Search Results

Euro VI emission standards have set a very strict limitation on particulate matter emissions of Gasoline Direct Injection (GDI) engine. It is difficult for GDI engine to meet the Euro VI PN regulation (6×1011#/km) without a series of complicated after-treatment devices such as Gasoline Particulate Filter (GPF). Previous research shows that GDI vehicles under cold start condition account for more than 50% of both particle number and mass emissions during the entire NEDC driving cycle. Dual Injection Gasoline engine is based on the GDI engine by adding a set of port fuel injection system. The good mixing characteristics of the port fuel injection system can help to reduce the particulate matter emissions of the GDI engine during the cold start condition.

Gasoline direct injection (GDI) has been a mainstream technology due to its higher thermal efficiency and better power output. However, with increasingly stringent emission regulations introduced (EURO VI PN limits: 6 x l011#/km), high particulate matter (PM) emission of GDI engine has been a serious problem that limits its further development. Previous studies have found that cold-start and warm-up operation conditions play the dominant role in engine-out particulate emissions. In this paper, emission characteristics during the cold-start were first studied by controlling the coolant temperature. A Cambustion DMS500 fast particle spectrometer was employed to analyze the PM emissions. In order to reduce the engine-out emissions of cold-start, a dual injection system which combines port-fuel-injection (PFI) and direct-injection (DI) was applied in a four-cylinder gasoline engine.

In this paper an estimation method on location of peak pressure (LPP) employing flame ionization measurement, with the spark plug as a sensor, was discussed to achieve combustion parameters estimation at quick start of HEV engines. Through the cycle-based ion signal analysis, the location of peak pressure can be extracted in individual cylinder for the optimization of engine quick start control of HEV engine. A series of quick start processes with different cranking speed and engine coolant temperature are tested for establishing the relationship between the ion signals and the combustion parameters. An Artificial Neural Network (ANN) algorithm is used in this study for estimating these two combustion parameters. The experiment results show that the location of peak pressure can be well established by this method.

An automobile heat pump system with conventional refrigerant (HFC-134a or HFO-1234yf) suffers significantly diminishment of heating capacity and system efficiency as the ambient temperature decreases. Natural refrigerant CO2 (GWP = 1) is considered as a promising alternative to HFC-134a in automobile air conditioning (MAC) applications with environmentally friendly advantage. In addition, CO2 automobile heat pump system is a promising heat pump technology for EVs with great heating advantages in a cold climate. This study aims to investigate the supercritical heat transfer characteristics of a compact micro-channel gas cooler applied in an automobile CO2 heat pump system. A simulation model of automobile gas cooler was developed by using segment-by-segment method, and validated by experimental results from Series Gas cooler (SGC) and One Gas cooler (OGC) CO2 heat pump systems. The error of heating capacity between calculated results and experimental results was less than 7%.

The heat pump with low global warming potential (GWP) refrigerants is imperative for the electric vehicle (EV) to slow down global warming and extend the driving range while meeting passengers' thermal comfort in low ambient temperatures. However, there are no appropriate refrigerants. To provide long-term and environmental-friendly refrigerants in the heat pump for EVs, herein, we reported newly developed low-GWP refrigerant mixtures, i.e., DL3B, whose GWP is lower than 140, the flammability (lower flammability limit and burning velocity), saturation pressure, lubricant miscibility, material compatibility were experimentally tested. A test bench that can investigate the performance of an R410A prototype was built. The drop-in tests of the DL refrigerant were carried out to evaluate the capacities and COPs for both cooling and heating modes in the EV heat pump system.

The electricity energy consumption for passenger cabin heating can drastically shorten the driving range for electric vehicles in cold climates. Mobile heat pump system is considered as an effective method to improve heating efficiency. This study investigates the system characteristics of mobile heat pump systems for electrical vehicle application. Based on KULI thermal management software, simulation models including HFC-R134a direct heat pump (DHP) and secondary loop heat pump (SLHP) were developed. The secondary loop employed in the SLHP includes a coolant pump, an indoor heater core and a plate heat exchanger, instead of an indoor condenser in the DHP. The use of a secondary loop has advantages to improve air outlet temperature uniformity. The simulation models were verified by measured data obtained from calorimeter experiments. By adopting simulation models, the effects of indoor and outdoor temperatures on system performance and cycle characteristics were discussed.