Engine Technologies for Achieving 45% Thermal Efficiency of S.I. Engine

Nakata, Kohei; Nogawa, Shinichiro; Takahashi, Daishi; Yoshihara, Yasushi; Kumagai, Atsunori; Suzuki, Tetsushi

doi:10.4271/2015-01-1896

Cited by 134 publications

(62 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…c * e 3800 T UBZ (3) In Equation (3), p c is the gas pressure, and T UBZ is the temperature of unburned zone, which is the same as the mean temperature during the intake and compression stroke [28].…”

Section: Improved Knock Resistancementioning

confidence: 99%

“…In spark-assisted homogeneous charge compression ignition (HCCI), which is the combustion system of a Volkswagen, the compression ratio (CR) plays an important role [2]. Engines achieve an efficiency of 45% for both Toyota [3] and Honda [4] cars that operate with the Miller/Atkinson cycle and a high exhaust gas recirculation (EGR) rate. The key to expand the lean burn limit includes a high CR, a high tumble, and an improved ignition system.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Lin

Yang

2020

Energies

View full text Add to dashboard Cite

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.

show abstract

Section: Improved Knock Resistancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Lin

Yang

2020

Energies

View full text Add to dashboard Cite

show abstract

“…Currently, internal combustion engines need to comply with severe regulations concerning fuel economy and pollutant emission. Focusing on spark ignition (SI) engines, actual trends to obtain a cleaner and more efficient combustion are turbocharging, water injection, high exhaust gas recirculation (EGR) dilution, and lean combustion [1][2][3][4][5]. Because of all these features, it is critical to ensure an effective ignition able to start a robust combustion; conventional spark plugs show their limits [6,7] and an excessive cycle-to-cycle variability (CCV) is linked to the use of conventional igniters in these conditions.…”

Section: Introductionmentioning

confidence: 99%

An Optical Method to Characterize Streamer Variability and Streamer-to-Flame Transition for Radio-Frequency Corona Discharges

et al. 2020

View full text Add to dashboard Cite

In recent years, radio-frequency corona ignition gained increasing interest from the engine research community because of its capability to extend the engine stable operating range in terms of lean and EGR dilution. The corona discharge generates streamers coming from a star-shaped electrode, generally consisting of four or five tips. The temporal and spatial variability of such streamers in length, orientation, and branching can be factors that affect the combustion onset and, therefore, engine cycle-to-cycle variability. Generally, the latter is reduced with respect to a conventional spark igniter at the same air–fuel ratio, but still present. In this work, analysis on the corona discharge and on the subsequent combustion onset was carried out in an optically accessible engine by means of the detection, via high-speed camera, of the natural luminosity of streamers and flames. A method to characterize spatial and temporal variability in motored conditions is firstly presented. A statistical analysis of the streamer behavior was performed, by separately analyzing the streamers generated by each tip of the star-shaped electrode. Finally, an original method aimed at determining the moment of the first flame appearance, caused by the combustion onset, is presented. The outcome of this work can be used to improve the knowledge on corona discharge, in particular on the stochastic behavior that characterizes the streamers. The presented optical analysis can also be adapted to other volumetric, single- or multi-point ignition systems.

show abstract

“…Numerous commercial software programs have been developed in the last two decades with the goal to cover requests coming from customers or market needs [42][43][44][45]. They permit reducing the time to obtain a product to its smaller time limits [22,23,[46][47][48][49][50]. Another important goal of using these software programs developed as tools consists the possibility to make a very quick decision on the choice of a viable design solution from a multitude of proposed solutions, based on different virtual analyses processes.…”

Section: Introductionmentioning

confidence: 99%

Kinematic and Dynamic Response of a Novel Engine Mechanism Design Driven by an Oscillation Arm

et al. 2020

View full text Add to dashboard Cite

The goal of this paper is to highlight the advantage fulfilled by a novel engine mechanism, the concept of which is based on an oscillating arm relative to the classical engine mechanism. Further, the results of this paper demonstrate the benefits of a novel type of mechanism and the major advantages in terms of functioning parameters of an engine. Their performances highly depend on the joint positions of the oscillating arm. The increases in the functional performances rate of success (i.e., piston stroke, volume of the combustion chamber or compression ratio) enable a superior engine power parameter (higher power, torque) and bring some additional improvement on the eco parameters of the engine related to consumption, emission, etc.

show abstract

Engine Technologies for Achieving 45% Thermal Efficiency of S.I. Engine

Cited by 134 publications

References 7 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

An Optical Method to Characterize Streamer Variability and Streamer-to-Flame Transition for Radio-Frequency Corona Discharges

Kinematic and Dynamic Response of a Novel Engine Mechanism Design Driven by an Oscillation Arm

Contact Info

Product

Resources

About