The motion trajectory equation of particles in the vortex in the cylinder is derived, and the principle of the formation of peripheral mixed airflow is proposed.
Invented the thermal mixing theory of diesel engines.
The energy velocity distribution equation of periodic pulsating flow was established, and the dimensionless equation of its frequency effect was obtained, thus solving the theoretical and design problems that have not been solved for many years in laminar flow meters. .
Successfully researched and developed my country's first high-speed diesel engine with a speed of more than 3,000 rpm and the first two-stage free piston engine compressor.
Create the Internal Combustion Engine Major in Colleges and Universities
Internal combustion engines are power machinery widely used in various departments of the national economy and national defense. In the early 1950s, not only did my country’s internal combustion engine industry base be very weak, but also colleges and universities had not yet been established. Internal combustion engine major. As an expert in this field, Shi Shaoxi immediately actively promoted and planned after returning to China, and established the internal combustion engine major of Tianjin University the following year (1952), becoming one of the pioneers of this professional discipline in my country. He personally serves as the director of the Internal Combustion Engine Teaching and Research Office and teaches courses on thermal engineering, gas dynamics, combustion, internal combustion engine design, high-speed diesel engine principles and design, and free piston engines. At the same time, he organized and translated the first set of Soviet internal combustion engine textbooks and their teaching plans and syllabus commonly used in Chinese colleges and universities, established an internal combustion engine laboratory, and paid attention to training young teachers, laying the foundation for higher education on internal combustion engines in my country.
In 1956, he was selected as one of the first batch of graduate tutors in my country and began to recruit graduate students. This is also the beginning of the training of senior internal combustion engine talents by our country's experts. He has always advocated the combination of teaching and scientific research, closely linking the continuous improvement of teachers' own quality and academic level with the better cultivation of talents for national construction, so that colleges and universities can become two centers of teaching and scientific research, so as to achieve the goal of producing both talents and achievements. Dual purpose.
After serving as the director of the Second Mechanical Department in charge of internal combustion engines and thermal energy in 1958, he established the Tianjin Internal Combustion Engine Research Laboratory with the support of Tianjin City;
In 1960, it was expanded into an education institute. The Tianjin Internal Combustion Engine Research Institute, co-led by the Ministry of Industry and Information Technology and Tianjin Municipal Chairman Mao Zedong, is personally directed by him, and has undertaken many important national scientific research projects and new product development tasks. He comprehensively organized and led the design, research and development of 105 series and 85 series diesel engines and various small gasoline engines, and made new breakthroughs in the development of small high-speed diesel engines. He successfully developed my country's first calibrated speed of 3000 rpm ( The new models in the laboratory (up to 4,000 rpm) can meet the needs of military power generation, speedboat auxiliary machinery and automobile power, and have made important contributions to the development of my country's internal combustion engine products.
In 1960, he also presided over the design and development of the first free-piston engine-compressor combination device, and wrote the book "Free-piston Engine", filling a gap in our country.
With the historic turning point in our country in 1976, Shi Shaoxi, who was in his sixties, also entered a new stage in teaching and scientific research.
In 1979, he served as vice president and director of the Department of Thermophysical Engineering of Tianjin University, and founded the engineering thermophysics major. Then he established the Thermal Energy Research Institute and served as the director concurrently, conducting extensive research on energy utilization and development. .
In 1981, he was selected as one of the first batch of doctoral supervisors in my country.
In 1984, he was appointed as a postgraduate tutoring professor at the World Open University in the United States.
In 1987, he presided over the establishment of the first State Key Laboratory of Internal Combustion Engine Combustion, and served as the director and director of the academic committee. At the same time, he established the only postdoctoral research station in the internal combustion engine discipline in my country. He has overall responsibility for leading the work of these two important departments. So far, he has trained 10 doctors and 40 masters, and has undertaken postdoctoral research guidance.
From 1981 to 1986, he served as the president of Tianjin University. During his tenure, Tianjin University has achieved considerable development, and has successively established the Graduate School, the School of Management, the School of Petrochemical Engineering, the Department of Materials Science and Engineering, the Department of Physics, the Department of Chemistry, the Department of Mechanics, the Department of Humanities and Social Sciences, and the Department of Foreign Languages. etc., so that it can be expanded from a multi-disciplinary engineering university to a comprehensive university that focuses on engineering and combines science, engineering, liberal arts, and management. He attaches great importance to international academic exchanges and holds many important positions in domestic and foreign academic circles.
After he became president, he established more extensive contacts and cooperation with foreign universities and established inter-school cooperative relationships with 22 universities in the United States, Britain, Canada, France, Germany, Japan, Poland, Norway, and New Zealand. Not only was he often invited to give lectures and participate in international academic activities abroad, he also organized two international conferences in China in 1984 and 1985.
In 1989, he organized the 18th Worldwide International Conference on Internal Combustion Engines (CIMAC) and served as chairman of the conference. As the chairman of the Chinese Internal Combustion Engine Society, he signed a cooperation agreement between the two countries with the German Internal Combustion Engine Association. He also signed an academic exchange agreement with the internal combustion engine subject group of a British university in the name of the chairman of the internal combustion engine subject group of a Chinese university, setting the direction for my country's internal combustion engine academic community. world and made important contributions to entering the advanced ranks.
The invention of the compound combustion system
From the late 1950s to the early 1960s, my country's industry and economy were facing an extremely difficult period. At that time, the performance of domestically produced diesel engines had obviously lagged behind, and some products also encountered difficulties in production and parts supply. The development of the national economy urgently requires the design of a new generation of products by one's own strength. Among them, the most critical issue is to find a combustion system suitable for our country's national conditions at that time. To this end, Shi Shaoxi proposed a new combustion method and named it the composite combustion process. After nearly four years of experimental research, it was successful and passed the appraisal in 1963. The invention of the compound combustion process was not only a new breakthrough in diesel engine combustion theory, but also contributed to its application, which had a significant impact at home and abroad. Regarding the fuel-air mixing and combustion methods of diesel engines, the traditional "space" or "volume" theory has always been followed. That is, when designing the combustion system, the fuel should be sprayed into oil mist and evenly distributed in the combustion chamber. space to prevent the oil beam from touching the wall.
In 1955, Meurer of the West German MAN Company went against the traditional concept and proposed the "oil film" or "wall type" combustion process (M process), which means about 95% of the fuel is sprayed on the combustion chamber wall. An oil film is formed on the air, and a small amount of oil mist mixes with air in the space and ignites, and the oil film evaporates and burns. This process is used on some of the company's products and has achieved good results in being quiet and smoke-free. However, after research and practice in our country, we have discovered some of its limitations. Two of the most prominent problems were that the production of fuel injectors was difficult to solve at that time and that it was difficult to start the engine from cold. Faced with the difficulties in the development of small and medium-sized high-speed diesel engines in my country, Shi Shaoxi proposed a new combustion system in 1959 that was suitable for China's national conditions and had the advantages of the above two combustion methods - a compound combustion process. He cleverly combines space combustion with oil film combustion, and uses the law of air vortex in the cylinder that changes with engine operating conditions to change the distribution ratio of fuel in space and wall surface, so that when the engine starts or runs at low speed, due to the low vortex speed , the space fuel is increased and has the characteristics of "space type", thus overcoming the shortcoming of difficulty in starting the M process; when the engine is running at high speed, due to the high vortex speed, more fuel on the wall, and the characteristics of "oil film type", the result is not only improved It reduces the combustion process of the diesel engine, reduces the fuel consumption rate, and can burn a variety of fuels. In particular, it avoids the use of small multi-hole injectors and uses the self-cleaning pintle injectors mass-produced in my country. It adapted to the manufacturing and use conditions of our country at that time. This is not only my country's first original combustion process, but also earlier than similar processes that later appeared abroad (such as Germany's D process and H process). Fujio Nagao, a famous professor at Kyoto University in Japan, commented on this new combustion process in the paper "Combustion in Compression Ignition Engines": "Professor Shi Shaoxi of Tianjin University invented a new method that combines ordinary combustion with wall combustion and achieved good results. Effect." The compound combustion system and its theory have been included in the college textbook "Principles of Internal Combustion Engines" and provided to Hungary as an international technical exchange material in 1973. This combustion system has been widely used in my country's X105 series diesel engines. It was produced by more than 30 factories with an annual output of more than 700,000 kilowatts. This achievement won the second prize of the National Invention Award in 1982.
Research on internal combustion engine cylinder flow and fuel spray
Shi Shaoxi holds many leadership positions in teaching, administration and part-time social work, but he has always been an academic leader and insisted on giving top priority to scientific research work. Wire.
He has always advocated taking his own innovation path on the basis of learning and absorbing other people's advanced ideas and technologies, combined with my country's actual conditions and development needs, and practicing it in scientific research practice. Therefore, he not only used the traditional "space type" and "oil film type" combustion methods of two different natures to complement each other's strengths and cleverly combined them to create a composite combustion system, but also continued to forge ahead in future work, and in fluid mechanics, New progress and results have been continuously made in experimental research on combustion, in-cylinder flow, and fuel atomization. In his study of air motion and particle motion in the combustion chamber, he proposed a new equation for the motion of particles in rotating airflow. Experiments have shown that this equation is much more accurate than the Pishinger equation that people have been using in the past. Through theoretical and experimental research, he developed the thermal mixing theory and proposed the principle of mixture formation around the diesel engine. In his study of the changing rules of the turbulent field during the compression process of direct-injection diesel engines, he conducted a comprehensive analysis of the energy conversion during the compression process, and discovered the changing rules of turbulent intensity in different parts of the combustion chamber near the top dead center. The discovery of this new law is of great significance to understanding the formation and combustion of mixed gas. In his research on the engine charging process, he also proposed a calculation formula for the in-cylinder swirl ratio at the end of the intake. Experiments have proved that it is more accurate than the internationally used Ricardo formula. For a long time, internal combustion engine scientists have always focused on combustion energy saving, the core of which lies in how to achieve the most effective mixing and combustion of fuel and air. To this end, while focusing on revealing the gas flow patterns in the cylinder, he also conducted research on fuel spray characteristics. He used high-speed schlieren method, laser holography method, laser shadow method, laser diffraction method and gas injection simulation method to study the spray characteristics of diesel engines and achieved some important results. For example, the wall splash of the oil beam has an important impact on mixing and combustion. Appropriate wall splash can increase the mixing rate and accelerate the combustion speed, but too much fuel hitting the wall will have the opposite effect. Under high injection pressure, the fuel jet will cause an "entrainment" effect, causing a vortex motion around the fuel beam. This phenomenon is called Toroidal movement, and the higher the injection pressure, the greater the intensity of the Toroidal movement. This is a new discovery. Experiments have proven that when the injection pressure reaches 130 MPa, the SMD value of the spray is much smaller than that under conventional injection pressure, generally between 5 and 10 microns. In addition, it was also found that the SMD tends to increase both forward along the spray axis and outward along the spray radius, and there is still a large amount of fuel that has not yet evaporated at the end and periphery of the oil jet. This is also different from the argument held by some scholars in the past that fuel evaporates into steam immediately after being ejected from the nozzle holes. These new findings are of great significance to the study of mixture formation and combustion processes in diesel engines.
Research on new engine testing technologies
Today's world has increasingly stringent performance and emission requirements for internal combustion engines, which requires in-depth research and solution of a series of theoretical and practical problems. However, the mixing and combustion of oil and gas in the internal combustion engine cylinder is an extremely complex transient process. To explore and master its inherent laws, its testing technology has become a decisive means. Shi Shaoxi has been attaching great importance to the development and application of new technologies in this field for many years, and has achieved many results. As early as 1949, he successfully developed a chip viscous flowmeter for measuring the air consumption of internal combustion engines. In 1957, he published a paper "On the Determination of Air Consumption of Internal Combustion Engines", in which he comprehensively analyzed the velocity changes of pulsating flow and The impact of pressure changes on measurement errors, and methods to eliminate or reduce measurement errors are proposed. This is also the earliest paper published in this field in my country, which has attracted the attention of relevant experts and promoted the development of research work in this area. In addition, he applied particle tracing method to in-cylinder flow measurement for the first time, which attracted international attention. The internal combustion engine cylinder pressure measurement error and its solution have always been a problem that the international internal combustion engine community attaches great importance to but has not yet been satisfactorily resolved. To this end, Shi Shaoxi conducted research on this topic and published the paper "Research on Numerical Simulation and Digital Signal Processing of Internal Combustion Engine Cylinder Pressure Measurement" at an international conference organized by the British Mechanical Engineering Society in 1987. For the first time, digital signal processing and digital filtering technology were successfully applied to internal combustion engine cylinder pressure measurement, and a new method for measuring cylinder pressure was proposed. In this method, a short manometric channel is retained to avoid thermal shock effects, while the channel effects are filtered out using digital filtering.
At the same time, three digital filtering methods have been developed to process dynamometer diagrams to replace the currently commonly used "smoothing method" and have achieved good results. In addition, a thermodynamic correction method for the measurement error of the internal combustion engine dynamometer diagram was also proposed. Shi Shaoxi has also done a lot of work in laser fog measurement and speed measurement technology. For example, in 1987 he successfully developed an automatic analysis and measurement system for diesel engine spray fields using the principle of laser diffraction. The system has the characteristics of parallel conversion of array photoelectric detectors, multi-channel synchronous triggering parallel sampling and digital delay control. It is suitable for real-time automatic analysis and measurement of instantaneously changing spray fields in diesel engines, etc., and can measure different moments in the injection process. spray for testing. This achievement has been appraised by experts and has reached the international advanced level. In 1988, he successfully researched the photoelectric modulation feedback laser Doppler velocimeter, which broke through the traditional LDA composition model and used variable frequency optical frequency shift technology and photoelectric hybrid feedback technology to connect the optical path and circuit to a closed-loop negative feedback tracking loop, improving the signal-to-noise ratio, reducing costs. This research result obtained a national patent.
Research on the use of methanol in internal combustion engines
With the emergence of the global oil crisis, internal combustion engines are facing a shortage of fuel resources and atmospheric environmental pollution caused by burning petroleum products. A growing problem. For this reason, many countries are actively conducting research on non-petroleum products as fuel for internal combustion engines, among which methanol is a potential fuel with abundant sources. If used as an alternative fuel for internal combustion engines, it will not only save a lot of diesel and gasoline, but also reduce emissions and pollution. In view of this, Shi Shaoxi first conducted research on methanol for diesel engines in my country in 1980, and published "Research on Methanol as an Alternative Fuel for Diesel Engines" and "Dual Combustion" at the 15th and 16th International Academic Conference on Internal Combustion Engine Combustion. "Research on the use of methanol for fuel combustion" paper. The paper "Research on Fuel Control System for Methanol Burning in Diesel Engines Using Dual Fuel Method" was published at the 8th International Alcohol Fuel Conference. In 1988, research on burning pure methanol (M100) was conducted on the 492Q gasoline engine and was successful. The thermal efficiency was increased by 33% to 48% compared with the original engine, and the fuel consumption rate reached the international advanced level. In 1989, "Research on Diesel Engines Using Hot Surface Ignition Method to Burn Pure Methanol (M100)" was completed. The thermal efficiency was 4% higher than that of the original diesel engine, and the power was also increased by 9.6%. These achievements have opened up new ways for our country to save a lot of oil and expand internal combustion engine fuel resources in the future.
Compiling monographs and large reference books
While busy with teaching and scientific research, Shi Shaoxi is also committed to the compilation of monographs, treatises and large reference books. He has published more than 70 papers in domestic and foreign publications.
In 1983, he founded "Journal of Internal Combustion Engines", which is the only high-level academic publication in my country's internal combustion engine industry. It contains both domestic and foreign manuscripts, including both Chinese and English manuscripts. The published papers have been included in many foreign information systems and have had a significant impact at home and abroad. In addition, he is the editor-in-chief of the magazine "Combustion Science and Technology", and concurrently serves as the deputy editor-in-chief of "Acta Thermophysics" and an editorial board member of "Science China" and "Science Bulletin".
In 1984, China Agricultural Machinery Press published the "Diesel Engine Design Manual" with more than 3.8 million words edited by him. This is my country's first large-scale reference book that comprehensively summarizes diesel engine design experience and incorporates the latest foreign technological achievements. It has high practical and academic value.
Since 1988, he has edited the "Internal Combustion Engine Design Manual" with more than 3 million words. The Machinery Industry Press has officially published it in 1992 as a key scientific and technological book. In addition, he also serves as the chief editor of the power machinery section of the Machinery Volume of the "Encyclopedia of China". He also participated in my country's science and technology development planning work in various periods, including the "1960 National Science and Technology Long-term Development Plan" formulated by the National Science and Technology Commission, "1978-1985 National Science and Technology Development Plan Outline", and 1986-2000 Basic Research The formulation of long-term development plans, etc., have contributed to the development of science and technology in our country.