|Aeristech HTT system. Source: Aeristech. Click to enlarge.|
UK-based Aeristech Ltd, recently secured £500,000 (US$760,000) with help from Oxford Investment Opportunity Network (OION), to further the development of its Hybrid Turbocharger Technology (HTT), a electromechanical turbocharging system designed to provide superior transient response—i.e., to eliminate turbo lag—in support of aggressive engine downsizing.
Hybrid Turbocharger Technology (HTT) uses a motor-driven compressor and a turbine-driven generator as separate systems. An intelligent control system manages power to the compressor. The separate components are connected electrically.
The separation of compressor and turbine enables a more optimal matching, and they can run at different steady-state speeds. The system can operate without a wastegate, using electrical energy storage to prepare for the next acceleration event.
|CPT Electric Supercharger|
|Another approach to electric boosting is Controlled Power Technologies’ VTES (Variable Torque Enhancement System) electric supercharger (earlier post).|
|VTES is an air-cooled Switched Reluctance machine, coupled to power electronics and an optimized radial compressor, that delivers high airflow, pressure and efficiency. The electric supercharger operates independently of engine speed, making it suitable to maintaining vehicle transient performance and driveability.|
|CPT recommends a combination of the highly dynamic electric supercharger in series with a conventional exhaust-driven turbocharger to optimize the overall response of the system, compared to other air charging methods.|
Boost pressure is directly controlled by the ECU. The ECU also has control of back-pressure in combination with VGT control. This provides excellent control over combustion and a responsive, refined driving experience, according to the company.
Aeristech’s says that its technology allows the electrical power to be transferred very efficiently. This takes advantage of recent developments in electric machine design, power electronics circuitry, and energy storage.
Aeristech also says that its technology is well-suited for hybrid, extended-range electric and biofueled vehicles. Hybrid vehicles typically operate a complex engine start-stop cycle, where the rapid changes in air flow demand the level of control provided by the HTT system. Biofuel blends require control over the ignition temperature of the mixed fuel in order to exhibit fuel flexibility. This can be achieved by varying charge air pressure via HTT’s integral control system.
Fuel flexibility requires the capability to handle diverse air/fuel ratios, exhaust gas volumes, and mean effective pressures. The Aeristech turbocharger can cope with a variable ratio of exhaust gas to inlet air volume. By controlling charge air pressure, the Aeristech turbocharger adjusts an engine’s effective compression ratio and can control auto-ignition when fuel composition changes, the company says.
The funding round was led by Midven who invested alongside Minerva Business Angels Network and members of the OION Network. The Carbon Trust supported the initial development phase of the HTT system through its incubation scheme and Aeristech was also awarded R&D grants totaling £500,000 to produce a prototype that was well received by the industry.
Aeristech is now undertaking bespoke HTT testing program s with a global vehicle manufacturer and a construction equipment vehicle manufacturer for off-highway vehicles. Aeristech will use the new funding to progress these testing programs.
The motor industry is now seeking to bring the highest efficiency, lowest cost turbo systems into its supply chain and it is forecast that by 2014 around 75% of all European light vehicles will be boosted by turbo technology. We are delighted to have secured the investment we need to progress the development of our unique HTT system and our objective is to capture a 10% share of this market over the longer term.
—Bryn Richards, CEO of Aeristech
In February, Aeristech was the regional winner of a Shell Springboard Innovation Award with the judges citing the carbon savings potential, innovation and commercial credibility of the HTT technology.