Jaguar gives $1.1M Hybrid a "GO," aims to outdue Porsche and match "Prius"

yes, they use stored electricity to claim better mileage than Prius .

 

Yes and we can get some details from the show car.
Jaguar Builds A Twin-Turbine Electric Supercar You Can’t Have | Autopia | Wired.com

I thought the turbines were the coolest part, but those are gone now. We can expect around a 9kwh battery and 390hp of motors at the front wheels. The rear wheel electrics should be gone, but some kind of parallel/serial hybrid system with a powerfull ice should take their place. Likely ice is the supercharged v8, or a lighter cosworth turbocharged I4 or V8.

 

(90,000 RPM Turbines = NOISE, high pitched SHRILL noise.

"..The rear electrics should be gone..."

Not, NEVER. This car is slated to be competitive with a Porsche, no FWD vehicle will EVER compete in that class. Plus which FWD or front drive leading AND lagging torque is well know to be patently UNSAFE on a low tractive roadbed.

All of the current hybrid "FE" conscious FWD and F/awd models disable regenerative braking the very INSTANT wheelslip/skid becomes a probability, impending. Some even automatically lower the overall regen capability as the OAT declines toward freezing.

So it will be the front electrics that might be eliminated or reduced, no more than 30% of the rear electric capability.

"..turbocharged I4 or V8..."

TurboCharging is a HORRIBLY inefficient engine design when FE is a primary consideration. Much better to use the (Atkinson) Miller cycle and put what would otherwise be WASTE energy to direct POWER.

How does a 12,000 RPM DFI miller cycle 200HP I4 sound..?

 

What if you want your car to sound like the batmobile. THey actually sound cool IMHO. I'm sure they are gone because of lag time spooling up. I still hope we see a turbine serial PHEV some day.

They are doing it like the porsche electric up front, ice driving the rear wheels with likely a flywheel type mg between the motor and transmission. Its 4wd. Didn't you read the article.

They have only 1 motor per axle. This and the porsche has a motor per wheel at the front. This should also have big ceramic brakes and be awd.

uh huh. where did you read that?

I am not sure why you think turbocharging a high powered engine is inefficient. That is what they put in the fastest cars. THey will either use the jaguar supercharged v8 or go to cosworth. Cosworth gets their boost from turbocharging. I know turbos were different when you were young. You should read up on the modern designs. It will also use lots of gas when you are accerating at 100mph. The turbines would still be efficient pumping out big horsepower.

 

I don't think turbine lag was such an issue since they would only drive the generator, and not drive the wheels directly. The real problem with them is about 500c exhaust gas temperature. The concept vehicle did not have any Stand Clear warnings. Can you imagine the melted front fascias every time a car pulled up behind at a stop light?

 

On that note I am off to put a turbine in the Prius' trunk. Take that tailgaters!! :third:

 

"..turbos were different when you were young.."

When I was young I was too busy keeping my nose to the grindstone to have paid much attention to anything outside work.

But the MAJOR aspect of forced induction, the need to derate/detune the engine, CR reduced from N/A standards, specifications, hasn't changed.

The only solution I am aware of is the Atkinson...MILLER cycle engine. dynamically delaying, variable delay, of the intake valve closing seems to offer the only possible solution currently.

Toyota appears to be using that actual technique in the current HSD non-DFI V6 engines. They are running the V6 in Otto mode, 13:1 compression ratio, for idle, low and moderate engine loads/loading. As the driver opens the throttle more and more a point is reached, nearing a full cylinder charge fill level, wherein that 13:1 would more certainly result in detonation, knock/ping. But before that point is reached the V6's e/VVT-i system begins transitioning into Atkinsom mode, delaying the closing of intake valves, allowing some (~30% at WOT) of cylinder charge to be "exhausted" back into the intake manifold.

At WOT that results in a effective CR, before boost, of ~10:1.

Add an SC and DFI...??

 

...

 

I'm not sure what you are going on about, this is about what is likely in the new jag, but let's clear some things up.

An engine is best designed for turbo or super charging, these changes can be small compared to redesigning a new engine. In modern designs DI and vvt are done to the base engine. This allows it to be electrically adjusted a great deal in its turbo or non-turbo form. Neither engine is detuned, electronics adjust the spark timing and fuel injection. The native compression ratio drops slightly for example in bmw's n55 which is state of the art they drop cr from 10.7 to 10.2. The boosted compression is increased though. The twin scrolling turbo is an improvement as it reduces the rpm that must be reached before the turbines can provide boost, this is less expensive than the sequential turbocharging used to do the same thing. The sonata turbo was able to add this technology with regular gasoline at a native cr of 9.5 and at a lower cost and higher efficiency than a similar non-turbocharged car. Supercharged engines also need lower native compression ratios, turbocharging is just one form of supercharging.

I'm not sure what problem this is the only solution for. Toyota says in their advanced engine that they have been able to boost efficiency rates with a turbo charger. I do not know a single engine that a supercharger has made more efficient. This is because the supercharger must be supplied with energy. There are many cars where a turbo engine is more efficient. The bmw 335i boosts its horsepower from 230 to 300, while maintaining the same highway milage and getting 1 mpg more in the city. IF they dropped a 230 hp 4 cylinder turbo they likely would easily have beat the numbers. The supercharged Jag XFR gets 2 mpg less on the highway than its normally aspirated twin.

DI could definitely improve the performance. Again I know of no examples of SC where engine efficiency improved. Super charging does provide more horsepower and/or torque at the cost of some efficiency. It can boost up these things in an atkinson engine which is more efficient but has lower hp and torque. Is that what you are thinking. Both aktkinson and turbocharging increase efficiency by reducing losses of energy in exhaust gasses. At higher power levels turbo and super charged engines run rich mixtures to cool the cylinders and avoid detonation. This technique allows for higher boosted compression but reduces fuel economy as some fuel is not burned in the engine but reacted in the cat.

 

...

 

I'll try as best I can to answer your questions.

I am talking about engines actually designed and programmed, not mods that are detuned without proper programming. Detuning is a poor term for what is going on. The engines have reduced base compression so that the electronics control it. Properely designed turbo charged engines can be made for efficiency or performance or a combination of both. Torque is always available at a lower rpm so friction can be lowered, and the turbine acts to reduce pumping losses.

Boosting native compression can ofcourse be done and has been done. Turbo and supercharging allow this to be done at a variable level. Higher compression does require intercooling as increasing compression will heat the air. With intercooling some of this heat can be removed, allowing higher effective compression without detonation . The sonata has a maximum boost of 17.4 psi or over 1 atmosphere. You do not want to run this compression at all time, only during heavy acceleration.

The most efficient engines are turbo diesels, and these are tuned for efficiency. The same technology can be used on gasoline, and can make engines more efficient.

I think conceptionally you do not understand that there is energy pumped out of an engine as exhaust. The longer expansion stroke of the atkinson engine allows it to use some of this energy, but it is not close to 100% efficient, and there is pressure. If you want it to develop more power the valve timing does need to change, then the turbo can kick in. This would not work in a mechanically built atkinson engine, but I don't think that can come up to the efficiency of a turbo engine.

Think of a turbo charger in 2 parts, a generator that is pushed by the exhaust gases. Imagine it electrically attached to a supercharger. Now the super charger can use less energy but not more than the generator supplies. There are a couple of other wrinkles, the generator can not turn if the engine rpms are too low, this is the turbo threshold. The generator also will lag engine rpms as it takes time to spin up, this is turbo lag. Both of these have improved a great deal in the last decade. The compressed air is cooled and then forced into the cylinder. This should illustrate why turbocharging can increase efficiency with the drawback of only being able to use the power from exhaust. BTW these electrical systems have actually been built, and electrically assited turbos have been built.

I know the millenia had a miller cycle engine, but I thought it had similar efficiency to engines at that time. I did a quick look up, and car and driver liked the engine, but the epa gave it and the faster infiniti i30t the same milage, and car and driver had better acceleration and mileage in the infiniti.

 

Not really impressed. Anything is possible with money. Real feats of engineering are putting advanced tech into the hands of those who don't have to own a hedge fund. If Toyota had a $100k price tag on the Prius it would get much better mileage and be better in every way.

 

The only major two short-comings, other the lack of market acceptance, of the Mazda was that the SC was driven 24/7 and the engine was always operating in FE challenged mode, poor CR for the low engine load/loading operating range.

I'm beginning to feel like we're a couple of 9 year olds talking past each other,..so, I out of here.

 

Were I made of money I would go out and buy a Mazda CX-7, "wire" the wastegate fully open, and then mill the head to get back up to the effective compression under full boost.

Or just initially mill the head and then see of the ECU "learns" enough to keep the boost level out of detonation operational range.

I have no doubts the FE would improve substantially.

But yes, the 0-60 time would suffer.

 

I apologize, I don't mean to be talking past you, but you put some of the same comments in many of the technical discussions that are incorrect. I'll try one more time.

The base engine for a supercharger and a turbocharger do not need to be different. This detuning as you call it would be similar for both for similar boost levels. I don't think designing a system to use its components properly is detuning, but proper system design. You see lower base compression that is small, in bmw's turbo six it is only about 5% lower which gives a little more headroom for compression range, some of the energy lost in expansion is recovered by the turbo so efficiency in the moderate operating range and higher power ranges increases while low power efficiency decreases.

The next item is that supercharging boosts the efficiency of an Atkinson engine but turbocharging will not. This is just incorrect. Here I will take the liberty of assuming the engine really has vvt and can change its valve profile. In this form we are not a fixed mechanical atkinson, and the requirement of supercharging for boost goes away. If we boost with a supercharger versus close the valves we are using the supercharger to pump the air instead of the pistons. This can be more efficient during a certain range, but we are adding back pumping losses. Compression can increase slightly without detonation because of intercooling, but efficiency gains are very slight. Some marine engines use the miller cycle for this efficiency gain, but AFAIK it has lower peak efficiency than an atkinson engine. This can significantly increase low end torque but we do this anyway in a hybrid with motors. The real change in a hybrid is more power, but when boost is significant then the supercharger becomes less efficient. If you pretend the base engine released its exhaust at 1 atm, then the boosted engine have greater than 1 atm pressure in its exhaust. This energy can be used in the turbocharged engine, but is wasted in a supercharged one.. The subaru hybrid prototype did use a turbo charged atkinson engine which it called miller cycle. Such an engine can be more efficient than the equivalent supercharged but low speed torque is worse and there is turbolag. Perhaps looking at a hybrid turbocharger design will help you understand trade offs. [ame="http://en.wikipedia.org/wiki/Hybrid_turbocharger"]Hybrid turbocharger - Wikipedia, the free encyclopedia[/ame] . It should be clear that a stand alone supercharger can not be more efficient than this beast. You should be able to clearly see in steady state a turbocharger recovers some of the energy it pumps into the system while a supercharger can not.

 

"..I will take the liberty.."

But that's EXACTLY what I propose, proposed, a multi-mode engine wherein the engine transitions between Otto to Atkinson then to Miller cycle mode as the driver's need, demand, for POWER increases.

But as of today there is only one e/VVT-i, Extended Variable Valve Timing with Intelligence, in use in the market. That is the HSD V6 in the RX450h and the HH. But in that case the transition is ONLY between Otto mode and Atkinson mode. 13:1 base/native AND effective CR in Otto mode, but reduced to 10:1, Atkinson cycle mode, as the cylinder "fill" level rises.

Add forced induction to the above and E/VVT-i would need to shift the non-boost CR to >10:1.

Forced induction design parameters...

It would be highly desireable, obviously, if the entire cylinder FILL could be "intercooled" post-compression/(HEATING). Since this is not practical the engineers strive for the optimal compromise. What do you suppose the effective CR limit might be if the ENTIRE cylinder fill could be "intercooled".

The lower the base/native compression is the more of the intake atmosphere can be externally compressed and THEN COOLED. But the flip side of that is the poor efficiency of the off-boost mode that results from lower and lower base/native CR.

See...??

Compromise.

Yes, the IDEAL would be a DFI Otto/Atkinson/Miller cycle engine. 18:1 CR for Otto mode, 15:1 for Atkinson mode and then >10:1 for Miller cycle mode.

 

A detrimental effect of turbocharging that often gets overlooked....

The need for a WASTEGATE.

An IDEAL turbocharging system would be producing maximum engine boost at exactly, and ONLY at, the same time the engine RPM reaches the maximum HP or torque level(whatever). But that would be IMPOSSIBLE unless you wished to tolerate HORRID turbo spool up LAG.

So, the wastegate "apperture", energy bypass port/opening is sized so as to begin limit turbo boost so as to not have the engine self destruct. So, in a modern typical Turbo engine application how much energy is WASTED were this not so...?

That's just one of the advantages of the CVT/PSD driven SC that I propose, plus NO throttle plate required. Rapid, INSTANT, SC (positive displacement) spool up, only enough intake airflow supplied for current DBW gas pedal position.

 

ok, I'm not sure why this number is magic, but you can make turbo charged engines at >10:1 CR, I even referenced one at 10.2:1. If boost was reduced by using miller timing it could even be used on regular gasoline.

There are engineering tradeoffs, but no I would not want to move the entire compression stroke out of the engine. At a CR of 10:1 the pressure increased to 25 bar, so 2.5x more air could be held at room temperature than comprehensively cooled. Detonation happens with a combination of heat and pressure so more air could safely be added. This would take a great deal of energy without some better technology.

Good. You do need to remember that efficiency at 10:1 is not exactly poor. The Toyota engine was 10:1 before it was modified for atkinson cycle in the prius. With DFI it might be able to sustain the 13:1 in otto mode and this is likely part of the advanced engine technology for Toyota. 13:1 is about the highest normally aspirated compression in regular gasoline engines. With miller valve timing the cooled air can be added later and use less of the cylinder stroke. It is less efficient though with current technologies at higher compressions.

Technology is always improving and we may get to DCCI, but with today's tech you can only get to 13:1 on otto cycle, that would keep the engine where it is in the prius but allow valve timing to increase power. To do that we stay at the prius's 10:1 effective compression on atkinson mode. With a hybrid turbo and an aggressive inter-cooler you might be able to get to 20:1 effective compression in miller cycle mode. It would likely be less expensive and just as efficient in miller cycle mode to drop base compression closer to 10:1.

 

A) The higher the base/native compression ratio is in relation to the possible maximum effective, ON-BOOST, compression ratio the LESS use can be made of forced induction.

B) The lower the base/native compression ratio is in relation to the possible maximum effective, ON-BOOST, compression ratio the MORE use can be made of forced induction.

Which one, A or B, results in the best FE off-boost, moderate speed cruising.?