The new MC construction hoists , model SC200/200, are more professional used for a long time in building, general engineering, warehouse, wharf, port, dock, wells bridge, power plant, or chemical industry,etc.
Product structure is made of modular, humanized design and leading manufacturing process, improves the applicability , reliability and comfort. The maximum lifting height can up to 300 meters.
the Passenger Hoist main characteristics
* The cage top setting of the driving mechanism with the buffer device, running more stable.
* Humanized cage design to increase the comfort of personnel;
* Unique structure detail design
* Leading production processes makes precision assembly, accurate and smooth transmission
* The best kit for the industry is reliable in quality
* Provide professional projects to solve special projects.
* The completely safety devices and the reliable control system
Passenger Hoist Passenger Hoist,Self Climbing Crane,Passenger Lift,Construction Passenger Hoist Miliscorp Industry Ltd , https://www.mctowercrane.com
Research on shifting strategy of automatic transmission for vehicle and power technology semi-trailer tractors Zhang Yang, Xi Junqiang, Chen Huiyan (School of Mechanical and Vehicle Engineering, Beijing Institute of Technology, Beijing 100081, China), improving the comprehensive performance of vehicles, using theoretical analysis and real vehicle test According to the characteristics of the vehicle powertrain itself, a comprehensive shift control strategy for the multi-speed transmission of the tractor is proposed. The test results show that the shift control method and shifting schedule designed for the multi-speed transmission can meet the requirements of the vehicle under different working conditions and achieve the expected goal.
+.3: A traction truck has high loading quality and complicated working conditions. In order to ensure good driving performance, the number of gears equipped with transmissions in heavy-duty trucks in the international market has increased in recent years. The use of multi-speed transmissions for heavy-duty trucks can increase the average speed of the vehicle, the power utilization of the engine and the fuel economy of the vehicle. However, due to the increase in the number of gears, the complexity of shifting is bound to increase, the shifting operation is more frequent, and the driver's driving proficiency is different, and the best performance of the vehicle cannot be exerted. In view of the fact that the automatic transmission has many features such as eliminating driver shifting technology differences, reducing driver fatigue, facilitating shifting operation, driving safety, etc., developing automatic shifting technology on a truck equipped with a multi-speed transmission has become a solution to this problem. Effective means.
Due to the current domestic development of heavy-duty trucks in the field of heavy-duty trucks, there is no mature experience in the development of automatic shifting control technology for multi-speed transmissions. Therefore, on the one hand, in order to meet the design requirements of automatic shifting vehicles for power and fuel economy, On the one hand, it can also provide data comparison for the test of the performance and handling characteristics of the vehicle after the automatic shift control system is installed. The author uses the combination of real road test and theoretical analysis to design a comprehensive shift control method for the multi-speed transmission of the tractor. Shifting rules.
The composition and structural principle of the multi-speed transmission is to achieve as many gear positions as possible while the transmission volume is not excessively increased, and also to avoid the structure of the transmission being too complicated, the multi-speed transmission generally adopts a segmented structure, that is, With a 4~6-speed transmission as the main body, the double-speed combined or half-speed insert multi-speed transmission is realized by adding auxiliary transmissions of different gear ratios in front of and behind the main transmission. The Datong DC12J150T multi-speed transmission equipped with the test vehicle EQ4195 is a 3-stage structure consisting of a main transmission and front and rear auxiliary transmissions. The transmission has 12 forward gear positions and two reverse gear positions. The cooperation between the main box and the two sub-boxes is completed. According to the difference between the high and low gears of the front sub-tank, 12 forward gear positions are defined as 1L, 1H (corresponding to the actual 1st and 2nd gear respectively) until 6H (corresponding to 12 gears) ), its transmission diagram is as shown.
The start-up test of the No. 3 no-load 2H忾 shows that both the 1H and 2H gears can achieve a smooth start of the no-load vehicle, and there is no significant difference in the slip time of the clutch during the start-up process, but the vehicle acceleration is improved and the number of shifts is reduced. From the point of view, it is decided to start the 2H file with no load.
It is the comparison of the starting process of the 1H and 2H gears when the vehicle is fully loaded.
(b) 2H starting point 2 road test result analysis All road tests are carried out on a manual EQ4195 sample vehicle. The road test is different for the vehicle under different load conditions, namely no load (7 400kg), full load (44000kg), different Drivers of driving conditions (urban roads, mountains, high speeds) and different driving styles were tested. The test collected a total of 15 signals, including engine speed, throttle opening, transmission input shaft speed, transmission output shaft speed, neutral signal, reverse signal, front sub-box high and low signal, rear sub-box low signal , shift stroke, position selection stroke, clutch displacement, brake pedal stroke, hand brake switch, shifting force, steering angle signal.
2.1 Starting gear selection test Because the quality of the whole vehicle is nearly 6 times different under the condition of no-load and full load, and the actual driving of the vehicle is mainly concentrated in these two conditions, the vehicle is started under different loads. test. And MAS.AcademicJournalElectronicPubli Zhang Yang, etc.: The semi-trailer automatic transmission shift strategy research can be seen from b, the engine speed from the start of 1H/ when starting with 2H gear Min quickly drops to about 320r/min, and the slip time of the clutch exceeds 3 S. Obviously, the start of the 2H gear is unreasonable for the engine and the transmission system. The full load should start with 1H.
2.2 Gear utilization test In order to provide the basis for the software design of the gear position use and control method of the vehicle electronically controlled automatic shift control system, and at the same time, the performance of the manual sample car is tested, and the road test is on the plain secondary road and mountain area. First-class highways and expressways have been tested for the utilization rate of gears. The test results are shown in Table 1 of 7K. From the statistical results of gear utilization, it can be seen that since the highway conditions are relatively simple, the utilization of high-end positions should be improved as much as possible. In order to facilitate the better fuel economy of the vehicle, in the plain secondary road, due to the high traffic density of the motor vehicle and pedestrians, the utilization rate of the H gear should be relatively increased under the premise of ensuring the power of the vehicle. A more obvious difference compared with the plain road is that in order to meet the climbing performance of the vehicle, the number of 3L and 4L gears should be increased in the mountainous section. Therefore, different changes should be applied to the plain and mountain areas in the automatic shifting control system. File control method.
Table 1 Statistical results of gear utilization rate of each working condition% Test road condition Plain secondary road mountain area first-class highway expressway 3 comprehensive shifting law design EQ4195 type semi-trailed traction truck adopts Cummins ISCe300 30 engine, 12-speed transmission, The gear ratios of each gear are 10.44, 8.65, 6.363, 5. The regular design method is as follows.
3.1 Two-parameter economic shifting rule under medium and small throttle opening The economical shifting law is determined by the throttle method.
The idea is: first determine the high-grade +1) acceleration curve % +1 under a throttle opening i, and find the intersection of it and the low-level throttle opening curve on the acceleration map, and find the corresponding high-end and The lower limit of the fuel consumption curve at the corresponding throttle opening, BP can determine the shift point under this throttle opening, as shown.
Given the road resistance, draw the different throttle acceleration cka and the vehicle speed t in the adjacent gear; a curve takes a certain throttle opening ai (+n), and obtains the intersection with the throttle opening curve of the low gear, from the dynamic fuel consumption In the figure, find the dynamic fuel consumption curve corresponding to the high-end curve A4. Draw the dynamic fuel consumption curve corresponding to each intersection in the low-level corresponding throttle opening SB. The speed corresponding to the intersection of curve A4 is the fuel consumption at that time, when L>hour> +, so \ is the shift point C corresponding to the shift point and returns to the ç‰/d diagram. The corresponding point is C, and the vehicle acceleration cba/dt corresponding to the C' point is the acceleration of the shift point.
By changing the high-speed throttle opening a, (, +u and road resistance in turn, all shift points can be found.
3.2 Two-parameter dynamic shifting under large throttle opening The driver needs to obtain better dynamic performance when the throttle opening is large. The determination of the shifting point is usually based on the traction characteristics of the vehicle. The intersection of the adjacent two-speed traction curves under the accelerator opening is used as the shift point. This power type shifting law can be obtained as long as the torque characteristics of the engine and the transmission ratio of the power train are known. In order to ensure the maximum power of the car, under the large throttle opening, the engine speed corresponding to the shift point obtained by this method may be after the maximum power point speed, but it is considered that the engine speed is too high. The frictional resistance of the engine increases, and the running noise is large. Therefore, if the shift point exceeds the maximum power point, it is generally selected at the corresponding speed of the maximum power.
The traction force of the vehicle can be calculated by the following formula: the relationship between the vehicle speed 〃 and the engine speed is above, the engine torque; ig is the transmission speed ratio; L is the rear axle speed ratio; T7 is the transmission efficiency; r is the wheel radius.
The shifting cycle may occur on the section with large slope, which is the result of the comparison between the flat shifting strategy and the mountain shifting strategy. It can be seen from the curve that the shifting control method of the flat road has obvious shifting cycles in the mountainous area. The mountain shifting strategy effectively solves the problem of shifting cycles.
The design principle of the power-type and fuel-economy shifting rules introduced in the front of the full-sleeve door is based on the design criteria of the dynamic shifting and the large throttle opening T using the dynamic shifting according to the small and medium throttle opening. According to the shift control method determined in the analysis of the original road test results, the comprehensive shifting rules of the Dongfeng EQ4195 mechanical automatic shifting system were formulated. As shown, the solid line represents the upshift curve and the dashed line represents the downshift curve.
4 Experimental study In order to verify the feasibility and effectiveness of the proposed shift control method and shifting rules, the EQ4195AMT prototype mainly carried out the comparative test of the mountain shift control method and the flat shift control method, and the manual gear The fuel economy comparison test of the prototype.
From the theoretical analysis, it can be seen that the influence of the mountain slope on the shifting strategy is mainly reflected in the low-grade area. The comparison between the various grades is relatively large. The same T-state is used to compare the results of the fuel consumption test. It can be seen that the mechanical automatic shifting can be seen. The models are different in driving. The fuel economy is better than the original manual transmission.
Table 3 Fuel economy comparison lyiOOkm model highway mountain road manual model AMT model 5 Conclusion The automatic shift control system can perform shifting operation according to the given shifting strategy and driving conditions, and achieve the expected control effect. The research on the AMT comprehensive shifting strategy of the multi-speed transmission is of great significance to the automation of the shifting operation of the truck.
