Development and experimental validation of a field programmable gate array–based in-cycle direct water injection control strategy for homogeneous charge compression ignition combustion stability

2019 ◽  
Vol 20 (10) ◽  
pp. 1101-1113 ◽  
Author(s):  
David Gordon ◽  
Christian Wouters ◽  
Maximilian Wick ◽  
Bastian Lehrheuer ◽  
Jakob Andert ◽  
...  
Keyword(s):  
Field Programmable Gate Array ◽  
Homogeneous Charge Compression Ignition ◽  
Water Injection ◽  
Combustion Stability ◽  
Compression Ignition ◽  
Field Programmable ◽  
Gate Array ◽  
Compression Ignition Combustion ◽  
Gas Recirculation ◽  
Homogeneous Charge

Homogeneous charge compression ignition is a part-load combustion method, which can significantly reduce oxides of nitrogen (NO x) emissions compared to current lean-burn spark ignition engines. The challenge with homogeneous charge compression ignition combustion is the high cyclic variation due to the lack of direct ignition control. A fully variable electromagnetic valve train provides the internal exhaust gas recirculation through negative valve overlap which is required to obtain the necessary thermal energy to enable homogeneous charge compression ignition. This also increases the cyclic coupling as residual gas and unburnt fuel is transferred between cycles through exhaust gas recirculation. To improve combustion stability, an experimentally validated feed-forward water injection controller is presented. Utilizing the low latency and rapid calculation rate of a field programmable gate array, a real-time calculation of residual fuel mass is implemented on a prototyping engine controller. Using this field programmable gate array–based calculation, it is possible to calculate the amount of fuel and the required control interaction during an engine cycle. This controller prevents early rapid combustion following a late combustion cycle using direct water injection to cool the cylinder charge and counter the additional thermal energy from any residual fuel that is transferred between cycles. By cooling the trapped cylinder mass, the upcoming combustion phasing can be delayed to the desired setpoint. The controller was tested at several operating points and showed an improvement in the combustion stability as shown by a reduction in the standard deviation of combustion phasing and indicated mean effective pressure.

Homogeneous charge compression ignition combustion stability improvement using a rapid ignition system

2020 ◽  
Vol 21 (10) ◽  
pp. 1846-1856 ◽  
Author(s):  
David Gordon ◽  
Christian Wouters ◽  
Shota Kinoshita ◽  
Maximilian Wick ◽  
Bastian Lehrheuer ◽  
...  
Keyword(s):  
Field Programmable Gate Array ◽  
Homogeneous Charge Compression Ignition ◽  
Combustion Stability ◽  
Compression Ignition ◽  
Ignition System ◽  
Combustion Properties ◽  
Field Programmable ◽  
Gate Array ◽  
Compression Ignition Combustion ◽  
Homogeneous Charge

When compared to traditional engines, homogeneous charge compression ignition has the potential to significantly reduce NO x raw emissions, while maintaining a high fuel efficiency. Homogeneous charge compression ignition is characterized by compression-induced autoignition of a lean homogeneous air–fuel mixture. Since homogeneous charge compression ignition does not utilize direct ignition control, it is strongly dependent on the state of the cylinder charge and can suffer from high cyclic variability. With spark-assisted compression ignition, it has been demonstrated that misfires can be reduced, while preserving the high thermal efficiency of homogeneous charge compression ignition as a result of the more favorable physical mixture properties due to dilution. However, spark-assisted compression ignition reduces the NO x benefits of homogeneous charge compression ignition, as it increases the local combustion temperatures. To merge the advantages of the homogeneous charge compression ignition and the spark-assisted compression ignition combustion processes, a field-programmable gate array for detailed simulation of the physical gas exchange is combined with a rapid spark system. The low latency and computational speed of the field-programmable gate array allows the simulation process to be implemented in real time. When combined with the rapid reaction time of the high-frequency current-based rapid ignition system, a feedforward controller based on the cylinder pressure or heat release is realized. The developed model-based controller determines if a spark is required to assist the homogeneous charge compression ignition combustion process. The use of the field-programmable gate array and rapid ignition system allows for the calculation of combustion properties and controller output within 0.1 °CA. This article presents the development and experimental validation of the developed controller on a single-cylinder research engine. The combustion stability has been significantly improved as reflected in an improved standard deviation of the indicated mean effective pressure and a reduction of the combustion phasing variations. Furthermore, compared to a traditional homogeneous charge compression ignition system, the hydrocarbon emissions can be reduced, while maintaining low NO x emissions.

scholarly journals Development and experimental validation of a real-time capable field programmable gate array–based gas exchange model for negative valve overlap

2018 ◽  
Vol 21 (3) ◽  
pp. 421-436 ◽  
Author(s):  
David Gordon ◽  
Christian Wouters ◽  
Maximilian Wick ◽  
Feihong Xia ◽  
Bastian Lehrheuer ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Real Time ◽  
Field Programmable Gate Array ◽  
Homogeneous Charge Compression Ignition ◽  
Exchange Process ◽  
Compression Ignition ◽  
Field Programmable ◽  
Gate Array ◽  
Gas Exchange Process ◽  
Homogeneous Charge

Homogeneous charge compression ignition has the potential to significantly reduce NO x emissions, while maintaining a high fuel efficiency. Homogeneous charge compression ignition is characterized by compression-induced autoignition of a lean homogeneous air–fuel mixture. Combustion timing is highly dependent on the in-cylinder state including pressure, temperature and trapped mass. To control homogeneous charge compression ignition combustion, it is necessary to have an accurate representation of the gas exchange process. Currently, microprocessor-based engine control units require that the gas exchange process is linearized around a desired operating point to simplify the model for real-time implementation. This reduces the models’ ability to handle disturbances and limits the flexibility of the model. However, using a field programmable gate array, a detailed simulation of the physical gas exchange process can be implemented in real time. This paper outlines the process of converting physical governing equations to an offline zero-dimensional gas exchange model. The process used to convert this model to a field programmable gate array capable model is described. This model is experimentally validated using a single cylinder research engine with electromagnetic valves to record real-time field programmable gate array gas exchange results and comparing to the offline zero-dimensional physical model. The field programmable gate array model is able to accurately calculate the cylinder temperature and cylinder mass at 0.1 °CA intervals during the gas exchange process for a range of negative valve overlaps, boost conditions and engine speeds making the model useful for future real-time control applications.

Exhaust gas recirculation stratification to control diesel homogeneous charge compression ignition combustion

2012 ◽  
Vol 13 (5) ◽  
pp. 429-447 ◽  
Author(s):  
Mathieu André ◽  
Bruno Walter ◽  
Gilles Bruneaux ◽  
Fabrice Foucher ◽  
Christine Mounaïm–Rousselle
Keyword(s):  
Homogeneous Charge Compression Ignition ◽  
Experimental Studies ◽  
Exhaust Gas Recirculation ◽  
Combustion Noise ◽  
Control Technique ◽  
Exhaust Gas ◽  
Compression Ignition ◽  
Compression Ignition Combustion ◽  
Gas Recirculation ◽  
Homogeneous Charge

A single-cylinder diesel engine was used to investigate the potential of exhaust gas recirculation dilution stratification as a control technique for homogeneous charge compression ignition combustion with early direct injections. Experimental studies on both all-metal and optically accessible engines were performed to understand the processes involved when exhaust gas recirculation is introduced separately in the intake ports. Laser-induced fluorescence diagnostics were carried out in the optical engine in order to provide fuel and exhaust gas recirculation distributions. The results indicate that depending on the intake configuration, the exhaust gas recirculation stratification can be maintained until late timings corresponding to the combustion event, leading to decreased maxima of heat-release rates, as well as decreased combustion noise levels. This result suggests that exhaust gas recirculation stratification may be used as a control parameter for combustion speed and therefore may contribute to the extension of the homogeneous charge compression ignition operating range. However, although exhaust gas recirculation stratification appears to be an interesting new control technique for homogeneous charge compression ignition combustion, its effect on the combustion was shown to be very sensitive to parameters such as the intake system configuration or the exhaust gas recirculation composition, showing that industrial use of this control technique requires further understanding of the physical phenomena involved.

In-cycle control for stabilization of homogeneous charge compression ignition combustion using direct water injection

2019 ◽  
Vol 240 ◽  
pp. 1061-1074 ◽  
Author(s):  
Maximilian Wick ◽  
Julian Bedei ◽  
David Gordon ◽  
Christian Wouters ◽  
Bastian Lehrheuer ◽  
...  
Keyword(s):  
Homogeneous Charge Compression Ignition ◽  
Water Injection ◽  
Compression Ignition ◽  
Direct Water Injection ◽  
Compression Ignition Combustion ◽  
Homogeneous Charge

Ion current–based homogeneous charge compression ignition combustion control using direct water injection

2020 ◽  
pp. 146808742092783 ◽  
Author(s):  
Denghao Zhu ◽  
Jun Deng ◽  
Raphael Dewor ◽  
Maximilian Wick ◽  
Jakob Andert ◽  
...  
Keyword(s):  
Heat Release ◽  
Homogeneous Charge Compression Ignition ◽  
Water Injection ◽  
Ion Current ◽  
Compression Ignition ◽  
Effective Pressure ◽  
Indicated Mean Effective Pressure ◽  
Direct Water Injection ◽  
Compression Ignition Combustion ◽  
Homogeneous Charge

Homogeneous charge compression ignition has proven to be both highly efficient and to operate with ultra-low NOx raw emissions. However, homogeneous charge compression ignition combustion is a dynamic process due to strong cycle-to-cycle coupling effects caused mainly by the residual gas. Compared to conventional spark-ignited and diesel engines, the lack of direct mixture composition and ignition control increases the challenge of combustion instabilities, especially at boundary conditions. To stabilize the combustion process, real-time in-cylinder combustion diagnostics and control are often used. In this study, for the first time, ion current detection technology and direct water injection are combined for homogeneous charge compression ignition combustion control. By analyzing the return map of the crank angle at 50% cumulative heat release under unstable conditions, it was identified that a misfire or incomplete combustion is usually followed by knocking-like early combustion with high cylinder pressure gradients. Through the correlation analysis between ion current and combustion, a cycle-to-cycle closed-loop control strategy was developed and implemented on a rapid control prototyping engine control unit. Real-time calculated ion current parameters were used to predict the 50% cumulative heat release position of the next cycle and prevent early combustion by direct water injection. The calculation results and controller performance were validated on a single-cylinder research engine. With the controller activated, the standard deviation of 50% cumulative heat release and dynamic programming to the max could be reduced by 19% and 11%, respectively. The coefficient of variation of indicated mean effective pressure was reduced by 12%. A slight increase in indicated mean effective pressure after activating the controller also shows the potential for efficiency improvement. Moreover, not only early combustion is controlled, but also late combustion is significantly reduced.

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