engine systems - eth z · engine systems 31.10.2016 eth ... identification measurement data sets...
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Engine Systems
31.10.2016 1ETH Zurich - DMAVT - IDSC www.idsc.ethz.ch
Idle Speed Control System
Idle Speed Control System
Hints:
Do not introduce more than two delays in your engine model
Read the instruction carefully
A modular identification process requires several different models
Save a copy of your current model and adapt it as required (you will have
to delete certain blocks)
Milestones
Milestone 1 Working Simulink Model
Complete: Friday, 04.11.2016
To pass milestone 1, each group has to create a simplified mathematical model of an engine. It has to be built in Simulink and reasonable values for the model parameters have to be estimated.
Outlook
Milestone 2 Validated Model
Complete: Friday, 18.11.2016
Identification measurement data sets are online as of today
Theory Exercises
Exercise #4 is online – complete within two weeks
Theory: Willans Approximation
General model for the conversion and distribution of energy
in an internal combustion engine
1. Chemical energy in the fuel is converted into mechanical work in the
form of pressure acting on the piston (mechanical work: ∫ 𝑝 ⋅ 𝑑𝑣)
2. A part of that work is lost due to friction and pumping losses
3. The rest of the work can be measured as torque generated by the
engine
4. 𝑤𝑜𝑟𝑘𝑡𝑜𝑟𝑞𝑢𝑒 = 𝑒𝑛𝑒𝑟𝑔𝑦𝑓𝑢𝑒𝑙 ⋅ 𝜂𝑡ℎ𝑒𝑟𝑚𝑜𝑑𝑦𝑛𝑎𝑚𝑖𝑐 − 𝑤𝑜𝑟𝑘𝑙𝑜𝑠𝑠𝑒𝑠
5. 𝑝𝑚𝑒 = 𝑝𝑚𝜑 ⋅ 𝑒 − 𝑝𝑚𝑒0𝑓 − 𝑝𝑚𝑒0𝑔
0.14
0.18
0.18
0.22
0.22
0.22
0.26
0.26
0.26
0.3
0.3
4000 5000 6000 7000 8000 90001
2
3
4
5
6
7
8
9
10
Willans-Approximation - applied on a real engine
Source: «Modeling and Control of the Formula Hybrid Powertrain», Bachelor Thesis Schär/Hedinger
Engine: 250 ccm, Naturally aspirated SI Gasoline engine, 1 Cylinder, 4 Stroke
Theory Exercise #3 – Exercise 4
Willans-Approximation - applied on a real engine
Theory Exercise #3 – Exercise 4
1. «Measure» the Willans lines at different engine speeds
Theory Exercise #3 – Exercise 4
1. «Measure» the Willans lines at different engine speeds
Theory Exercise #3 – Exercise 4
1. «Measure» the Willans lines at different engine speeds
Theory Exercise #3 – Exercise 4
1. «Measure» the Willans lines at different engine speeds
Theory Exercise #3 – Exercise 4
1. «Measure» the Willans lines at different engine speeds
Theory Exercise #3 – Exercise 4
3000 4000 5000 6000 7000 8000 9000-3.5
-3
-2.5
-2
-1.5
-1
3000 4000 5000 6000 7000 8000 9000
0.35
0.4
0.45
2. Estimate the Willans parameters
Theory Exercise #3 – Exercise 4
3000 4000 5000 6000 7000 8000 9000-3.5
-3
-2.5
-2
-1.5
-1
measured values
fit
3000 4000 5000 6000 7000 8000 9000
0.35
0.4
0.45
measured values
fit
2. Estimate the Willans parameters
Theory Exercise #3 – Exercise 4
3000 4000 5000 6000 7000 8000 9000-3.5
-3
-2.5
-2
-1.5
3000 4000 5000 6000 7000 8000 9000
0.35
0.4
0.45
2. Estimate the Willans parameters
Theory Exercise #3 – Exercise 4
3. Use lines to model then efficiency map of the engine
Theory Exercise #3 – Exercise 4
0.10.1
0.1 0.110.11
0.110.12
0.12
0.120.13
0.13
0.13 0.14
0.14
0.14 0.15
0.15
0.150.16
0.16
0.16
0.170.17
0.17
0.180.18
0.18
0.190.19
0.19
0.20.2
0.2
0.21 0.21
0.21
0.22 0.22
0.22
0.23 0.23
0.23
0.24
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0.25
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0.26
0.26
0.2
7
0.27
0.2
7
0.28
0.28
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0.29
0.3
0.3
0.31
0.310.32
0.33
2000 4000 6000 8000 10000 12000
0
2
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10
Validation of the efficiency map
Theory Exercise #3 – Exercise 4
The End