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Personal mobile vehicles have been extensively studied recently, for the benefit of fuel economy and transportation efficiency. This study proposes a personal vehicle system comprising a new tilting mechanism -Stephenson six-bar linkage- combined with a new diamond-shape wheel arrangement chassis for high maneuverability. The present personal concept vehicle not only makes all the wheels and body lean simultaneously, and achieves an effective tilting angle of 32° in cornering, but can also, in normal attitude, turn in a narrow space with the steering front wheel and freely steering rear wheel. The current prototype of the proposed diamond-shape tilting chassis of personal vehicle concept, driven by 1.5kW hub motor in the front wheel, tandem two-seat, is 1m wide by 2.1m long. Preliminary test results indicate that the minimum turning radius is 1.05m for turn-in-spot, and the anti-rollover capability is almost 0.5g.

This work studies the potential to use nanoparticles as additives in lubrication oil to improve friction and wear properties. The friction coefficient, electrical contact resistance and wear depth are experimentally measuring using a reciprocating sliding tribo-tester at various temperatures, contact pressures and sliding velocities. The test results show that the nanoparticle as additive in base oil can reduce friction and wear by up to 50% in mixed and boundary regimes, but in a commercial engine oil, it has a relatively minor effect. The material properties, size and shape of nanoparticles affect their tribological properties. The mechanisms of friction and wear behavior improved are briefly discussed.

A new fuel injection concept called micro-pulsation fuel injection (μPFi) system had been developed for an internal combustion engine. The μPFi system composes an engine management system, a fuel-circulating device, and thermal-bubble fuel injectors with micropumps. The μPFi system had been installed in a commercial 4 stroke, 125cc motorcycle and tested in engine and chassis dynamometers. The measured CO and HC+NOx emissions were 1.5g/km and 1.14g/km respectively in ECE-40 test mode without catalyst converter and secondary air. The results showed that the motorcycle with μPFi system achieves superior exhaust CO emissions than the carburetor system while keeping comparable vehicle performance.

The in-cylinder direct-injection systems have been developed and incorporated in the small two-stroke motorcycle engines for the purpose of reducing the HC emissions. The fuel systems under assessment include the solid-fuel cylinder-wall, air-assisted cylinder-wall and air-assisted cylinder-head injection systems. Through the chassis dynamometer tests carried out, these injection systems were investigated and compared. The results show that adopting the injection approach could achieve significantly lower HC emissions than the carburetor version of the same engine. The maximum reduction in HC emissions was accomplished by air-assisted cylinder-head injection, and the reduction percentage was around 46%. However, it was also found that, due to the occurring of the irregular combustion at light load, very high engine-out HC emissions still existed in spite of the adopted injection type. To improve that, a skip-injection control strategy at idling was then developed.

A 125c.c. motorcycle is retrofitted with catalytic converter in order to demonstrate the emission reduction technology applied to the widely used vehicles in Taiwan. The retrofitting process minimizes the vehicle modifications while maintains the engine performance characteristics and accomplishes the maximal emission reduction results. Parameters of installation locations, substrate materials, cell density, precious metal composition/loading and catalytic converter size are all investigated in the chassis dynamometer test cell. Results of the motorcycle tested in ECE40 cycle show that significant reduction in HC emission can be achieved. But the reduction of CO emission is moderately low with the catalytic converter. The exhaust smoke is also decreased to certain extent. Use of secondary air improves the conversion efficiency of HC and CO very much effectively by supplying adequate oxygen from a reed valve system.

A low-pressure air-assisted fuel injection system had been applied to a 2-stroke motorcycle to reduce the fuel consumption and emissions. This system injected atomized fuel into cylinder through a nozzle located in cylinder wall and resulted in fuel economy and emission improvements. In the ECE40 test, the average fuel consumption and hydrocarbon emission of the fuel-injected motorcycle were reduced by 27.5% and 38.3% compared to the carburetor version.

An air-assisted direct injection system has been developed and applied to a two-stroke spark-ignited motorcycle engine of 82 c.c. displacement to reduce exhaust emissions, particularly unburnt hydrocarbons. The injection system, which induces a small amount of compressed air and metered fuel from electronic-control valve, delivers the air/fuel mixture into the cylinder. This paper shows the preliminary results of engine dynamometer tests. Also investigated are the improvement of combustion and reduction of unburnt HC emission by the use of dual spark plugs and skip injection techniques at light load engine condition.