Controlling Engine Load by Means of Early Intake-Valve Closing

Effect of advancing the closing angle of the intake valves on diffusion-controlled combustion in a HD diesel engine

“…In-cylinder thermodynamic conditions during the closed cycle (compression, combustion and expansion) can be directly controlled by adjusting the intake valve closing angle (IVC), which defines the total intake mass flow rate and the effective compression ratio of the engine [6]. Interesting improvements in terms of NO x emissions and fuel consumption have been obtained with this strategy in spark ignition engines [7,8]. The potential of advancing IVC, together with turbocharging, for NO x emissions control has also been explored in Diesel engines with success, achieving reductions in the range of 10-20% of this pollutant [6,9,10].…”

Variable valve timing for fuel economy improvement in a small spark-ignition engine

“…The optimization of intake and exhaust valve timing can provide significant reductions in pumping losses at part load operation [1][2][3]. In this paper, the benefit of engine load control performed by using a simple variable cam phaser has been analyzed and the influence of the VVT strategy on the combustion process and engine performance has been evaluated.…”

Combining Unthrottled Operation with Internal EGR under Port and Central Direct Fuel Injection Conditions in a Single Cylinder SI Engine

“…Regardless, Tuttle concluded that 96 was the maximum delay that could be tolerated due to loss of effective compression ratio, which would significantly limit the attainable speed-load map (assuming no external compression was available). In subsequent work (8), it was concluded that the EIVC strategy was favourable for part-load, allowing dethrottled operation over a wider speed-load window, albeit reliant on 200 crank range of inlet valve closing.…”