Experiment and Simulation Analysis on Heat load of Heavy-duty Vehicle Diesel Engine

The paper has explored the solutions to the thermal overload in the cylinder head of a heavy-duty vehicle 6-cylinder diesel engine and the thermal cracks in the valve-bridge of the engine. The experiments include measuring the temperature of the cylinder head bottom and testing the flow distribution of coolant through the upper nozzles of cylinder head bottom. The follow-up analysis was conducted on the causes of the excessive thermal load of the cylinder head bottom, the thermal cracks in the valve-bridge region, and the rationality of the structure of the water jacket for the cylinder head. The mechanism of the water jacket of cylinder head was further inquired. Then 3-D CFD numerical simulation of water jacket in the sixth cylinder, which is in the worst cooling condition, is performed. To enhance the flow form in water jacket and lower the cost of enhancement, we proposed 4 schemes of water jacket and conducted the numerical simulations to these schemes. It was identified that all these schemes have efficiently improved the flow field in water jacket. In the typical proposed scheme 1 in which 6 nozzles of all the 10 upper nozzles were blocked, the coolant flow rate on the bottom of the water jacket and in the cylinder head valve-bridge region increased by about 68.73%. The measuring results of the cylinder head bottom temperature show that the maximum temperature in the valve-bridge region of cylinder head is reduced by 9.2 °C and the temperature gradient reduction is 19.55 percent, suggesting that the thermal load and thermal stress of the studied diesel engine cylinder head has been significantly lowered.

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Analysis of the engine test cycles from China VI heavy duty vehicle standard and China automotive test cycle

E3S Web of Conferences ◽

10.1051/e3sconf/202126801020 ◽

2021 ◽

Vol 268 ◽

pp. 01020

Author(s):

Xiaowei Wang ◽

Chuanqi Wang ◽

Tao Gao ◽

Tengteng Li ◽

Hailiang Lao

Keyword(s):

Regression Analysis ◽

Diesel Engine ◽

Vehicle Emission ◽

Engine Test ◽

Heavy Duty ◽

Test Cycle ◽

Emission Standard ◽

Exhaust Temperature ◽

Heavy Duty Vehicle ◽

Low Load

This paper studied the engine test cycles including world harmonized steady cycle (WHSC), world harmonized transient cycle (WHTC) , china heavy-duty steady cycle (CHSC) and china heavy-duty transient cycle (CHTC) based on a diesel engine which meet the China VI heavy duty vehicle emission standard. The results show that regression analysis of speed, torque and power all meet the requirements of the China VI heavy duty vehicle standard. For this engine, NOx, PM and THC pollutants under CHSC are 134.5%, 29.6% and 94.4% higher than those under WHSC, respectively. PN emissions of CHSC is 65.6% lower than that of WHSC. NOx, PM and PN pollutants under CHTC are 62.9%, 96.4% and 64.3% higher than those under WHTC, respectively. The exhaust temperature of the first 350 seconds at CHTC is lower, which poses a greater challenge to the conversion efficiency of the after-treatment system at low speed and low load.

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Energy Efficient Thermoelectric Generator-Powered Localized Air-Conditioning System Applied in a Heavy-Duty Vehicle

Journal of Energy Resources Technology ◽

10.1115/1.4039607 ◽

2018 ◽

Vol 140 (7) ◽

Cited By ~ 4

Author(s):

Yuan Ran ◽

Yadong Deng ◽

Tao Hu ◽

Chuqi Su ◽

Xun Liu

Keyword(s):

Fuel Economy ◽

Energy Efficient ◽

Air Conditioning ◽

Thermoelectric Generator ◽

High Efficiency ◽

Simulation Analysis ◽

Heavy Duty ◽

Efficient Technology ◽

Air Conditioning System ◽

Heavy Duty Vehicle

Thermoelectric technology applied in vehicle has become significantly essential due to the global energy crisis and the environmental protection issues. A novelty energy efficient technology called localized air-conditioning (LAC) powered by thermoelectric generator (TEG), i.e., TEG-powered LAC, is proposed in order to better utilize the generated power of TEG, only then will the fuel economy improvement be achieved. This system which has little impact on the original automotive electrical system is basically comprised of LAC, TEG, converter, and battery. The TEG can directly convert thermal energy to electrical energy to power the novelty energy-efficient air-conditioning system called LAC. The submodels of LAC and TEG are built and integrated into a heavy-duty vehicle to quantitatively assess its performance by simulation analysis. The results indicate that the novelty TEG-powered LAC system can work normally with high efficiency and improve the fuel economy by 3.7%. Therefore, this system resolves the problem of proper use of the TEG's power and provides a fully new perspective to substitute the mechanical loads to engine with electrical loads powered by TEG to improve the fuel economy with much more practicality and rationality.

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