We are talking with a Southern California Company (Jungle Motors) about a Prius kit which is claimed to provide 40 miles of electric only driving, up to 52 MPH. The kit includes a 10kW battery pack, some circuitry changes, charger, etc.
Has anyone had experience with Jungle Motors, or installed their kit? Any information would be greatly appreciated.
Thanks for reading this post.
Harry Smith
The current Prius HSD *cannot* go faster than 42mph on electric alone...
"Elmo P. Shagnasty" wrote in news: snipped-for-privacy@mara100-84.onlink.net:
Elmo,
True -- they have a couple of circuit boards that they say gets around that limitation. For us it is a deal breaker if they turn out not to be correct...
Harry
Hmmmmmm. As I understand the current HSD, that's not an electrical issue that can be fixed with some circuit boards. It's a physical limitation of the motor/generators.
Your understanding is wrong. The gasoline motor on the current Prius starts if the speed is above 42 mph but the electric motor also continues to operate. There is no physical limitation...it's just an optimization programmed into the system by Toyota based on the current battery and motor capacity. Similarly, the gasoline motor never runs below 1,000 rpm not because of any physical limitation (the motor would run just fine at 500 rpm) but because it's an optimization. The whole point of the system is to maximum efficiency.
The ICE and electric motors are not just multiple inputs to the drive system; the way it is designed, the speed of one directly affects the speed of another.
The planetary gear system is basically the same thing as the differential on a rear-wheel drive car. In that scenario, the input to the differential is the drive shaft, the the two outputs are the right and left drive wheels. Turning the driveshaft causes both wheels to move forward, but if one wheel is slowed down, the other will speed up, so that their combined RPM is equal for any given input RPM.
In the synergy drive, the driveshaft is now the output shaft, one wheel is replaced by MG2, and the other side has the ICE & MG1. With this arrangement, the speed of the output shaft is the COMBINED speed of the ICE/MG1 + MG2.
To make things simple for illustration, assume the planetary gears have a 1:1 ratio. (the numbers are purely fictitious, and are only to illustrate the concept.) To get a 100 RPM output speed, the ICE/MG1 and MG2 must both be running at 100 RPM. If the ICE/MG1 is increased to 200 RPM, then MG2 must be at 50 RPM. If MG2 is at 200 RPM, then the ICE/MG1 would reduce to 50 RPM. In actual use, the ICE/MG1 is spun at its most efficient speed, and MG2 spins at whatever speed is required to give the desired output speed. This includes spinning backwards if the required output speed is slow, but the ICE/MG1 wants to run at a high RPM, such as going slowly up a steep hill.
When the ICE/MG1 is not moving, then MG2 must spin much faster to compensate, since it's providing all the RPM.
Not true. If MG2 is spinning, ICE and/or MG1 must also spin, but they are not necessarily contributing power.
Two constraints for MG1 are relevant here:
- MG1 runs at a speed to keep the ICE at the desired speed for efficiency
- MG1 must not be allowed to exceed the redline, to avoid damage to itself.
Therefore it is possible to run electrically at high speeds without the ICE "running", but MG1 must spin the ICE to stay under its speed limit.
Below approximately 42 mph, the ICE need not spin.
No. Please look at the diagram at this link:
No, it's not. The drive speed is always the MG2 speed (followed by the chain drive and gear reduction).
MG2 can run backwards but in that case the car is also moving in reverse and in the Prius, the ICE speed must then be zero when the MG2 is running in the reverse direction. You can see this with the flash simulation (and also when you drive the Prius). When yo switch the 'shift' lever on the Prius from 'D' to 'R' you are really just changing the inverter output to run MG2 in the reverse direction and telling the computer to not start the ICE.
The MG2 speed is set by the Prius driver with the 'accelerator' pedal. The computer then sets the ICE speed to provide the necessary power required. It is not possible for both the ICE and MG1 to not be turning unless the vehicle is stopped and the MG2 speed is also zero.
You may be telling the computer not to start the ICE, but in fact the ICE could already be running (for example after just starting the car).. IME this happens every time I back out of my drive. The ICE usually starts during the manoevre. Are you implying that it is physically not possible for the ICE to run when the car is in reverse, 'cos this blatantly ain't the fact.
Chas
That isn't the way I read David. I understand the ICE is running at that time simply to bring your catalytic converter up to temperature. Under this condition the computer is telling the ICE to run even if shaft power isn't needed. Same goes for the climate control system demanding heat.
It's interesting that after owning my '04 for more than five years (yes, I was an early adopter!), and observing countless discussions among people with significant tech skills, I've found no consensus regarding the fundamental operation of the system!
Early on, I installed a ScanGauge and also a multiled indicator that shows regen braking, friction braking, and ICE fuel pump power. The ScanGauge permits selection of engine load, rpm, water temp, and many other parameters - and displays any set of four. Lots of data.
Observing that information, it's still not easy to understand what's really happening in this car. Driving 60mph, for example, when I take my foot off the gas the engine "quits" (fuel pump stops delivering) and rpm falls but not to zero. The only things of which I'm certain is that the car will run perfectly and economically.
But like my wonderful wife of nearly four decades, "understanding" is not a prerequisite to "satisfaction". I like this car a lot!
Ike
It's interesting that after owning my '04 for more than five years (yes, I was an early adopter!), and observing countless discussions among people with significant tech skills, I've found no consensus regarding the fundamental operation of the system!
Early on, I installed a ScanGauge and also a multiled indicator that shows regen braking, friction braking, and ICE fuel pump power. The ScanGauge permits selection of engine load, rpm, water temp, and many other parameters - and displays any set of four. Lots of data.
Observing that information, it's still not easy to understand what's really happening in this car. Driving 60mph, for example, when I take my foot off the gas the engine "quits" (fuel pump stops delivering) and rpm falls but not to zero. The only things of which I'm certain is that the car will run perfectly and economically.
But like my wonderful wife of nearly four decades, "understanding" is not a prerequisite to "satisfaction". I like this car a lot!
Ike
There's no transmission or clutch on the Prius so it is impossible for the ICE to move the car in the reverse direction since the ICE crankshaft will only rotate in the direction that moves the car forward. The ICE can (and does) start when the car is moving in reverse but, since it is rotating in the 'wrong' direction it rotates against the MG2 rotor and runs only MG1. If you play with the flash simulation you'll see that if it runs too fast the generator will overspeed so the computer optimization is to keep the ICE off in reverse unless it's needed to charge the battery. I haven't tested this on my '06 Prius but from just the simulation, it looks like the MG1 will overspeed if the vehicle goes faster than 20 mph in reverse with the ICE on so I would presume that the computer will shut the ICE down if the vehicle speed is more than 20 mph in reverse (which wouldn't be a typical way to drive anyway). On my Prius, normally what happens when you shift into reverse is the ICE shuts down and reverse is electric-only with the MG2 powering the wheels.
The ICE will spin without generating power at speeds above 42 MPH, such as when going downhill or decelerating, or in 'B' mode, where it's used to create drag. In other situations where the ICE is not needed, the car will move, but the ICE *does not* spin, as in zero RPM.
Doesn't this contradict your previous statement that when MG2 is spinning, the ICE must also spin?
All the components are connected to the wheels via the planetary gearbox (what is essentially a differential) The speed of any 1 component is directly in proportion to the other components.
I think much of the disagreement is due to which is being called MG1 vs MG2. I may have had it reversed from what some descriptions use, but the relationship between the components is still the same.
Here is a flash gadget that demonstrates this. The references to MG1/MG2 are reversed from my earlier description, but the concept illustrated is the same:
Back to something close to the original question, then, are the modified plug-in 2G Prius limited to 41 mph in the all-electric mode? Apparently so. If that is the case, then achieving 100 mpg with a 40-mile round trip commute would be difficult if the commute is largely rural with speed limits of 55 mph & up. Certainly there would be an improvement under such conditions.
I wonder if one of the improvements to the 3G eliminates or at least raises this number closer to 60 mph. We'll know soon enough. In reading through the sparse 3G material at the Toyota site I got the impression it was configured for some future enhancement.
My previous statement said the ICE OR MG1 OR both must spin whenever MG2 is rotating. If BOTH MG1 and ICE are stopped, MG2 (and the car) cannot move.
"Mr. G" ...
Thanks for this link, it is enlightening. One thing that I can see clearly from this is that I can set it so that at 110 MPH the MG2 is at 6500 RPM and the ICE is at 0 RPM [zero]. This tells me that at over 42 MPH the ICE _can_ indeed be not spinning. Might there be some manner of connect/disconnect between the ICE and the planets? Or how else is this explained? Tomes
The simulator will let you set it for 110 MPH with the ICE not running, but that doesn't mean it can happen in reality (though the simulator DOES try to indicate you're exceeding the limits). At 110 MPG and the ICE at 0, MG1 would need to spin backwards at 16,900 RPM, which is more that 2.5x the 6500 redline.
Try this: Set the ICE RPM to zero, and slide MG2 up until you hit 42 MPH. Everything is fine. BUT, if you try to make MG2 go any faster to increase the vehicle speed, 3 things happen to indicate you're exceeding the limits:
- The MG1 tach turns red, to show you're exceeding the +/-6500 RPM redline
- The line showing the connection among the ICE/MG1/MG2 turns red because you've gone beyond the parameters of what the flash can properly display (it can't show any motor past its redline)
- The line actually starts to bend, which becomes more obvious the further you push MG2. This line must be straight, which illustrates the direct mechanical connection via the planetary gears, just as in a RWD differential.
So to your last question, there is NO disconnect anywhere in this system; no clutch, torque converter, etc. When one turns, either one or both of the other components must also turn, and at an RPM in direct proportion to the sum of the other two.
Only if the ICE isn't needed for other things--such as warming up the catalytic converter or providing cabin heat, or providing charge to a fully (relatively speaking) discharged traction battery.
For those of us who get in in the morning and back out of our garages, typically the ICE will run as soon as the coolant is pumped back out of the vacuum bottle and the system knows the temperature state of the engine/coolant. The engine runs even though we're backing out.
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