Truck design

2.1 Solution 1 based on dynamic objective function
2.1.1 Constraints
1) The maximum climbing grade of the car is greater than or equal to 35%;
2) 1.7 ≥i1≥i2≥i3≥i3/i4≥ ≥ i8≥ i9≥ 1.3
3) The maximum speed of the car is greater than 90km/h;
4) The car starts on the spot and continuously shifts gears (0~80km/h) with an acceleration time of no more than 76 seconds;
5) The fuel consumption per 100 kilometers at a constant speed of 40km/h is less than 27L;
6) The car's fuel consumption per 100 kilometers under multiple working conditions is no more than 37L.
2.1.2 Vehicle performance simulation calculation results
The power performance is obtained through GT-DRIVE simulation calculation of the power transmission system of this optimized plan. The power performance of the vehicle is mainly evaluated from the climbing performance, maximum speed and acceleration performance. As the speed ratio of each gear increases, the maximum gradeability of the car increases accordingly. Although the main reduction ratio is increased, due to the overspeed gear, the car's speed increases from 96.5km/h to 98.2km/h. After optimization, the car's acceleration ability has been significantly improved, including continuous shifting when starting in place ( The acceleration time for overtaking in direct gear (3080km/h) was reduced by 2.46s, or 3.2%; the overtaking acceleration time in direct gear (3080km/h) was reduced by 9.19s, or 13.7%. Therefore, it can be seen from the above simulation calculation that the power of the car has been greatly improved.
2.1.3 Analysis and evaluation
By comparing the economic calculation results of the car before and after optimization, it is found that due to the main focus on power matching, after optimization, the main reduction ratio increases, so that the fuel consumption per 100 kilometers at constant speed in each gear increases, but the change rate is not large, and neither More than 5%; the car's multi-working mode fuel consumption is 36.66L/100km, an increase of 5.25% compared with before optimization. When optimizing with power as the main focus, it does not mean that optimization only considers the power of the car, but should be carried out on the basis of ensuring that the fuel economy of the car does not deteriorate. This solution enhances the power as much as possible while ensuring a certain fuel economy of the original vehicle. The simulation results show that the optimization effect is obvious.