Longitudinal Vehicle Dynamics Part 1 Flashcards
72) 4 gears, instead of 5 influence leading to:
a) Lower consumption;
b) High performance;
c) Depends on the gear ratio.
c) Depends on the gear ratio.
73) At fixed delivered power:
a) It is more convenient to use the engine at low chocking (close to the curve of maximum power); b) It is more convenient to use the engine at high chocking (close to the curve of maximum power);
c) The chocking doesn’t interfere with the assessment of convenience.
a) It is more convenient to use the engine at low chocking (close to the curve of maximum power);
74) At equal delivered power, for the consumption, it’s more convenient:
a) Low chocking (the kilometric consumption, instead, usually improves at long gears, with a lot of (low) chocking);
b) High chocking;
c) The chocking doesn’t interfere with the assessment of convenience.
a) Low chocking (the kilometric consumption, instead, usually improves at long gears, with a lot of (low) chocking);
75) To adopt 5 gear ratios instead of 4:
a) Improves the acceleration characteristics of the vehicle;
b) Can improve the acceleration characteristics of the vehicle;
c) Improves the acceleration a characteristic of the vehicle, but it’s necessary to consider the gear shifting time.
c) Improves the acceleration a characteristic of the vehicle, but it’s necessary to consider the gear shifting time.
76) The hourly consumption is measured in:
a)
g
CVh ;
b)
dm3
kWh ;
c)
dm3
s
.
b)
dm3
kWh ;
77) The consumption by travelled distance unit is obtained by multiplying the hourly consumption by: a) The inverse of the travelling speed;
b) The travelling speed;
c) The travelling speed and the fuel’s specific heat capacity.
a) The inverse of the travelling speed;
78) The consumption Q(V ) by distance unit:
a) Increases with the speed;
b) Decreases with the speed;
c) Has a minimum at increasing the speed.
c) Has a minimum at increasing the speed.
80) The greatest contribution, beyond that of the mass, for the calculation of the translating apparent mass is due to:
a) The engine inertia;
b) The wheels inertia;
c) The transmission inertia.
a) The engine inertia;
81) The main factor that influences the transmissible power:
a) Weight;
b) Slippery road;
c) Torque at the driving axle.
b) Slippery road;
82) The clutch’s maximum torque:
a) Is approximately equal to the one of the engine;
b) Is greater than the one of the engine;
c) Is smaller than the one of the engine.
b) Is greater than the one of the engine;
83) The efficiency of the clutch is the ratio between:
a) The dissipated energy at the clutch and the energy provided by the engine;
b) The energy provided to the vehicle and the energy dissipated at the clutch;
c) The energy provided to the vehicle and the energy provided by the engine.
c) The energy provided to the vehicle and the energy provided by the engine.
84) The efficiency of the clutch is important to:
a) Overheating (only after repeated starts);
b) Mechanical resistance;
c) Friction components consumption.
c) Friction components consumption.
85) The efficiency of the clutch:
a) Is close to 0.5;
b) Is approximately equal to 1;
c) Is lower than 0.5.
c) Is lower than 0.5.
86) The value of the acceleration in first gear increases by decreasing the transmission ratio: a) Always;
b) Only up to a certain value;
c) Never.
b) Only up to a certain value;
87) The acceleration of the vehicle increases the maximum transmissible power for adherence reasons if: a) The vehicle is FWD;
b) The vehicle is RWD with hg null;
c) The vehicle is RWD with hg different from 0.
c) The vehicle is RWD with hg different from 0.
88) The influence of the acceleration over the transmissible power for reasons of adherence is as greater as:
a) The greater is the ground slope;
b) The greater is the center of gravity height;
c) The highest is the longitudinal grip coefficient.
b) The greater is the center of gravity height;
89) The translating apparent mass is:
a) Variable with the speed;
b) Constant;
c) Constant, if the gear ratio is fixed.
c) Constant, if the gear ratio is fixed.
90) The maximum transmissible power at high speed is greater for:
a) FWD;
b) RWD;
c) 4WD.
c) 4WD.
91) The practice of tracing only two curves X f and X rrelative to the minimum and maximum
loads is more realistic in the case of a passenger vehicle (normal or sportive) or in the case of an industrial vehicle?
a) Industrial vehicle.
a) Industrial vehicle.
92) The maximum speed for adherence reasons is obtained intersecting:
a) The available power at the wheels with the power needed for motion;
b) The available power at the wheels with the transmissible power at the wheels; c) The power needed for motion with the transmissible power at the wheels.
c) The power needed for motion with the transmissible power at the wheels.
93) The curves Q (V ) present a minimum at rather low speed, and that last is found in a zone at which
the engine works:
a) Very chocked with low efficiencies;
b) With high chocking;
c) With low chocking.
a) Very chocked with low efficiencies;
94) At the alternating engine with controlled ignition, the efficiency decreases:
a) With increasing the delivered power at low regime;
b) With decreasing the delivered power at high regime;
c) With decreasing the delivered power.
c) With decreasing the delivered power.
95) At the A linear term of the formula of the power needed for motion is inserted: a) The ground slope contribution;
b) The (static) rolling resistance contribution;
c) Both.
c) Both.
96) At the B linear term at the velocity of the formula relative to the power needed for motion, is present: a) The ground slope contribution;
b) The quadratic term of the rolling resistance (dynamic);
c) Both.
b) The quadratic term of the rolling resistance (dynamic);
97) With respect to the graph
PMAX
mg V MAX
are more economical the isolated vehicles or those with trailer?
a) Those with trailer.
98) If the power and velocity are fixed, it is convenient to choke (for the specific consumption): a) Little;
b) A lot;
c) Doesn’t matter.
a) Little;
