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In this research, with proposed design of hydraulic-controlled variable valve lift system, a feed pump is used to supply the low-pressure oil into the hydraulic pump which will compress low-pressure oil as high-pressure oil and pumps the high-pressure oil into the hydraulic cylinder. In the meanwhile, the intake valve opened in accordance with the plunger is pushed by the hydraulic cylinder. To achieve the change of intake valve lift, a DC motor connected with the control rack that is used for controlling oil-drain time of the hydraulic pump. In addition, a solenoid valve is installed in order that the intake valve will be closed quickly without controlling the drain flow when the maximum valve lift is reached. Commonly, the throttle is not required with variable valve lift system, but the throttle is kept for engine start. Hence, except for engine cranking condition, the throttle maintains in wide open (WOT) under different test conditions.

This paper develops an adaptive idle speed control strategy for a V2, 1000 cc four-stroke, water-cooled, port injection SI engine. In order to verify the proposed strategy, the non-dimensional engine model including charging and torque dynamics is established in Matlab/Simulink software based on previously experimental verification. The integration of dynamics above will be a multi-input-single-output (MISO) system, which inputs are throttle angle and spark advance angle, and the output is engine speed. The proposed adaptive controller is developed on the model-based structure. The system parameters are updated by recursive least square (RLS) method so the system is able to represent the actual operation. The updated system parameters adjust control gain by derivation of closed-loop gain and pole placement.

Butanol is deemed as the potential alternative fuel for future development, and the previous researches show poor injection spray atomization when high butanol concentration blended fuel applying on stock small scooter engines. In this research, a platform is built to observe the spray atomization phenomena with 2.5kg/cm2 (2.452bar) 、 3.5kg/cm2(3.433bar) injection pressures and various n-butanol volume percent concentration blended fuels, B60, B80 and B100. After that, engine experiments are undergone with above conditions under wide open throttle (WOT) with stoichiometric air fuel ratio (AFR) at 4000rpm. The experiment results are analyzed and discussed from different aspects eventually. Injection spray observation shows that worse spray atomization appears accompanied with higher concentration blended fuel. But when the injection pressure increases, higher shear force acting on the injection spray improves the breakup of fuel and enhances the effect of fuel spray atomization.

In this paper, the off-line analysis method is applied to develop three-way catalytic converter (TWC) diagnostic strategy including oxygen sensor (O2 sensor) diagnostic strategy with common narrow band oxygen sensor (EGO sensor) in Matlab/Simulink software. Moreover, Mototron ECU (Engine Control Unit) is used for monitoring catalyst deterioration. However, aged catalyst is difficult to possess so the different catalytic conversion efficiency (CCE) is simulated by using exhaust by-pass valve. The CEC (China Engine Corporation) 1L V2, four stroke, water-cooled engine is selected as target engine to conduct engine dynamometer test. After making sure O2 sensor operates normally, the catalyst diagnostic strategy test is executed. The experimental result shows that the catalyst deterioration accurately can be detected when the failure phenomenon takes place.