27% Fuel Savings Projected as 2/4-stroke Research Prototype Engine Completes Initial Testing
VAN BUREN TWP., Mich., March 25 /PRNewswire/ — Ricardo and a consortium of automotive partners today announced the completion of an advanced prototype research program based on the highly innovative 2/4SIGHT engine concept. This gasoline engine concept uses novel combustion, boosting, control and valve actuation technologies to enable automatic and seamless switching between two- and four-stroke operation, with the aim of delivering significant performance and fuel economy improvements through
aggressive downsizing.
The 2/4SIGHT engine concept uses a direct injection gasoline combustion system in which the design of intake and exhaust ports, combined with appropriate changes in boost supply, fuel injection, ignition and valve timing, enable operation both in two-stroke and four-stroke modes. An advanced control system coupled with flexible valve actuation manages driver demands and coordinates operation of the boost system, valves and fuel injection equipment at an individual cylinder level. This enables smooth transitions between two- and four-stroke operation without torque interruption in both transient and constant torque conditions.
Prototype engine configuration
The research prototype engine is based on a single bank of a 2.1-liter V6, which in 6-cylinder 2/4SIGHT configuration is intended to deliver levels of performance and drivability more usually associated with a 3-4 liter V8 gasoline engine. In order to enable the project team to assess control strategies in a completely unrestricted manner, an electro-hydraulic valve (EHV) actuation system was used for the prototype development rig
The air handling system of the 2/4SIGHT concept is based on two-stage boosting and intercooling using a Rotrex supercharger and Honeywell turbocharger. For simplicity in the initial test bed prototype configuration however, boosting is provided by an external compressed air supply. The engine control system of the prototype is a DENSO rapid
prototyping system working with DENSO gasoline direct injection and ignition components. The prototype engine was built at the Ricardo Shoreham Technical Centre and installed for testing at the Sir Harry Ricardo Laboratories of the University of Brighton, UK.
Development test results
Testing of the prototype 2/4SIGHT engine has enabled development and
validation of the combustion system which has been optimized for operation
in both two and four-stroke modes. The flexibility of the advanced control
system — developed jointly by DENSO and Ricardo — allows rapid changes to
high level code which, coupled with the flexibility of the EHV valvetrain,
has enabled the project team to develop and optimize a new control strategy
for the 2/4SIGHT engine, including the management of two-four-stroke
switching.
Highlights of the development test results include:
— Smooth and reliable switching between two- and four-stroke modes under
both constant torque conditions and transient operation.
— Control strategies amenable to implementation in cost-effective
mechanical valvetrain hardware.
— Extremely high two-stroke specific torque demonstrated of 150 Nm/L at
1000 rev/min and 230 Nm/L at 2500 rev/min, opening the prospect of
highly aggressive engine downsizing using the 2/4SIGHT engine concept.
Significant improvements in fuel economy
Following completion of the test program, Ricardo has carried out a
vehicle drive cycle and acceleration performance simulation based on the
steady state fuel consumption and full load performance of the 2/4SIGHT
engine. The study was carried out using the Ricardo powertrain blockset in
the MSC “EASY5(TM)” software package that allows detailed modeling of
engines, transmissions, drivelines, tires and aerodynamics. The baseline
vehicle for the study was an 1800 kg passenger car sold in the European
market with a 3.5-liter naturally aspirated V6 gasoline engine and 5 speed
conventional automatic transmission with torque converter. To verify the
validity of the models and input data, the baseline vehicle fuel
consumption results were compared with published data, which were
reproduced by the model to an acceptable accuracy of 1%.
Development test results
Testing of the prototype 2/4SIGHT engine has enabled development and
validation of the combustion system which has been optimized for operation
in both two and four-stroke modes. The flexibility of the advanced control
system — developed jointly by DENSO and Ricardo — allows rapid changes to
high level code which, coupled with the flexibility of the EHV valvetrain,
has enabled the project team to develop and optimize a new control strategy
for the 2/4SIGHT engine, including the management of two-four-stroke
switching.
Highlights of the development test results include:
— Smooth and reliable switching between two- and four-stroke modes under
both constant torque conditions and transient operation.
— Control strategies amenable to implementation in cost-effective
mechanical valvetrain hardware.
— Extremely high two-stroke specific torque demonstrated of 150 Nm/L at
1000 rev/min and 230 Nm/L at 2500 rev/min, opening the prospect of
highly aggressive engine downsizing using the 2/4SIGHT engine concept.
Significant improvements in fuel economy
Following completion of the test program, Ricardo has carried out a
vehicle drive cycle and acceleration performance simulation based on the
steady state fuel consumption and full load performance of the 2/4SIGHT
engine. The study was carried out using the Ricardo powertrain blockset in
the MSC “EASY5(TM)” software package that allows detailed modeling of
engines, transmissions, drivelines, tires and aerodynamics. The baseline
vehicle for the study was an 1800 kg passenger car sold in the European
market with a 3.5-liter naturally aspirated V6 gasoline engine and 5 speed
conventional automatic transmission with torque converter. To verify the
validity of the models and input data, the baseline vehicle fuel
consumption results were compared with published data, which were
reproduced by the model to an acceptable accuracy of 1%.
Having completed development of the prototype 2/4SIGHT engine, the
partners are currently negotiating potential sources of funding and support
for a vehicle demonstration program. Commenting on the successful
completion of the prototype engine development program, Ricardo technology
director, Neville Jackson, said: “The completion of the prototype engine
development program of the 2/4SIGHT engine and demonstration of its
two-/four-stroke switching capability is an important milestone for the
project partners. While significant further research and development
challenges remain, not least in the vehicle demonstration of this advanced
engine concept, the initial prototype development project has demonstrated
the potential of 2/4SIGHT to offer improved gasoline fuel economy and
reduced CO2 emissions, while also maintaining or improving vehicle
performance. In addition to validating the 2/4SIGHT concept, the research
project is also delivering significant benefits in terms of its many
constituent technologies which are likely to see application in the more
immediate term.”
The 2/4SIGHT project team
The 2/4SIGHT project was led and coordinated by Ricardo. In addition
the company was responsible for design and development of the prototype
engine and integration of its systems. DENSO was responsible for
development and supply of the direct fuel injection and advanced engine
control systems. Ma 2T4 contributed its knowledge and expertise of
valvetrain switching technology. Brunel University, UK, carried out
single-cylinder engine testing and development. The University of Brighton,
UK, carried out multi-cylinder engine testing and combustion and cooling
system analysis. The 2/4SIGHT project was part-funded by the British
Government through the Technology Strategy Board. The Board’s mission is to
promote and support research into, and development and exploitation of,
technology and innovation for the benefit of UK business, in order to
increase economic growth and improve the quality of life.
About Ricardo
Ricardo the Eco-Innovation Technology Company, is a leading independent
provider of technology, product innovation, engineering solutions and
strategic consulting to the world’s automotive, military, transport and new
energy industries. The company’s skill base represents the state-of-the-art
in low emissions and fuel-efficient powertrain technology, and can be best
summarized: “Ricardo is Fuel Economy.”
With technical centers and offices throughout Europe, the U.S. and
Asia, Ricardo provides engineering expertise ranging from vehicle systems
integration, controls & electronics, hardware and software development, to
the latest driveline and transmission systems and gasoline, diesel, hybrid
and fuel cell powertrain technologies. Its customers include the world’s
major automakers and suppliers as well as manufacturers in the military,
commercial, off-highway and clean energy sectors. The company also serves
in advisory roles to governmental and independent agencies. Ricardo’s U.S.
operation, Ricardo, Inc., is headquartered in Van Buren Township, Michigan.
Ricardo plc posted sales of $344 million in financial year 2007 and is a
constituent of the FTSE TechMark 100 index – a group of innovative
technology companies listed on the London Stock Exchange. For more
information, visit http://www.ricardo.com.