TY - JOUR
T1 - Skip cycle system for spark ignition engines
T2 - An experimental investigation of a new type working strategy
AU - Kutlar, Osman Akin
AU - Arslan, Hikmet
AU - Calik, Alper T.
PY - 2007/2
Y1 - 2007/2
N2 - A new type working strategy for spark ignition engine, named skip cycle, is examined. The main idea is to reduce the effective stroke volume of an engine by cutting off fuel injection and spark ignition in some of the classical four stroke cycles. When the cycle is skipped, additionally, a rotary valve is used in the intake to reduce pumping losses in part load conditions. The effect of this strategy is similar to that of variable displacement engines. Alternative power stroke fractions in one cycle and applicability in single cylinder engines are specific advantageous properties of the proposed system. A thermodynamic model, besides experimental results, is used to explain the skip cycle strategy in more detail. This theoretical investigation shows considerable potential to increase the efficiency at part load conditions. Experimental results obtained with this novel strategy show that the throttle valve of the engine opens wider and the minimum spark advance for maximum brake torque decreases in comparison to those of the classical operation system. The brake specific fuel consumption decreases at very low speed and load, while it increases at higher speed and load due to the increased fuel loss within the skipped cycles. In this working mode, the engine operates at lower idle speed without any stability problem; and moreover with less fuel consumption.
AB - A new type working strategy for spark ignition engine, named skip cycle, is examined. The main idea is to reduce the effective stroke volume of an engine by cutting off fuel injection and spark ignition in some of the classical four stroke cycles. When the cycle is skipped, additionally, a rotary valve is used in the intake to reduce pumping losses in part load conditions. The effect of this strategy is similar to that of variable displacement engines. Alternative power stroke fractions in one cycle and applicability in single cylinder engines are specific advantageous properties of the proposed system. A thermodynamic model, besides experimental results, is used to explain the skip cycle strategy in more detail. This theoretical investigation shows considerable potential to increase the efficiency at part load conditions. Experimental results obtained with this novel strategy show that the throttle valve of the engine opens wider and the minimum spark advance for maximum brake torque decreases in comparison to those of the classical operation system. The brake specific fuel consumption decreases at very low speed and load, while it increases at higher speed and load due to the increased fuel loss within the skipped cycles. In this working mode, the engine operates at lower idle speed without any stability problem; and moreover with less fuel consumption.
KW - Fuel consumption
KW - Part load
KW - Power frequency
KW - Pumping loss
KW - Skip cycle system (SCS)
KW - Spark ignition (SI) engine
UR - http://www.scopus.com/inward/record.url?scp=33845874368&partnerID=8YFLogxK
U2 - 10.1016/j.enconman.2006.07.004
DO - 10.1016/j.enconman.2006.07.004
M3 - Article
AN - SCOPUS:33845874368
SN - 0196-8904
VL - 48
SP - 370
EP - 379
JO - Energy Conversion and Management
JF - Energy Conversion and Management
IS - 2
ER -