WAVE-RT: Real Time In-Cycle Engine Models for HiL and SiL

Ricardo Software
WAVE-RT: Real Time
In-Cycle Engine Models
for HiL and SiL Simulation
A New Approach: WAVE-RT
AVE-RT is a real-time, crank-angle resolved, and physically-based engine modeling tool
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designed for SiL and HiL testing of engine management systems. It has distinct advantages over
the current state of the art in both technical features and process of model development.
•Crank-resolved and independent treatment of cylinders
•Modeling of wave effects in the intake and exhaust systems
•Physically-based engine sub-models
•Automatic generation and parameterisation from existing WAVE engine model
Introduction
o satisfy future emission legislation more
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advanced engine technologies are required.
More complex control strategies need to be
designed, tested and validated for integration
in new Engine Control Units (ECUs). These
include:
•Multi-turbocharger systems
•Multi-EGR route systems
•Variable valvetrain systems
•Closed-loop combustion control
S oftware and Hardware in the loop (SiL and
HiL) testing is necessary for control systems
which rely on sensor feedback, hence “inthe-Loop”. For Engine Management Systems
a model of the engine is required to provide
the feedback
horough testing and validation is required
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prior to real engine/vehicle application.
Levels of testing are:
•Software-in-the-Loop (SiL)
•Hardware-in-the-Loop (HiL)
•HiL is the next level of testing whereby
the overall control system hardware and
software are tested. This requires the
engine model to run in real-time
How does
WAVE-RT run
real-time?
The combination of approximate mathematical modelling
and highly optimised code implementation allows WAVE-RT
to run on today’s mainstream
HiL system hardware
Engine
Build Data
•SiL is important for development and early
testing of control strategies, where all
software and models run on the same PC
platform
Engine
Model
Config.
Engine
Model
Reduction
Air path configured
in Ducts
Model Validation
Model
Parameters
RT
Implementation
on Hil
In-cycle
Model
for Sil
Capacitances and Branches
configured for RT model by
identifying fast/slow dynamics
in WAVE model and establishing
trade-off between execution
speed and accuracy
Target
H/W
ECU
Quasi-Propagatory wave modelling
based on approximate solution of
Method of Characteristics. This allows
the application of ordinary differential
equations with a fixed step solver
Application of fast mathematical
functions (e.g. log, exp, sin, cos)
instead of standard C-library
functions
Use of polynomial functions instead of
look-up tables to model turbocharger
and valve flow characteristics
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Features
Advantages over MVEMs
• Models fixed- and variable-geometry
turbochargers, heat exchangers, EGR, diesel and
gasoline engines
• Developed in ANSI-standard, MISRA-compliant C
code
• Can be compiled to be driven by any desired
simulation tool
• Delivered with solver libraries for SiL simulation on
Windows and Linux
• Delivered with solver libraries for HiL simulation
on multiple vendors’ platforms
-- Possible to support any vendor who will
cooperate with Ricardo to compile solver
libraries
• Transient response of the model much closer to real engine
due to wave effects capture. This leads to benefits in the
control strategy development for:
-- Complex air systems with multi-turbochargers and multiroute EGR systems
-- Variable valve timing and lift, particularly camless systems
• Crank-resolved independent cylinder model and possibility
to observe cyclic variations between cylinders. This is useful
for:
-- Closed-loop combustion control
-- Control of regenerative after treatment systems (post
injection, AFR control and torque compensation)
• Automatic generation and parameterisation from existing
WAVE engine model. This reduces significantly the
calibration effort required to produce the final model and
the time required for development and testing of control
strategies
Summary
• New engine technologies are pointing out the necessity of
simulation models oriented to the development and testing of
control systems
• WAVE-RT is a new modelling approach developed for testing of
Engine Management Systems. It includes the following features:
-- Crank-resolved and independent treatment of cylinders
-- Modeling of wave effects in the intake and exhaust systems
-- Physically-based engine modeling
-- Automatic generation and parameterisation from existing
WAVE engine model
• Simulation results show a close match with the donor WAVE
model and real-time capability on HiL platform has been
demonstrated
Example
• Engine model based on a turbocharged 4-cylinder Diesel engine with EGR and
VGT
-- Engine model comprises 98 ducts and 89 capacities
-- Simulation step size equal to 27.78 μs (1 CA deg resolution at 6000 rpm)
• Engine model has been implemented on HiL platform to prove WAVE-RT
real-time capabilities
-- Model has been tested both in open-loop (i.e. without ECU feedback
signals) and in closed-loop (with a real ECU controlling the engine
actuators)
• Real-time capability of WAVE-RT has been demonstrated during HiL
simulations
-- Simulation step size equal to 25 μs in open-loop testing (0.9 degree CA
resolution at 6000rpm) and equal to 50 μs in closed loop testing (1.8
degree CA resolution at 6000 rpm) to prevent overruns
-- AMD Opteron processor at 2.2 GHz
• Examples of other successfully converted engines:
-- 16 cylinder 600+ liter ship gas engine with multiple turbos
-- 6 cylinder sports car SI engine
-- 6 cylinder 10 liter truck Diesel turbo engine
-- and more
For further information about WAVE-RT and the Ricardo range of software products please contact us:
UK: +44 (0)1273 794444 USA: +1 (734) 394 3860
Email: [email protected]
www.ricardo.com/wave-rt
Delivering Value Through Innovation & Technology
www.ricardo.com