The Hurricane is as Tame as the Kitten

Toyota once took turbines very seriously indeed. We look back at Aichi’s efforts.

1987 Toyota GTV. Image: oldconceptcars.com

Automotive technologies have a natural tendency to evolve. With Rover of Solihull firmly closing the door on gas turbines by the mid-1960s, we open an eastward-facing door, to see how Toyota took up the baton.

First mooted in 1965, sixty months of intense development took place at an undisclosed cost. The results brought forth a two-shaft gas turbine, intended for a bus chassis. A further five years of research entailed, the outcome being a car based turbine, the flagship Century being the chosen home for such a noble power unit. With its V8 removed, the gas turbine was not mechanically connected to the drivetrain. Instead, those ultra high revolutions charged a bank of batteries, in turn feeding motors to both front wheels – the gas turbine hybrid[1].

The Century tests were reasonably positive but Toyota’s engineers quite naturally wanted to improve matters further. For more, read less. Additional development reduced the system dimensions and weights with a grand reveal at the 1977 Tokyo motor show – the gas turbine powered, ridiculously cute and diminutive Sports 800 coupé.

As a production petrol powered pocket rocket, the Sports 800 coupé had harboured giant-killing performance with nimble handling and low weight, the elfin-like petrol producing 45bhp to shift 580Kgs. Plumbing in the single shaft turbine tipped the scales to the tonne, halved the number of forward gears and reduced power to 30bhp. Neither performance nor economy figures were revealed. Button cute the car might have been, but this pretty show had very little go[2].

Hybridisation maintained a germinating course within Aichi. With the 800 a production un-reality, the eighteen years of constant research and development came to close as their plans diverged. Smaller turbines were deemed more suitable for public transport applications, while petrol hybrid powertrains would gain impetus from good old fashioned internal combustion.

One further turbine spin arrived however in the form of the 1987 GTV (Gas Turbine Vehicle), based on the platform of the contemporary Soarer coupé model. Toyota engineer, Masumi Iwai had headed those initial mid-60s forays into turbine propulsion. Twenty years later, as Chief Project Engineer for Research and Development, Iwai, a genial chain smoker was determined for the concept to succeed, almost regardless of time and cost[3]. The car itself was close to the 6-Series BMW in size, yet was more elfin in weight, and slipperier in coefficients.

Image: oldconceptcars.com

GTV was a fully operational and road legal (in Japan) concept with rear wheel drive, speed sensitive power steering, along with all-round independent double wishbones suspended by air springs. ABS remained whereas the donor car’s AWD and AWS was omitted. Good for 125mph[4], the car idled at 10,000 rpm. A dashboard mounted button worked the handbrake, the dash containing two sources of amazement for Car’s Georg Kacher[5]. The first was a rear-view video camera feed to a small, square tv screen (“most distracting but crystal clear”), alongside the turbine’s separate counter of revolutions which peaked at 53,000 though appeared to reach almost 70,000 rpm at V-Max.

Regenerating waste heat to increase efficiency, GTV differed from previous incarnations by incorporating one turbine to drive the compressor, the second being drive shaft connected. A two stage heat exchanger lowered exhaust gas temperatures to a rated 1050° C. Iwai observed that significant improvements could be had “at 1350,” but this required greater usage of ceramics, with added cost. Iwai’s team were impressed by the turbine’s reliability too, with one of their prototypes having reached 38,000 miles without requiring anything beyond normal servicing.

Nevertheless, he was also acutely aware of the car’s shortcomings. Firstly, the engine’s weight, a stout 440 lbs. Compare that to a contemporary Celica’s 330 lbs mill, swiftly followed by poorer fuel economy to the tune of 20-30% to that of a reciprocating equivalent. Even with instant torque, turbine lag made for kangaroo style progress at city driving speeds, hardly conducive to a Toyota’s normal easy going, slick image. The meatiest problem encountered however was that of torque and its affects upon the automatic transmission fitted to early prototypes[6], the turbine producing more turning effort than the converter could initially cope with. Shaft speeds were reduced and a softening of the gearbox’s characteristics slowly but surely began to yield results.

Image: oldconceptcars.com

While overall, Car found in the GTV’s favour, turbine lag rather spoiled Kacher’s review of this competent and indulgent coupé, a matter readily acknowledged by Toyota’s Mister Turbine. Iwai informed his interrogator that it would take “ten to fifteen years” (from mid-1988) in order to see a viable production creation – the new millennium.

Replacing these turbines with a petrol engine led to a car born from those patient years of trial and error – the Prius, whose silky CVT gearbox would be honed in the GTV – and the only item from the 1987 prototype to make it to series production.

But does the gas turbine have any future now in an automotive application? While the amount of research, time and financial investment remain incontrovertible, there is no getting away from the fact that electric motors and batteries drive the current momentum. Perhaps in this battery EV free-for-all, Toyota have despaired of ever seeing the project take flight. But akin to Hollywood, the car industry loves a sequel, so never say never.

 

[1] The fuel (of whatever form chosen) which produced the power was converted into electrical energy by the generator. Fixed direct current (DC) entered the chopper or Electricity Control Unit, creating variable direct current to both boot mounted battery and wheels.

[2] At the close of that 22nd motor show, Toyota quietly tucked away the tiny turbine prototype until the 2009 motor show. Whether nostalgia brought it back into the public domain is unclear but the car had somehow grown an ugly and large bonnet scoop along with alloy wheels and a black roof. Your author could find no information regarding underbody changes.

[3] “Management have not questioned cost. When that happens, the final countdown has begun.”

[4] “Drive fast, the car is best at speed” – Iwai.

[5] Featured in the August 1988 issue of Car magazine.

[6] The original auto-box had originated in a Toyota Crown. A manual gearbox was tried very briefly but soon rejected.

 

Sources: classiccars.fandom/ Wonkypedia/ Road & Track/ Car Magazine.

Author: Andrew Miles

Beyond hope there lie dreams; after those, custard creams?

14 thoughts on “The Hurricane is as Tame as the Kitten”

  1. Good morning, Andrew. I know very little about gas turbines. The main advantages as far as I know are they’re reliable and they deliver a lot of power relative to the weight of the engine. They make perfect sense in an aircraft.

    The downside is the throttle response, or lack there off. It takes time to spool up, but also it takes time to slow down.
    For that reason, if we ever get to see the gasturbine in a production vehicle I think it will be a hybrid where the turbine charges the batteries, which powers the electric motors that drive the car. Steve Randle argued something similar in the ‘Idée Fixe’ series here on DTW.

  2. Gas turbines can be designed with very high thermo dynamic efficiency (that’s why they are used in power stations) but this efficiency is limited to running at fixed speed and within a very narrowly defined bandwith of load (that’s why you don’t save any fuel by making turbine powered aircraft fly slower). This is the exact opposite of what you want from an engine in a car and combined with what Freerk correctly mentioned it makes a gas turbine inherently unsuited for directly powering a car.
    But if you can run the turbine at constant speed in a hybrid it just might make sense.
    Volvo built the ECC with an 80 kW gas turbine from one of their portable power generators powering a hybrid drivetrain

  3. Thank you, Andrew. I think I recall reading the original Car magazine article and being impressed by the use of ceramics in powertrains, more than anything else.

    Turbine power is great – it’s just better placed outside the car and powered by wind, water or steam. In a sense, through EVs, we now finally have it.

  4. Try this six minute Japanese video (with subtitles) to experience the sounds of the GTV. The turbine is an elegant form of power production along with an enigmatic soundtrack.

    1. Very cool – that’s what cars of the future should sound like. One thing – it seemed to be quite loud, especially from the outside. I’m not sure what they could do about that. Wonderful, though, even if it does seem to be an engineering dead-end.

    2. Thanks, for sharing the video, Andrew. It does sound good 🙂

  5. Jaguar also saw gas turbine hybrid battery electric powered vehicles as a possibility and had a turbine powered generator electric car, the CX75. Announced at the 2010 Paris show, the car was a joint venture between Jaguar and Williams Advanced Engineering, (yes, that Williams of F1 fame), with 2 Bladon microturbines repurposed from their normal use as stationary generators to considerably more mobile ones powering a battery pack that fed four Yasa electric motors, one per wheel.
    The ‘micro turbines’ were replaced by a specially engineered 1.6 litre 500 hp four cylinder piston engine. before the project was abandoned in 2012.
    Despite that, the CX75 got a second chance at fame when it’s body was draped over a tube frame powered by a V8 engine and it ‘starred’ along with an ‘Aston Martin DB10’ in the Bond film, ‘Spectre’

    1. David: The powertrain for the original CX-75 concept was, I am reliably informed, not viable. Not so much in theory, as I understand it, more in execution. Anyway, it’s doubtful that JLR were all that serious about it, despite the PR noise surrounding it and their purchase of Bladon Jets. It was only when JLR decided to progress with a production version that Williams became involved, I believe, providing the combustion-engine powertrain and carrying out the bulk of the development.

      They might have been better off sticking the V8 in it from day one. There was certainly little wrong with how it looked.

  6. The gas-turbine hybrid CX-75 re-emerged – at least in spirit – at Geneva in 2018 as the Techrules REN complete with Bladon Jets turbines and styling by the Giugiaros. It’s all gone rather quiet since – it’s not clear whether Techrules achieved their production target of ten cars per year.

  7. There is also the issue of size. The smaller the gas turbine, the less efficient it can be. GTs have a scaling issue that won’t go away. It is inherent to them. I can’t reproduce the governing equations here, but the problem is unavoidable. Go small, lose efficiency. The trouble is that as the GT is reduced in size, the air molecules it has to deal with don’t shrink in proportion. They remain the same. For the small GT*, it is as if the air is stickier or thicker. Further, beyond a certain point the internal clearances can’t be reduced any further than what is usually practice for large GT engines anyway. This results in proportionately greater internal leakage- an efficiency loss. It all leads to higher fuel consumption. Small GT are just not all that efficient. On the other hand, if you go larger, much larger, things go very well…

    *sub 1,500 shp

    1. Thanks Eion, that’s what I thought.

      Robert, that was new news to me, thank you. How does the company run by the Guigiaros manage with being an entity within the VW group?

      J T, the scaling problem and resolving the efficiency loss also came up against, as all hybrids do, the continuing efficiencies in all their forms, of improving battery technology for pure electrics. Will there be a time with no hybrids?

  8. Italdesign Giugiaro S.p.A. is the consultancy owned by VW Group – nominally Lamborghini, last time I looked.

    The Techrules work was by GFG Style, which has no connection with VW Group. It was founded in 2015 by Giorgetto and Fabrizio Giugiaro after Giugiaro senior sold his remaining share in Italdesign to Audi AG.

  9. Hi David

    Perhaps. Perhaps not. There is a type of hybrid which has been discussed and tested but has not made it into the wild as yet. This is the type where there are two types of charge storage device on board he vehicle. One is used for fast charge and discharge (power dense) while the other is operated much more gently (energy dense). An example would be a battery/super-capacitor pairing. This provides the opportunity to have really aggressive regeneration without worrying about hurting the battery (through excessive current). The super-cap would deal with sudden transients (large power excursions, both acceleration an regeneration) while the battery would provide the range (since super-caps are generally not great for energy density and batteries are much better). Keep an eye out for this sort of hybrid. It may turn out to be a better EV than a pure battery one.

    The thermal efficiency of a system is not the most important issue to consider though. It may be one of several matters worth consideration or it may be of no serious import at all. What really counts is user value. You could refer to that as personal utility or personal economics or individual subjectivity. In essence the situation is that there is a mixture or collection of variables that an individual evaluates and depending on personal preferences comes up with a choice of what matters, what does not matter and finally what they are going to choose to do. Same sort of deal applies for those who manufacture items, vehicles included.

    GT thermal efficiency is not great but that does not prevent its adoption in the automotive sector. After all, millions of people drive their autos in modes which deliver thermal efficiencies of less than 10% on a daily basis and without issue. The GT, installed in the appropriate vehicle would likely address a niche. So, if not thermal efficiency, what are the barriers?

    In the case of the gas turbine the main impediments preventing it from scale production are the cost of tooling-up, setting in place the necessary supply-chains and finally manufacturing it in suitable form for automobiles, trucks or buses. On top of all that are the interferences, irrationalities and economic dislocations of government regulations, taxes and compliances. If an attempt to go ahead and manufacture were to be made, then it would result in a product which would be expensive- a top of the market item. That in turn would place significant limitation on the chance for profitability (certainly in the short term and well into the medium term if not longer than that) and increase the investment risk dramatically. Being sure of a decent IRR is not possible here. This is the leading impediment to producing GT vehicles. Putting that aside it turns out there is another matter to look into.

    Since the majority can’t afford to purchase a car outright they borrow for it. Most people borrow heavily to fund their lifestyles anyway. This (unfortunately) includes borrowing for transportation, furniture, entertainment, clothes and food. The West lives well beyond its means by expropriation and borrowing, so going into debt to fund consumption is not considered unusual behaviour. Assuming the GT were available the determinant for whether a purchase occurred would be whether the purchaser felt they were able to cope with the monthly payments, not whether they could repay the principle (which over decades many never do anyway). Normally we could expect this situation to expand the potential market niche for a GT vehicle but not for now. Debt is getting too expensive and it is about to get much more expensive yet, assuming new debt could even be obtained by most at all. We should expect to see increasing defaults and foreclosures at all levels (including sovereign debt). Some will actually experience it directly. So, aside from capital and regulatory issues for manufacturers, this is another reason the GT is unlikely to show up in production very soon. Who’ll be able to afford it?

    Note: The situation at present is a process of fundamental structural alteration. The process is replacement of debt based fiat currencies with a commodity based currency or several commodity based currencies. Going into a significant debt, let alone remaining in one, is a suicidal choice right now. This applies right across the board, including vehicles, regardless of powertrain- ICE, GT, EV.

    As much fun as some of the EV are, they are more expensive than conventional vehicles and provide less utility for the user. This has not been changing. Therefore the expectation is that there will be far fewer of them purchased. The regular person will be caught without sufficient capital or the means to acquire it. Further, as Western Europe de-industrialises (it is uncompetitive now and that’s getting a lot worse on an almost daily basis), the real cost of a purchase is accelerating further and further away from affordability. The collapse of the purchasing power of the local currency (e.g. Euro, GBP) really hurts here. Imposition of regulation and legislation will not be a cure. The cure is something very few people know about and even fewer would be prepared to entertain.

    In summary, two things.

    Thermal efficiency is nice, but it is not as important as some would like to pretend. There are other matters with much stronger influence in the individual’s decision to purchase (or not), shaping the type and depth of market a manufacturer has to address.

    You sure are all in for a wild ride through interesting times. Hope you’re ready!

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