Research and Analysis of the CDV Internal-Combustion Engine Gas Distribution Phase in the Low Temperature Start Process

2014 ◽  
Vol 889-890 ◽  
pp. 474-478
Author(s):  
Lei Ming Shi ◽  
Li Ge Mei ◽  
Zhi Hong Wang ◽  
Yi Ming Shao
Keyword(s):  
Low Temperature ◽  
Internal Combustion Engine ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Exhaust Emission ◽  
Intake Valve ◽  
Gas Distribution ◽  
Angle Change ◽  
Distribution Phase ◽  
Start Process

With the help of CDV internal-combustion engine start process test in the low temperature, it was investigated and analysed for the effects of the intake advance angle of gas distribution phase in the low temperature start and its exhaust-emission performance of internal-combustion engine. In the process of test ,the intake-advance angle change was from 1 °- 11 °and the valve overlap angle change was from 38 ° - 48 °. The internal-combustion engine was started according to the test number of the requirements. It was observed and calculated for starting conditions and exhaust emission with PC. The results show that the appropriate delay of intake valve open timing, and hence the change of valve timing overlap of the intake valve and exhaust valve, and the proper decrease of in-cylinder fresh intake gas, not only significantly improve the performance of internal combustion engine low temperature start combustion work, shortening start duration, but also help to reduce the quantities of HC and CO emissions during the low temperature start process.

scholarly journals GAS DISTRIBUTION PHASES HYDRAULIC CONTROLLED INTERNAL COMBUSTION ENGINE VALVES

2022 ◽  
Vol 16 (4) ◽  
pp. 47-52
Author(s):  
Nail Adigamov ◽  
Andrey Negovora ◽  
Larisa Zimina ◽  
Alexey Maximov
Keyword(s):  
Internal Combustion Engine ◽  
High Speed ◽  
Combustion Engine ◽  
Hydraulic Drive ◽  
Internal Combustion ◽  
Valve Timing ◽  
Gas Distribution ◽  
Time Section ◽  
Engine Valves ◽  
Opening And Closing

The efficiency of an agricultural car or tractor depends on the characteristics of the engine determined by the gas distribution mechanism (GRM). Traditional timing with fixed valve timing does not provide high-quality gas exchange at all engine operating modes. The aim of the work is to improve the characteristics of the engine by using the hydraulic drive of the timing valves. The drive allows you to turn off individual valves, set the moments of their opening and closing in an arbitrary way, provide several triggering of the internal combustion engine valves during the operating cycle. The drive is controlled by an electronic control unit (ECU). The advantage of the drive is its ease of integration into the internal combustion engine. The hydraulic drive ensures that the timing valves are lifted to a height of about 14 mm. The law of displacement of the valve, revealed experimentally, is close to trapezoidal. The use of a hydraulic valve drive has a positive effect on the "time-section" factor in the area of low and medium crankshaft rotational speeds. The increment of the factor "time-section" is due to the significant speeds of opening and closing the valves. Due to the peculiarities of the kinematic characteristics of the movement of the valves when using a hydraulic drive for their movement, the use of serial phases of gas distribution of the engine is impractical. Numerical modeling of the operation of the internal combustion engine determined the regularity of the change in valve timing from the high-speed operating mode of the engine. Optimization criterion is the achievement of maximum engine power. When choosing the valve timing, the possibility of meeting the intake and exhaust valves with the engine piston was excluded. The use of optimal phases leads to an increase in power up to 4.5% at a low crankshaft speed. With an increase in the speed mode, the increase in power decreases, and with a high frequency of rotation of the crankshaft, its slight decrease (1.4%) is observed. An increase in torque, up to a power utilization factor of 0.9, and its subsequent decrease, allow stabilizing the vehicle speed on a road with variable resistance. An increase in the working pressure in the hydraulic drive of the valves makes it possible to intensify gas exchange even at a high speed of rotation of the crankshaft

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