Turbocharging technology has been widely used in all kinds of models, but who can think that half a century ago, almost no one heard of Turbo?
Even if you are loyal to naturally aspirated engines, there is no denying that the emergence of turbochargers has had an indelible impact on the automotive industry. Whether it’s a gasoline or diesel car, tall like a Ferrari 488 GTB or grounded like Volkswagen Golf, you can see the shadow of a turbocharger. From birth to popularization, what kind of course has it gone through?
The emergence of the first turbocharged model
The “age” of turbocharger is actually the same as that of internal combustion engine, but at the beginning of its birth, no one thought of applying it to the engine of civil vehicle. It was first widely used in aircraft engines, but due to its huge size, it is unlikely to be installed in automobile engines. But because of its obvious benefits, it’s only a matter of time before it’s used in cars.
The first to use turbo technology in automotive engines was the European automakers Porsche 930, Saab 99 turbo and BMW 2002 turbo, which were among the first to use turbo engines. However, more is being squeezed out of turbine technology by American manufacturers. In 1962, General Motors thought that the 3.5-liter V8 engine power of Oldsmobile cutlass was not satisfactory, but Oldsmobile did not replace it with other V8 engines owned by general motors. Instead, it took a new approach and cooperated with industrial turbine manufacturer Garrett to build a legendary JETFIRE V8 engine.
In the 1960s, how to apply turbochargers to the cars facing Volkswagen was a great challenge for engineers. The compression ratio of JETFIRE engine is 10.25:1, so it is easy to encounter engine knock without modern engine management system. To solve this problem, Oldsmobile created a system to inject “turbo rocket liquid” (a 1:1 mixture of water and methanol) into the cylinders.
Although the cutlass model with the JETFIRE engine is significantly faster than the same model with the naturally aspirated engine, it has not won the market’s favor due to its high price. And the turbo rocket liquid injection system proved to be an impractical solution, so the JETFIRE was shut down a year later, with less than 4000 units sold.
Small progress in turbocharging
Although JETFIRE failed in the market, the automotive industry soon began to tap the application potential of turbochargers again. In 1965, a second mass market turbocharged model was launched, and it still comes from the United States. The international harvest scout uses a 2.5-litre turbocharged four cylinder engine with 110 horsepower, 20 horsepower more than the same naturally aspirated engine. What’s more, it can completely use ordinary grade gasoline and no longer need the assistance of water methyl liquid.
But just two years later, IH decided to abandon the turbo engine and switch to a non turbocharged 3.2-litre four cylinder engine. It has been proved that a naturally aspirated engine with a larger displacement can consume less fuel than a turbocharged engine with the same power. With the arrival of the 1974 oil crisis, the prospects for turbocharged engines look even bleaker.
In 1973, automakers began to see the potential for turbines to make cars faster. In that year, BMW 2002 turbo was put into mass production. Although the speed of the model did improve a lot, it had serious problems such as turbine hysteresis and high fuel consumption, which was even considered as a safety hazard. So like JETFIRE, it stopped production a year after its launch.
Just as the 2002 turbo “died”, the Porsche 911 Turbo was born. When the first model came out, it became the fastest mass production vehicle in the world. For turbocharged engines, this is undoubtedly a very important milestone. From then on, people’s enthusiasm for turbocharging began to rise, and Saab 99 turbo also came into being in this period.
When a diesel engine encounters turbocharging
1978 is a special year for turbochargers. In that year, Buick equipped Regal with a turbocharged V6 engine, which eventually evolved into a high-volume grand national model. More importantly, however, it was the year of the turbo diesel engine. The Mercedes Benz 300sd came out that year, equipped with Garrett turbocharger, completely changed the diesel engine.
Although it is still controversial which is better for gasoline engine, the effect of turbo is much more obvious for diesel engine. Because diesel combustion cycle depends on high compression, forced intake is a simple way to improve power and efficiency. It has also been proved that turbocharging is more suitable for diesel engines than naturally aspirated engines. Since the Peugeot 604, which uses turbo diesel engines, was launched in 1979, half of the civil vehicles in Europe have adopted such power combinations.
How is a turbine enough?
If you can put a turbocharger on the engine, it should be possible to put two on it – that’s what Maserati thought in 1981, and biturbo was born. Although it’s not a good car, it’s the first commercial car sold in the world that uses a dual turbo. The theoretical basis of twin turbine is that two parallel working turbines can reduce turbine hysteresis. Although it is not always the case in reality, it does make a great contribution to the improvement of vehicle power.
The Porsche 959, which was launched in 1986, shows another way to reduce turbine hysteresis by using twin turbines – unlike the parallel twin turbines with two turbines working independently, the 959 uses sequential twin turbines, one at low speed and the other (or both) at high speed. Although this approach may have an impact on reliability, it is reported that the failure rate of the fourth generation of supra’s sequential twin turbine engine is less than 1%, which shows that it does not constitute a major problem.
The future of turbocharging
Over the past 50 years, turbochargers have undergone considerable changes. Today, the complexity of turbochargers is no less than that of the engine itself, and its next change may come soon: the electric assisted turbochargers show increasing potential.
The traditional turbocharger transforms the exhaust gas of automobile into the power needed by the compressor, while the electronic turbine can store part of the electric energy, and continue to provide power for the compressor when it does not reach the optimal speed. In theory, this eliminates the effect of turbine hysteresis.
Maybe it will take time for us to see the electronic turbine become the mainstream, but just like the development history of turbocharger, automobile manufacturers never spared time and energy to improve the turbocharger. Where will it go in the future? Let’s see.