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.

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.

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.

The effect of fuel composition and additive packages on deposit properties and homogeneous charge compression ignition combustion

2019 ◽  
Vol 21 (9) ◽  
pp. 1631-1646
Author(s):  
Joshua Lacey ◽  
Karthik Kameshwaran ◽  
Zoran Filipi ◽  
Peter Fuentes-Afflick ◽  
William Cannella
Keyword(s):  
Combustion Chamber ◽  
Homogeneous Charge Compression Ignition ◽  
Fuel Composition ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Single Cylinder ◽  
Compression Ignition Combustion ◽  
Deposit Layer ◽  
Combustion Chamber Deposit ◽  
Homogeneous Charge

Homogeneous charge compression ignition combustion is highly dependent on in-cylinder thermal conditions that are favorable to auto-ignition, and the presence of deposits can dramatically impact the in-cylinder environment. Because fuels available at the pump can differ considerably in composition, and fuel composition and the included additive package directly affect how deposits accumulate in a homogeneous charge compression ignition engine, strategies intended to bring homogeneous charge compression ignition to market must account for this fuel and additive variability. In order to investigate this impact, two oxygenated refinery stream test fuels with two different additives were run in a single cylinder homogeneous charge compression ignition engine. The two fuels had varying chemical composition; one represents a “dirty” fuel with high aromatic content that was intended to simulate a worst-case scenario for deposit growth, while the other represents a California Reformulated Gasoline Blendstock for Oxygenate Blending fuel, which is the primary constituent of pump gasoline at fueling stations across the state of California. The additive packages are typical of technologies that are commercially available to treat engine deposits. Both fuels were run in an experimental, single-cylinder homogeneous charge compression ignition engine in a passive conditioning study, during which the engine was run at steady state over a period of time in order to track changes in the homogeneous charge compression ignition combustion event as deposits accumulated in-cylinder. Both the composition and the additive influenced the structure of the combustion chamber deposit layer, but more importantly, both the rate at which the layer developed and the equilibrium thickness it achieved. The overall thickness of the combustion chamber deposit layer was found to have a significant impact on homogeneous charge compression ignition combustion phasing.

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