Browse Topic: Knock

Items (1,791)

Optimization of HEV Vehicle’s Engine Modulated Noise

2025-01-0084To be published on 05/05/2025

One 1.5L Miller-cycle turbocharged four cylinder gasoline hybrid engine is installed on a certain hybrid vehicle. When accelerating at low to medium speeds with a small throttle, there is a "da da" knocking noise inside the car, which seriously affects the overall sound quality of the vehicle. By analyzing the vibration and noise data of the engine, it was found that the frequency of the abnormal knocking sound is 200-1000Hz, which presents a half order characteristic in the time domain, that is, one knocking occurs when the engine crankshaft rotates twice. Through Hilbert demodulation analysis of the vibration data in the problem frequency range, it was found that the knocking noise was modulated in the frequency domain, with a modulation frequency of half of the crankshaft rotation frequency. By building a fully flexible multi-body dynamic model of a hybrid powertrain and inputting the engine's cylinder pressure excitation, the combustion excitation is coupled with mechanical

Dan, Kong

Experimental Investigation for the Effect of Cavity Geometry on the Flame Propagation and Auto-Ignition in RCM

2024-32-0060

04/18/2025

In this experiment, we investigated the auto-ignition and flame propagation behavior by using flat piston and cavity pistons which has different geometries, depth, and width of the cavity. In this study, flame behavior inside the cavity is visualized with the ion-probes, which is embedded every 3mm radially from the center of the piston. We also used the pressure sensor in the combustion chamber and high-speed camera through the quartz window near the cylinder wall. Flame appearance obtained with high-speed camera shows that the flame propagation of the cavity piston is faster than that of flat piston. This is considered because of the outward induced flow in the squish area. That is, the flame propagation inside the wide cavity area pushes the unburned gas outwardly and induced the outward flow in the squish area. This induced flow promotes the flame propagation. As a result, unburned gas is consumed rapidly, and thus, it is also found that the intensity of Knocking is reduced by

Yamaguchi, Riki, Esaki, Daigo, Tateishi, Tokua, Osaf, Ali Hassan, Miyoshi, Akira, Shimokuri, Daisuke, Yatsufusa, Tomoaki, Terashima, Hiroshi, Hara, Takaya, Honda, Yuya, Tadokoro, Tadashi, Kawano, Michiharu

Effects of Hydrogen Addition on Spark Knock Suppression under High Engine Speed and Boosted Conditions

2024-32-0108

04/18/2025

The effect of hydrogen addition on spark knock suppression under high engine speed (4800 rpm) was investigated at the intake pressures of 96 kPa and 120 kPa. The experimental results showed that hydrogen addition has a slight effect on advancing the knock limit at 96 kPa, whereas a greater spark knock suppression effect can be achieved by increasing the intake pressure. To elucidate the influences and differences of hydrogen addition on the ignition process under low and high intake pressures, chemical kinetic analyses were performed using a two-zone combustion model. The calculation results showed that the reduction of heat release in the end gas resulting from the consumption of OH radicals by hydrogen can only be achieved at the initial stage of the ignition process. This leads to the smaller knock suppression effect at low intake pressures, where a remarkable heat release at this stage is absent. On the other hand, an increase in intake pressure results in a remarkable heat release

Goto, Jun, Ueno, Yoshito, Kobashi, Yoshimitsu, Shibata, Gen, Ogawa, Hideyuki, Kojima, Kentaro

Impact of Ordinal Proximity of Frequency Components on the Auditory Perception of Engine Knocking

2024-32-0032

04/18/2025

This study examines the acoustic properties of engine-knocking sounds in gasoline engines, arising from misfires during spark ignition that negatively affect driving performance. The aim was to understand the frequency characteristics of acceleration sounds and their connection to the proximity of the order components. The study also explores “booming,” where two different frequencies of sounds occur simultaneously, potentially linked to the unpleasant nature of engine knocking. Using a sinusoidal model, we generated engine acceleration sound models with 5th-, 10th-, and 15th-order components, including engine knocking. Two types of sound stimuli were created: one with the original amplitude (OA) and one with a constant amplitude (CA) for each component order, emphasizing the order-component proximity in CA sounds. Aural experiments with 10 participants in an anechoic room using headphones and the MUSHRA method revealed an inverse relationship between OA and CA ratings as the component

Suzuki, Ryuhei, Ishimitsu, Shunsuke, Nitta, Misaki, Sakakibara, Mika, Hakozaki, Tomoyuki, Fujikawa, Satoshi, Iwata, Kiyoaki, Matsumoto, Mitsunori, Kikuchi, Masakazu

Prediction of Pre-Ignition Borderline on Supercharged SI Engine by Livengood-Wu Integral

2024-32-0008

04/18/2025

The LSPI (Low Speed Pre-Ignition) is one of the consecutive abnormal combustion cycles of supercharged SI engine with direct injection fuel supply system [1]. The LSPI occurs when the engine is running at low speed and high load condition. It is important for the SI engine to control essentially with alternative fuel, e-fuel and hydrogen in the future. It is considered that the LSPI would be caused by the autoignition of the deposit, the lubricating oil from ring crevice, the lubricating oil from piston crown and so on [2, 3, 4, 5]. Among of these causes, this research focuses on the scattering lubricating oil from piston crown. The previous our research has reported on the two points. One is about the frequency and quantity of the lubricating oil scattering from piston crown [6]. Another is about the frequency of abnormal combustion by the engine test [7]. As the result, it has been cleared that the frequency of abnormal combustion is 1/10 of scattering frequency of the lubricating

Omori, Takaya, Tanaka, Junya

Effects of Critical Compression Ratio on Rating Gasoline Knock Propensity

2025-01-8451

04/01/2025

It is common practice in the automotive industry to explore the knock limits of fuels on an engine by a comparison of the knock limited spark advance (KLSA) at threshold knock intensity. However, the knock propensity of gasolines can be rated by changing one of three metrics on a variable compression ratio Cooperative Fuels Research (CFR) octane rating engine while holding the other two variables constant: knock intensity, spark timing, and critical compression ratio. The operational differences between the standard research octane number (RON) rating and modern engine operation have been explored in three parts. The first part focused on the effects of lambda and knock characterization. The second part studied the effects of spark timing. This third part explores the knock ratings of several gasolines by comparing the critical compression ratios at constant combustion phasing and knock intensity. The threshold knock intensity was based on the standard octane rating D1 pickup or by

Kolodziej, Christopher, Hoth, Alexander

Knock Assessment in Wankel Rotary Engine Adopting Low Octane Rating Fuels

2025-01-8452

04/01/2025

Series hybrid vehicles with internal combustion range extenders are a promising solution for sustainable transportation. In this application, net zero carbon emissions can be achieved using renewable fuels. Fischer-Tropsch-derived e-gasolines/naptha allow for high energy density and safe liquid fuels. However, Fischer-Tropsch naptha fuel derivatives must undergo several processing stages to reach current engine-grade octane ratings, negatively affecting the synthesis's profitability and energy efficiency. Gasoline engine technologies capable of operating with low-octane fuels could allow the adoption of unprocessed Fischer-Tropsch gasoline. The rotary Wankel engine design suits range extenders thanks to its high power-to-size ratio. In this study, the knocking tendency of homogenous charge spark-ignition rotary Wankel engines is numerically assessed through Chemkin-Pro spark-ignition engine zonal model for knock assessment. Rotary Wankel engines are modeled by providing the

Brunialti, Sirio, Vorraro, Giovanni, Turner, James, Sarathy, Mani

Experimental Investigation between Pre-Ignition, Knocking, Vibration and Performance in an Internal Combustion Engine

2025-01-8380

04/01/2025

Otto cycle internal combustion engines have undergone technological developments that can be fueled by various types of fuels in different mixture proportions. To achieve this, a detailed study of the main factors that influence the engine combustion process is necessary. The objective of this study is to evaluate the effects of varying the ignition advance on the performance parameters and vibration level of the engine operated with regular gasoline, podium gasoline, ethanol and a mixture of ethanol with regular gasoline. The experimental tests consisted of operating an Otto cycle engine on a bench dynamometer under full load conditions, varying rotation and ignition advance by 5, 10 and 20% in relation to the original ignition advance and correlating the levels of pre-ignition, knock, engine vibration levels with engine performance parameters. The results showed that the engine vibration level was influenced by the type of fuel used, engine performance parameters and the presence of

Santana, Claudio

Impact of Oxygenated Fuel Components on Engine Performance and Particulate Emissions in Gasoline Blends

2025-01-8446

04/01/2025

The challenges with electrification in the automotive industry have led to rethinking the decisions to ban internal combustion engines. Nonetheless, decarbonization of transportation remains a regulatory priority in many countries, irrespective of the energy source for automotive powertrains. Renewable oxygenated fuel components can help with the rapid decarbonization of gasoline fuels in the current fleet. Ethanol is one of the primary renewable components typically used for blending in gasoline primarily at 10% v/v but up to 20% v/v substitution which corresponds to 3.7 to 8.0% oxygen by mass. However, a range of oxygenates could be used instead of ethanol. This study aimed to determine if the engine could discriminate between different oxygenates in gasoline fuels blended at the same octane (RON) and oxygen levels. Oxygenates such as methyl-tert-butyl-ether (MTBE) and ethyl-tert-butyl-ether (ETBE) were considered in this study. Blends were made using a combination of n-heptane, iso

Kalaskar, Vickey, Mitchell, Robert, Pourreau, Daniel

Experimental and Numerical Investigation of Different Dilution Techniques in a High-Performance H2 - Fueled SI Engine

2025-01-8424

04/01/2025

Nowadays, hydrogen (H2) is rising as a key solution to fuel internal combustion engines (ICE) since it allows carbon free combustion process. At the same time, ICE fueled with H2 can reach similar performance and driving experience of gasoline fueled ones. In stoichiometric conditions, hydrogen shows higher flame speed, lower ignition energy and lower quenching distance than gasoline. Mainly for these reasons, H2 combustion is characterized by a high risk of abnormal combustion (i.e. knock and pre-ignition), relevant NOx emissions and high heat losses. On the other hand, the wide flammability range and high combustion stability of H2 allow the use of different techniques to reduce combustion reactivity. This work presents a combined approach, experimental and numerical, to assess the benefits of three mixture dilution methods. The experimental campaign, in different operating conditions, was carried out on a production derived high specific power gasoline Single Cylinder Engine (SCE

Tonelli, Roberto, Medda, Massimo, Gullino, Fabrizio, Silvestri, Nicola, Zaffino, Francesco, Mariconti, Roberto, Rossi, Vincenzo

Influence of Methanol-to-Gasoline Fuel Formulation on Knock Propensity and Flame Speed

2025-01-8400

04/01/2025

Drop-in gasoline fuels that originate from renewable, low-net-carbon sources, such as methanol-to-gasoline (MTG), are an important bridge in the transition between traditional fossil fuels and electrification of the transportation sector. The composition of these fuels can be tuned by adjusting the settings of the chemical processes used to create them, which can be leveraged to formulate optimized fuels for higher knock resistance or higher flame speed. This study investigated how the distribution of hydrocarbon classes and molecular structure of a renewable MTG gasoline surrogate affected knock and flame speed using chemical kinetic modeling. The original MTG surrogate was modified by increasing the relative amount of a certain hydrocarbon class while the concentration of other hydrocarbon classes is reduced equally. Increasing normal- and iso-alkanes increased reactivity and penalized octane sensitivity, olefins increased octane sensitivity while keeping the research octane number

MacDonald, James, Lopez Pintor, Dario, Matsubara, Naoyoshi, Kitano, Koji, Yamada, Ryota

Control Re-Optimization of a Series-Parallel Hybrid Powertrain Fueled with High-Octane Gasoline

2025-01-7028

01/31/2025

High-octane gasoline has the potential to improve engine efficiency but has been reported to marginally reduce and even increase vehicle fuel consumption. The objective of this study is to evaluate the fuel-saving effect of high-octane gasoline on series-parallel hybrid electric vehicles (HEVs) under the re-optimized powertrain control, including engine control and energy management. Firstly, a bench test was conducted on a spark ignition engine fueled with three fuels with research octane numbers of approximately 92, 95, and 98, named 92#, 95#, and 98#. Then the engine control parameter (i.e., spark advance) was re-optimized for maximum engine efficiency and acceptable particle number emissions with the knock constraint. Finally, the energy management was re-optimized for a series-parallel hybrid powertrain equipped with the engine. It was found that 95# and 98# even increased vehicle fuel consumption by 0.2% and 0.6% without the re-optimization of powertrain control compared with 92

Tan, Guikun, Li, Ji, Li, Yanfei, Wang, Changhui, Sun, Yuncai, Xu, Anzhao, Shuai, Shijin, Xu, Hongming

Analysis of the Characteristics of Hybrid Vehicles and Low-Viscosity Lubricating Oil Based on Real Road Tests in Four Extreme Environments

04-18-02-0009

01/07/2025

As countries around the world attach more importance to carbon emissions and more stringent requirements are put forward for vehicle emissions, hybrid vehicles, which can significantly reduce emissions compared with traditional fuel vehicles, as well as low-viscosity lubricating oil, have become significant trends in the industry. In this article, a total of nine vehicles of 48 V mild-hybrid models and full-hybrid models are tested. Using three kinds of low-viscosity lubricating oil and driving a total of 120,000 km in environments with low temperature, high humidity, high temperature, or high altitude, the engines are then disassembled and scored. The effects of the four extreme environments on the engine starts–stops, ignition advance angle, engine power, state of charge (SOC), acceleration performance, and oil consumption characteristics of hybrid vehicles are studied; the oxidation characteristics and iron content change characteristics of low-viscosity lubricating oil are analyzed

Zhu, Gezhengting, Hu, Hua, Pan, Jinchong, Luo, Yitao, Hua, Lun, Jiao, Yan, Jiang, Jiandi, Shao, Heng, Xu, Zhengxin, Yan, Jingfeng, Wei, Guangyuan, Zhang, Heng

Experimental Investigation of Performance and Vibration Parameters of an Otto Cycle Engine Operated with Regular Gasoline, Premium Gasoline, Pure Ethanol and Mixture of Ethanol with Regular Gasoline

2024-36-0001

12/20/2024

Otto cycle internal combustion engines have undergone technological developments that can be fueled by various types of fuels in different mixture proportions. To achieve this, a detailed study of the main factors that influence the engine combustion process is necessary. The objective of this study is to evaluate the effects of varying the ignition advance on the performance parameters and vibration level of the engine operated with regular gasoline, premium gasoline, ethanol and a mixture of ethanol with regular gasoline. The experimental tests consisted of operating an Otto cycle engine on a bench dynamometer under full load conditions, varying rotation and ignition advance by 5, 10 and 20% in relation to the original ignition advance and correlating the levels of pre-ignition, knock, engine vibration levels with engine performance parameters. The results showed that the engine vibration level was influenced by the type of fuel used, engine performance parameters and the presence of

Santana, Claudio Marcio, Santana, Linicker Lopes Bruno, Almeida, Helder Giostri Alves

Fuel Design Concept to Improve Both Combustion Stability and Antiknocking Property Focusing on Ethane

2024-01-4276

11/05/2024

For realizing a super-leanburn SI engine with a very-high compression ratio, it is necessary to design a new fuel which could have low ignitability at a low temperature for antiknocking, but high ignitability at a high temperature for some contribution to stable combustion. C2H6 has a very-long ignition delay time at a low temperature, close to that of CH4, but a short ignition delay time at a high temperature, close to that of gasoline. C2H6 also has a laminar burning velocity about 1.2 times higher than that of gasoline. C2H6 addition to gasoline could be a good example of fuel design to improve both combustion stability and antiknocking property. In the present study, the antiknocking effect of adding CH4, C2H6, or C3H8 with the RON of 120, 115, or 112, respectively, to a regular-gasoline surrogate fuel with the RON of 90.8 has been investigated in an SI engine with a stoichiometric mixture. With the energy fraction of the gaseous fuel of less than 0.35, knocking limit CA50 is

Kuwahara, Kazunari, Shimizu, Taisei, Okada, Atsuki

Premixed Dual-Fuel Combustion of Camelina sativa Oil and Ethanol

03-18-01-0001

08/06/2024

Dual-fuel (DF) engines enable efficient utilization of a low reactivity fuel (LRF), usually port-injected, and a high reactivity fuel (HRF) provided directly into the cylinder. Ethanol and Camelina sativa oil can be ecologically effective but not fully recognized alternatives for energy production using modern CI engines equipped with a common rail system and adopted for dual fueling. The high efficiency of the process depends on the organization of the combustion. The article describes the premixed dual-fuel combustion (PDFC) realized by dividing the Camelina sativa dose and adjusting its injection timing to the energetic share of ethanol in the DF mixture. The injection strategy of HRF is crucial to confine knock, which limits DF engine operation, but the influence of EGR is also important. The research AVL engine’s dual-fueling tests focused on combustion process modification by the proposed injection strategy and cooled EGR at different substitution rates. For all examined points

Pawlak, Grzegorz, Skrzek, Tomasz, Kosiuczenko, Krzysztof, Płochocki, Patryk, Simiński, Przemysław

Effects of Dimethyl Ether and Propane Blends on Knocking Behavior in a Boosted SI Engine

03-17-07-0056

06/12/2024

Dimethyl ether (DME) is an alternative fuel that, blended with propane, could be an excellent alternative for exploring the use of fuels from renewable sources. DME–propane blends are feasible for their comparable physicochemical properties; these fuels may be pressured as liquids using moderate pressure at ambient temperature. Adding a proportion of DME with a low octane number to a less reactive fuel like propane can improve the combustion process. However, the increased reactivity of the mixture induced by the DME could lead to the early appearance of knocking, and this tendency may even be pronounced in boosted SI engines. Hence, this study experimentally analyzes the effect of E10 gasoline (baseline) and DME–propane blends, with varying proportions of DME in propane ranging from 0% to 30% by weight, in increments of 5% on knocking tendency, combustion characteristics, gaseous emissions, and particle number concentration, under different intake pressure conditions (0.8, 0.9, 1.0

Soto, Lian, Han, Taehoon, Boehman, Andre L.

Potential Analysis of Defossilized Operation of a Heavy-Duty Dual-Fuel Engine Utilizing Dimethyl Carbonate/Methyl Formate as Primary and Poly Oxymethylene Dimethyl Ether as Pilot Fuel

03-17-07-0053

04/18/2024

This study demonstrates the defossilized operation of a heavy-duty port-fuel-injected dual-fuel engine and highlights its potential benefits with minimal retrofitting effort. The investigation focuses on the optical characterization of the in-cylinder processes, ranging from mixture formation, ignition, and combustion, on a fully optically accessible single-cylinder research engine. The article revisits selected operating conditions in a thermodynamic configuration combined with Fourier transform infrared spectroscopy. One approach is to quickly diminish fossil fuel use by retrofitting present engines with decarbonized or defossilized alternatives. As both fuels are oxygenated, a considerable change in the overall ignition limits, air–fuel equivalence ratio, burning rate, and resistance against undesired pre-ignition or knocking is expected, with dire need of characterization. Two simultaneous high-speed recording channels granted cycle-resolved access to the natural flame luminosity

Mühlthaler, Markus Sebastian, Härtl, Martin, Jaensch, Malte

Deflagration-Based Knock of Methanol SI Combustion and its Implications for Combustion Noise

2024-01-2819

04/09/2024

Methanol emerges as a compelling renewable fuel for decarbonizing engine applications due to a mature industry with high production capacity, existing distribution infrastructure, low carbon intensity and favorable cost. Methanol’s high flame speed and high autoignition resistance render it particularly well-suited for spark-ignition (SI) engines. Previous research showed a distinct phenomenon, known deflagration-based knock in methanol combustion, whereby knocking combustion was observed albeit without end-gas autoignition. This work studies the implications of deflagration-based knock on noise emissions by investigating the knock intensity and combustion noise at knock-limited operation of methanol in a single-cylinder direct-injection SI engine operated at both stoichiometric and lean (λ = 2.0) conditions. Results are compared against observations from a premium-grade gasoline. Experiments show that methanol’s end-gas autoignition occurs at lean conditions, leading to the typical

Singh, Eshan, Strickland, Tyler, Abboud, Rami, MacDonald, James, Lee, Sanguk, Lopez Pintor, Dario

Effect of Port Water Injection on the Knock and Combustion Characteristics for an Argon Power Cycle Hydrogen Engine

2024-01-2612

04/09/2024

Argon power cycle hydrogen engine is an internal combustion engine that employs argon instead of nitrogen of air as the working fluid, oxygen as the oxidizer, and hydrogen as the fuel. Since argon has a higher specific heat ratio than air, argon power cycle hydrogen engines have theoretically higher indicated thermal efficiencies according to the Otto cycle efficiency formula. However, argon makes the end mixture more susceptible to spontaneous combustion and thus is accompanied by a stronger knock at a lower compression ratio, thus limiting the improvement of thermal efficiency in engine operation. In order to suppress the limitation of knock on the thermal efficiency, this paper adopts a combination of experimental and simulation methods to investigate the effects of port water injection on the knock suppression and combustion characteristics of an argon power cycle hydrogen engine. The results show that the port water injection can effectively reduce the knock intensity of the argon

Tang, Yongjian, Deng, Jun, Xie, Kaien, Jin, Shaoye, Li, Liguang

Fuel Sensitivity Affects on the Knock and CoV Limits of a Spark Ignited Engine

2024-01-2816

04/09/2024

Engine knock is one of the limiting factors in determining the compression ratio and engine efficiency for spark ignited engines. Using the Southwest Research Institute Knock-CoV test method, it was previously shown that the knock limited load versus combustion phasing (CA50) has a constant slope. All of the knock mitigation strategies tested provided a shift to these knock limited loads but also increased the slope. That is, for the same CA50 retard the knock limited load could be increased more. Our hypothesis was that due to fuel sensitivity, or the difference between the RON and MON, the reactions that lead to knock will behave differently as the pressure-temperature history changes with engine speeds and loads. The fuel affects on the knock and CoV limits were studied by testing fuels with various sensitivities including methanol, E85 (85% ethanol) and Iso-octane. Methanol and E85 have higher sensitivities compared to the baseline gasoline fuel and as a result showed a steeper

Mitchell, Robert, Conway, Graham, Wang, Yanyu

Effects of Ethanol Blending on the Reactivity and Laminar Flame Speeds of Gasoline, Methanol-to-Gasoline, and Ethanol-to-Gasoline Surrogates

2024-01-2817

04/09/2024

Ethanol blending is one method that can be used to reduce knock in spark ignition engines by decreasing the autoignition reactivity of the fuel and modifying its laminar flame speed. In this paper, the effects of ethanol blending on knock propensity and flame speed of petroleum and low-carbon gasoline fuels is analyzed. To do so, surrogate fuels were formulated for methanol-to-gasoline (MTG) and ethanol-to-gasoline (ETG) based on the fuels’ composition, octane number, and select physical properties; and 0-D and 1-D chemical kinetics simulations were performed to investigate reactivity and laminar flame speed, respectively. Results of MTG and ETG were compared against those of PACE-20, a well-characterized surrogate for regular E10 gasoline. Similarly to PACE-20, blending MTG and ETG with ethanol increases the fuel’s research octane number (RON) and sensitivity. The trends of the ethanol blending effects were slightly stronger with PACE-20 and MTG than with ETG, with 13.6% volume of

MacDonald, James, Lopez Pintor, Dario, Matsubara, Naoyoshi, Kitano, Koji, Yamada, Ryota

A Comparative Study of Knock Formation in Gasoline and Methanol Combustion Using a Multiple Spark Ignition Approach: An Optical Investigation

2024-01-2105

04/09/2024

Engine knock is a major challenge that limits the achievement of higher engine efficiency by increasing the compression ratio of the engine. To address this issue, using a higher octane number fuel can be a potential solution to reduce or eliminate the propensity for knock and so obtain better engine performance. Methanol, a promising alternative fuel, can be produced from conventional and non-conventional energy resources, which can help reduce pollutant emissions. Methanol has a higher octane number than typically gasolines, which makes it a viable option for reducing knock intensity. This study compared the combustion characteristics of gasoline and methanol fuels in an optical spark-ignition engine using multiple spark plugs. The experiment was carried out on a single-cylinder four-stroke optical engine. The researchers used a customized metal liner with four circumferential spark plugs to generate multiple flame kernels inside the combustion chamber. The results indicated that

Uddeen, Kalim, Tang, Qinglong, Shi, Hao, Almatrafi, Fahad, Magnotti, Gaetano, Turner, James

Efficiency Enhancement and Lean Combustion Performance Improvement by Argon Power Cycle in a Methane Direct Injection Engine

2023-01-1618

10/31/2023

Argon Power Cycle (APC) is an innovative future potential power system for high efficiency and zero emissions, which employs an Ar-O2 mixture rather than air as the working substance. However, APC hydrogen engines face the challenge of knock suppression. Compared to hydrogen, methane has a better anti-knock capacity and thus is an excellent potential fuel for APC engines. In previous studies, the methane is injected into the intake port. Nevertheless, for lean combustion, the stratified in-cylinder mixture formed by methane direct injection has superior combustion performances. Therefore, based on a methane direct injection engine at compression ratio = 9.6 and 1000 r/min, this study experimentally investigates the effects of replacing air by an Ar-O2 mixture (79%Ar+21%O2) on thermal efficiencies, loads, and other combustion characteristics under different excess oxygen ratios. Meanwhile, the influences of varying the methane injection timing are studied. Results indicate that by

Wang, Chenxu, Deng, Jun, Su, Xiang, Cui, Wenyi, Tang, Yongjian, Li, Liguang

Analysis of Real-World Preignition Data Using Neural Networks

2023-01-1614

10/31/2023

1Increasing adoption of downsized, boosted, spark-ignition engines has improved vehicle fuel economy, and continued improvement is desirable to reduce carbon emissions in the near-term. However, this strategy is limited by damaging preignition events which can cause hardware failure. Research to date has shed light on various contributing factors related to fuel and lubricant properties as well as calibration strategies, but the causal factors behind an individual preignition cycle remain elusive. If actionable precursors could be identified, mitigation through active control strategies would be possible. This paper uses artificial neural networks to search for identifiable precursors in the cylinder pressure data from a large real-world data set containing many preignition cycles. It is found that while follow-up preignition cycles in clusters can be readily predicted, the initial preignition cycle is not predictable based on features of the cylinder pressure. This indicates that the

Kaul, Brian, Maldonado, Bryan, Michlberger, Alexander, Halley, Scott

Analysis of a Split Injection Strategy to Enable High Load, High Compression Ratio Spark Ignition with Hydrous Ethanol

2023-01-1616

10/31/2023

High compression ratios are critical to increasing the efficiency of spark ignition engines, but the trend in downsized and down sped configurations has brought attention to the nominally low compression ratios used to avoid knock. Knock is an abnormal combustion event defined by the acoustic sound caused by end-gas auto-ignition ahead of the flame front. In order to avoid engine-damaging levels of knock, low compression ratios and retarded combustion phasing at high loads are used, both of which lower efficiency. Low carbon alternative fuels such as ethanol or water-based alcohol fuels combine strong chemical auto-ignition resistance with large charge cooling characteristics that can suppress knock and enable optimal combustion phasing, thus allowing an increase in the compression ratio. Of course, these high cooling potential fuels are not immune to knock at high loads at high enough compression ratios and are subject to the same combustion phasing strategies (i.e., spark retard

Gandolfo, John, Kumar, Mohit, Gao, Mingyang, Lawler, Benjamin, Gainey, Brian

Performance of the Mixture of Ammonia and Ammonia Decomposition Products as a Carbon-Free Fuel for Spark Ignition Engines

2023-01-1638

10/31/2023

This work is devoted to assessment of the reactivity of the ammonia-based mixed fuels consisting of ammonia and products of its decomposition to hydrogen and nitrogen. For these purposes the thermodynamic, chemical kinetics and engine cycle simulations are performed. The dependence of the mixed fuels laminar flame speed, which is a measure of fuel reactivity, on ammonia decomposition degree is obtained. It is shown, that if about 37% of ammonia are decomposed and mixed with remaining ammonia (either hydrogen/nitrogen or pure hydrogen), then the reactivity of obtained mixture is similar to that of natural gas in a wide range of conditions. The engine performance parameters are estimated and compared for two fuels with the similar reactivity: natural gas or ammonia-based mixed fuels. It is shown, that the reduction of engine power by 8% is obtained when transferring from natural gas to considered ammonia-based mixed fuel. Reduction of NOx emissions is about 50% due to lower combustion

Zaev, Ivan, Smirnov, Sergey, Gordeev, Vladislav

Divided Exhaust Period Assessment for Fuel-Enrichment Reduction in Turbocharged Spark-Ignition Engines

03-17-03-0022

10/26/2023

Turbocharged spark-ignition (SI) engines, owing to frequent engine knocking events, utilize retarded spark timing that causes combustion inefficiency, and high turbine inlet temperature (Trb-In T) levels. Fuel enrichment is implemented at high power levels to prevent excessive Trb-In T levels, resulting in an additional fueling penalty and higher CO emissions. In current times, fuel-enrichment reductions are of high strategic importance for engine manufacturers to meet the imminent emissions regulations. To that end, the authors investigated the divided exhaust period (DEP) concept in a 2.2 L turbocharged SI engine with a geometric compression ratio of 14 by decoupling blowdown (BD) and scavenge (SC) events during the exhaust process. Using a validated 1D engine model, the authors first analyzed the DEP concept in terms of pumping mean effective pressure (PMEP) and engine knocking (KI) reduction. Subsequently, the authors examined the effectiveness of the DEP concept using a “low

Kumar, Praveen, Yu, Xin, Zhang, Anqi, Baur, Andrew, Engineer, Nayan, Roth, David

A Study of the Mechanism of High-Speed Knocking in a Two-Stroke SI Engine with High Compression Ratio

2023-01-1824

10/24/2023

Experimental methods and numerical analysis were used to investigate the mechanism of high-speed knocking that occurs in small two-stroke engines. The multi-ion probe method was used in the experiments to visualize flame propagation in the cylinder. The flame was detected by 14 ion probes grounded in the end gas region. A histogram was made of the order in which flames were detected. The characteristics of combustion in the cylinder were clarified by comparing warming up and after warming up and by extracting the features of the cycle in which knocking occurred. As a result, regions of fast flame propagation and regions prone to auto-ignition were identified. In the numerical analysis, flow and residual gas distribution in the cylinder, flame propagation and self-ignition were visualized by 3D CFD using 1D CFD calculation results as boundary conditions and initial conditions. Flame propagation calculated by 3D CFD was found to be directional due to in-cylinder flow caused by scavenging

Eto, Kuniyoshi, Kuboyama, Tatsuya, Moriyoshi, Yasuo, Yamada, Toshio, Yatsufusa, Tomoaki, Suzuki, Yusuke

Visualization and Statistical Analysis of Passive Pre-chamber Knock in a Constant-volume Optical Engine

03-17-03-0020

10/20/2023

This study investigates the behavior of pre-chamber knock in comparison to traditional spark ignition engine knock, using a modified constant-volume gasoline engine with an optically accessible piston. The aim is to provide a deeper understanding of pre-chamber knock combustion and its potential for mitigating knock. Five passive pre-chambers with different nozzle diameters, volumes, and nozzle numbers were tested, and nitrogen dilution was varied from 0% to 10%. The stochastic nature of knock behavior necessitates the use of statistical methods, leading to the proposal of a high-frequency band-pass filter (37–43 kHz) as an alternative pre-chamber knock metric. Pre-chamber knock combustion was found to exhibit fewer strong knock cycles compared to SI engines, indicating its potential for mitigating knock intensity. High-speed images revealed pre-chamber knock primarily occurs near the liner, where end-gas knock is typically exhibited. The study identified that increasing pre-chamber

Lee, Dong Eun, Yu, Xin, Baur, Andrew, Qiao, Li

Simulation of charged species flow and ion current detection for knock sensing in gasoline engines with active pre-chamber

2023-32-0005

09/29/2023

Recently, it has been wildly recognized that active pre- chamber has a significant effect on extending the lean burn limit of gasoline engines. Ion current signals in the combustion is also considered as a promising approach to the engine knock detection. In this study, the feasibility of employing ion current in an active pre- chamber for combustion diagnosis was analyzed by three-dimensional numerical simulation on a single- cylinder engine equipped with active pre-chamber. The flow characteristics of charged species (NO+, H3O+ and electrons) in the main chamber and pre-chamber under knock conditions are investigated at different engine speeds, intake pressures and ignition timings. The results show that the ion current can theoretically be used for the knock detection of the active pre- chamber. The peak value of the electron or H3O+ mass fraction caused by knocking backflow can be used as knock indication peak. Intake pressure is the most critical factor affecting the intensity of

MIAO, Xinke, FEI, Shengyi, DENG, Jun, LI, Liguang, HU, Yinuo, MA, Junjie

Pre-ignition Behavior of Gasoline Blends in a Single- Cylinder Engine with Varying Boost Pressure and Compression Ratio

2023-32-0120

09/29/2023

Pre-ignition in a boosted spark-ignition engine can be triggered by several mechanisms, including oil-fuel droplets, deposits, overheated engine components and gas-phase autoignition of the fuel-air mixture. A high pre-ignition resistance of the fuel used mitigates the risk of engine damage, since pre-ignition can evolve into super-knock. This paper presents the pre-ignition propensities of 11 RON 89-100+ gasoline fuel blends in a single-cylinder research engine. Albeit the addition of two high-octane components (methanol and reformate) to a toluene primary reference fuel improved the pre-ignition resistance, one high-RON fuel experienced runaway pre-ignition at relatively low boost pressure levels. A comparison of RON 96 blends showed that the fuel composition can affect pre-ignition resistance at constant RON.

Rönn, Kristian, Larmi, Martti, Pehlivanlar, Benjamin, Göbel, Christoph, Pischinger, Stefan, Karvo, Anna, Lehto, Kalle, Fryjan, Johannes

Study of Knocking Mitigation and Thermal Efficiency Enhancement of Pre-chamber Jet Combustion in Stoichiometric Gasoline Engine

2023-32-0006

09/29/2023

Pre-chamber jet combustion is known to be effective in knocking mitigation as it can increase the combustion speed in spark ignition engines. Therefore, a study was made of the effect of knocking mitigation and thermal efficiency improvement when passive type pre-chamber jet combustion is applied to a gasoline stoichiometric spark ignition combustion engine. Compared to conventional spark ignition combustion engines, pre-chamber jet combustion has enhanced penetration of flame propagation depending on flow rate and flow velocity at the pre-chamber jet hole, and the flame propagation combustion rate inside the pre-chamber. Due to the jet ejected from the pre-chamber, the flame could quickly reach the end of the bore. Moreover, the combustion period was shortened, and the unburned portion of the end gas in the latter half of the combustion was reduced, resulting in knocking mitigation. Furthermore, increasing the number of jets by increasing the number of pre-chamber holes caused the

Ando, Hirokazu, Shintani, Yusuke, Kobayashi, Hiroki, Shiina, Ryosuke, Kimura, Noritaka

Numerical Investigation of Knocking in a Small Two-Stroke Engine with a High Compression Ration to Improve Thermal Efficiency

2023-32-0079

09/29/2023

This study aimed to achieve both a high compression ratio and low knock intensity in a two-stroke engine. Previous research has suggested that knock intensity can be reduced by combining combustion chamber geometry and scavenging passaging design for the same engine specifications with a compression ratio of 13.7. In this report, we investigate whether low knock intensity can be achieved at compression ratios of 14.4 and 16.8 by adjusting the combustion chamber geometry and scavenging passage design. As a result, the mechanism by which combustion chamber geometry and scavenging passage design change knock intensity was clarified.

Eto, Kuniyoshi, Kuboyama, Tatsuya, Moriyoshi, Yasuo, Yamada, Toshio, Yamazaki, Takahiro, Yamaguchi, Shiro

Effect of Olefin Content in Gasoline on Knock Characteristics and HCHO Emission in Lean Burn Spark Ignition Engine

2023-32-0083

09/29/2023

In transportation sector, higher engine thermal efficiency is currently required to solve the energy crisis and environmental problems. In spark ignition (SI) engine, lean-burn strategy is the promising approach to improve thermal efficiency and lower emissions. Olefins are the attractive component for gasoline additives, because they are more reactive and have advantage in lean limit extension. However, owing to lower research octane number (RON), it is expected to exhibit the drawback to reducing the anti-knock performance. The experiments were performed using a single-cylinder engine for 6 fuel types including gasoline blends which have difference in RON varying between 90.4 and 100.2. The results showed that adding olefin content to the premium gasoline provided unfavorable effect on auto-ignition as the auto-ignition happened at unburned gas temperature of 808 K which was 52 K lower at excess air of 2.0. Thus, it reduced anti-knock performance. Additional oxygenated fuels such as

Shinabuth, Dittapoom, Ohmori, Yuya, Kitajima, Katsuki, Ono, Tomoya, Sakaida,, Satoshi, Sakai, Yasuyuki, Konno, Mitsuru, Tanaka, Kotaro

Research on Super-Lean Burn Spark Ignition Engine with In-Cylinder Water Injection using Gasoline Surrogate Fuels

2023-32-0055

09/29/2023

The combination of super-lean burn spark ignition engine (excess air ratio λ ≈ 2) and in-cylinder water injection (WI) makes it possible to achieve thermal efficiency higher than 50%. Toward future fuel diversification including carbon-neutral fuels, technologies to improve SI engine thermal efficiency applicable to various fuels are required. In this study, the effect of in-cylinder WI on SI engine performance with a compression ratio of 17 and λ = 1.85 is investigated using premium gasoline, 5 components surrogate fuels for premium gasoline (S5H), and for regular gasoline (S5R). In the case of premium gasoline and S5H, spark timing can be advanced to MBT (minimum advance for best torque) by WI and gross indicated thermal efficiency (gITE) increases to 51.2% (premium gasoline) at water/fuel weight ratio (W/F) = 57.7% and 50.8% (S5H) at W/F = 62.9%. In the case of S5R, on the other hand, a strong knock forces a large spark retard at no-water condition. Although the water injection

Nagasawa, Tsuyoshi, Ishibashi, Soh, Kosaka, Hidenori

End-Gas Autoignition Prediction Using Reverse Livengood-Wu Integral with Ignition Delay Time Equations for Gasoline Surrogate Fuel

2023-32-0081

09/29/2023

A high-accuracy knocking or end-gas autoignition prediction model with low computational loads is necessary to develop thermal-efficiency improvement technologies for SI engines efficiently using computational techniques. Livengood-Wu integral has been applied widely as a simple and practical model to predict in-cylinder autoignition timing. In the present study, a high-accuracy model based on Livengood-Wu integral, has been investigated. First, a small set of ignition delay time equations for a premium-gasoline surrogate fuel has been developed, which can reproduce the temperature-, pressure-, equivalence ratio-, and EGR-dependences of ignition delay time under constant-volume condition, produced using a detailed reaction mechanism. Then, Livengood-Wu integral using the ignition delay time equations has been applied to predict in-cylinder autoignition timing produced using the detailed reaction mechanism. Numerical analyses have found X of Livengood-Wu integral and error factors in

Kuwahara, Kazunari

Engine Knocking Detection by Measuring Cylinder Pressure, Combustion Flame, Vibration and Radiation Noise

2023-32-0080

09/29/2023

Knocking is an important issue in improving the efficiency of spark ignition engines. It can be detected by photographing with high-speed cameras or measuring in-cylinder pressure or engine vibration or engine radiation sound. However, these methods each have the problems for example sensor damage risk or necessity of machining the engine. In this paper, we propose the efficient measurement method and the effective evaluation method with the restricted measurement results for engine knocking detection by utilizing the simultaneous measurement results of knocking with these sensors.

Murase, Michio, Kasahara, Taro, Kuboyama, Tatsuya

Understanding degradation of engine oil additives and its effect on abnormal combustion in a gasoline engine

2023-32-0035

09/29/2023

Engine oils and their additives are formulated to meet required performance areas such as lubrication, detergency, dispersancy, anti-wear, and so on. Understanding degradation of engine oil additives is important to formulate oils with long time durability. Engine oil additives have been found to affect abnormal combustion in turbocharged gasoline direct injection (TGDI) engines, called low speed pre-ignition (LSPI). Some of metal containing additives such as zinc dithiophosphates (ZnDTP) and molybdenum dithiocarbamates (MoDTC) have been found to reduce LSPI events. In this study, we investigated degradation of ZnDTP and MoDTC in gasoline engine operation and effects of the degradation on LSPI performance.

Onouchi, Hisanari, Tanaka, Isao, Elliott, Ian, Ketterer, Nicole

Effect of Working Gas Composition on Combustion and Knocking in Argon Closed-Cycle Hydrogen Engine

2023-32-0170

09/29/2023

In recent years, the automotive industry has been clearly moving toward carbon neutrality, and internal combustion engines that use fossil fuels are becoming unsustainable. On the other hand, hydrogen engines do not emit CO2 during operation, and if the working gas of a hydrogen engine is replaced with argon and oxygen (by removing the produced water and circulating argon), the thermal efficiency can be dramatically improved. However, when the high adiabatic compression temperature of argon is added to the inherent knocking problems of hydrogen engines, the knocking problem becomes even more pronounced, and no effective solution to avoid knocking has been found to date. In this study, the effects of argon, oxygen, and hydrogen concentrations on combustion and power, respectively, were investigated to determine the effects of working gas composition on combustion and knocking, and the control effects of oxygen rich or hydrogen rich on knocking was investigated.

Chen, Zhili, Tomita, Yuki

Fuel Effects on the Onset of Knock and the Intensity of Superknock at Stochastic Preignition-Relevant Engine Conditions

03-17-02-0010

09/05/2023

To have a more complete understanding of the fuel effects on each subsequent stage of a stochastic preignition event in a spark-ignition engine and to build on the previous work of understanding the propensity of fuel to initiate and sustain a preignition flame, this work is focused on examining the role of fuel on the onset of knock and the intensity of superknock once the unburned mixture reaches certain conditions ahead of the preignition flame. Using a “skip advance” spark test method to simulate preignition flames initiated at different cylinder conditions, more than 20 single- and multicomponent fuels were ranked based on the condition required to reach the onset of knock (the start of end-gas autoignition) and the condition that leads to severe superknock intensities. It was found that average knock intensity can be mainly explained by the unburn mixture fraction and the thermodynamic condition of the unburned mixture and, not surprisingly, that the fuel ranking for the onset of

Yu, Xin, Costanzo, Vincent, Chapman, Elana, Davis, Richard

Advanced, Guided Procedure for the Calibration and Generalization of Neural Network-Based Models of Combustion and Knock Indexes

03-17-02-0009

08/30/2023

In the last few years, the artificial neural networks have been widely used in the field of engine modeling. Some of the main reasons for this are, their compatibility with the real-time systems, higher accuracy, and flexibility if compared to other data-driven approaches. One of the main difficulties of using this approach is the calibration of the network itself. It is very difficult to find in the literature procedures that guide the user to completely define a network. Typically, the very last steps (like the choice of the number of neurons) must be selected by the user on the base of his sensitivity to the problem. This work proposes an automatic calibration procedure for the artificial neural networks, considering all the main hyper-parameters of the network such as the training algorithms, the activation functions, the number of the neurons, the number of epochs, and the number of hidden layers, for modeling various combustion indexes in a modern internal combustion engine

Brusa, Alessandro, Shethia, Fenil Panalal, Mecagni, Jacopo, Cavina, Nicolò

Meta-Model Optimization of Dual-Fuel Engine Performance and Emissions Using Emulsified Diesel with Varying Water Percentages and Injection Timing

2023-24-0032

08/28/2023

As emission restrictions become more stringent and conventional fuel supplies become more limited, dual-fuel engines are emerging as a promising solution that offers both environmental and economic benefits. However, the performance of these engines is often hampered by the issue of knocking, which can negatively impact their overall operation, and also by the increase in NOx emissions at high load. This work investigates the use of pilot injection properties by combining the use of emulsified diesel of different water percentages with injection timing to reduce both knock intensity and NOx emission rate. Specifically, a dual fuel operation case at full load with high enrichment of the primary fuel (natural gas) with hydrogen is considered in order to create conditions for high knocking and high NOx emission rates. The online optimization principle is used for the creation of the meta-model, utilizing the Radial Basis Functions technique (RBF), and the search for the optimum in

Sehili, Youcef, Loubar, Khaled, Tarabet, Lyes, Mahfoudh, Cerdoun, Lacroix, Clément

Correlation of Oil Originating Particle Emissions and Knock in a PFI HD SI Engine Fueled with Methanol

2023-24-0036

08/28/2023

A viable option to reduce global warming related to internal combustion engines is to use renewable fuels, for example methanol. However, the risk of knocking combustion limits the achievable efficiency of SI engines. Hence, most high load operation is run at sub-optimal conditions to suppress knock. Normally the fuel is a limiting factor, however when running on high octane fuels such as methanol, other factors also become important. For example, oil droplets entering the combustion chamber have the possibility to locally impact both temperature and chemical composition. This may create spots with reduced octane number, hence making the engine more prone to knock. Previous research has confirmed a connection between oil droplets in the combustion chamber and knock. Furthermore, previous research has confirmed a connection between oil droplets in the combustion chamber and exhaust particle emissions. However, the co-variation between oil originating particle emissions and knock has not

Ainouz, Filip, Adlercreutz, Ludvig, Cronhjort, Andreas, Stenlaas, Ola

Sound Quality Evaluation Metrics on Diesel Engines

2023-01-1128

05/08/2023

When people evaluate the engine NVH, they are not only mentioning whether the engine is loud or not, they say that is noisy or quiet. The difference between these two comments is the way they quantify the engine NVH, from the noise level or the sound quality. Lots of engineers used objective tools to quantify engine sound quality performance for years. In this paper, we would like to propose a novel sound quality matrix for the diesel engine which includes loudness, sharpness, mid-frequency, and high-frequency knocking parameters to perform the sound quality evaluation. In addition, an application case is described in this paper to demonstrate the usage of the new matrix.

Tan, Yang, Zhang, Boyu, Yuan, Zhao

Development of a Supercharged Octane Number and a Supercharged Octane Index

2023-01-0251

04/11/2023

Gasoline knock resistance is characterized by the Research and Motor Octane Number (RON and MON), which are rated on the CFR octane rating engine at naturally aspirated conditions. However, modern automotive downsized boosted spark ignition (SI) engines generally operate at higher cylinder pressures and lower temperatures relative to the RON and MON tests. Using the naturally aspirated RON and MON ratings, the octane index (OI) characterizes the knock resistance of gasolines under boosted operation by linearly extrapolating into boosted “beyond RON” conditions via RON, MON, and a linear regression K factor. Using OI solely based on naturally aspirated RON and MON tests to extrapolate into boosted conditions can lead to significant errors in predicting boosted knock resistance between gasolines due to non-linear changes in autoignition and knocking characteristics with increasing pressure conditions. A new “Supercharged Octane Number” (SON) method was developed on the CFR engine at

Hoth, Alexander, Kolodziej, Christopher P., Waqas, Muhammad, Szybist, James, Miers, Scott A.

A Comparison of Virtual Sensors for Combustion Parameter Prediction of Gas Engines Based on Knock Sensor Signals

2023-01-0434

04/11/2023

Precise prediction of combustion parameters such as peak firing pressure (PFP) or crank angle of 50% burned mass fraction (MFB50) is essential for optimal engine control. These quantities are commonly determined from in-cylinder pressure sensor signals and are crucial to reach high efficiencies and low emissions. Highly accurate in-cylinder pressure sensors are only applied to test rig engines due to their high cost, limited durability and special installation conditions. Therefore, alternative approaches which employ virtual sensing based on signals from non-intrusive sensors retrieved from common knock sensors are of great interest. This paper presents a comprehensive comparison of selected approaches from literature, as well as adjusted or further developed methods to determine engine combustion parameters based on knock sensor signals. All methods are evaluated on three different engines and two different sensor positions. The investigated approaches include a convolutional neural

Kefalas, Achilles, Ofner, Andreas, Posch, Stefan, Pirker, Gerhard, Gößnitzer, Clemens, Geiger, Bernhard, Wimmer, Andreas

CFD-Based Assessment of the Effect of End-Gas Temperature Stratification on Acoustic Knock Generation in an Ultra-Lean Burn Spark Ignition Engine

2023-01-0250

04/11/2023

End-gas temperature stratification has long been studied with respect to its effect on stoichiometric spark-ignition (SI) engine knock. The role of temperature stratification for homogeneous-charge compression ignition (HCCI) engine operation is also reasonably well understood. However, the role of temperature stratification in ultra-lean SI engines has had less coverage. Literature is lacking well-controlled studies of how knock is affected by changes in the full cylinder temperature fields, especially since cycle-to-cycle variability can impede a determination of cause and effect. In this work, the knocking propensity of specific cylinder conditions is investigated via 3D computational fluid dynamics (CFD) simulations utilizing a large eddy simulation (LES) framework. The end-gas temperature stratification is systematically varied such that all other parameters remain relatively constant (including the flow field, thereby avoiding cycle-to-cycle variability) allowing for direct

Strickland, Tyler, Sjöberg, Magnus, Matsubara, Naoyoshi, Kitano, Koji, Kaneko, Kazuki

The Hybrid IC Engine – Challenges of Hydrogen and E-Fuel Compatibility within Current Production Boundaries

2023-01-0397

04/11/2023

Increasingly stringent greenhouse gas and emission limits demand for powertrain electrification throughout all vehicle applications. Beside fully electric powertrains different configurations of hybrid powertrains will have an important role in upcoming and future vehicle generations. As already discussed in previous papers, the requirements on the combustion engine in hybrid powertrains are different to those in a conventional powertrain solution, heading for brake thermal efficiency targets of 45% and above within the product lifecycle for conventional fuels. Focus on product cost and production and assembly facility investment drives reuse of technology packages within modular powertrain technology platforms, with different combinations of internal combustion engines (ICE), transmissions, and e-drive-layouts. The goal of zero carbon operation requires compatibility of ICE for sustainable fuels. Ethanol, Methanol and in particular Hydrogen has significant impact on ICE subsystems

Schoeffmann, Wolfgang, Kapus, Paul, Plettenberg, Mirko, Howlett, Michael

Effects of Water Addition on Flash-Boiling Spray of Gasoline and Gasoline/Water Mixtures

2023-01-0307

04/11/2023

To improve the thermal efficiency and inhibit the knock tendency of gasoline direct injection (GDI) engines, water injection technology has a bright application prospect. Utilize gasoline/water mixture as a way to realize this technology can lower the cost of modifying the engines and bring potential for better spray qualities. Hence it is essential to give deep insight into the effects of water on spray atomization, evaporation and mixture formation for gasoline/water mixtures. A spray synchronous measurement experimental system with a single hole nozzle is used to investigate the spray morphology, spray width and droplet size distribution of gasoline/water mixtures sprays under different water volume fractions (0 %, 20 %, 35 %) and different initial fuel temperatures (50 °C~ 130 °C). There are critical temperatures of 80 °C(G100), 100 °C(G80) and 120 °C(G65), above which the ‘collapsed’ spray appears. Noticeably, unlike the collapsed spray caused by jet-jet interactions in the multi

Liu, Yifu, Yu, Yang, Hou, Xinghui, Wu, Zhijun

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