Economy with Superior Thermal Efficient Combustion (ESTEC)

Yamada, Tetsu; Adachi, Shouji; Nakata, Kohei; Kurauchi, Takashi; Takagi, Isao

doi:10.4271/2014-01-1192

Cited by 27 publications

(9 citation statements)

References 4 publications

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“…Therefore, gear 3, gear 2, gear 1, and the eccentric sleeve rotate, and the piston position is changed. 9.5 to 10.1 under full load conditions, as Mazda [26] and Toyota [27] verified.…”

Section: Design Of Dsc-vcrmentioning

confidence: 67%

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A Predictive Study of a New VCR Engine with High Expansion Ratio and High-Efficiency Potential under Heavy Load Conditions

Lin

Yang

2020

Energies

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Facing the future, whether working alone or with electric motors, a new type of variable compression ratio (VCR) engine that can achieve a high thermal efficiency under heavy load conditions is necessary. Hence, we propose a dual shaft control variable compression ratio (DSC-VCR) engine based on a gear-driven eccentric sleeve. With the improved position of gears, DSC-VCR allows for double larger gears to share the load, and the engine can operate with a larger eccentric size and a narrower adjustment range compared to other similar mechanisms. This helps to reduce the difficulty of chamber shape design, avoid collisions between valves and piston, and above all, makes the engine operate with a larger overexpansion ratio (OER, the ratio of expansion stroke and compression stroke) under all conditions to improve engine efficiency. Based on a 1.5 T four-cylinder engine, the OER can be increased to over 1.16 with the eccentric size of 6.5 mm. According to the theoretical thermal efficiency calculation while considering turbocharging, the per millimeter increase of eccentric size improves the theoretical efficiency by 0.0025–0.006. The predictive simulation presented that the reduction of residual gas helps to increase the compression ratio (CR) from 9.5 to 10.1 under a full load condition. Larger OERs and CRs help to reduce brake specific fuel consumption (BSFC) by 6%–8%. In the case of a 75% load, about 3.51% of efficiency increase was realized. All of these prove that DSC-VCR is a high-efficiency potential mechanism for the future.

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“…Therefore, gear 3, gear 2, gear 1, and the eccentric sleeve rotate, and the piston position is changed. 9.5 to 10.1 under full load conditions, as Mazda [26] and Toyota [27] verified.…”

Section: Design Of Dsc-vcrmentioning

confidence: 67%

“…Simultaneously, a reduction of the residual gas fraction is helpful to increase the minimum CR from 9.5 to 10.1 under full load conditions, as Mazda [26] and Toyota [27] verified.…”

mentioning

confidence: 87%

A Predictive Study of a New VCR Engine with High Expansion Ratio and High-Efficiency Potential under Heavy Load Conditions

Lin

Yang

2020

Energies

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“…Future work will consider the application of the proposed feedback combustion control strategy to engines integrated into hybrid electric vehicles (HEVs). 35 In such architecture, the torque generated during the longer throttle tip-out can be used to charge the battery, rather than driving the vehicle. Therefore, electrification has the potential to enable a highly optimized combustion process that maximizes fuel efficiency for a variety of drive cycle scenarios.…”

Section: Discussionmentioning

confidence: 99%

Learning reference governor for cycle-to-cycle combustion control with misfire avoidance in spark-ignition engines at high exhaust gas recirculation–diluted conditions

Maldonado

Kolmanovsky

et al. 2020

International Journal of Engine Research

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Cycle-to-cycle feedback control is employed to achieve optimal combustion phasing while maintaining high levels of exhaust gas recirculation by adjusting the spark advance and the exhaust gas recirculation valve position. The control development is based on a control-oriented model that captures the effects of throttle position, exhaust gas recirculation valve position, and spark timing on the combustion phasing. Under the assumption that in-cylinder pressure information is available, an adaptive extended Kalman filter approach is used to estimate the exhaust gas recirculation rate into the intake manifold based on combustion phasing measurements. The estimation algorithm is adaptive since the cycle-to-cycle combustion variability (output covariance) is not known a priori and changes with operating conditions. A linear quadratic regulator controller is designed to maintain optimal combustion phasing while maximizing exhaust gas recirculation levels during load transients coming from throttle tip-in and tip-out commands from the driver. During throttle tip-outs, however, a combination of a high exhaust gas recirculation rate and an overly advanced spark, product of the dynamic response of the system, generates a sequence of misfire events. In this work, an explicit reference governor is used as an add-on scheme to the closed-loop system in order to avoid the violation of the misfire limit. The reference governor is enhanced with model-free learning which enables it to avoid misfires after a learning phase. Experimental results are reported which illustrate the potential of the proposed control strategy for achieving an optimal combustion process during highly diluted conditions for improving fuel efficiency.

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“…The increased focus on extended-expansion engines such as Miller and Atkinson cycles also are targeting the recovery of exhaust energy, but within the first expansion process. 15–17 However, geometric constraints within a single reciprocating cylinder typically limit the additional expansion in these implementations to 40%–50%.…”

Section: Introductionmentioning

confidence: 99%

Low-load expander deactivation studies for a light-duty single-shaft piston-compounded engine

Andruskiewicz

Durrett

Najt

2019

International Journal of Engine Research

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A single-shaft, piston-compounded engine has shown great potential for improvements in efficiency over current state-of-the-art light-duty engines through the use of an efficient second expansion process to more fully recover energy still present in the exhaust gasses. This process inherently works well at mid to high loads where the displacement ratio of the piston expander can be maximized and fully utilized, but the positive-displacement nature of piston compounding creates a liability in efficiency and exhaust gas temperature at low loads. This study examined the trade-offs in efficiency, exhaust temperature, and engine design for various methods of mitigating the low-load deficiencies of the piston-compounded design. An optimum solution was identified, and these results were then used to guide the design of an experimental piston-compounded engine.

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Economy with Superior Thermal Efficient Combustion (ESTEC)

Cited by 27 publications

References 4 publications

A Predictive Study of a New VCR Engine with High Expansion Ratio and High-Efficiency Potential under Heavy Load Conditions

A Predictive Study of a New VCR Engine with High Expansion Ratio and High-Efficiency Potential under Heavy Load Conditions

Learning reference governor for cycle-to-cycle combustion control with misfire avoidance in spark-ignition engines at high exhaust gas recirculation–diluted conditions

Low-load expander deactivation studies for a light-duty single-shaft piston-compounded engine

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