The rise time of the current in the injector is determined by the inductance of the solenoid. The current would be given by the exponential formulaHi, here you can see how the LM1949 works. I measured the injector current by using a 0,1 Ohm resistor in series to measure the voltage drop (I = V / R). The injector pulse duration is 8ms.
The P&H circuit starts with full current and reduce the current to 1A as soon as the maximum of 4A is reached. I was a bit surprised how long it takes ([email protected],2V) to magnetize the injector coil. The behavior is similar to an capacitor. The peak time will be a bit shorter with 14V supply voltage.
For my PWM settings in the previous installation I reduced the peak time to 1ms. After the 1ms the PWM mode started with the current limitation. The correct setting in my opinion would have been 2,5ms for the peak time in PWM mode.
It is better than my German!My English is not the best. I guess some of my sentence are a bit confused J
I started with crank sensor only, inkector PWM mode and batch fire. In the last couple of days, I added the Cam signal, installed the P&H board, and did the modifications on the MS2 hardware for injector output 3 + 4. I will run the system in full sequential from now (without PWM). The ignition will be still over the single coil. The WastedSpark and PWM idle valve will be upgrade when the basics are ok.
The MS2 clock signal should be sufficient to check if the CPU got a reset by electrical noise. The timer starts from the beginning as soon as the CPU restarts.
Thanks for the explanation with the fuel pressure regulator. I did not understand the problem with the relation of fuel pressure and manifold pressure. I will still keep the D-Jet regulator even when the VE table looks not plausible. The look of my injection system should be as close as possible like the original D-Jet system. The Megasquirt should be hidden.
I will test the modified system as soon as my injectors are back. I will keep you updated.
You must know this...but I didn't see it in your posting, so it scared me, and it bears repeating...you must have 6Ohms of current limiting in series with the Injector current!, which with an Injector R Value of around 1.3Ohms drops the Injector voltage to around 3V...you cannot put 12 or 14V directly on the Injectors!
Switching the ground connection on the injector is the norm for most modern applications. The hot side is switched on the D jet system. I don't know whether Bosch maintained that arrangement with the later LH digital systems where the injector resistors are mounted on a cluster usually on an inner fender wall.Thomas;
"Of course I will connect the injector directly to 14V. But the ground will be controlled by the P&H board. "
That is called "low side switching" and that is OK...a switch to control current can be in the high side OR the low side, but not what I am referring to...I am pointing out that you MUST limit the current in (each) Injector with a 6Ohm resistor in the current path. You may NEVER connect a full 12V across the Injector (which has a resistance of only 1.3Ohms), because without current limiting limiting, the current would be upwards on 9Amps, and the Injector would surely not survive!
Here is an excerpt of the output circuit with Injectors showing voltages:
View attachment 67995
OK...I've got it...the drive circuit of the MS Sys throttles the current back (with PWM?) and doesn't allow unlimited current for a prolonged time...my comments were based on the D-Jet control sys...