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#11
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China Radio International
In article
, D Peter Maus wrote: Dave wrote: On Tue, 15 Jul 2008 18:14:47 +0000, D Peter Maus wrote: I've never had trouble with it. Ignition noise is a PITA to remove. I have switching power supplies all over the house. Including the UPS for the buildling. I don't get noise in my radios from the UPS. But if I fire up my motorcycle, whole bands become unlistenable. I never did get all the ignition noise out of the radio on my 308. Even the Caravan had some ignition noise. Are diesels still quiet (electrically)? You're joking, right? No that's David for you and that's Billy boy right behind him. -- Telamon Ventura, California |
#12
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China Radio International
Telamon wrote:
In article , Dave wrote: On Tue, 15 Jul 2008 18:14:47 +0000, D Peter Maus wrote: I've never had trouble with it. Ignition noise is a PITA to remove. I have switching power supplies all over the house. Including the UPS for the buildling. I don't get noise in my radios from the UPS. But if I fire up my motorcycle, whole bands become unlistenable. I never did get all the ignition noise out of the radio on my 308. Even the Caravan had some ignition noise. Are diesels still quiet (electrically)? Yes. Sorry pal, but after I got some rude replies from the Great Lakes Dynamic Duo I did some research and my suspicions were confirmed: "With the use of high pressure injectors it takes a 100V pulse to actually fire the injector. There is also some back EMF from the solenoids as the pulse ends and the solenoid opens. Unfortunately the diodes to clamp the back EMF are usually located in the Injector Driver Module (IDM) where they protect the IDM from the back EMF transient. By that time the couple feet of wire connecting the two has radiated the emission. In my 95 7.3L Power Stroke, the back pulse significantly exceeded 1000 volts. That's more than "some" backpulse, hi hi. Place the clamping diodes at the injectors, shield the wires, and round the edges of the pulse that fires the solenoid and the problem should subside. Not recommended for appliance operators/drivers or vehicles in warranty. The shields inside the Ford Diesel cables were grounded only at one end. I grounded them at the solenoid ends to valve cover bolts, and did other grounding to the vehicle. I was always afraid to clamp the injector solenoids because any back-pulse clamping would slow release times significantly. As far as I could tell, NOTHING clamped the solenoids. My brand new PSD appears to have the same problem. 73 Tom _______________________________________________ RFI mailing list http://lists.contesting.com/mailman/listinfo/rfi" I thought that would be the case. |
#13
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China Radio International
In article ,
Dave wrote: Telamon wrote: In article , Dave wrote: On Tue, 15 Jul 2008 18:14:47 +0000, D Peter Maus wrote: I've never had trouble with it. Ignition noise is a PITA to remove. I have switching power supplies all over the house. Including the UPS for the buildling. I don't get noise in my radios from the UPS. But if I fire up my motorcycle, whole bands become unlistenable. I never did get all the ignition noise out of the radio on my 308. Even the Caravan had some ignition noise. Are diesels still quiet (electrically)? Yes. Sorry pal, but after I got some rude replies from the Great Lakes Dynamic Duo I did some research and my suspicions were confirmed: "With the use of high pressure injectors it takes a 100V pulse to actually fire the injector. There is also some back EMF from the solenoids as the pulse ends and the solenoid opens. Unfortunately the diodes to clamp the back EMF are usually located in the Injector Driver Module (IDM) where they protect the IDM from the back EMF transient. By that time the couple feet of wire connecting the two has radiated the emission. In my 95 7.3L Power Stroke, the back pulse significantly exceeded 1000 volts. That's more than "some" backpulse, hi hi. Place the clamping diodes at the injectors, shield the wires, and round the edges of the pulse that fires the solenoid and the problem should subside. Not recommended for appliance operators/drivers or vehicles in warranty. The shields inside the Ford Diesel cables were grounded only at one end. I grounded them at the solenoid ends to valve cover bolts, and did other grounding to the vehicle. I was always afraid to clamp the injector solenoids because any back-pulse clamping would slow release times significantly. As far as I could tell, NOTHING clamped the solenoids. My brand new PSD appears to have the same problem. Anything CAN be badly engineered to point that it will cause problems. Everything written above can be very effectively mitigated if any thought was applied to EMI/RFI. Proper RF bypassing of solenoids is well known. The high voltage spark in a internal combustion engine is broadband and it is very difficult to create a small RF current loop to prevent radiation from it. -- Telamon Ventura, California |
#14
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China Radio International
Telamon wrote:
The high voltage spark in a internal combustion engine is broadband and it is very difficult to create a small RF current loop to prevent radiation from it. The point is that old diesels with mechanical injector pumps were quiet; modern diesels (out of the box) are not. |
#15
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China Radio International
Dave wrote:
Telamon wrote: The high voltage spark in a internal combustion engine is broadband and it is very difficult to create a small RF current loop to prevent radiation from it. The point is that old diesels with mechanical injector pumps were quiet; modern diesels (out of the box) are not. Some of the most irritating sources of radio noise were old diesels. They'd wipe out AM listening every time I passed one. Diesels were never quiet. One was so bad it interfered with the AM in our 59 Impala from St Louis to the Lake of the Ozarks. He stayed with us the entire run, and we had no radio in the car for 4 1/2 hours. My father was ready to climb out of is skin. |
#16
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China Radio International
In article ,
Dave wrote: Telamon wrote: The high voltage spark in a internal combustion engine is broadband and it is very difficult to create a small RF current loop to prevent radiation from it. The point is that old diesels with mechanical injector pumps were quiet; modern diesels (out of the box) are not. The point is you have no point. -- Telamon Ventura, California |
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