SCHOOL OF ENGINEERING
EEET2394 – ELECTRONIC SYSTEMS FOR AUTOMOTIVE APPLICATIONS
TUTORIAL 1
1. Compression Ratio (CR) is an important factor in determine engine efficiency. The higher the
compression ratio, the more efficient the engine. For the engine configuration given in Table 1,
calculate the effective compression ratio (i.e., the volumetric ratio between Bottom Dead Centre
(BDC) and Top Dead Centre (TDC)).
Component
Crankshaft stroke
Piston rod length
Piston wrist pin height
Piston volume
Cylinder bore
Block deck height
Combustion chamber volume
Head gasket bore
Head gasket thickness
Value
3.5
5.956
1.774
5
4.02
9.48
62
4.1
0.041
Units
inches
inches
inches
cc (cubic centimetres)
inches
inches
cc (cubic centimetres)
inches
inches
Table 1. Engine configuration.
Hint: Construct a diagram labelling the important components of the engine which relate to the
overall capacity.
Note: 1 inch = 25.4 mm.
2. Processing of sensor data is critical to the operation of a modern engine. Many circuits within the
Engine Control Unit (ECU) are dedicated to measuring a voltage or current. In most cases the
incoming signal needs to be processed before the microprocessor converts the analogue signal to a
digital equivalent. This can generally be achieved by using operational amplifiers.
a) Non-inverting amplifier
i) For the ideal non-inverting operational amplifier in Figure 1, determine the closed loop gain
(AF).
ii) Assuming that Vs is 200mV, determine the values for RF and R1 such that the output voltage
is 3.4V.
iii) What series of device(s) could be placed at the output of the operational amplifier to limit
the voltage as to not damage the 5V input to the microprocessor?
iv) Confirm your result in a SPICE engine.
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EEET2394
Tutorial 1
Figure 1. Ideal non-inverting operational amplifier.
b) Inverting amplifier
i) For the ideal inverting operational amplifier in Figure 2, determine the closed loop gain (AF).
Figure 2. Ideal inverting operational amplifier.
ii) Assuming that a maximum output required is ±4.7V, determine the values of RF and R1 if the
maximum input voltage is ±13.8V (Let V1 and V2 = 15V).
iii) Confirm your result in a SPICE engine.
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