For thousands of years, the core of the human technology tree seems to be "burning something". Since Prometheus brought fire, burning firewood, burning coal, burning charcoal, burning oil, "playing with fire" has become the most splendid scientific and technological civilization on the blue planet, and the car internal combustion engine is the sweet fruit of this scientific and technological tree. But isn't it right, isn't electrification now? Even the paranoid Mazda and Subaru in the automotive combustion engine world seem to be immune. However, just like the mobile phone circle LCD is never a slave, under the leadership of Toyota-based automobile manufacturers, yamaha and Kawasaki Heavy Industries have been introduced. In the context of this cooperation project, a hydrogen-fueled V8 internal combustion engine is ready to be released.
Hydrogen fuel for gasoline?
The most superficial advantage of using the internal combustion engine structure is to be able to continue to stand on the shoulders of giants. Just like the currently disclosed hydrogen fuel V8 engine, it is based on the Lexus RC F's 2UR-GSE 5.0L V8. In the case of gasoline engines, the Lexus engine has a maximum horsepower of 477 hp and a maximum torque of 530 N·m. After the conversion to hydrogen fuel, the maximum horsepower is 455 hp and the maximum torque is 540 N·m (data details are unclear). Although the horsepower is relatively small, the torque is correspondingly increased, and the maximum torque can be reached at 3600 rpm, and the maximum torque of the gasoline version needs to wait until 4800 rpm. However, although the data and prospects are very good, is it really so simple to directly "burn hydrogen"?
As the number one element on the periodic table, hydrogen itself is an extremely active being. Whether it is the permeability of metals or the extremely flammable nature, for internal combustion engines with full mechanical ignition, the use of hydrogen as fuel undoubtedly requires all-round strengthening. For example, Yamaha said that for this hydrogen fuel engine, it has been modified in the injector, cylinder head, intake/exhaust and other components. As for the incredibly eye-catching and exaggerated 8-1 exhaust pipe, not to mention. We'll "speculate" one by one.
High calorific value and high defects on the table
Hydrogen as a fuel can be seen as a natural ultra-high octane gasoline, plus hydrogen and oxygen mixed gas fuel speed is faster, so as the fuel of the internal combustion engine, hydrogen has good explosion resistance. And among the fuels currently in use, hydrogen has almost the highest calorific value (except for nuclear fuel). If compared to gasoline, the heat value of hydrogen combustion is almost three times that of it. The summary is that hydrogen fuel burns fast, flame propagation speed is fast, and ignition energy is low. If the structure of the gasoline engine is applied, the most likely problem is early combustion, tempering and even deflagration.
Therefore, this modified hydrogen fuel engine will directly change the position of intake and exhaust, and the exhaust will be integrated on the inside of the V-type engine, while the intake structure will be placed on the outside. This reduces the length of the intake tract and reduces the impact of heat dissipation on the intake duct during the operation of the internal combustion engine, resulting in premature combustion caused by excessive mixed gas temperature. At the same time, it is also conducive to a balanced increase in the intake of the cylinders on both sides, after all, after the heat value is increased, the required air intake is also correspondingly increased.
After switching to hydrogen fuel, high compression ratio is also a mature way to suppress abnormal combustion phenomena such as early combustion and tempering. Therefore, many other brands of hydrogen fuel internal combustion engines use turbocharged form. But turbocharging adds heat dissipation pressure, and temperature is undoubtedly the "enemy" of sensitive hydrogen. The Lexus V8 engine selected by Toyota and Yamaha is itself a naturally aspirated structure, but its original compression ratio can reach 12.3. So choosing it to modify it is certainly not a whim. As for high-pressure direct injection, it is also necessary, and the injection of hydrogen fuel will only be more demanding and more accurate than in the fuel era. In terms of ignition, it is expected to use spark plugs with a smaller ignition area and better heat dissipation.
Brain-opening guessing, waiting for Yamaha to punch in the face?
In order to overcome the active characteristics of hydrogen fuel, in addition to the above mature technical applications in the internal combustion engine, there are also some possibilities for swords to go sideways. For example, a more direct approach can also inject cold air and even water into the cylinder to reduce the combustion temperature, stabilize the engine power and reduce nitrogen oxide emissions (hydrogen combustion produces nitrogen oxides, not "zero emissions" in the complete sense). For the combustion of hydrogen, water is inherently renewable in the cycle. But the accuracy of water injection may be more demanding than fuel. Because the water sprayed directly into the cylinder may cause the oil to lose its lubricating effect and seriously corrode the cylinder wall.
Since it was mentioned earlier that hydrogen combustion also produces nitrogen oxides, the flexible use of this "exhaust gas" may also be a new topic for hydrogen fuel internal combustion engines. After all, nitrogen is a well-known inert gas, and the nitrogen produced after combustion is returned to the intake link, which can effectively reduce the oxygen content in the mixed combustion gas and achieve the purpose of overcoming early combustion and tempering. However, this structure requires more precise calculations and more complex diversion structures. It is also prone to the side effects of reducing power and even incomplete combustion.
Buy a car to send Yamaha tuning? Materials science pressure is great
After guessing, let's go back to the structure that is currently visible. When the intake air occupies the outside of the V8 engine, the exhaust structure is squeezed into the inside. The exhaust of the 8 cylinders is directly assembled into an exhaust pipe, and such an exaggerated exhaust structure seems to be an oath of friendliness to emissions during hydrogen fuel combustion. According to Yamaha's expression, the exhaust structure under the design can produce a very unique high-frequency sound. It seems that Yamaha, who started making musical instruments, did not forget his old business when he modified the engine. The pursuit of natural sound is also one of the important reasons why everyone's love for the internal combustion engine is not forgotten.
As for the modification of parts such as cylinder heads, I guess it is more in terms of materials. As a part of the engine that is outstanding in processing accuracy and complexity, the cylinder head not only faces the high temperature erosion and friction of the traditional fuel internal combustion engine era, but also faces the challenge of "hydrogen embrittlement" in the context of hydrogen fuel. That is, at the beginning, the "corrosion" of hydrogen on metals. As a core component of the vehicle specification level, when the "corrosion" of hydrogen exceeds the limit of traditional internal combustion engine manufacturing metal such as steel, cracks will occur, eventually leading to engine failure. The conventional method is mainly to use a layer of copper, molybdenum, silver and other metals, as well as other special treatments to reduce the "corrosion" of hydrogen. This treatment is also suitable for parts including other "hydrogen sprayers", "hydrogen fuel tracks" and so on.
Write at the end:
Hydrogen fuel can make the combustion engine technology sustainable within a hundred years, solve the problem of energy sustainability, ensure emission standards, and also take care of consumer habits and traditional preferences, and even obtain a lower cost than hydrogen fuel cells and other paths. And its problem is also obvious, that is, how to overcome the personality problem of this super "lively" energy. When the names of Yamaha, Mazda, Subaru and other tech giants came together. We still seem to have a reason to wait for good news about them in this age of electrification.