針對水冷四行程機車之冷卻液散熱效果進行相關研究，利用冷卻系統添加複合碳系奈米流體(HCBNF)溶於原廠冷卻液，再加入分散劑GA(阿拉伯膠)進行電磁加熱攪拌3 h與超音波震盪1 h，以製備複合碳系奈米冷卻液(HCBNC)。分別進行在不同濃度及溫度的沉降、比熱、導熱、黏度及磨潤試驗探討基礎性質，實驗分別試驗base、0.02 wt.％、0.04 wt.％、0.06 wt.％的HCBNC，基礎試驗中沉降試驗的結果發現HCBNC在靜置30天，0.04 wt.％效果非常穩定幾乎沒有沉澱現象。黏度試驗發現0.06 wt.％黏度高於其他的濃度；比熱試驗發現 0.04 wt.％濃度低於其他濃度和base；熱傳導試驗0.04 wt.％為最佳導熱係數；最後磨潤試驗0.04 wt.％、0.06 wt.％兩者的磨耗改善率高於base。綜合以上四項試驗結果，選用濃度0.04wt.％進行後續實驗。
將最佳濃度0.04wt.％ HCBNC加入於熱交換系統平台及實車實驗，在熱交換系統平台中水散熱性能改善率為37.5 ％、空氣散熱性能改善率為6.45％，而引擎暖車性能實驗中水散熱性能改善率為23 ％、空氣散熱性能改善率為7.94％。在實車HCBNC分別與原廠冷卻液與純水相比ECE-40行車型態燃油消耗量改善12 ％、14 ％，定速50 km/h行車型態燃油消耗量改善9 ％、13 ％，平均燃油消耗量(km/L)改善11 ％、14 ％。平路與爬坡行車型態測試油門開度固定25 %，平路行車型態車速改善率3 ％、4 ％，爬坡行車型態車速改善率8 ％、18 ％。
在四項實驗ECE-40 行車型態試驗、定速行車型態試驗、爬坡行車型態試驗、平路行車型態試驗，HCBNC分別與原廠冷卻液與純水相比平均對於汽缸壁溫度下降17.25 %、10.5 %；出水口溫度改善率9.5 %、9.25 %；汽缸壁(排氣管) 溫度下降9.75 %、7.75 %；火星塞溫度下降8.25 %、8.75 %。在廢氣排放添加HCBNC分別與原廠冷卻液與純水相比的HC排放總量減少13 %、20 %；CO排放總量減少39 %、 49 %，而CO2排放總量減少20 %、28 %。在PM排放測試，HCBNC與原廠冷卻液在粒徑2 μm以下總量減少7 %，在粒徑3 μm以上總量減少77 %。

To carry out related research on the cooling effect of the cooling liquid of the water-cooled four-stroke locomotive, use the cooling system to add the composite carbon nanofluid (HCBNF) to the original cooling liquid, and then add the dispersant GA (gum arabic) for electromagnetic heating and stirring for 3 hour and Ultrasonic vibration for 1 hour to prepare composite carbon nano-coolant (HCBNC). The sedimentation, specific heat, thermal conductivity, viscosity and wear tests at different concentrations and temperatures were carried out to explore the basic properties. The experiments were tested for base, 0.02 wt.%, 0.04 wt.%, and 0.06 wt.% HCBNC, and the sedimentation test in the basic test. As a result, it was found that the 0.04 wt.% effect of HCBNC was very stable after 30 days of standing and there was almost no precipitation. The viscosity test found that the viscosity of 0.06 wt.% was higher than other concentrations; the specific heat test found that the concentration of 0.04 wt.% was lower than other concentrations and base; the thermal conductivity test was 0.04 wt.% as the best thermal conductivity; the final tribology test was 0.04 wt.%, The tribology improvement rate of both 0.06 wt.% is higher than that of base. Based on the above four test results, a concentration of 0.04wt.% was selected for subsequent experiments.
The optimal concentration of 0.04wt.% HCBNC was added to the thermal platform and the actual vehicle experiment. In the heat exchange system platform, the water heat dissipation performance improvement rate was 37.5%, the air heat dissipation performance improvement rate was 6.45%, and the engine warm-up performance test. The improvement rate of reclaimed water heat dissipation performance was 23%, and the improvement rate of air heat dissipation performance was 7.94%. Compared with the original coolant and pure water, HCBNC in real vehicles has improved ECE-40 type fuel consumption by 12% and 14%, and fixed speed 50 km/h type fuel consumption by 9% and 13%. The average fuel consumption (km/L) improved by 11% and 14%. The throttle opening is fixed at 25% for flat road and hill-climbing mode tests, the speed improvement rate for horizontal road mode is 3% and 4%, and the speed improvement rate for hill-climbing mode is 8% and 18%.
In the four experiments ECE-40 running mode test, constant speed running mode test, climbing mode test, flat road mode test, HCBNC was compared with the original coolant and pure water on the average cylinder wall temperature Decrease by 17.25%, 10.5%; water outlet temperature improvement rate of 9.5%, 9.25%; cylinder wall (exhaust pipe) temperature decreased by 9.75%, 7.75%; spark plug temperature decreased by 8.25%, 8.75%. Adding HCBNC to exhaust gas emissions reduces the total HC emissions by 13% and 20% compared with the original coolant and pure water respectively; the total CO emissions are reduced by 39% and 49%, and the total CO2 emissions are reduced by 20% and 28%. In the PM emission test, the total amount of HCBNC and the original coolant is reduced by 7% when the particle size is below 2 μm, and the total amount is reduced by 77% when the particle size is above 3 μm.

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