plus if Jamie's injector is more like a valve a slow closure might
increase wear. Although, I think, Xylene is a bit greasy so maybe it's
not so bad. It'll also depend on the contaminants in there.

that how all the car manufacturers do it, a temperature/current
protected
fet with a clamp voltage at something like 36/42/55 volts

Yes, one has do get rid of the stored energy quickly and the only way to
do that is to allow the inductor to shoot up to a higher voltage. A full
bridge isn't going to cut it for fast action, not enuogh volts.
 
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