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cujet
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I've been chased by carjackers and successfully outran them. Minutes later they killed a woman nearby during a cajacking and were arrested as the train trapped them. In any case, I'll never have a personal vehicle that can't get away from those with evil intentions. My wife was hassled on the highway by road ragers, same thing. Her truck has a 5 Star tune that deletes the speed limiter and that probably saved her life. Such thinking by Volvo is not smart. When you need it, you need it.
That car would have 5 square meters of panels, or about 750 watts of panel power. Here in Florida with 4.7 hours of annualized sunlight per day those panels could provide as much as 3kwh of battery power (to the wheels) . Or about 8-9 miles of range. While that would be a wonderful benefit to parking in the sun, and I believe it's worthwhile to have optimized panels on EV's, it's not enough power to meet 70% of annual driving needs. It's claimed the average American drives over 13,400 miles per year.
When ever the publication is full of meaningless buzzwords, it's good to be skeptical. This "leading-edge, decarbonizing, three-pillar sustainability, disruptive, hybrid, ground-breaking R&T will stay the course.. In fact, when the need to obfuscate the obvious exists, buzzwords are the favored method. Reality: Running an inefficient gas turbine engine to turn a 3000 volt generator, that powers a controller, which in turn runs a motor that drives (in essence) a ducted fan, is an exercise in extreme waste. The engineers know it, and we should know it too. I've posted on this before, but the significant waste heat of a gas turbine turbofan engine is used effectively for propulsion, often (but not always) by mixing it with the cold fan discharge air. Moving the gas turbine to a remote location (embedded) negates any possibility of that benefit. It also reduces the effective discharge velocity unless other energy wasting methods are used to heat the air (multi stage fans, for example) .
The array of props increase airflow over the wing during takeoff, greatly lowering the speed at which such a small wing can perform. The original Technam wing has about twice the surface area.
Electric drive has an interesting advantage, that of nearly silent takeoffs. The fixed pitch props can turn more slowly on takeoff, yet still receive full rated power. Then prop RPM increases as airframe speed increases. This is very unlike piston engines that make full power at only one RPM.
Quote sd: "Last gasp for the high performance IC engine? ,,. Reminds me of the last of the turbo compound aircraft engines in the early 50's" And yet, nearly 70 years ago, those turbo compound aircraft engines produced better passenger MPG than all but the best we produce today. Put another way, 70 years ago, we could push unrefined aircraft as far per gallon of fuel. It becomes even more interesting when we realize that Jet-A has more energy per gallon than avgas. Battery powered electric airliner propulsion remains extremely unlikely, as there is no useful heat, this limits speed. Couple that with the short run times and heavy landing weights, and we have a non starter.
That's a good looking car from that angle. When do we get them here?
Electric aircraft propulsion has some severe limitations that are not readily apparent to the layman. Today's gas turbine engines use the heat of combustion not just to drive the turbine, but to raise the tailpipe temperature. A higher temperature has a higher speed of sound. The speed of sound being the limiting factor in discharge velocity. If the discharge air is cold, such as an electric motor, driving a fan or prop while at the frigid temperatures of high altitude cruise, the discharge velocity is limited to speeds far lower than today's current cruise speeds! The secret to high speed cruise has always been significant heat. An afterburner (reheat) is a great example of one way to achieve a high duct discharge velocity. Another way is to use the heat of compression of a multi stage low bypass fan, then mixing the hot air with the very hot exhaust of, you guessed it, really hard running and hot turbines. Limiting speed to 350 MPH as is typical with electric drive, greatly increases the time required to travel a specific distance. Remember, it's not unusual to see 100mph headwinds at cruise altitudes. Batteries won't be up to the task. Gas turbine engines will. Ever wonder why piston engine driven "turbofans" don't work? Now you know. NOTE: a G550 corporate jet can fly at 4000 feet altitude, with an EPR (engine pressure ratio) of just 1.03 and be going 250 MPH. Very little duct pressure, but lots of heat, increasing the volume and discharge velocity. Doing the same with electric drive and no heat, will require an EPR (inlet to exhaust pressure) of 1.50. In other words, lots of electrical power.
Quote Lad: "Why would you buy a 33 mpg dirty diesel? Wait a while longer and get a BEV truck that runs on cheap electricity and gets 150 mpge without the downside of high maintenance, and pollution the diesel delivers" Answer: Because it can go 4x more than 125 miles while pulling a load. Answer #2: Because net energy consumption is lower with an efficient diesel at 45+% thermal efficiency , when compared to a BEV, powered by the average 38% eff powerplant, with 7% elec transmission line losses running a battery charger with 10% losses and charging batteries with 10% losses, running motors with 10% losses. People look at how many watts they consume from a battery to go a distance. With ZERO regard to how much energy is used up generating the power at the plant.
Quote Lad: "Way too late in the cycle of innovation to be considered, just another ICE polluter, albeit more efficient" Absolutely incorrect. The North East corridor of the United States consumes copious amounts of energy heating homes, businesses and buildings. In fact, compared to power generation and travel, heat is by far, the number one consumer of energy there. Any well designed CHP system meets the efficiency of the best furnace, and coupled with a heat pump, can far exceed it. Short of nuclear powerplants, we will be consuming natural gas for energy. Might as well do it efficiently.
Companies would not put this much effort into a "dying" technology if it were not necessary. As much as I want EV's to replace fuel powered vehicles, the difference in energy density between today's best batteries and diesel can't be ignored. However, I'm not sure I see an advantage in thermal efficiency over Toyota's 41% TE gas engines.
An interesting looking experiment, however it falls short of PV area optimization. There is at least another 250W of surface area available. A redesign to maximize the hood, roof and tail areas, along with windshield angle changes, would result in considerably more surface area for panels. Aerodynamic drag could be maintained at sufficiently low levels with careful attention. It's good to know that a raked windshield provides very little aerodynamic benefit, so a more upright windshield could leave more room for PV. Even with conventional PV, it's possible to achieve 1KW of surface area. There were a few folks who came close. This lends itself to an onboard charge circuit that can directly DC charge EV batteries from any external, properly configured PV array. No more converting PV power to AC, to power your charger that then converts back to DC. Purchase panels and plug them in.
It claims "It is the marine sector’s first hybrid power module of this type produced." I'm thinking that German U boats were hybrids, and they were designed and used in World War I.
Quote Thomas Pederson: "cujet, Why on Earth would you keep the foot on the gas coming up to a stop where you know you have to brake?!? The only thing gained from that is higher fuel consumption and more brake wear." For practical reasons, that's why. On urban surface streets, coasting from a "hypermile" speed of 42MPH to zero, timed exactly to recover 100% of the energy takes time. With much of that time spent slowing to a crawl, often in neutral with engine off. VW TDI cars on LRR tires coast like crazy. Hypermile driving is fun, when nobody is being inconvenienced. This is not the case here. The last thing I want to do is intentionally annoy my fellow Americans. That's simply rude and inconsiderate of their needs and wants.
Quote: "Gerdes is an expert hypermiler". Enough said. It's not just the car, it's the annoying driver. There is no way that car kept up with traffic. Hypermile driving is so incredibly annoying to others. It's fine if alone on the road, but not in daily traffic. Hypermilers typically cruise at the most efficient speed (read 42 MPH) and "lift" throttle and even shut the engine off, 3200 to 3700 feet before every stop. They are annoying beyond belief.
OK, I can see this when you compare a diesel Jetta to a gas Jetta. I owned a 2006 Jetta TDI for 70,000 miles+, and I enjoyed driving the car. The poor reliability was the only reason I sold it. Even so, the private resale was not horrible. I sold it for 1/2 what I paid for it. However, if you compare a Prius (a similarly capable car with equal interior room) to the Jetta TDI, I'll bet a dollar, the Prius costs less to own. Not to mention far superior reliability.
Fantastic. Toyota has just achieved 44% thermal efficiency. The exact same thermal efficiency my 1930's designed Lister CS diesel achieves at it's peak. Of course, the Lister CS uses a cast iron piston, chrome plated bore and cast iron cylinder head. This results in less combustion heat rejection than similar aluminum parts.
I'm missing something obvious here. Why have an intercooler and a recuperator? Is the idea to simply cool off the compressed air, then use waste exhaust heat to re-heat it prior to combustion? I don't follow the logic.
So a downsized engine and battery energy is where fuel savings comes from. That's not a real savings, as energy needs to be put into the battery pack before each climb or takeoff. Also, there is something missing in the youtube video. The fact that piston powered, non turbocharged aircraft with constant speed props often don't get throttled back at typical cruise altitudes. As the altitude related HP loss typically matches the aerodynamic drag decrease at higher altitudes. What normally happens is the RPM is reduced slightly, from 2700 to 2400-2500 depending on aircraft model and engine/prop type. The main reason a fixed pitch prop equipped aircraft gets throttled back, once at cruise altitude, is to avoid too much RPM.
A properly constructed aluminum body will last nearly forever. My Cessna aircraft is now 45 years old and still in excellent shape.
From a practical standpoint, most consumers don't want to pay too much for a car. It really is that simple. I'd love a Volt or Tesla. When the Volt first came out, I drove it, loved it, and looked into purchase. Financing $50,000 for what is in essence, a compact car, made zero sense. Even with the incentive. I'd still be subject to a massive car payment. $1041 per month, zero down, 0% interest rate, 48 months. NO THANK YOU> I'll purchase 3ea. Toyota Yaris, or 2ea. Toyota Prius.
Bob tasa, I am inclined to disagree with a number of your points. First, the Volt is a battery/gas vehicle. Turbocharging a smaller engine with electric (or conventional) turbo's does not result in stunning MPG. Yes, it's a small help, under some conditions, but BSFC numbers don't improve to the 100MPGe range as it does via efficient battery-electric drive. I also don't understand your "step sideways" comment. It promises to be a more refined drivetrain. What's not to like about refinement? Or more efficient operation, or better battery range? Finally, compared to the cars I drive, the Volt is not/does not look "cheap" or low "quality" in any way. Not all of us can afford expensive vehicles, oozing with hand stitched leather, 40 series tires or other luxuries. Compared to a Yaris, or my little Honda, the Volt is far more car, and far quieter.
Interesting that the Continental TSIO-550 has a BSFC of 0.5. Most aviation engines are considerably more efficient than that. The Typical number for fuel injected engines is 0.42 in cruise configuration. In fact, the simple addition of electronic ignition with a proper advance curve, on aircraft engines, often brings the BSFC numbers down to 0.38 Lb/hp/hr. Another thought about Jet fuel vs. Avgas. Jet A is 6.5 Lb/gal. Avgas is 6.0 pounds per gallon. Certainly, the energy content of the Jet A is higher than gas. Remember that a full tank of Jet A weighs somewhat more. Reducing useful load. I'd rather see an aircraft specific, 120 degree V6 turbodiesel, with a "hot-V" configuration (the exhaust exits above, into the V) with a centrally located turbocharger. This results in 3 cranks throws, perfect primary balance, and the ability to go direct drive. Gear reduction drives are particularly troublesome and expensive in aviation.
R-P, thank you for the more detailed thoughts on the Motiv design. It's a good bit of information to chew on. Know that you and I disagree on a number of minor points, such as reciprocating compressor efficiency, turbocharger effectiveness sans intercooler and the required heat transfer of the Motiv combustion chamber (I certainly don't see 2 tiny cylinders doing the work of 4 or 6 larger ones as thermally feasible) Even so, I do see why you have confidence in the Motiv design. And, I agree that with proper design, it's likely to achieve good BSFC numbers. Quote: "Only the work done by the piston turning the crankshaft is harnessed as net work output." Note: We regularly design turbocharged engines with more intake pressure than exhaust pressure, resulting in recapture of some exhaust energy. SJC, there will always be a need for energy portability. Being tied to the grid and/or batteries won't work everywhere. Aviation is one example.
This has been one of the more interesting threads on this site. It's nice to see such interest in alternate designs. I often reside in the past, so please excuse my vantage point. While the energy required to drive a turbocharger is not free, it's exhaust energy, not crankshaft energy. There are some advantages there, especially when compared to crank driven piston compressors. It's been done before and has never been effective on conventional engines. With the possible exception of the Shindawa hybrid 4 engine that used the area under the piston to compress air (even then, it's not a great success). Nor do I see packaging problems of turbochargers as a serious issue. Example: a "hot V" 120 deg V6 with centrally located turbocharger or inline 6 with directly mounted turbo. Charge air cooling can be used, or not. In the discussion above, no mention has been given to increasing the expansion ratio of a conventional compression ignition engine via valve timing and geometric changes. I also have to wonder about heat transfer issues in the main combustion chamber. In the gas turbine engine world, we maintain reasonable temperatures with massive quantities of additional air. How is such a small cylinder going to cope with such high thermal loading?