Internationally speaking, it is not wrong to say that LPG is clean energy, but the premise is that it must meet two conditions. First, the purity of LPG must reach the energy standard for automobiles, and the second is that the engine must meet the requirements. Only in this case can the use of LPG (liquefied petroleum gas) be truly clean energy.
——— Professor Hua Wei, Director of the Huagong Natural Gas Research Center, member of the Chinese People's Political Consultative Conference, and chief scientist of the National Fundamental Research Institute for Energy Efficiency
At present, there is no single fuel engine developed specifically for LPG in China. Almost all LPG engines are produced by the process improvement of gasoline engines or diesel engines. The LPG (liquefied petroleum gas) engines used by Guangzhou Public Transport are mainly produced and customized by domestic engine companies such as Yuchai, Weichai, and Cummins. The technical deficiency of LPG (liquefied petroleum gas) engines changed from diesel engines to diesel engines, which leads to problems such as insufficient combustion and increased production of nitrogen oxides.
———Department of Vehicle Engineering, Department of Engineering, South China Agricultural University Professor Liu Zhongguo, Automotive Engine Expert
In response to doubts about the environmental protection of LPG (liquefied petroleum gas) buses in Guangzhou, the People’s Congress’s representative recently confirmed that the 172 LPG (liquefied petroleum gas) buses in Shanghai were used for exhaust pollution inspection. There were 150 vehicles that met the standards. 22 vehicles that exceeded the standards were retested after being repaired. There were 21 vehicles that met the standards. The total compliance rate of the rechecks was 99.4%.
According to Huang Zuzhao, deputy director and senior engineer of the Guangzhou Environmental Monitoring Center, the center randomly sampled 172 LPG (liquefied petroleum gas) buses from FAW, Second Automobile, Sanqi, and the tram companies. At present, the overall emission of LPG (liquefied petroleum gas) buses is in good condition in our city, said Huang Zuzhao.
Huang Zuzhao also revealed that at present, Guangzhou is referring to advanced international and domestic practices, and hastened to study and formulate a regular inspection and compulsory maintenance system for motor vehicle exhaust pollution (referred to as the I/M system for short). This quarter will adopt mandatory measures to supervise enterprises and do a good job. The maintenance of various types of vehicles including LPG (liquefied petroleum gas) vehicles ensures that the vehicle's exhaust emissions meet the standards. At present, the system is soliciting opinions from all walks of life and strives to issue an announcement before the end of the year.
Two questions
Why the first inspection rate is less than 90%
Although only one of the 172 vehicles sampled last failed to meet the standard, the initial inspection compliance rate was only 87.2%. Huang Zuzhao explained that there are many reasons for this, such as the lack of maintenance and repair of the vehicle emission control system, the post-processing device of the vehicle configuration being damaged, deteriorated, or being replaced in time beyond the service period. Excessive gas conditions.
He said that after the first inspection of vehicles with exhaust gas exceeding the standard, after undergoing maintenance and repair, emissions will be greatly improved, so the retest rate will generally be higher. This also shows that the maintenance of motor vehicles is very important for pollution control. The result of the sampling inspection of the motor vehicle exhaust pollution in Guangzhou from January to September this year showed that the first inspection compliance rate was 85.6%.
Why do you not invite NPC deputies to supervise the scene?
Since the deputies of the National People's Congress questioned them, why didn't they go to the scene to supervise them? Huang Zuzhao said that the spot inspection was carried out according to normal procedures and the vehicles were inspected strictly in accordance with the relevant national emission standards and testing technical specifications. So far, no request has been received from the NPC deputies or other parties to put on-site inspections. If delegates put forward requirements in this regard, they can invite deputies to the NPC (including representatives of all sectors of the community) to participate in the supervision in the future.
Expert interpretation
The problem lies in the inherent deficiency of engine technology
Guangzhou LPG (liquefied petroleum gas) bus engine is basically transformed from diesel engine
Professor Liu Zhongguo, former head of the Department of Vehicle Engineering at the School of Engineering, South China Agricultural University, introduced that at present, there is no single fuel engine developed specifically for LPG in China. Almost all LPG (liquefied petroleum gas) engines are manufacturers of gasoline engines. Or the diesel engine is produced by process improvement. The specific LPG (liquefied petroleum gas) engines used in Guangzhou buses are mainly produced by custom-made domestic engines such as Yuchai, Weichai, and Cummins. The technical deficiency of the LPG (liquefied petroleum gas) engine changed from diesel engine to diesel engine resulted in problems such as insufficient combustion and increased production of nitrogen oxides during operation, and the lack of performance of the engine in terms of dynamic performance and economic performance.
Liu Zhongguo said that there are currently three kinds of air intake methods for diesel LPG engines modified by diesel engines: one is closed-loop electronically controlled air-fuel mixture control (ie, LPG (liquefied petroleum gas) is mixed with air in the air intake), and electronically controlled single-point injection And electronically controlled multi-point injection. Among them, electronically controlled single-jet engines are widely used in Guangzhou, such as Yuchai YC 6 1 2 ZLQ E and Weichai WT 615.00LPG (liquefied petroleum gas). These engines have at least two shortcomings: First, control In some cases, the intake air volume is not easy to control, resulting in incomplete combustion of LPG (liquefied petroleum gas) in the cylinder, which increases the hydrocarbon content in the exhaust gas. Second, the cylinder temperature is too high. Because the diesel engine is transformed, the cylinder is burned by the LPG. Temperatures tend to be high, causing oxygen and nitrogen to react more easily to produce more nitrogen oxides at high temperatures. At the same time, engine parts are more easily lost and lubrication performance is reduced.
Chinese laboratories are far from entering the phase-out period
The engine mileage is 1268 kilometers, and the engine is only a few days old
After the exclusive disclosure of the laborers' test report by the newspaper, on the 22nd, the Guangzhou Environmental Protection Bureau issued a draft that the results of the inspections based on the research report of the National People's Congress represent no practical significance for evaluating the environmental performance of Guangzhou LPG buses. The sampled car was a model that was eliminated in Guangzhou.
Yesterday, this newspaper received the "Test Report" of the "Study Report on the Experimental Analysis of HEV, LPG (Liquefied Petroleum Gas) and Diesel Buses" from China Labor. According to the “Sample Vehicle Description†on page 3 of “Inspection Reportâ€, it states that the diesel vehicle submitted for inspection was transformed from Yuchai State III LPG (liquefied petroleum gas) engine based on the urban passenger car produced by Zhengzhou Yutong Bus Co., Ltd. ( The LPG (liquefied petroleum gas) bus is a 1268-kilometer-long engine. The reporter learned from the bus company that the daily mileage of a bus in Guangzhou is about 200 kilometers.
Is 1268 km out of the model? Prof. Liu Zhongguo said: With a daily distance of about 200 kilometers, the engine can be installed for only a few days. "This is obviously not a knock-out car."
Hong Kong has been engaged in Guangzhou for more than 30 years
Prof. Hua Wei said that it is mainly controlled by LPG (liquefied petroleum gas) purity and engine technology reasons.
The successful use of taxis in Hong Kong for more than 30 years has made it difficult for Guangzhou's emissions to achieve compliance. Professor Hua Wei, director of the Huagong Natural Gas Research Center, a member of the Provincial Committee of the Chinese People's Political Consultative Conference (CPPCC), and chief scientist of the National Fundamental Research Institute for Energy Efficient Energy, said that he is subject to LPG purity and engine technical reasons.
As early as 2004, Hua Wei proposed that it has several advantages over LPG (liquefied petroleum gas) fuel natural gas (LN G): resource potential is far greater than oil; price is cheaper; tail gas pollution is less, fuel is saved, and noise is lower . When Lin Shusen was appointed as secretary of the municipal party committee, he explicitly stated that “the environmental issue of LPG (liquefied petroleum gas) has not been resolvedâ€.
Internationally speaking, it is not wrong to speak only about LPG (liquefied petroleum gas) as a clean energy source, but only if it satisfies two conditions. First, the purity of LPG (liquefied petroleum gas) must reach the energy standard for automobiles, and the second is that the engine must meet the requirements. Only in this case can the use of LPG (liquefied petroleum gas) be truly clean energy.
Hong Kong's minibuses have used LPG for more than 30 years. Their LPGs are imported from abroad. Only one of them contains only one part per thousand, but the current domestic LPG (liquefied petroleum gas) contains that ingredient. Ten ten thousandths. The engines of Hong Kong are all of Japan's original, and they were specially made to Toyota. Therefore, LPG has been more successful in Hong Kong taxis. However, at present, LPG engines used in the country are all modified from diesel engines. Some of them are well-tuned, others are not well-changed, and are mixed.
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