Ferdinand Porsche as hybrid drive pioneer
Reconstruction of the “Semper Vivus” hybrid car from 1900.
As an automotive designer and founding father of the present-day Dr. Ing. h.c. F. Porsche AG, Stuttgart, Professor Ferdinand Porsche (1875-1951) is considered to be one of the leading engineers of his day. He made automotive history with vehicles such as the Austro Daimler “Sascha” (1922), the Mercedes-Benz S-Types (1926) or the Auto Union Grand Prix-racing car (1933) and the Volkswagen “Beetle” (1934).
The name Porsche has been associated with pioneering innovations in automotive engineering since the beginning of the last century. In 1900 Ferdinand Porsche unveiled his “Lohner Porsche”, an electric car with wheel-hub drive and soon after this car featured all-wheel drive and four-wheel brakes, another world first. A highlight of his early years as an automotive designer was the Lohner-Porsche “Semper Vivus” that went down in history 111 years ago as the first functional hybrid car.
Porsche’s reconstruction of the “Semper Vivus” is a tribute to this visionary invention by Ferdinand Porsche. The fully functional replica of the “Semper Vivus” was built based on original drawings and exhaustive research. The faithful replica, whose visionary design impresses to this very day, was the outcome of collaboration between Porsche Engineering and Karosseriebau Drescher, a coachbuilding company based in Hinterzarten.
The history of the Lohner-Porsche “Semper Vivus”
Ferdinand Porsche was busy designing and developing his cars as long ago as 1896. The first fruit of this endeavour was an electric vehicle known as the “Lohner-Porsche” driven by steered wheel hub motors that caused a sensation at the Paris World Exhibition in 1900. This was soon followed by ever more impressive proof of just how innovative Ferdinand Porsche was. A racing car boasting four wheel hub electric motors became the world’s first all-wheel drive passenger car that also marked the automotive engineering debut of four-wheel brakes. No less visionary was Ferdinand Porsche’s next idea. Again in 1900, he combined his battery-powered wheel hub drive with a petrol engine – the principle of the serial hybrid drive had been born.
Ferdinand Porsche had entered uncharted territory with this first functional, full-hybrid car in the world, the “Semper Vivus”. In this vehicle, two generators twinned with petrol engines formed a single charging unit, simultaneously supplying electricity to wheel hub motors and batteries. In autumn 1900, Ferdinand Porsche set to work on a first prototype with “petrol-electric hybrid drive”. Presumably he based the world’s full hybrid car on a conversion of his electric racing vehicle from the Semmering-Bergrennen race. To this end he combined his electrical wheel hub motors with two combustion engines with no mechanical connection whatsoever to a drive axle. Instead, they each drove an electric generator supplying both the wheel hub motors and accumulators with electricity. It was the birth of serial hybrid drive. As a full hybrid concept, the “Semper Vivus” (“Always Alive”) was also able to cover longer distances purely on battery power until the combustion engine had to be engaged as a charging station.
To save weight and create space for a petrol engine, Ferdinand Porsche swapped the original 74 cell accumulator in his electromobiles for a smaller battery with only 44 cells. In the middle of the vehicle he installed two water cooled 3.5 PS (2.6 kW) DeDion Bouton petrol engines for generating electricity, driving two generators, each producing 2.5 hp (1.84 kW). Both engines operated independently of one another, each delivering 20 amperes with a voltage of 90 volts. The electricity generated by the dynamos initially flowed to the wheel hub motors, with the surplus power being forwarded to the batteries. An additional special side effect was that it was also possible to use the generators as electric starter motors for the petrol engines by reversing the direction of rotation.
In practice, Ferdinand Porsche still had to contend with the principal problem of his wheel hub cars – the vehicle’s heavy weight. Although the total weight of his “Semper Vivus” hybrid car was only 70 kg more than the original version, the 1,200 kg of the prototype was a challenge for the soft rubber mix of the pneumatic tyres at that time. In other respects as well the hybrid concept was still a long way away from being ready for series production. With its bodiless chassis, exposed petrol engines and unsprung rear axle, the “Semper Vivus” may have impressed the trade visitors to the Paris Motor Show in 1901 but potential car buyers must have felt that the Spartan prototype was not really for them. The interaction of engine, batteries and control system also still needed a lot of development and in addition to the ambitious control technology, fouling of the accumulators due to dirt being thrown up was a constant problem. And yet the hybrid concept had pointed to new possibilities that Ferdinand Porsche resolutely set about turning into reality.
The road to the Lohner-Porsche “Mixte”
Again in 1901 Ferdinand Porsche developed the revised concept of his “petrol-electric hybrid car” into a variant that was ready to go into series production under the name Lohner-Porsche “Mixte” (borrowing the French term “voitures mixtes”). With a four-cylinder, front-mounted engine, this model mirrored the vehicle concept of the Mercedes then just recently designed by Wilhelm Maybach but with its two wheel hub motors still conforming to the concept of a serial hybrid car. Ferdinand Porsche was now using a powerful 5.5 litre, 25 hp (18 kW) four-cylinder engine from the Austrian Daimler engine company as an electrical generator. The engine was connected to the electrical generator located under the seat by means of a driveshaft, with control handled by a primary controller next to the steering wheel.
To solve his vehicles’ weight problem, Ferdinand Porsche was constantly reducing battery size, while also attempting to design a dust-proof battery housing. While the Lohner-Porsche “Mixte” was only able to drive a few kilometres on electric power alone because of the reduced battery capacity, the unladen weight of the four-seater touring car including body fell to around 1,200 kg. In normal driving mode the petrol engine and generator ran at a constant speed, feeding wheel hub motors and battery with electricity at a constant voltage. In addition to his drive concept’s high-level of efficiency, the car offered other advantages as well: By reversing the polarity, the generator could be used as an electric starter motor, obviating the need for the strenuous, not unhazardous cranking of the engine.
Before 1901 was out, Ludwig Lohner and Ferdinand Porsche had pulled off a respectable result with five sales of the Lohner-Porsche “Mixte”, a selling price of approximately 14,000 Krone apiece making the cars a very exclusive commodity. Moreover, the purchaser of this initial series was Emil Jellinek, the well known general agent of the Daimler engine company in Stuttgart-Untertürkheim, who had been the inspiration behind the first Mercedes only the year before by naming the model after his daughter. Despite this contact a cooperation agreement to supply Mercedes engines failed to materialise and only seven Lohner-Porsches with Daimler engines were built. From 1903 onwards, petrol engines from Panhard & Levassor were used, because in the meantime the large French automotive manufacturer has acquired the licence rights for France, Great Britain and Italy from Ludwig Lohner.
At about the same time as the change in engine supplier, Ferdinand Porsche again significantly modified his cars’ drive concept. For the familiar weight reasons, but also to reduce production costs, he dispensed with the purely electric driving capability and shrunk the battery to a minimum for initiating the starter motor. He replaced the missing energy storage unit with a further innovation: The generator, designed as a stationary-armature machine, was fitted with an electro-mechanical speed regulator patented as a “device for automatically regulating electric generators”. Ferdinand Porsche also ushered in a further stage in hub wheel motor development. A redesigned hub casing allowed the kingpins to be relocated nearer to the centre of the wheel. This steering geometry patented in May 1902 significantly reduced the effect of road impacts as well as the force needed to turn the steering wheel. To reduce the unsprung mass of the wheels, Ferdinand Porsche also reduced the diameter of his wheel hub motors, which he compensated for by using wider windings.
In April 1902, having incorporated these improvements, Ferdinand Porsche took his place on the starting grid for the Exelberg race. His two-seater Mixte racing car was impressive not just visually on account of its modern proportions but on the track as well. His Lohner-Porsche seemed to cope effortlessly with even the steepest gradients of the 4.2 km long gravel road leading up to the Exelberg, emerging as the victor in the large car class. Porsche received no less high profile publicity in the autumn of 1902 when he chauffeured Austrian Archduke Franz Ferdinand during a military manoeuvre in the Lohner-Porsche. The aristocratic passenger seems to have liked the vehicle with its elegant touring body because soon afterwards Ferdinand Porsche received a thank you letter testifying “just how satisfied in every respect his Imperial Majesty” was.
Despite these impressive demonstrations, the sales figures of the “Mixte” production variants remained far lower than anticipated. The enormous technical development costs between 1900 and 1905 compared with sales of only eleven hybrid cars. The main problem was undoubtedly the high sales price: Depending on design and equipment, a Lohner-Porsche “Mixte” cost between 14,400 and 34,028 Krone, in some cases making it almost twice as expensive as comparable, conventionally powered motor vehicles. This was compounded by the high maintenance cost of the complex drive system that was unable to keep pace with the ever increasing reliability of normal petrol driven cars. Purely electric vehicles however were economically more successful. Approximately 65 Lohner-Porsche electric cars were sold during the first five years of series production to the end of 1905.
The project / The reincarnation of the “Semper Vivus”
In November 2007 the Porsche museum decided on one of the most interesting and challenging projects of its history: the reconstruction of a faithful replica of the Lohner-Porsche “Semper Vivus” dating from 1900. Even 111 years after its invention, building this first functioning hybrid car in the world was a great challenge for all involved. Ultimately it was not just about achieving the maximum attention to detail visually but also achieving the same performance as the original. The Porsche Museum entrusted the workmanship to a team of experts led by coachbuilder Hubert Drescher, who had already proved his competence in numerous difficult restoration projects. In common with a number of racing car projects the aluminium body of the Porsche Type 64 museum exhibit originates from the workshop of the Hinterzarten coachbuilder.
The commencement of work was initially preceded by exhaustive research in various archives the length and breadth of Europe. The outcome of this was a handful of black-and-white photos and an original technical drawing that provided an initial basis. As with Ferdinand Porsche, the replica of the “Semper Vivus” initially began on a blank sheet of paper. That meant that what was initially required, in addition to a good deal of imagination, was extensive research and calculations in order to be able to recreate an accurate likeness of the electrically driven wheel hub motor. As no specifications or other helpful records had survived, experts initially created ready reckoners and design drawings on graph paper in the time-honoured fashion. This involved the painstaking study and laborious measurement of photos and drawings. As there was no functioning wheel hub motor in existence, technical details such as performance and range had to be resurrected and calculated from scratch.
When it came to selecting materials, coachbuilder Drescher took his inspiration, among other sources, from coaches and carriages from the dawn of the 20th century. This required the assistance of experienced suppliers who were entrusted with the manufacturing of the special materials. The fully functioning replica of the “Semper Vivus”, which took approximately three years to reconstruct, doesn’t however just comprise recreated components. For example, it was possible to fit some original components including combustion engines.
Facts and figures on the “Semper Vivus“
Engine: 2x Single cylinder De-Dion-Bouton combustion engine
Output : 2.5 hp (1,85 kW) per cylinder
Electric motor output : 2.7 hp (2 kW) per wheel
Top speed: 35 km/h (22 mph)
Range: 200 km (124 miles)
Overall width : 1,880 mm
Overall length : 3,390 mm
Overall height: 1,850 mm
Total weight: 1.7 t
Front wheel weight (single): 272 kg (with wheel hub motor)
Track width front: 1,350 mm
Track width rear: 1,540 mm
Wheelbase : 2,310 mm
Ground clearance: 250 mm