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ME 50400 and ECE 59500

AUTOMOTIVE CONTROL Sample Final Examination

Note: You may make any reasonable assumption in case of missing parameter(s).

1. Circle the most appropriate answer for the following statements:

(a) An Exhaust Gas Recirculation (EGR) system reduces NOx emissions by: i) A ii) B iii) C iv) D

(b) A turbocharger in a Diesel engine causes exhaust gas to pump more fresh air into the combustion chamber which helps:

i) A ii) B iii) C iv) D (c) An traction control system for an automobile on a low friction coefficient surface helps: i) A ii) B iii) C iv) D

(d) For a yaw stability control system, which of the following actuation systems is more likely to generate the commanded yaw torque effectively? Explain.

i) A ii) B

(e) The malfunction indicator light (MIL) of On-Board Diagnostics (OBD II) turns on when emission level exceeds the federally mandated limits by: i) A

ii) B iii) C

iv) D

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2. Consider designing an air-fuel ratio (lambda) controller for a four cylinder SI engine with

manifold fuel injection. Assume that you can model the engine with a second order transfer function with a zero on the right half s-plane. The transfer function has the following form.

)1)((

)()(

)(

)(

dssc

bsasG

sU

s

where (s) is the air-fuel ratio and U(s) is the control variable (e.g. fuel injection time). Design a PID (proportional plus derivative) controller to obtain the following response characteristics: Settling time (2%) = Ts sec; Max overshoot < OS %. To ensure stability you must have all the closed loop poles on the left half s-plane.

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3. Consider the transmission torque control of an automobile driveline. Assume that the driveline torque model for the transmission torque control problem can be represented by the state space model in equation (7.175) of your textbook. It is desired to design a proportional controller with only output feedback, i.e.

TorqueonTransmissiz

Torqueferencer

zrKu

_

_Re

)(*

321

3

2

1

;

333231

232221

131211

,

mmmM

dD

where

DuxMz

b

b

b

B

aaa

aaa

aaa

Awhere

uBxAx

The transfer function is between z and u is approximately given by:

1 2 31 2 3

The design requirements are: n = wn rad/sec and = dr. You may need to assume additional non-dominant desired pole locations. Design the controller based on this specification and state if the designed proportional gain, K is implementable.

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4. Consider the linearized vehicle model with state variables as vehicle body side slip angle

and vehicle yaw rate. This model captures the vehicle dynamics in X-Y and directions. The vehicle parameters are as follows: mCoG = A kg; vCoG = B m/s; lF = c m; lR = d m; JZ = F kg-m2; cF = G N/rad; cR = K N/rad; Iwi = L kg-m2; reff = M m;

Design a yaw stability control system with only proportional and integral (PID) feedback to obtain a desired natural frequency of wn Hz and damping ratio of dr. Assume that the control yaw moment is generated by the steering (use w as control input). Assume that the vehicle is bb m wide and center of gravity is located at the center. Also assume that the nominal vehicle velocity is V m/s. What are your PID gain values? Note your observations on the stability of the closed loop system.

10

.

.

1..

22

2

y

J

lcvm

c

vJ

lclc

J

lclcvm

lclc

vm

cc

W

Z

FF

CoGCoG

F

CoGZ

FFRR

Z

FFRR

CoGCoG

FFRR

CoGCoG

RF

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5. Design a brake-based traction control system to maintain wheel acceleration slip at sr.

Assume no engine intervention. Given the vehicle parameters in problem 3, design a PD controller for the vehicle traction control system. Assume that the road surface is covered with packed snow with a peak friction coefficient of mu_max at a slip ratio of sr. Also, assume that the static weight distribution of the vehicle weight is Wf % front axle and Wr % rear axle. You may neglect the dynamic weight transfer due to acceleration / deceleration and steering.

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6. (a) Explain how a hybrid-electric vehicle (HEV) is able to provide significant improvement

in fuel economy over conventional IC engine based vehicles. (b) The friction characteristics at the road-tire interface is very important for a vehicle dynamics control system. Describe how you would estimate the friction coefficient of this interface in real time in a vehicle dynamics control algorithm. (c) Describe at least five benefits of a throttle-by-wire (TBW) system. (d) Describe how a Plug-in Hybrid Electric Vehicle (PHEV) is able to provide better fuel economy over Hybrid Electric Vehicle (HEV) within a driving range.

(e) Describe your vision of a future automobile with at least three advanced features / functions that are not offered on any currently available vehicles.

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7. Circle the most appropriate answer for the following statements:

(a) Parallel hybrid configuration had advantages over series hybrid in: i) A ii) B iii) C iv) D

(b) Wheel slip in the definition of Burckhardt requires: i) A ii) B iii) C iv) D (c) An ABS control system for an automobile on a low friction coefficient surface helps: i) A ii) B iii) C iv) D

(d) The first action needed for a traction control event is: i) A ii) B iii) C iv) D

(e) In driveline control, which of the following statement is most accurate: i) A

ii) B iii) C

iv) D

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8. Circle the most appropriate answer for the following statements:

(a) State of Charge (SoC) in a NiMH battery in a Hybrid Electric Vehicle is maintained in the following range:

i) A ii) B iii) C iv) D

(b) Road friction coefficient generally reaches its peak at a wheel slip ratio of: i) A ii) B iii) C iv) D (c) For an internal combustion engine, the most desirable air-fuel ratio is: i) A ii) B iii) C iv) D

(d) For a vehicle weighing 2000 kg on a 0.3 peak friction coefficient surface, the maximum achievable acceleration / deceleration is approximately:

i) A ii) B iii) C iv) D

(e) The maximum allowable filtered jerk level in a driveline is approximately: i) A

ii) B iii) C

iv) D