ANALYSIS OF THE BRAKING PROPERTIES OF THE MAN CLA 16.220 FOR SEVERE OPERATING CONDITIONS

Аннотация

The braking feature is provided by the operation of the brakes. According to current state standards, cars are equipped with three mandatory braking systems (working, stopping and spare). Vehicles weighing more than 12 tons or intended for use in mountainous areas must also be equipped with an auxiliary brake system. KEYWORDS: Car, braking, slope, mountain roads. “ANALYSIS OF THE BRAKING PROPERTIES OF THE MAN CLA 16.220 FOR SEVERE OPERATING CONDITIONS” P age 52 | 8 INTRODUCTION passengers and pedestrians, are calculated on the example of the car "MAN CLA 16.220" [1- The rapid development of the country's 7]. economy, along with the creation of great opportunities for the transport of goods and METHODS passengers by road, complicates the flow of The forces acting on the vehicle during traffic on the roads of the country, resulting braking are shown in Figure 1. The in an increase in the number of road deceleration forces between the wheel and accidents. The braking properties of the car, the road are and . They will be in the which play an important role in ensuring the opposite direction to the traffic [8-17]. safety of road accidents and drivers, Figure 1. Forces acting on the vehicle during braking The sum of the forces projected on a plane P and P - Brake force on the front and T1 T2 parallel to the base plane is equal to the rear wheels, N inertial force: P R ; i i  M  j  P P P P P P ; T a c T1 T2 f1 f2 i w P and P - wheel resistance of the front f1 f2 (1) and rear wheels, N Where: M - vehicle mass, kg a P  f R ; fi i j - deceleration of the car, m/s2 c P - resistance to climbing, N i  - coefficient of account of rotating masses T P  M gi; during braking ( =1,03…1,05) i a “ANALYSIS OF THE BRAKING PROPERTIES OF THE MAN CLA 16.220 FOR SEVERE OPERATING CONDITIONS” P age 53 | 8 P - air resistance, N  - Coefficient taking into account the w H issues of rotation when the car is moving in P  K F V2; w a I cash:  1 k g 1 ; H G r2 2 We make the following definitions: a P P P ; P  P  P ; in which case: T1 T2 T f1 f2 f If the vehicle is braked together with the brake system and the engine [24-31], the  M  j  P P P P ; T a c T f i w deceleration is determined as follows: (2) P P P P P P When constructing j  f  v  a given vehicle, j  TD T f i w xx g, m/s2; c a c TD G  a bp two different braking modes are considered, here: P - total friction of the engine (applied namely, the deceleration of the vehicle when TD M и the vehicle is braked only by the brake system to the drive wheel), P  TD TP ; TD r TP and when the vehicle is braked together with the brake system and the engine [18-23]. M - total friction torque of the engine, TD H м If the vehicle is braked using only the brake system, the deceleration is determined as M V a п b g; TD л 1 ei 1 follows: a =0,0008, b =0,15 - for gasoline engines 1 1 P P P P P j  T f i w xx g,m/s2; a =0,001, b =0,2 - for diesel engines c T G  1 1 a H (3) V – – engine capacity, l л Where: P - the force expended to overcome xx п – number of revolutions of the engine e the resistance in the transmission when the shaft, rpm/min car is moving in cash; (brought to the front  – coefficient of account of rotational wheels), N вр masses when braking together with the P   20,025V  M g103; xx a a I и2  I engine; 1  TP k g вp G r2 G - car weight; N a a 1(и2 ); 1 КП 2 G  M g a a “ANALYSIS OF THE BRAKING PROPERTIES OF THE MAN CLA 16.220 FOR SEVERE OPERATING CONDITIONS” P age 54 | 8 The braking distance is the distance travelled I и2 I   M гл g 0,04…0,06;   k g  during braking. It is defined as follows: 1 G r2 2 G r2 a a V2 V2 k 0,03…0,05; S  a  a э , m; T 26 j 26g c It is advisable to brake the car together with There are two different braking modes for the brake system and the engine only if the constructing the  dependence of t and S j > j condition is met. The higher the a T T c c TD T for a given vehicle: braking speed of the car, the higher the value of P , so j > j . However, since  is 1) when the wheels are braked before locking TD c c вр TD T (pH = 0.7); always greater than  , j > j will occur H c c TD T when the vehicle's braking speed is low [32- 2) when braking with locked wheels (phb = 40]. The projection of the point of 0.8 ph). intersection of the two curves on the abscissa Draw a graph of the dependence of t and S T T axis shows the minimum speed at which the on  : a vehicle brakes together with the brake The braking characteristics of the MAN CLA system and the engine. 16.220 were calculated accordingly: When