Diethoxymethane as tailor-made fuel for gasoline controlled autoignition

2019 ◽  
Vol 37 (4) ◽  
pp. 4691-4698 ◽  
Author(s):  
Bastian Lehrheuer ◽  
Fabian Hoppe ◽  
K. Alexander Heufer ◽  
Sascha Jacobs ◽  
Heiko Minwegen ◽  
...  
Keyword(s):  
Controlled Autoignition

Understanding the infiuence of valve timings on controlled autoignition combustion in a four-stroke port fuel injection engine

2005 ◽  
Vol 219 (6) ◽  
pp. 807-823 ◽  
Author(s):  
Li Cao ◽  
Hua Zhao ◽  
Xi Jiang ◽  
Navin Kalian
Keyword(s):  
Gas Exchange ◽  
Gasoline Engine ◽  
Fuel Injection ◽  
Exchange Process ◽  
Combustion Process ◽  
Intake Valve ◽  
Time Model ◽  
Port Fuel Injection ◽  
Cycle Simulation ◽  
Controlled Autoignition

Controlled autoignition (CAI) combustion, also known as homogeneous charge compression ignition (HCCI), was achieved through the negative valve overlap approach by using small- lift camshafts. Three-dimensional multicycle engine simulations were carried out in order better to understand the effects of variable intake valve timings on the gas exchange process, mixing quality, CAI combustion, and pollutant formation in a four-stroke port fuel injection (PFI) gasoline engine. Full engine cycle simulation, including complete gas exchange and combustion processes, was carried out over several cycles in order to obtain the stable cycle for analysis. The combustion models used in the present study are a modified shell ignition model and a laminar and turbulent characteristic time model, which can take high residual gas fraction into account. After the validation of the model against experimental data, investigations of the effects of variable intake valve timing strategies on the CAI combustion process were carried out. These analyses show that the intake valve opening (IVO) and intake valve closing (IVC) timings have a strong infiuence on the gas exchange and mixing processes in the cylinder, which in turn affect the engine performance and emissions. Symmetric IVO timing relative to exhaust valve closing (EVC) timing tends to produce a more stratified mixture, earlier ignition timing, and localized combustion, and hence higher NO x and lower unburned HC and CO emissions, whereas retarded IVO leads to faster mixing, a more homogeneous mixture, and uniform temperature distribution.

Compound disturbance rejection control of spark ignition–controlled-autoignition hybrid combustion for gasoline engines

2017 ◽  
Vol 232 (2) ◽  
pp. 264-281 ◽  
Author(s):  
Kang Song ◽  
Hui Xie ◽  
Tianyuan Hao
Keyword(s):  
Disturbance Rejection ◽  
Combustion Process ◽  
Spark Ignition ◽  
State Observer ◽  
Operating Conditions ◽  
Extended State Observer ◽  
Smooth Transition ◽  
Model Parameters ◽  
Extended State ◽  
Controlled Autoignition

Spark ignition–controlled-autoignition hybrid combustion is a promising concept because of its capability to achieve a smooth transition between spark ignition combustion and controlled-autoignition combustion, but it suffers from transient control owing to the high sensitivity to the operating conditions. In this paper, a control solution based on the principle of disturbance rejection is proposed for spark ignition–controlled-autoignition hybrid combustion. The complexity, the non-linearity and the cross-coupling inside are removed by idealizing the combustion process into three independent integrators, for the combustion timing channel, the indicated mean effective pressure channel and the λ (excessive air coefficient) channel respectively. All the other dynamics that deviate from the integrators (internal and external) are ‘lumped’ together as the total disturbance for each channel. With the total disturbance estimated in real time via the extended-state observer and eliminated by the disturbance rejection law, the enforced plant, i.e. the integrator, is controlled by a simple proportional controller. To enhance the response further, a non-linear model-inversion-based feedforward controller is added. In order to attenuate the slow time-varying disturbances, four correction factors for the model parameters are embedded in the model for online estimation. Validations by both simulations and experiments confirm the superiority of the proposed solution in terms of a fast transient response and a high robustness. By using the bandwidth-parameterization-based extended-state observer tuning method and a Kalman-filter-based extended-state observer, the controller is easy to tune, making it a promising candidate for applications of spark ignition–controlled-autoignition hybrid combustion.

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