# Presentation: 468995

## Using Hardware-in-the-Loop Simulations to Improve EPA Emissions Testing

- The Cooper Union
- February 24, 2009

## Engine Testing Basics

- Real World- Most realistic, uncontrolled environment, high cost

- Simulated- Low cost, quick results, not always valid

- HIL Testing- Combined simulation and real world design screening environment

## Engine Testing Basics

## Motivation and Background

- Powertrain Testing Basics
- 	Important specific terminology
**Road Load **
**F = F****Aero**** + F****Tires**** +F****Road Slope**** + Ma**
**Driving Cycle**
**Engine Dyno vs. Chassis Dyno**

- Powertrain Testing Basics

**Notes:**
This terminology is important to understand when comparing the old EPA FTP-75 test to the proposed new test method

## Motivation and Background

- Powertrain Testing Basics
- 	The EPA FTP-75 Emissions test: Driving Cycles

- EPA FTP-75 Test

- FTP-72 test

- Addition of Hot Start,1990

- SFTP tests introduced in 2000

**Notes:**
FTP-72 test based on survey of typical commutes in different US cities in 1960s.
Test is occasionally updated to try to better match current conditions.
A/C and higher speeds are included in supplemental tests.

## Motivation and Background

- Powertrain Testing Basics
- 	Basic Equipment Overview
- 	    1. Powertrain, Engine/Transmission
- 	    2. Power Absorption Unit (load)
- 	    3. Measurement  and Control Systems

- Powertrain Testing Basics

## System Design

- Goals of new system
- 	Proposal for new testing system

- Goals of new system

-    Driver

- Powertrain

-   Chassis

- Road Load

- Driving
- Cycle
- Speed

- Actual
- Speed

- Real

- Real

- Real

- Simulated

**   ****EPA System**

-    Driver

- Powertrain

-   Chassis

- Road Load

- Driving
- Cycle
- Speed

- Actual
- Speed

- Simulated

- Real

- Simulated

**Proposed System**

- Simulated

**Notes:**
Because the powertrain is the only component really being tested it makes sense to simulate all of the other components. 
-B/C the driver is automated it will be easier to follow different driving cycles rather that having to take time for human drivers to learn the new cycles.
-the elimination of the actual chassis allows test to be done in a smaller facility with a much less expensive engine dyno instead of a chassis dyno. Also test using different simulated chassis’ can be done without changing any hardware
-the road load simulation for the proposed system is much more complete and calculates the road load in real time at all speeds and accelerations

## System Design

- System Components

- System components

## Motivation and Background

- Powertrain Testing Basics
- 	Basic Equipment : Powertrain

- Powertrain

- Powertrain as a mechanical system

- Powertrain as an open thermodynamic system

- Exhaust

- Mechanical Power

## System Design

- System Components: Dynamometer
-  	Eddy Current Dynamometer
-  		-Creates torque by moving conductor through magnetic field
-  		-Advantages: Little to no wear, low inertia, fast simple control
-  		-Disadvantages: Cannot develop torque, poor cooling

- Dynamometer

## System Design

- System Components: Dynamometer
-  	Eddy Current Dynamometer, Performance curves

- Eddy current cannot create max torque at low RPM
- Engine max torque and power curves must be within dyno operating range

- Dynamometer

## System Design

- System Components: CarSim

**Vehicle model**
- Suspension
- Tires
- Aerodynamics
**Solver**
- Differential equations of motion
- Numeric solver

- CarSim

## System Design

- System Components: CarSim

- CarSim

**Import/Export**
- Powertrain
- Driver model
- Tire Model
**HIL Examples**
- ABS/TCS
- Engine Control
- Shift Schedules

## System Design

- System Components:
- Measurement and Control
- Automated throttle, transmission
- 	and load control
- Measurement of torque, speed,
- 	fuel flow, temperatures
- 	and pressures
- Many different emissions
- 	collection and
- 	measurement
- 	methods

- Measurement and Control

**Notes:**
Emphasize that this is a huge part of power train testing but that the basics measurement and controls techniques are similar to those used for any electromechanical system

## System Design

- System Components:
- Measurement and Control

- Measurement and Control

- Software simulates road loads and driver inputs and sends controls to test stand.
- Speed and torque measurements are taken and used as inputs to simulation.

## System Design

- System Components: LabView

- LabView allows graphical programming of measurement and control systems
- Uses the CarSim DLL solver with imports and exports
- Data is sampled at 25Hz, CarSim solver runs at 1kHz
- 16bit, 250kHz Data acquisition card

- LabView

## Results

- Test Procedure

- Test Procedure

- 1) Create vehicle model

- 3) Export to LabView

- 4) Run in real time with powertrain

- 2) Create driving cycle

## Results

- Example driving cycle

- Example Driving Cycle

## Conclusions and Further Work

- -Testing system that combined real world and simulations
- -System for early design screening
- -Future emissions and efficiency studies
- -Development of new driving cycles