Electric Boosting System for Light Truck/SUV Application

Turbo diesel engine use in passenger cars in Europe has resulted in 30-50% improvement in fuel economy. Diesel engine application is particularly suitable for US because of vehicle size and duty cycle patterns. Adopting this technology for use in the US presents two issues--emissions and driveability. Emissions reduction technology is being well addressed with advanced turbocharging, fuel injection and catalytic aftertreatment systems. One way to address driveability is to eliminate turbo lag and increase low speed torque. Electrically assisted turbocharging concepts incorporated in e-TurboTM designs do both. The purpose of this project is to design and develop an electrically assisted turbocharger, e-TurboTM, for diesel engine use in the US. In this report, early design and development of electrical assist technology is described together with issues and potential benefits. In this early phase a mathematical model was developed and verified. The model was used in a sensitivity study. The results of the sensitivity study together with the design and test of first generation hardware was fed into second generation designs. In order to fully realize the benefits of electrical assist technology it was necessary to expand the scope of work to include technology on the compressor side as well as electronicmore » controls concepts. The results of the expanded scope of work are also reported here. In the first instance, designs and hardware were developed for a small engine to quantify and demonstrate benefits. The turbo size was such that it could be applied in a bi-turbo configuration to an SUV sized V engine. Mathematical simulation was used to quantify the possible benefits in an SUV application. It is shown that low speed torque can be increased to get the high performance expected in US, automatic transmission vehicles. It is also shown that e-TurboTM can be used to generate modest amounts of electrical power and supplement the alternator under most load-speed conditions. It is shown that a single (large) e-TurboTM consumes slightly less electrical power for the same steady state torque shaping than a bi-Turbo configuration. However, the transient response of a bi-Turbo configuration in slightly better. It was shown that in order to make full use of additional capabilities of e-TurboTM wide compressor flow range is required. Variable geometry compressor (VGC) technology developed under a separate project was evaluated for incorporation into e-TurboTM designs. It was shown that the combination of these two technologies enables very high torque at low engine speeds. Designs and hardware combining VGC and e-TurboTM are to be developed in a future project. There is concern about high power demands (even though momentary) of e-TurboTM. Reducing the inertia of the turbocharger can reduce power demand and increase battery life. Low inertia turbocharger technology called IBT developed under a separate project was evaluated for synergy with e-TurboTM designs. It was concluded that inertial reduction provided by IBT is very beneficial for e-TurboTM. Designs and hardware combining IBT and e-TurboTM are to be developed in a future project. e-TurboTM provides several additional flexibilities including exhaust gas recirculation (EGR) for emissions reduction with minimum fuel economy penalty and exhaust temperature control for aftertreatment. In integrated multi-parameter control system is needed to realize the full potential of e-TurboTM performance. Honeywell expertise in process control systems involving hundreds of sensors and actuators was applied to demonstrate the potential benefits of multi-parameter, model based control systems.« less