Recently, Tianjin University’s research on methanol as an alternative fuel to diesel oil won the second technology invention award for Outstanding Science Research Achievements in Higher Institutions by the Ministry of Education. The alternative fuel using methanol developed by Professor Yao Chunde’s team could effectively improve the combustion efficiency and reduce emissions from heavy diesel vehicles. This technology is being used in over a hundred pilot vehicles in 12 provinces and 2 cities.

The diesel engine is a major power device used for China’s economic development. According to statistics collected by the China Internal Combustion Engine Industry Association, heavy-duty commercial vehicles featuring high emission and lengthy working time accounted for 75% of land transportation in 2016. In 2016, of the 270 million tons of fuel consumed by internal combustion engines, diesel was about 160 million tons. Most noteworthy, heavy-duty vehicles accounted for 14% of commercial vehicles, consuming 50% of the 160 million tons diesel oil. Diesel vehicles are the main source of air pollution.

There has been a paradox to improving the combustion efficiency for diesel vehicles: for the emission of nitrogen oxides (NOx) and particulate matter, when one is decreases, the other is increases. Using methanol in the fuel could solve this problem.

Methanol is a clean fuel for internal combustion engines. It has extensive raw material for production, rich production capacity, mature production technology, clean combustion performance, ease of use and transport. However, methanol cannot be directly applied to diesel engines because of its low calorific value, high ignition temperature, poor evaporation and because it is a bit corrosive.

Yao and his team explored the concept of starting an engine with pure diesel and when it fully warms up switching to and running the engine on a diesel/methanol fuel mixture. When the engine reaches a set temperature, the electronic control system is triggered to inject methanol into the inlet through a nozzle installed in the intake manifold. As a result, methanol and air is well-mixed and burn together with the diesel in the cylinder. This technology successfully reduces both nitrogen oxides (NOx) and particulate matter emissions. Currently, the maximum substitution rate of methanol for diesel oil has reached to 45.6% and the average rate has reached 32.7%. The fuel efficiency has increased by 8.7% and the highest value increasing from 43.4% in the original machine to up to 47.6% now.

SINOTRUCK, CAMC, the Shaanxi Heavy Duty Truck Co. Ltd. and the Dongfeng Motor Corp. have adopted this technology and the pilot vehicles have been operating in 12 provinces and 2 cities in China. Methanol can replace 30% of diesel fuel consumption which means saving 48 million tons of diesel per year (taking the diesel consumption of 2016 as an example which reached to 160 million tons). The average substitution ratio of methanol to diesel is 1.5 (that is, 1.5 tons of methanol to replace 1 tons of diesel fuel). Calculations using these figures suggest that the amount of methanol consumed per year will be 72 million tons. This will be of great significance for alleviating the shortage of oil and giving full play to the excess capacity of methanol production in China. Supposing the average price of methanol is 2000 yuan per ton and the average price of diesel oil is 6500 yuan per ton then 172 billion yuan per year can be saved on the cost of fuel.

Editors: Sun Xiaofang and Ross Colquhoun