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[YesAuto Technology Channel] Since I disassembled the 2.0L Chuangchi Blue Sky gasoline engine last year, I have been curious about its development background. This is because the ultra-high compression ratio gasoline engine does not “follow the trend of small-displacement turbocharged engines”, and it has truly created a world of its own in the world. In this season when the maple leaves in Hiroshima first saw red, I had the honor to come to the headquarters of Mazda Japan to have a face-to-face communication with Mr. Mitsuo, who is respected as the father of Chuangchi Blue Sky Engine. Next, please join me in a conversation with the well-known person, Mr. Mitsuo, to learn about the unknown things behind Chuangchi Blue Sky technology.

● Everyone sees Mr. Mitsuo and his Mazda

My meeting with Mr. Renjian Mitsuo was in the conference room of Mazda headquarters. When I first saw Mr. Mitsuo, what he showed was the Japanese manner of being humble and polite. After a simple greeting, we started our interview. What difficulties did Renjian encounter when developing the Chuangchi Blue Sky gasoline engine? How did he reduce fuel consumption while ensuring the power output of the Chuangchi Blue Sky gasoline engine? How to solve the knock problem caused by high compression ratio? All this will be revealed for you in the following interview.

When I asked him why he chose Mazda instead of Toyota, Honda or Nissan, Mr. Renjian gave me a very simple answer: “I was born in Okayama Prefecture near Hiroshima, Okayama and Hiroshima are very close. After graduating from school, I plan to develop in the automobile industry. My parents also hope that I can find a job close to home. This is how I entered Mazda.”

● Chuangchi Blue Sky is a wreck under the emission regulations and business crisis

With the continuous upgrading of emission regulations in Europe and the United States, if Mazda continues to use the engine technology at the time, it will not be able to meet future emission regulations upgrade requirements. This is an important reason for Mazda's comprehensive technological innovation. In the face of increasingly stringent emission regulations, other Japanese car companies (such as Toyota and Honda) have embarked on the road of hybrid vehicles. Toyota is even more foresight, as early as 1997 launched the first generation of Prius models. Japanese citizens pay great attention to environmental protection, coupled with the large tax deductions for hybrid vehicles, there is a “hybrid-only environmental protection theory” in Japanese society, which believes that only hybrid vehicles are environmentally friendly vehicles, and vehicles equipped with only internal combustion engines are obsolete , Unenvironmentally friendly cars. For Mr. Ren Jian, who had more than 20 years of engine development experience at that time, hybrid power was not the only development direction, and internal combustion engines still had great potential for improvement in thermal efficiency. Under the leadership of Mr. Renjian, Mazda insisted on improving the internal combustion engine and finally achieved the success of the Chuangchi Blue Sky project.

This “from scratch” car-building project is called “SKY” project internally by Mazda, and translated into Chinese as “Blue Sky Project”. The Blue Sky Project has carried out a full range of innovations on Mazda models, including technology, design, and manufacturing processes. Since then, the name of Chuangchi Blue Sky has been used on all of the company's innovative technologies.

Perhaps it is because Mazda’s products launched with one heart, or Mazda’s product strength has been comprehensively improved, so that after Mazda launched the Chuangchi Blue Sky concept, the entire brand influence has been greatly strengthened, allowing the company to really go out. The haze of the crisis. The development of Chuangchi Blue Sky Engine led by Mr. Renjian was approved by the management in 2006 and then started. Due to the management's trust in Mr. Renjian and support for the technical route of Chuangchi Blue Sky Engine, even if the company's operating conditions are poor, the engine development project funding has not been reduced. Not only that, but the management did not cut R&D funding for other technologies of the “SKY” project, which shows how high hopes the project is placed.

● Achieving ultra-high compression ratio did not take too many detours

The management recognized the advantages of Chuangchi Blue Sky gasoline engine technology in fuel consumption and lower manufacturing costs. Mr. Renjian therefore has sufficient funds and human resources to promote this project. In fact, before the project was finalized in 2006, Mr. Renjian had already conducted experimental research on gasoline engines with ultra-high compression ratios and made test engines. Its main research purpose is to improve the thermal efficiency of gasoline engines by increasing the engine compression ratio.

But from the experimental results, Mr. Renjian noticed that when the compression ratio was increased to 15:1, the torque drop was not as severe as expected. This is because before the spark plug is ignited, the air-fuel mixture has been compression-ignited, which is equivalent to advancing the actual ignition timing, thus avoiding the torque from further decreasing due to the increase in compression ratio.

The 4-2-1 exhaust system avoids the phenomenon of exhaust interference and makes the exhaust smoother; coupled with the atmospheric valve overlap angle realized by the intake and exhaust valve timing system to sweep high-temperature exhaust gas, reduce the temperature in the cylinder, and avoid The occurrence of knocking. At the same time, the valve timing system also contributes to the introduction of more fresh air, increasing engine power. The intake valve timing regulator controls the motor to allow the Chuangchi Blue Sky gasoline engine to quickly switch to the Otto cycle with a compression ratio of up to 14:1 under high load conditions, which improves the engine's fuel efficiency under high load conditions.

● Actual fuel consumption is closer to theoretical fuel consumption

The Chuangchi Blue Sky gasoline engine has been a product launched a few years ago, and its advantages have been widely promoted in the media, but how much can it really be said? This time to see Mr. Renjian is indeed a good opportunity to find out the advantages of this engine.

The characteristic of a small-displacement turbocharged engine is that it has lower fuel consumption under low load/torque output conditions, but after entering medium-high load/torque output conditions, the fuel consumption performance is not ideal. Moreover, the smaller the displacement, the worse the performance of the turbocharged engine in the medium and high load/torque output conditions. When the vehicle speed exceeds 30km/h, the engine enters a medium load/torque output condition. At this time, the Chuangchi Blue Sky gasoline engine has lower fuel consumption performance than the small-displacement turbocharged engine. The picture above shows the situation at 1500rpm. When the engine speed is increased to 2000rpm, the Chuangchi Blue Sky gasoline engine still maintains the same advantage in fuel consumption compared to the small-displacement turbocharged engine under medium and high load/torque output conditions. This also shows that when the vehicle speed is 60-80km/h (the highest gear), the vehicle equipped with the Blue Sky engine has better fuel economy.

According to the fuel consumption test standards of the Ministry of Industry and Information Technology, the comprehensive fuel consumption of the Golf 1.4T automatic transmission model is 5.4L/100km, and the comprehensive fuel consumption of the Mazda 3 Axela 2.0L automatic transmission model is 6.2L/100km. The 1.4L small-displacement turbocharged engine beats the 2.0L Chuangchi Blue Sky gasoline engine under this test standard.

Mr. Ren Jian also mentioned that the actual fuel consumption performance of Chuangchi Blue Sky engine is relatively close to the theoretical fuel consumption. On the contrary, the actual fuel consumption of a small-displacement turbocharged engine is 15-20% worse than the theoretical fuel consumption (that is, fuel consumption increases by 15-20%). This also proves from the data why the actual fuel consumption of the small-displacement turbocharged engine is relatively high.

● The significance of Chuangchi Blue Sky for people seeing the light

The target fuel consumption of the Chuangchi Blue Sky gasoline engine has reached the design expectations of Mr. Ren Jian. This gives him a sense of accomplishment in his work. But Mr. Jian, who loves to pursue new things and seeks excitement, quickly emerged from the satisfaction of Chuangchi Blue Sky gasoline engine and invested in new R&D projects.

In the interview, Mr. Renjian also mentioned frankly that the actual fuel consumption of the Mazda 2 equipped with the 1.3L Chuangchi Blue Sky gasoline engine did not reach the Toyota Prius's level, but compared to the hybrid version of the Fit at that time, it was in actual fact. Fuel consumption performance will be better.

The average speed of the user's daily car is generally higher than 30km/h (40-50km/h in the urban area and 60-70km/h in the suburbs). At this average speed, the low fuel consumption performance of the 1.3L Chuangchi Blue Sky gasoline engine is reflected. In addition, during high-speed cruising, the second-generation Honda Fit hybrid model only uses engine-driven vehicles. The 1.3L LDA engine on it has a lower fuel consumption performance during high-speed cruising than the 1.3L Chuangchi Blue Sky gasoline engine, which leads to actual use of vehicles. The fuel consumption in the process is higher than that of Mazda 2.

● Adopt the second-generation Chuangchi Blue Sky engine technology with 18:1 ultra-high compression ratio and gasoline compression ignition

“The first-generation Chuangchi Blue Sky gasoline engine has achieved fuel consumption levels equivalent to that of some hybrid systems, and has changed the Japanese society’s understanding of naturally aspirated engines. The goal of the second-generation Chuangchi Blue Sky gasoline engine is The level of carbon dioxide emissions of electric vehicles is equivalent (Note: The carbon dioxide emissions of pure electric vehicles mentioned here refer to the carbon dioxide emissions generated by the use of non-renewable energy power generation at this stage).” Mr. Renjian said confidently. Due to confidentiality reasons, Mr. Renjian could not disclose too many technical details to us. However, after repeated inquiries, I still obtained some overview of the second-generation Chuangchi Blue Sky gasoline engine that we had never known before.

However, homogeneous combustion requires that the air-fuel mixture in the combustion chamber is evenly distributed, and the atomization of gasoline in the direct injection engine takes time, which makes it difficult to increase the speed of the homogeneous compression ignition engine. The second-generation Chuangchi Blue Sky gasoline engine only achieves homogeneous compression ignition with a compression ratio of 18:1 in the low and medium load areas to reduce fuel consumption in the low and medium load areas. As for whether the high-load area uses the 14:1 compression ratio of the first-generation Chuangchi Blue Sky gasoline engine (the domestic adjustment is 13:1), Mr. Ren Jian did not reveal too much. But judging from the fuel consumption performance chart, the second-generation Chuangchi Blue Sky gasoline engine has better fuel consumption at high load than the first-generation.

It is worth mentioning that, because homogeneous compression ignition is only implemented under certain working conditions, the second-generation Chuangchi Blue Sky gasoline engine is also equipped with spark plugs to achieve spark plug ignition in other working conditions. In addition, the new Chuangchi Blue Sky gasoline engine will continue to use the existing Chuangchi Blue Sky engine technology and hardware to ensure that the mass production cost of the engine is within a reasonable level. In terms of oil requirements, the design goal of the second-generation Chuangchi Blue Sky gasoline engine is to allow the engine to work stably without relying on high-grade gasoline. The use of low-grade gasoline only affects the power output and does not affect the stability of the engine. Mr. Renjian said that since the engine is still in the development stage, it needs more tests to determine whether the compression ratio of 18:1 will be reduced when entering the country. There is no conclusion yet. It is reported that the second-generation Chuangchi Blue Sky gasoline engine may be officially put into the market in 2018.

● A new generation of rotary engine with lower fuel consumption

At the Tokyo Motor Show, Mazda released a new generation of Chuangchi Blue Sky rotary engine (English name “SKYACTIV-R”), the engine uses a dual-cylinder rotor structure, each cylinder displacement is 800mL. The engine is also equipped with an electric turbocharger and a hybrid system. The maximum output of the new powertrain is 450 horsepower (331 kilowatts).

The biggest feature of a rotary engine is that it can output more power under the same displacement, and its volume is relatively small, which is very suitable for sports cars with low body and limited engine compartment volume. This is also the biggest feature and specialty of the rotary engine which is different from the ordinary piston reciprocating internal combustion engine. The mass-produced model of the Mazda RX-VISION concept car equipped with a new rotary engine is expected to be put on the market in 2018, and it is quite worth looking forward to both in terms of styling and technology.

Editor's summary: Ren Jian Guangfu will use the second-generation Chuangchi Blue Sky gasoline engine to challenge the carbon dioxide emission level of pure electric vehicles. Can he succeed? Can he once again remind the world that the performance of internal combustion engines has great potential to tap , We will wait and see. (Photo/Car Home Zhai Yuan Picture/Wen Car Home Chang Qinglin)