Author Topic: AISV Air Injection Solenoid Valve  (Read 4419 times)


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AISV Air Injection Solenoid Valve
« on: March 18, 2015, 02:24:23 AM »
A bit of silliness, this one.  :o

If you don't know the AISV, you can look at my post about exhaust changes to read about the AISV location, routing, etc.

This is the whole system, not including the reed valve in the head. The AISV valve is in the bottom left corner, connected upside down in the photo. Oops.

I tested the AISV with a 5W bulb connected up instead of the AISV unit.

Below about 4,000 rpm (manual says 3,500 rpm, seems about right), air is sucked into the exhaust to help emissions and the bulb stayed off, so the AISV is open by default and gets no power. And this is also obvious because I can suck air through it when it is disconnected. Above 4,000 rpm, and with a steady or opening throttle, the bulb came on, meaning the AISV valve is closed. As soon as the throttle is closed above 4,000 rpm, the bulb went off. The bulb won't come on below 4,000 rpm regardless of the throttle.

On the move, I later found that the AISV will stay closed at high speed even when the throttle is closed, until the speed drops enough so the revs are below 3,500rpm.

If I disconnect the AISV and don't put a load there, the yellow warning light on the dash stays on telling me there is a fault - annoying. If I put a small load, say 1W, the warning light is still on. When I got to a little over 2W load, the warning light goes off, and this gets reliable around 4W. The AISV unit uses 6.5W (13V / 26R = 0.5A) and (13 x 0.5 = 6.5).

So for lack of a better idea, I decided to fit some under-tray lights to use the AISV power. Totally silly but hey, why not.

EDIT : I've now partly changed the use of the AISV - it also charges a 9V battery and this powers an underseat bucket light.

The charger uses a maximum of 2W of the 6.5W maximum available. The battery can power this light even when the ignition is off and it doesn't drain the main battery.

They are connected up using this circuit - the TP5100 charges the battery and the two diodes protect the circuit and battery.

I took the tray off and fitted the wiring and bulb holders. They were made out of some aftermarket indicators I had never used. The test bulbs here don't draw enough juice to turn off the warning light.

This is how they look installed and illuminated. They’re not bright enough to notice during the day because the light has to reflect off the road to be seen, and that’s fine. It's a bit of a chav idea to do this anyway, but here in Asia, pimping your scoot with colourful lights is very popular. So I'm trendy. Finally.  ;)

Nice of SYM to have created the perfect recess for these lamps. They are slightly recessed from the underside of the scooter so they won’t get damaged going over speed bumps, over kerbs, etc, and shouldn’t pick up tons of dirt either.

The light is more noticeable at night of course when the front area under the scoot is lit up. They don't extend to where the headlamp beams are visible. Just an under glow.

The ECU (orange/black wire = ground) grounds/sinks the supply voltage (red/yellow wire = positive 13V) up to 500mA, and the charger uses 150mA so the bulbs can be us to 350mA - about 2W each bulb. The connector here makes it easy to disconnect for removing the tray.

So, next up, a really big spoiler, stretched chassis, lowered suspension, and an airbrush of my favourite Korean girl band. ;-)

Yeah right. Oh, BTW, I also removed the last of the AISV stuff by removing the metal pipe and blanking off the ports. Removing the AISV stuff has taken about 350g off unsprung weight and another 150g (net) off the frame. Not anything significant but less unsprung weight is always a good thing.

cheers !  ;D

« Last Edit: April 10, 2015, 09:29:55 PM by thoppa »
Ninja 650R
Citycom 300

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