【Preface】
Whenever oil prices continue to rise, there will always be huge changes in the automotive industry.
In the early days of the birth of the automobile, the pure internal combustion engine was not the only protagonist, when the electric revolution arose, a new round of technological revolution was driven by electricity, so in the early 20th century electric vehicles also tried to compete with the internal combustion engine.
In the 1970s, after the first oil crisis, Japanese car companies took advantage of the fuel economy of small displacement engines to successfully enter the world's largest automobile market. Since then, the global automotive industry has changed from dominating Europe and the United States to a three-legged stage in Europe, the United States and Japan, and "fuel-saving and durable" has also become a Japanese car label.
By 1990, the third oil crisis, triggered by the Gulf War, took only three months to raise the price of crude oil from $17 to $36 a barrel. The pressure of rising oil prices is transmitted to the consumer side, and the huge fuel consumption pickup trucks, large-displacement cars, vans, etc. produced by the three giants of the United States have been abandoned by consumers again.
Although the big three tried to use electric vehicles to ensure their lead, they did not expect to kill a "Prius" halfway. Equipped with a new internal combustion engine + motor assembly called the "Toyota Hybrid System", the drive system became the most successful consumer product in the era of high oil prices.
Time has passed, and in 2022, global crude oil prices soared to nearly $130 per barrel due to the Russo-Ukrainian War, which forced U.S. oil prices to rise to $4.14 per gallon, breaking their highest price since 2008. Even China's domestic oil prices are more than 9 yuan / liter across the board.
Under such high oil prices, the global auto industry will inevitably usher in a reshuffle, so what will the trend be?
Since the development of hybrid power, with fuel-saving performance, it has finally occupied a place in the automobile market. It was born more than 100 years ago in the era when machinery and electricity were in full bloom, but it was in a mixture of internal and external difficulties, and the ending at that time was regrettable.
In 1839, the world's first pure electric vehicle appeared, subject to battery technology, pure electric mileage is short, has not been widely standardized promotion. German engineer Nicolaus Otto invented the internal combustion engine in 1876, making it possible to miniaturize generator sets.
In 1901, 23-year-old German Ferdinand Porsche (founder of Porsche) installed gasoline generator sets on pure electric vehicles, solving the problem of short range of electric vehicles, and the world's first hybrid car appeared.
This basic hybrid structure is actually the same as Nissan's e-POWER now, called tandem hybrid, also known as extender hybrid.
▲ Ferdinand Porsche's hybrid electric vehicle
At the beginning, this hybrid was quite popular, because the pure electric car mileage was ridiculously short, and the fuel car needed to be manually shifted, and it should be known that there was no synchronizer for manual shifters at that time (manual transmissions with synchronizers began to be loaded in 1928), and two-legged clutches were required when changing gears, which only professionals could operate.
But later, with the improvement of the transmission and the improvement of the user's demand for vehicle performance, the weakness of the hybrid was exposed - the high cost, low top speed, durability and other aspects are not as good as traditional fuel vehicles, and even the fuel economy is far behind. So the hybrid entered the hibernation period, and few people asked about it, until the emergence of modern electronic and electrical technology in the 1960s began to give new life to the hybrid.
Hybrid key technology - energy brake recovery, developed by the American automobile company Amitron in 1967, and evolved into electric auxiliary drive and energy brake recovery in 1982, with the blessing of this technology, modern hybrid prototypes appeared. Here we have to mention Victor Walker, the father of hybrid cars, who did a lot of hybrid research in the 1960s and 1970s and built the first prototype of the modern hybrid, a Buick Skylark with a 16kW electric motor.
Victor Walker and Buick Skylark
Although the hybrid system composed of motor-generator-battery can improve the fuel economy of the vehicle by about 10 to 20%, it is still not enough, so engineers mounted the Atkinson engine on the hybrid vehicle, which can make the hybrid system more powerful.
The engine of a conventional fuel vehicle is the well-known four-stroke engine, which includes intake, compression, work and exhaust.
▲ Four-stroke engine
The thermodynamic cycle exhibited during its operation is the Otto cycle, which is named after Otto, the inventor of the internal combustion engine.
▲ Ideal Otto cycle – thermal cycle diagram
12 is the intake stroke, the intake valve is opened, the exhaust valve is closed, the piston is downward, the cylinder volume becomes larger, and the gas pressure is slightly smaller than the atmospheric pressure;
23 is the compression stroke, the intake valve and exhaust valve are closed, the piston upward consumes mechanical energy, the cylinder volume decreases, and the pressure increases;
34 During the combustion process, the pressure and temperature in the cylinder increase sharply; then push the piston downward work, that is, 45 work stroke;
The 56 exhaust valve opens, releases the remaining pressure and discharges the exhaust gases, and then the piston goes up to complete the 21 exhaust stroke.
Among them, 56 is to rely on the remaining pressure for exhaustion, although the cylinder pressure is not high at this time, but if it is used to do work, the thermal efficiency can also be improved. Thus, only six years after Otto invented the internal combustion engine, the challenger was ushered in, and in 1882, the British engineer James Atkinson invented the Atkinson cycle internal combustion engine to improve efficiency.
▲ Atkinson cycle (light yellow + orange) and Otto cycle (light yellow) contrast
The figure above is a schematic diagram of the comparison between the Atkinson cycle and the Otto cycle, the Otto cycle is the light yellow area enclosed by 12341, the size of the area is the size of the single cycle work, and the Atkinson cycle is the sum of the light yellow and orange surrounded by 1234A1, of which the orange area of 1 and 4 and 4A is the size of the work extracted from the waste heat (comparable to the capitalists at that time).
It should be noted that compression is from 12, while the work expansion is 34A, which means that the expansion ratio of the whole body must be longer than the compression ratio, and to achieve this goal, the clever Atkinson cleverly designed three sets of mechanisms.
Atkinson "Differential Engine", 1882
Atkinson "Cycle Engine" 1887
The "Cycle Engine" is compact and can be applied to vehicles. As can be seen from the animation, its crank linkage mechanism is a multi-link mechanism, which is more complex than the Otto cycle, and in the era of "cold weapons (pencil + ruler)" that did not have the blessing of software such as CAE/CAD, it was possible to design and debug this set of multi-link, think about how many people were at that time.
Judging from the GIF, do you feel very familiar, yes! It's Nissan again... The Nissan variable compression ratio engine is also a multi-link mechanism, which is very similar to this mechanism.
It is reported that at that time, the thermal efficiency of this Atkinson "Cycle Engine" was 20% to 30% higher than that of the Otto cycle, and it was mass-produced by a British internal combustion engine company and continued to sell for nearly 10 years.
Because the Atkinson engine had two major shortcomings - the compactness was not as good as the Otto cycle engine, and the liter power was lower, not many people in that era were willing to sacrifice the power performance of the internal combustion engine for thermal efficiency.
In 1957, american engineer Ralph Miller reintroduced the "Atkinson" cycle on ship power and power plants and overcame the compactness problem, and he achieved the goal of an expansion ratio greater than the compression ratio only through the gas distribution mechanism. How? He designed an engine with an ultra-high compression ratio so that the expansion ratio was also increased synchronously, and then adjusted the distribution mechanism to increase the rear angle of the intake delay, so that part of the mixture entering the cylinder was discharged back into the intake manifold, which prevented deflagration and detonation due to excessive compression ratio.
▲ Otto cycle and Miller cycle (Atkinson cycle)
This cycle is named the Miller cycle, and its thermal efficiency improvement is not as obvious as the Atkinson cycle, but it solves the shortcomings of the poor compactness of the Atkinson engine, so there is a high commercial value.
In 1993, Mazda addressed Atkinson's low rise and first commercialized it. The KJ-ZEM V6 engine was Mazda's most advanced engine at the time, with a displacement of 2.3 liters and a V6 structure, and was continuously selected as one of the "Ward Top Ten Engines" from 1995 to 1998.
The engine added a supercharging mechanism to increase the lifting power, and the final lifting power was 70kW/L (total output 162kW), but the supercharging consumed part of the power, so the extra power squeezed out of the Miller cycle was "volatilized" in part, and the final energy saving effect was not satisfactory.
▲Mazda Millenia sedan (equipped with Miller engine)
Since the hybrid has motor assistance, low lift power is not a fatal problem, while fuel saving can make the hybrid more powerful – which is why modern hybrid systems generally use Atkinson (Miller) engines.
By the end of the 1980s, the technology required for hybridization was in place to compete with conventional fuel vehicles. Although the internal factors of technology have been solved, the external factors have always been shrouded in the hybrid, and the external factors are cheap gasoline.
Assuming that gasoline prices remain low and there is no interference from forces such as the government, the advent of hybrids will be delayed for decades. This logic also exists in the current energy sector, where modern technology has been able to "grow" clean energy (wind, photovoltaics), but most countries are still "harvesting" fossil energy because fossil energy is cheap.
Heaven gave hybrids a chance, and the Gulf War in the early 1990s triggered a skyrocket in oil prices, from $17 to $36 a barrel.
Automobile manufacturers in various countries began to pay attention to automobile fuel economy, especially Japanese manufacturers, japan with scarce resources can not afford high oil prices, hybrid naturally became the most favored object of development budget, in 1997 Toyota Prius came out with epoch-making significance, since then entered the golden age of hybrid development (this life)... What is hybrid like in this life, we continue in the next part.
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