Effect of Retarded Injection Timing on Knock Resistance and Cycle to Cycle Variation in Gasoline Direct Injection Engine

Zhou, Lei; Shao, Aifang; Hua, Jianxiong; Wei, Haiqiao; Feng, Dengquan

doi:10.1115/1.4039322

Cited by 13 publications

(3 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It can be seen that in both injector positions, the knock tendency is decreased by retarding the gasoline injection timing, which is consistent with our previous work. 43 It should be noted that although retarding the injection timing of gasoline can suppress the knock, the engine performance simultaneously deteriorates, which will be discussed later. Overall, it can be concluded that the ethanol injection position will play an important role in the dual-fuel dual-direct injection engine.…”

Section: Knock Suppressionmentioning

confidence: 99%

Effects of the injection timing on knock and combustion characteristics in dual-fuel dual-injection engines

Liu

Kang

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part D:

Self Cite

View full text Add to dashboard Cite

To utilize ethanol fuel in spark ignition engines more efficiently and flexibly, a new ethanol/gasoline dual-direct injection concept in gasoline engine is proposed. Therefore, based on the dual-fuel dual-direct injection system, the effects of different injection timings and two injector positions on the characteristics of combustion were studied comprehensively, and the effects of different octane numbers and temperature stratifications on knock and combustion were explored. The results show that as for Position A (ethanol injecting toward spark plug), with the delay of injection timing, knock tendency and its intensity increase initially and then decrease due to the comprehensive effect of ethanol evaporation and fuel stratification; on the contrary, for Position B (ethanol injecting toward end-gas region), retarding the injection timing of ethanol can effectively reduce the knock propensity. As for the engine performance, a dual-direct injection performs best, especially the retarded injection timing of ethanol for Position A. It can be found that with the delay of the fuel injection timing, the torque first increases and then decreases. The brake-specific fuel consumption decreases initially and then increases at maximum brake torque spark timing.

show abstract

Section: Knock Suppressionmentioning

confidence: 99%

Effects of the injection timing on knock and combustion characteristics in dual-fuel dual-injection engines

Liu

Kang

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part D:

Self Cite

View full text Add to dashboard Cite

show abstract

“…Some detailed investigations are conducted in literature. 16 The percentages of knock and cycle-to-cycle variation under different intake temperature levels are studied using extensive experiment data, which show that high intake temperature increases the knock occurrence percentage and significantly influences the knock cycle-to-cycle variability. These variations also reflect different burn-rate in the combustion process which is important since they are correlated with engine torque and performance.…”

Section: Introductionmentioning

confidence: 99%

Cycle-based LQG knock control using identified exhaust temperature model

Tang

Wen

Archer

et al. 2022

International Journal of Engine Research

View full text Add to dashboard Cite

Spark ignition engines are often desired to be operated close to their knock borderline when MBT (maximum brake torque) cannot be achieved for optimizing combustion efficiency. Under this circumstance, a calibrated baseline spark timing, along with other control parameters such as intake and exhaust valve timings, is found for the engine control system to maximize fuel economy, and a stochastic scheme can be used for the control based on a large number of history data. However, cycle-to-cycle combustion variations still exist, resulting in a relatively conservative baseline control. To reduce cycle-to-cycle combustion variations, a real-time cycle-wised knock compensation is required. The correlation between exhaust temperature at the current cycle and knock intensity at the next cycle was found in our earlier research. In this paper, a cycle-to-cycle spark timing compensation scheme is developed based on the measured exhaust temperature when the engine is operated close to its knock borderline. To make model-based control possible, [Formula: see text]-Markov COVER (COVariance Equivalent Realization) system identification was used to obtain a linearized engine exhaust system model from incremental spark timing to associated exhaust temperature and knock intensity. Accordingly, a Linear–Quadratic–Gaussian (LQG) controller is designed, based on the identified model, to minimize the knock intensity fluctuations based on incremental exhaust temperature variation. The LQG control strategy was integrated with the existing entire knock control architecture, where the baseline spark timing is generated based on the offline machine training with an online updating scheme developed earlier, and demonstrated experimentally. Note that the cycle-based compensation only adds incremental spark timing to the baseline control so that knock combustion variations can be reduced. Three test scenarios are used to demonstrate the effectiveness of the proposed cycle-to-cycle compensation scheme when the engine is knock-limited. With the help of cycle-to-cycle based compensation, it was demonstrated that engine spark timing can be further advanced about one crank degree while maintaining the same knock intensity up-limit due to reduced knock combustion variations. Note that this is corresponding to 0.5%–1.0% fuel economy for this engine when it is operated under knock condition.

show abstract

“…Many studies have been conducted to investigate the mechanisms of knock and super-knock [11][12][13][14][15][16][17][18][19][20][21][22][23]. Konig et al [11] observed the flame propagation and auto-ignition events by using high-speed natural light and Schlieren photography.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of End-Gas Autoignition and Pressure Oscillation in a Downsized SI Engine Using Large Eddy Simulation

Zhong

Liu

2019

Energies

View full text Add to dashboard Cite

Knock and super-knock are abnormal combustion phenomena in engines, however, they are hard to study comprehensively through optical experimental methods due to their inherent destructive nature. In present work, the methodology of large eddy simulation (LES) coupled with G equations and a detailed mechanism of primary reference fuel (PRF) combustion is utilized to address the mechanisms of knock and super-knock phenomena in a downsized spark ignition gasoline engine. The knock and super-knock with pressure oscillation are qualitatively duplicated through present numerical models. As a result, the combustion and onset of autoignition is more likely to occur at top dead center (TDC), which causes end gas at a higher temperature and pressure. It is reasonable to conclude that the intensity of knock is not only proportional to the mass fraction of mixtures burned by the autoignition flame but the thermodynamics of the unburned end-gas mixture, and the effect of thermodynamics is more important. It also turns out that two auto-ignitions occur in conventional knock conditions, while only one auto-ignition takes place in super-knock conditions. However, the single autoignition couples with the pressure wave and they reinforce each other, which eventually evolves into detonation combustion. This work gives the valuable insights into knock phenomena in spark ignition gasoline engines.

show abstract

Effect of Retarded Injection Timing on Knock Resistance and Cycle to Cycle Variation in Gasoline Direct Injection Engine

Cited by 13 publications

References 21 publications

Effects of the injection timing on knock and combustion characteristics in dual-fuel dual-injection engines

Effects of the injection timing on knock and combustion characteristics in dual-fuel dual-injection engines

Cycle-based LQG knock control using identified exhaust temperature model

Numerical Analysis of End-Gas Autoignition and Pressure Oscillation in a Downsized SI Engine Using Large Eddy Simulation

Contact Info

Product

Resources

About