NEW TECHNICAL SOLUTION FOR HYBRID TURBOCHARGERS

− Internal combustion engines have an efficiency of operating which can be exploit to increase its performance. Part of the residual gases can be recovered through the technical solutions such as turbocharging. The turbocharging solution is one of the most popular technical solutions for increasing the energy performance of internal combustion engines. For the turbocharging process it is used a turbocharger. The turbocharger can contribute also with new technical solutions to increase the energy performance of the internal combustion engines. One of the solutions proposed for the theoretical and experimental research is the hybrid turbocharger, which has a double function, namely to compress the fresh air for the internal combustion engine, and to generate electric energy for the electric engine of the vehicle both for consumption other to be stored in batteries. This article aims is to present the result of the experimental research of the hybrid turbocharger, simulate and validate the new solutions for increasing the energy performance of internal combustion engines through hybrid turbochargers using a coupled electric generator. The simulations will be made using the AMESim Sofware developed by Siemens to demonstrate the efficiency of the new solutions such as a hybrid turbocharger through calculations. The tests will be carried out with the test bed CIMAT. CIMAT test bed is a machine which provides higt pressure air which simulate the combustion gases of an engine. The pourpose of the CIMAT test bed is to rotate the hybrid turbocharger turbine and also the compressor wheel. More technical information about the hybrid turbocharger test will be presented in the article and also constructive details. Based on the technical information and input data in the first phase it will be made an application for the simulation and validation of the prototype to demonstrate the great potential of the turbocharger to produce also green energy.

The internal combustion engines have developed in the last years and also the expectations like performance, pollution in balance with the costs, therefore the research area expanded also. (Mithun D. et al., 2017) More energy efficiency and less polluting processes are required in the internal combustion engines sector. The compression-ignition engines are used in generating electricity, marine and transportation and the Otto engine for transportation use but in both cases the processes can be improved and made enable to higher pressure ratios and also to generate electricity in sufficient operating conditions. (Heim K., et al., 2016). One of the ways to improve the engine performance is to improve the turbocharger performance. To demonstrate that the turbocharger has a great capability of improvement it was built a hybrig turbocharge, namely a turbocharger coupled to a gear ratio and to a electrical generator.(figure 1) To obtain the higt speed turations the hybrid turbocharger is connected to a compress air machine produce by CIMAT Balancing Machines. The CIMAT machine has the main aim to provide compressed air to the ranking of 1 to 2 bars. The compressed air simulates the exhaust gases of the engine and it can deliver a high turbine speed which rotates the connecting shaft between the compressor and the electric generator. I also mention that the electric generator is connected to the compressor side by a shaft. In figure 2 it can be seen the CIMAT Turbo Test Pro. [3] In figure 3 it can be seen how the hybrid turbocharger is whith the CIMAT machine connected. The CIMAT machine can provide information of the turbocharger boost pressure ratio test real life spin test, turbocharger rotational speed measurement, turbocharger air loss test, position sensor test, compressor section performanace test. In tabel 1 are detailed all important components of the hybrid turbocharger such as: turbocharger components, gear ratio (1:10) and the electrical generator of 100W also with the main symbols used by the simulation with AMESim software.

OBJETIVE
The general objective of this experimental paper is to demenostrat that the turbocharger has very great performance improvement. But to demonstrate this aspect, it must also be presented the simulation and validation results of the hybrid turbocharger prototype. The experimental work test will simulate the hybrid turbocharger on the CIMAT test bed which provides the comprimate aer for the turbocharger whith the aim to simulate the engine exaugst gases. The results will be collected for the mechanical part using CIMAT maschine that will supply, the rotation, mass flow, inlet / outlet pressure, temperature parameters and for the electrical part using Siemens PLC and InfoU software which will deliver information about electrical current (Amper), voltage (Volt) and power (Watt). In figure 4 it can be seen the general view of the hybrid turbocharger with the main components of the simulationg system.

RESULTS
The results will show the electrical parameters resulting from the turbocharger rotation, namely: the current intensity, the voltage and the resulting power. This is the green energy produced by the turbocharger at a constant speed of 162400 revolutions per minute, with a resulting pressure of about 1 bar. In figure 6 it is showed the resulting voltage of the electrical motor from the experimental research in relation to time. The experimental research value rage is from 0 to 25 Volt. And in figure 7 it is showed the resulting voltage from the AMESim simulation in relation to time with the simulation rage value from 0 to 23 Volt.    About the experimental research on the mechanical side stood following parameters, namely: speed rotor shaft of the turbocharger, the pressure ration, PR and the compressor outlet pressure.
In figure 12 it is showed the speed rotor shaft in rotation per minute from the experimental research relation to time. The experimental research value rage is from 0 to 162400 rpm. And in figure 13 it is showed the speed rotor shaft in rotation per minute, rpm simulated with AMESim in relation to time with the simulation rage value from 0 to 162400 rpm. In figure 14 it is showed the pressure ratio, PR from the experimental research in relation to time. The experimental research value rage is from 0 to 1. And in figure 15 it is showed the pressure ratio, PR simulated with AMESim in relation to time with the simulation rage value from 0 to 1.

CONCLUSIONS
The new turbo compound systems for the automotive industry for internal combustion engine to recover energy has three basic elements: the extended shaft to accommodate the electrical energy generator at the blower end, a gear that reduce the rotation of the turbocharger and a cooling system for the generator witch is optional.
Observing the values obtained through the experimental part and the simulation part it can be stated that the turbocharger has a great potential for development and to obtain ecological electric energy for the vehicle. The hybrid turbocharger can be used at hybrid engines but also for the classic solution of the internal combustion engines. Parallel sequential turbocharging systems can be generate namely to able to operate in different modes, to generate electric energy for the electric engine of the vehicle both for consumption and to be stored in batteries to cover the full batery range. computer consumers and to compress air for the engine. (