The Zing! (Custom-built prototype hybrid tadpole trike)

[dcb]

My comment was regarding a well considered drivetrain, i.e. mass production, not necessarily what ken is doing, which seems pretty well considered also.

[sendler]

Originally Posted by dcb

My comment was regarding a well considered drivetrain, i.e. mass production, not necessarily what ken is doing, which seems pretty well considered also.

I was agreeing with you.

[drmiller100]

at what efficiency do your batteries charge? Discharge?

Are you going to the Vetter challenge?

[dcb]

Originally Posted by drmiller100

at what efficiency do your batteries charge? Discharge?

Are you going to the Vetter challenge?

This was a pretty well considered response from ken:

Originally Posted by Ken Fry

...5. Is energy moving through the batteries? There is a level-road, still-wind cruise speed at which the engine has to provide all the energy to more the car. At that condition, all the energy effectively bypasses the battery. In the more typical case, in which the engine comes on for 20 minutes and then shuts off for perhaps a similar time, the the losses in and out of the battery matter. With lead acid, these can be a deal killer. With Lithium X they tend to be small in both directions, often 95% in and 95% out, but worse if you get up to 80% charge... at which point you should not be charging.

Conditions: Mainly temperature, which is why most systems are actively heated and cooled. Secondarily, charge rate, with either way high or way low being not so good.

...

so pony up for lithium, but might need to spend energy on heating the pack (engine coolant?) and efficiency takes a dive at roughly 80% SOC (save the rest for regen I recon). 0.95 * 0.95 efficient at best, fairly constant power input for charging so not hard to optimize, driving demands (and if the engine is on or not) will determine actual discharge efficiency.

I looked up a discharge curve for lithium, higher currents do not have a huge effect on capacity like lead, but some energy might be lost in the additional voltage drop (like 7% or so?).

[NeilBlanchard]

The percentages are not the only consideration to overall fuel consumption. The displacement and power of the ICE required matters a lot; as does the powerband tuning. Also, the length of time you need to run the ICE matters a lot.

In a serial hybrid like the Zing! it would not be possible to get the ICE used for the genset to power the wheels mechanically and have anything like the performance that the electric motor gives. The valvetrain would have to allow for wider RPM powerband and thus would lose peak efficiency.

If it was a parallel hybrid, the ICE would have to run at varying RPM's so the efficiency would not be optimal except in some situations. And the ICE would have to be run continuously, rather than periodically.

And if you consider a typical long drive profile, which has a short period of slower speeds with stop and go driving at the beginning *and* the end, with a longer period of sustained higher speeds -- a parallel hybrid would possibly be left with a depleted battery and be forced to limp along on the ICE power alone. This would require a multi-gear transmission.

I would like to hear how the Zing! does for fuel efficiency in daily use in the real world, as a serial hybrid. And if it is possible to set up the ICE so that it could either spin the generator, or mechanically spin the rear wheel -- i.e. be both a serial and a parallel hybrid (but not a combination hybrid like the Prius and Volt) -- that would be very interesting, too.

Ken, have you considered do an energy/fuel log here on EM? I'm not sure if it is set up for both plugin charging and fuel use?

[user removed]

In their 2006 documents the EPA combined with Ford, Eaton, the University of Michigan, as well as others stated that an 80% improvement could be accomplished by improvements in the power train that used capacitive storage of regeneration energy as well as separating the engine's function from the act of driving the vehicle itself.

Combine that with engine efficiency improvements that are a reality today, 5 years later, when you separate the engine from directly driving the wheels, and you have a combination of efficiency improvements that was predicted to improve economy by 120%.

Since 2006 we have seen improvements in manufactured cars that incorporate some of these ideas. Direct injection, automated manual transmissions, fuel injection that actually occurs during the combustion stroke, all steps in the right direction but there is much more room for improvement.

The key ingredient that has yet to be incorporated is capacitive energy storage at extremely high efficiencies.

All of these things point to a direction in development that could best be defined by the EPA's call for a "clean sheet of paper" design of a replacement for the bent axis variable displacement hydraulic pump-drive they used in their 3800 pound demo vehicle that averaged 80 MPG using a 1.9 liter diesel engine.

It's all about load levelling and short term averaging of the highly variable load requirements of normal vehicle operation. In essence to incorporate the proven technology of pulse and glide into the vehicle's power train itself. Bottom line is the self hypermiling car, a vehicle that can maintain a given speed while the engine cycles on and off, only consuming fuel and creating energy at it's highest level of efficiency.

My clean sheet of paper design was conceived with all of this knowledge as the cornerstone of its design and development. It was also a principle factor that the design would be simple as well as inexpensive to produce when mass production occurred, while retaining reliability that surpassed anything on the market today. This is a crucial component, you have to build it at a competitive price, it has to last a very long time, and it has to be very low maintenance, and when maintenance is required it has to be simple to fix.

I am not aware of any design that can compete with a IVT hydraulic drive when you compare all of the relevant factors, cost, efficiency, and reliability. Affordable, reliable, and efficient.

In fact, you may not even consider it a real hybrid, since by eliminating the accumulator from the circuit it simply becomes a direct hydraulic drive that has no limit for final drive ratio. It could go from 1000 RPM of the engine to 1 RPM of the wheel, to 1 RPM of the engine to 1000 of the wheel. No drive can come close to that range of ratios.

The accumulator has the responsibility of capacitive storage of energy. This means you do not have to sacrifice engine efficiency in any direct drive. It allows the engine to work at it best efficiency regardless of the power train demand requirements. All you need to have is an engine with sufficient power to cover all situations where sustained demand is much higher than the normal demand. You have to climb the mountains. You have to recover a reasonable amount of deceleration energy. You have to recover almost all of the energy in 20 revolutions of the wheels in a panic stop.

You have to do all of this at an efficiency level of 80% or more.

This may be perceived as a thread hijack by some. I feel it is an opportunity for all to understand that the last number of posts have touched on a subject where there actually is a better solution that the ones discussed. That is my opinion and it has some credibility from independent investigation by qualified professionals.

Thanks for your time
Mech

[Ken Fry]

Originally Posted by pete c

What sort of lifespan are we looking at with the engine? Air cooled thumpers running flat out aren't really known for being the longest lasting engines ever made. Being a honda, I guess it will be as good as that breed of engine can be.

On the bright side, it's a 500 dollar motor. If you burn one up every 2 years, WGARA?

The engine actually runs at about 65% of its original rated power, and at lower than the standard 3600 rpm, so I am expecting 1000-1250 hours. For someone who drives the car 12,000 miles per year, the engine would last forever (but would require proper storage). For someone who drives 18,000 miles per year, the engine would run for 3000 of those. At 60 mph, that would be 50 hours... so about 20 years.

[Ken Fry]

Originally Posted by dcb

so pony up for lithium, but might need to spend energy on heating the pack (engine coolant?) and efficiency takes a dive at roughly 80% SOC (save the rest for regen I recon). 0.95 * 0.95 efficient at best, fairly constant power input for charging so not hard to optimize, driving demands (and if the engine is on or not) will determine actual discharge efficiency.

I looked up a discharge curve for lithium, higher currents do not have a huge effect on capacity like lead, but some energy might be lost in the additional voltage drop (like 7% or so?).

Good summary. In very cold weather, the pack will be preheated while charging, but is otherwise heated and cooled by cabin air exhaust, the batteries being happiest in the same conditions as humans.

[Ken Fry]

Originally Posted by drmiller100

Are you going to the Vetter challenge?

Hi Doug,
Yes, I plan to go to the one in Ohio, in July. You going?

[drmiller100]

thinking about the one in may or june.