“Lean Powertrain Development”

Sam Akehurst, University of Bath, Powertrain & Vehicle Research Centre

Funded Under EPSRC Project Codes EP/C540883/1 & EP/C540891/1

Expected Project Outcomes:•A practical method for complex Powertrain design and

calibration•A more integrated and better optimised Powertrain

solution•Reduction of intensive experimental and modelling

procedures•Predictive methods developed for understanding the

effects of emerging hardware•Reduction in final product complexity

How about Hybrid Vehicles?Future Vehicle powertrains may well include some hybrid components, but hybrid vehicles are not a total solution•Toyota Prius & Honda Insight are no more fuel economic than existing diesel powered vehicles•Vehicle performance must still exist when batteries are flat

•Therefore demands original size engine

•Start/stop capability a useful benefit•Some potential for regenerative braking•Strong hybridisation requires large mass addition (batteries and electric machines)

Objective~“Develop an integrated approach to Powertrain design, performance optimisation

and rapid calibration, through a simulation model based philosophy”

The Optimisation Task•Targets- Minimise fuel consumption, and meet emissions targets and driver performance expectations•A multi dimension problem, many complex interactions and trade-offs to consider•Considerable number of mechanical constraints•Potential to use Multi Objective Genetic AlgorithmsA Novel Approaches to Virtual Prototyping

• Utilising Hardware in the Loop (HIL)• Real time models of powertrain components can be operated interfacing with existing hardware in many combinations•New technologies will be prototyped either in software or through novel emulating hardware in the test cell environment

What is a Powertrain?•The complete system that converts raw fuel into tractive motion at the wheels

•Includes engine, transmission, exhaust treatment and control systems

•A complex combination of interacting sub-systems under computer control with multiple actuators and sensors•Fundamental to vehicle performance, emissions production and fuel consumption (CO2)A Typical Vehicle Powertrain

The Problem, Current Industry Practice• Separate sub system development process- Little

integration, compromised result • Simulation tools used intensively, but at sub system

level – Little integration to achieve optimisation • New technologies selected off the shelf- Rarely

optimised for required duty• Lead time to market compromised by multiple

iterations during development

Vehicle Baseline Testingon University of Bath Rolling Road

Engine Testing a Combination of Real World and Virtual Environments

Time Plan for Research

Implementation

CalibrationControl

Engine

Vehicle & Transmission

Virtual

Reality

Hard

ware

in th

e

Loop

Matlab/SimulinkHierarchical Software Tool for Optimisation and Model Development

Powertrain

Bespoke ModellingPrototypeHardware

Real WorldHardware

VirtualHardware

Why Diesel?•CO2 Targets, Fleet Average of 140g/km by 2008, 120g/km by 2012•Currently 169g/km, of which average diesel is 25% lower than average gasoline vehicle•Results of this research will transfer to gasoline