车辆工程试题（Vehicle engineering test）2002 wuhan university of technology automobile theory examinationNoun interpretation (3 * 3)The minimum transmission ratio of the transmission line: the ratio of the transmission to the transmission ratio of the gearbox is the product of the transmission ratio of the main reducer.Car braking efficiency: the wheel does not lock the maximum braking deceleration and the ratio of adhesion coefficient between wheel and ground, namely when the wheel will lock braking intensity and by using the ratio of the adhesion coefficient.The static reserve coefficient of the car: the ratio of the difference between the neutral to as and the cars center of mass to the front axle and the wheelbase L.Fill in the blanks (2 * 5)When the car is moving, there are always rolling resistance and air resistance.The failure of the top of the car is related to the longitudinal passing of Angle beta through the minimum clearance of the geometrical parameters.The automobile power factor is the difference between the driving force Ft and air resistance Fw and the ratio of automobile gravity.The action time of the automobile brake is the sum of time t2 needed to eliminate the time t1 and brake growth of the shoe and brake drum.For vertical vibration, the frequency range of human sensitivity is 4-12.5 Hz. For horizontal vibration, the frequency range of human sensitivity is 0.5-2Hz.Choice question (2 * 5)The air drag coefficient of a car is (B)A0.1 B0.3 C0.6 D0.82. The furrow capacity of dongfeng EQ1092 mainly depends on (A)A rear wheel C rear wheel or front wheel D rear wheel and front wheel3. The power of a car depends mainly on (B)A acceleration capacity B maximum speed C vehicle quality D maximum climbing abilityThe power factor (A) that the car can generate when the car is replaced by the arrival gear.A reduces B increases C does not change D decreases or increasesWhen the car body vibrates, if the natural frequency of the body increases, then (A)A body vibration acceleration increases B body vibration accelerationThe dynamic deflection of C suspension increases the deflection of D suspensionJudgment (2 * 5)Automobile brake power is always equal to ground power (x).When the car is moving, the engines power is always equal to rolling resistance, ramp resistance, acceleration resistance, air resistance of four resistance combined (x).Sliding adhesion coefficient occurs at a slip rate of 15% to 20% (x).For single cross arm independent suspension: when the small lateral acceleration, such as the right turn of the car, the wheel is tilted to the right (square root).For the body, the wheel vibration system, the natural frequency of the body is less than the main frequency (x).Please describe the method to determine the transmission ratio of transmission head. (6)Analysis: to determine the maximum transmission ratio, consider three problems with maximum creep, adhesion rate and minimum speed.The maximum transmission ratio of the ordinary car Ftmax = Ff + Fimax shall calculate the attachment rate of the driving wheel and check whether the attachment condition meets the slope or acceleration requirements.Please use the schematic diagram and describe the driving force and the driving resistance balance to analyze the dynamic performance of a four gearbox. (8)Please use the engine load characteristic diagram and the automobile power balance diagram to analyze the influence of the use factors on the fuel economy of the car. (10)The axial load of the front axle of a car is 46 percent of the total mass, the wheelbase is 2.6 m, the center of mass is 0.9 m, and the dynamic distribution coefficient of the vehicle is 0.6. What is the synchronous attachment coefficient of the car? 2) what happens when the car is traveling at a high speed on a road with a adhesion factor of 0.8, such as emergency braking? Can you explain the reason of this phenomenon from force analysis? (12 points)On the analysis of vehicle vibration, such as simplifying the body to the quality system model, the body quality of m, the spring stiffness for k, the damping coefficient of the vibrator for c, vertical displacement of the car body for z, input of road roughness function is q, the road space frequency for n, pavement spatial frequency power spectral density of Gg (n). Auto speed of 72 km/h., could you tell me the body vertical vibration acceleration power spectrum density of? (10)Reference:The total mass of a car is 1820kg. The vehicle front axle load is 53% of the total mass, and the wheelbase is 3.10 m.The lateral stiffness of a front wheel is 31310N/rad, and the lateral stiffness of a rear wheel is 55095N/rad. When the vehicle is traveling at a steady speed of 36km/h, its steering radius is 20m. What is the difference between the front side Angle (absolute value) and the rear side Angle (ab