Next Generation Diesel Engine Control

Detroit Diesel Corporation

M. Allain, C. Savonen, Y. Kalish, H. Zhang

1DaimlerChrysler Truck Group

• Engine Control Requirements

• Inverted Models For Controls

• Results

• Limitations

Outline

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Steady-State ?

Transient Engine Control Makes Advanced Combustion Techniques Possible Over-the-road

Engine Control Requirements

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• Flawless Steady-State Stability • Fast Transient Response • Reduced Emission Variability • Increased Diagnostic Capability • Integration of Additional Control Variables

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Multiplication Of Control Variables

2001 2004 2007 2010 2013+

1 Actuator

• Injector Valve

3 Actuators

• Injector Valve • EGR Valve • VGT

6 Actuators

• 2 Injector Valves • EGR Valve • VGT • Inlet Throttle • HC Doser

7 Actuators

• 2 Injector Valves • EGR Valve • VGT • Inlet Throttle • HC Doser • Urea Doser

10+ Actuators

• 2 Injector Valves • EGR Valve • VGT • Inlet Throttle • HC Doser • Urea Doser • VVT • Charge Cooler Bypass • EGR Cooler Bypass • …

Increasingly Flexible Diesel Engine Systems

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Traditional Engine Control

EGR Valve

Position feedback

PID EGR Flow

+ -

RPM

Load

EGR Setpoint Control Signal

Next Step: Model-Based Engine Control

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Next Step – Inverted Control Model

modelu y model -1

y u

EGRm •

Δ EGR Valve Position

Δ EGR Flow

+ -

EGR setpoint

Measured EGR

RPM Load

Model-Based Control System

model -1

EGRm •

Significant Improvements Obtained in Stability & Response Time

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Can We Take It Further ?

EGR Valve

Position feedback

EGR Flow

+ -

RPM

Load

EGR Setpoint

NOx

RPM

Load

NOx Setpoint

+ -

Can we build a model, which calculates optimum setpoints in real-time ?

Black Box Model

EGR Setpoint

Emissions & Fuel Economy

Targets Injection Timing Setpoint

Injection Pressure Setpoint

Air-fuel Ratio Setpoint

model -1

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Engine-out NOx

HC

CO

BSFC

Calibration Layers

Turbo Int. Throttle EGR Valve

Feedback Control

Setpoints Internal Setpoints Control Logic

Actuators Sensors AFR

EGR %

Injection Timing Injector

Torque

Injection Quantity

Combustion &

Aftertreatment

Engine-out PM

Injection Pressure

HC Dosing Quantity

Urea Dosing Quantity

Feedback Control

Feedback Control

Feedback Control

HC Doser

Urea Doser

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Neural Network Engine Control

• Are Forward Models Accurate ?

• How Accurate Must The Inverted Models Be ?

Black Box Model

EGR Setpoint

Emissions & Fuel Economy

Targets Injection Timing Setpoint

Injection Pressure Setpoint

Air-fuel Ratio Setpoint

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Neural Network Model Evaluation

PM Model Is More Challenging:

� Additional Inputs

� Time History of Inputs

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Neural Networks

y = f (Wp +b)

p y

Weights Biases

• Fixed Pre-defined Structure

• Training With Existing Input-Output Data

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Neural Network Engine Control

Problem: Setpoint vs. Actual !

Black Box Model

EGR Setpoint

Emissions & Fuel Economy

Targets Injection Timing Setpoint

Injection Pressure Setpoint

Air-fuel Ratio Setpoint

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Intermediate Solution - Dynamic Compensation

AFR Setpoint Model

AFR setpoint

Emission & Fuel Economy Targets + -

Actual AFR

ΔAFR x

x ΔEGR

∂ NOx ∂ AFR

∂ NOx ∂ EGR

Operating Conditions Final EGR

setpoint

+

+ EGR Setpoint

Model

Emission & Fuel Economy Targets

Take Advantage of Fast-responding Engine Systems

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Preliminary Controller Evaluation

Steady-state Results

Objective:

� Dial-in the Requested NOx Level

� Have the Controller Adjust the Engine Setpoints to Meet the Emission Targets

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Preliminary Controller Evaluation

Transient Results

Dynamically Calculating The Optimum Setpoints

Model Inaccuracy Can Be Compensated By Adjusting the Emission Setpoints

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Limitations

• Large Amount Of Transient Data Required

• Over-the-road Application

• Hardware Variability (engine-to-engine)

• Increased Computing Power Requirement

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Summary

• Developing Transient Engine Models For Real-time Use

• Models Were Inverted For Control Application

• Results Obtained To Date Indicate Strong Potential

• Major Challenge Is Applicability To Varying Ambient Conditions

- Possible On-board Model Adaptation

• Next Steps Include The Application To Standard ECU

Acknowledgements

• Department of Energy Headquarters

- Gurpreet Singh

- Roland Gravel

• National Energy Technology Laboratory

- Carl Maronde

- Jeffrey Kooser

• Atkinson, LLC

- Chris Atkinson

- Gregory Mott

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