1st E-Supercharged Prius Build, WIP/doesn't work......

Thanks for starting this thread! Glad you were able to reference Julian's work and issues he had with the Gen1 NHW10.

 

Looking forward to hearing more about this!

Before it slows down, how does it pull?

 

I'll probably run into something similar with my build.






Originally Posted by Julian Edgar

Throttle Shut-Down

"So what was making the electronic throttle momentarily close itself at full power? If in fact it was because the hybrid system couldn’t cope with the extra power, the effect would be most pronounced when power was at its maximum...say, on a cold night. And that’s just what proved to be the case. When the weather provided me with an 11-degree C evening, I was able to get the throttle-shutdown to repeatedly occur. (But what about those inconsistent full-load mixtures? Well, if the air/fuel ratio meter was watched like a hawk, it was possible to get in peak power runs with the mixtures satisfactorily rich. You just couldn’t do it consistently.)

So the obvious answer to the automatically closing throttle was to lower boost at the very top end, so reducing power. Since the greatest driving improvement over standard occurred due to the mid-range boost, dropping boost a bit at peak power would make very little difference. But how to decrease boost? With the ex-Subaru IHI turbo’s wastegate connected, 7 psi was the minimum boost available – and that’s what I was running. (The boost level had risen from 6 to 7 psi with the redesigned intake plumbing.) Modifying the turbo wastegate actuator to achieve a lower boost was possible, but it would mean taking off the turbo to access the wastegate actuator. Which in turn would mean removing a front driveshaft, taking off the exhaust, draining the ‘gearbox’ of oil, and so on. A lot of work.

Instead, was it possible to bleed off some of the boost? Already in the system was a GFB blow-off valve running a shortened internal spring – a modification performed on the valve when it was fitted to the supercharged car as a recirc valve. In this design of valve, boost pushes on the base of the piston, trying to open it against both the internal spring pressure and the pressure in the boost-sensing hose. If the boost being fed in via the hose was reduced, it was likely that the internal piston would be pushed open, so allowing some boost to escape. By placing a bleed solenoid in the boost pressure feed hose, the pressure in this hose could be regulated. using the Independent Electronic Boost Control (IEBC) kit, the action of this solenoid valve could be mapped.

The system was quickly set up and the solenoid valve opening set to 0 per cent at lower injector duty cycles. (The IEBC kit sets its output duty cycles on the basis of input injector duty cycles. That is, any relationship between injector duty cycle – ie engine load – and output duty cycles can be set via the hand controller.) At higher engine loads, the solenoid was gradually brought on line, until at very high engine loads, it was completely open, so acting as a bleed of the boost pressure in the feed hose to the blow-off valve.

The mapping of the control system was initially done very coarsely but the system soon showed it was possible to drop boost to 5 psi at the top end of the engine power band. This stopped the auto throttle shut-down procedure – the system was sufficiently sensitive that even a 2 psi boost decrease made enough difference."

 

If youre giving it full boost before the ICE has time to spool up, it may be causing the issue. Try getting the ICE spooled up and then giving it 5 PSI.

 

Do you know how much margin there is in the torque from MG1?

One issue with getting more power out of the ICE in a Prius is that MG1 has to provide the balance torque for the engine - as you increase the engine torque there will be some point where MG1 will not be able to rotate at the commanded speed even with maximum allowed current from the controller (it will tend to go backwards) and the system will lose control. Before that happens I would expect the system to protect itself by for example closing the throttle. I wonder if that is happening?

kevin

 

Any way this is related to the fuel pressure? Possibly the A/F ratios? The OBD will only read what the ECU is telling the car it needs to be at. Not necessarily what the actual AFRs are. My Torque app is always in the 14s unless i let off the gas after a long run of WOT. Then i see the AFRs run lean. But during the WOT, the car is adding a LOT of timing. Not sure if this is the extra air its getting with the intake setup or the free flowing exhaust i have. I know i'll need to run a Wideband AFR setup to see what the car is actually running VS what the OBD is telling the car to run. Its next on my list along with aftermarket oil pressure and boost monitoring gauges.

Julian ended up running a return line and 2nd fuel pump because he was experiencing issues with not enough. Ended up with something around 85psi fuel pressure to maintain air/fuel ratio of around 12:1 – 12.5:1 under WOT.

Another thing to check is the voltage on the MAF. If the voltage is out-of-range of what the ECU can handle. Think our max is 5.0v. May need to look into voltage clamping the MAF.

 

Such good info - People ^^^


iPhone ?

 

This thread is awesome. I look forward to seeing a Turbo Prius! Especially if you could control when it engages.

 

knock sensor?

Posted via the PriusChat mobile app.

 

Thanks for stopping by the shop to share us your project! We all got to put our minds together to get all the Gremlin's out

Was looking forward for my MAP controller to help alleviate your issue's - but

 

Did you try a Tom's Fuel Map Controller?

Anyone try the SS Voltage clamp yet? VC3-100 Voltage Clamp |