Abstract
This paper studies the operating uniformity of a high-pressure common-rail diesel engine based on crankshaft segment signals. Engine nonuniformity or unevenness refers to the crankshaft torque fluctuation caused by cylinder-to-cylinder differences, which are caused by misfiring or difference in fuel supply or air supply. The experiments were conducted on a diesel engine of the YN30CR model. Based on the relationships among the cylinder pressure, the instantaneous crankshaft angular speed, and the crankshaft segment signal, it is found that the crankshaft segment signal can be used to characterize the operating nonuniformity of the diesel engine. Based on the Fast Fourier Transformation (FFT) from the angular domain to the frequency domain in analyzing the fluctuation patterns of the crankshaft segment signals at different operating conditions, the nonuniformity information was extracted. In order to further reveal the relationship between the fluctuation phenomena of the crankshaft segment signal and the cause of the fluctuation, the torque acting on the crankshaft of the multi-cylinder diesel engine was studied to quantify the operating nonuniformity of the diesel engine. The results show that the crankshaft segment signal can reflect the uniformity of the engine torque very well in both phase and amplitude, and the degree of nonuniformity of the engine torque can be reflected by the amplitudes of the low-order non-dominant harmonics of the crankshaft segment signal below the firing frequency. The crankshaft segment signal is very consistent with the variation pattern of the engine torque.
Highlights
The China National VI emissions standard imposes stringent requirements for vehicles on energy saving and emissions reduction
In order to explore the critical relationship between cylinder-to-cylinder combustion difference and the instantaneous crankshaft speed and correctly use the crankshaft segment signal to characterize engine operating nonuniformity, the combustion difference between cylinders and the influence of the cylinder pressure on engine performance were studied through experimental testing
It is observed that the cylinder pressure curves of different cylinders of the high-pressure common-rail diesel engine are very similar with small differences at the peak values
Summary
The China National VI emissions standard imposes stringent requirements for vehicles on energy saving and emissions reduction. The associate editor coordinating the review of this manuscript and approving it for publication was Xiaosong Hu. been used to study the torque uniformity of high-pressure common-rail diesel engine cylinders. Y. Wang et al.: Research on the Characteristics of Operating Non-Uniformity of a High-Pressure Common-Rail Diesel Engine vibration signal from the crankshaft speed signal. The detection method based on band-pass filtering to extract the nonuniformity signals of multiple cylinders in the literature [21] has an advantage of high anti-interference, which can provide an important basis for the correction and fault diagnosis of engine nonuniformity. It is proved that the crankshaft segment signal can characterize the operating nonuniformity of the diesel engine based on the relationship between the cylinder pressure and the crankshaft segment signal. It is found that the crankshaft segment signal can characterize engine nonuniformity very well
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