Mention hybrid vehicles and one immediately thinks of Toyota and the 1997 Prius, the first commercially successful passenger car of this type. There are, however, earlier examples and today we look at an unlikely pioneer, Briggs & Stratton.
Outside the US, the name Briggs & Stratton is most often associated with lawnmower engines of modest capacities and power outputs. This understates considerably the size and global reach of the company. Founded in 1908, Briggs & Stratton is the world’s largest manufacturer of small-capacity internal combustion engines for agricultural, industrial, marine and recreational applications.
Headquartered in Milwaukee, Wisconsin, the company manufactures around ten million engines annually in plants located in North and South America, Europe and Australia, and sells in over 100 countries worldwide.
In the late 1970’s, following the fuel crisis earlier in that decade, Briggs & Stratton began thinking about the viability of hybrid power. It recognised that most road vehicles of that era were highly inefficient: their large capacity internal combustion engines were required to produce enough power and torque to accelerate them up to the speed limit on highways but, thereafter, only a fraction of the power output was required to maintain speeds, typically no more than 20 hp.
The company decided to build a road car, not with the intention of putting it into series production, but to act as a showcase for its technical capabilities and an inducement to US auto makers to produce their own hybrids, which might, it hoped, be powered by Briggs & Stratton engines. That car, the six-wheeled Hybrid Concept, was unveiled in 1980 to an astonished and bemused audience.
In today’s terms, the car was a parallel hybrid: the wheels could be driven either by the internal combustion engine, the electric motor, or both combined. Electrical power was provided by a bank of twelve six-volt high-capacity lead-acid batteries, each weighing 66 lbs (30 kg) and connected in series to produce 72 volts. Total energy capacity was 250 Ah. A separate twelve-volt 68 Ah battery was installed under the bonnet to power the accessories.
The DC electric motor was capable of providing 8 hp continuously, or 20 hp intermittently. The petrol engine was an off-the-shelf Type 42 twin-cylinder horizontally opposed four-stroke air-cooled unit with a capacity of 42.33 cubic inches (694 cc) and producing 18 hp. This engine was more usually used in large garden tractors and to drive stationary equipment such as generators. The petrol tank could hold seven gallons (US).
Briggs & Stratton scavenged parts from other auto manufacturers as required to build the Hybrid Concept. The front suspension, steering, clutch and four-speed gearbox were from the Ford Pinto. The doors, windscreen and dashboard were taken from the contemporary Volkswagen Scirocco Mk1. One of the most remarkable aspects of the design was its six-wheel layout. The reason for this was that the rearmost pair of wheels supported an internal ‘trailer’ which carried the considerable weight of the batteries independent of the rest of the car. The driven wheels were the second pair at the rear (i.e. the’middle’ pair).
Given its one-off construction, the design is, to my eyes at least, remarkably well executed, particularly the neat integration of the Scirocco doors and windscreen, neither of which I would readily have identified. The car has a highly contemporary for 1980 sharp-edged, angular style, not unlike the 1979 Dodge Omni 024 coupé (apart from the extra wheels, of course!)
The Hybrid Concept was styled by Brooks Stevens, a renowned industrial designer, born in Milwaukee in 1911. Stevens’ designs included motorcycles for Harley-Davidson and the highly influential 1963 Jeep Wagoneer SUV. More controversially, he was associated with promoting the concept of planned obsolescence whereby US automakers would facelift their models annually to stimulate sales.
Stevens was responsible for the initial design work on the Hybrid Concept but handed the project to his son, Kip, for completion. The car is a 2+2 coupé with (very) occasional rear seat accommodation, similar to a contemporary Porsche 911.
The Hybrid Concept weighed a hefty 3,200 lbs (1,454 Kg). The weight distribution was 1,200 lbs over the front wheels and 1,000 lbs over each pair of rear wheels, that being the combined weight of the internal trailer and batteries supported by the rearmost wheels.
Electric-only range was between 40 and 60 miles. Top speed was around 68 mph, achieved on a closed test track, and petrol consumption was around 30 mpg (US) at a steady 55 mph ICE-only running. This is very unimpressive today but, forty years ago, the typical mid-size US sedan was achieving just 10 to 15 mpg (US) in similar conditions. On the road, the car was stiffly suspended and rather noisy inside, betraying its weight and relatively primitive drivetrain, but it performed well enough to keep pace with regular traffic.
The Hybrid Concept remained a one-off and was displayed for a few years in the 1980’s before being retired to the Briggs & Stratton Museum in Milwaukee, where it remains today. It was certainly a ground-breaking design from an unlikely source, but ultimately failed in its mission to persuade US auto manufacturers to embrace Hybrid technology at that time.
In fairness, the lead-acid batteries were simply too heavy and lacking in energy capacity to be viable in real-world driving conditions. That said, Briggs & Stratton deserves credit for its pioneering work and the company is now a major manufacturer of Lithium-Ion battery powered equipment.