High Compression Ratio Engine Research Articles

The effect of ignition energy on the lean combustion limitation in high compression ratio engines

This study examined the impact of ignition energy for various loads on extending the limitations of lean combustion (LLC) and enhancing thermal efficiency using a high compression ratio (CR = 17) engine. It combined high compression ratio design、lean burn and high ignition energy to achieve more than 50 % indicated thermal efficiency. The findings indicated that a 424 mJ ignition energy proved helpful in reducing the ignition delay (CA0-10), widening the LLC to λ = 2.1, and achieving the highest thermal efficiency of 50.3 % at λ = 1.9 with lower exhaust loss and heat transfer loss when IMEP raised from 8.5 bar to 10 bar. Nevertheless, due to the high coefficient of variation of indicated mean effective pressure (COVIMEP), the constraints of lean combustion only reached λ = 1.45 and λ = 1.3 under IMEP = 12 bar and 13 bar, and its corresponding thermal efficiency was 45.1 % and 43.0 %, respectively. In terms of emissions, NOx was more sensitive to a bigger rise in ignition energy than other gases, and the variation of CO, THC, and NOx did not connect to a slight increase in ignition energy. The CO, THC, and NOx also tended to stay unchanged in ultra-lean conditions, remaining at about 900 ppm, 2797 ppm, and 38 ppm, respectively.

Study of water injection on suppressing knock in a high compression ratio and supercharged hybrid gasoline engine

This study investigated the effects of a direct water injection from both macroscopic characteristics and chemical kinetics aspects in high compression ratio engines, specifically regarding knocking concerns. On the one hand, −80 °CA is thought to be the ideal water injection timing (WIT) in terms of lowering mixture temperature, knock suppression, and water droplet dispersion. The mixture temperature is lowered to below 760 K by −80 °CA of WIT. When ignition timing (IT) is maintained at 2 oCA or −3 oCA, respectively, the water-fuel ratio (WFR) of 0.4 and 0.6 is the threshold for the impact of water droplet mass on combustion. The knock intensity decreases with increasing water-fuel ratio, and the pressure rise rate threshold of 0.6 bar/°CA is a knock-occurrence criterion. On the other hand, spontaneous combustion of end mixtures first occurs beneath the exhaust valve, transporting burned gases and raising temperatures. The IC4H7 concentration is higher in the mid-to-high temperature areas near the cylinder liner. Elevated concentrations of CH2O indicate high-temperature reactions, while increased levels of CH3 and HCO signify auto-ignition onset. Whether the IT is 2 oCA or −3 oCA, both IC4H7 concentration and OH concentration observe a declining trend with the increase of WFR.

Investigation of intake air temperature effect on co-combustion characteristics of NH3/gasoline in naturally aspirated high compression ratio engine with sub-chamber

Recently, ammonia (NH3), which has a higher energy density than hydrogen, has gained attention for zero-carbon emission goals in the transportation sector. However, in a conventional internal combustion engine (ICE), NH3 combustion mechanism is still under investigation. In this paper, to further expand the knowledge on the adoption of NH3 in ICEs, authors conducted NH3/gasoline co-combustion experiments in a modified, 17.7:1 compression ratio, naturally aspirated spark-assisted CI engine with sub-chamber. The sub-chamber was chosen in order to enhance the combustion speed of NH3. In addition, the sub-chamber was equipped with glow and spark plugs to overcome the high auto-ignition temperature of NH3. Engine performance and NOX emissions were studied under three different intake air temperatures. During the experiments, NH3 content was increased gradually where the engine was run under lean conditions. Although higher NH3 content was achieved compared to our previous work, increasing the intake air temperature resulted in decreased charging efficiency. In addition, corrosion was found on the piston ring after 120 h of operation, negatively affecting the engine performance. Furthermore, NH3/gasoline co-combustion duration was shortened drastically with the influence of the sub-chamber, where the longest combustion duration under the present conditions was found to be 17°CA.

Experimental Investigation of Spark-Assisted Compression-Ignition with Ammonia-Hydrogen Blends

Carbon-free emissions and stable operation of ammonia-fueled internal combustion engines have been demonstrated in recent studies through combustion strategies suited to the fuel’s unique properties. High ignition energy and slow flame speed of ammonia are typically compensated for by hydrogen addition and/or enhanced ignition systems while the high octane rating of ammonia allows high compression ratio. The experimental study in this work investigates the performance of ammonia in spark-assisted compression-ignition (SACI) mode, where the cylinder charge is spark ignited and a subsequent auto-ignition event results in a faster burn and more ideal combustion phasing. The high-compression ratio engine was fueled by 100% anhydrous ammonia or blends with small quantities of hydrogen (2.5% and 5% by volume). Fuels were port-injected for a homogeneous intake charge mixture at stoichiometric equivalence ratio. Two different engine speeds were tested at several intake temperatures and spark timings. All cases showed an inflection point in the apparent heat release rate (AHRR) followed by more rapid rate of heat release, signaling the onset of auto-ignition. Blending hydrogen in the fuel benefited gross indicated mean effective pressure (gIMEP) at maximum brake torque (MBT) timing, but pure ammonia fuel was more stable across a wide range of spark timings and intake temperatures. Burn durations in the present study were similar to those of conventional SI engines fueled by gasoline indicating that the combustion enhancement of SACI compensated for the lower flame speed of ammonia. The control of SI percent, defined as the fraction of heat release before auto-ignition compared to the total heat release, is shown to be strongly related to the sensitivity of auto-ignition timing to spark timing. Unburned ammonia emissions are hypothesized to be primarily driven by unburned gases trapped in the crevices and are mitigated slightly through blending hydrogen in the fuel or by increasing intake temperature. However, the addition of hydrogen and increasing intake temperature led to increased nitric oxide (NO) emissions. Of primary concern because of its potent global warming potential, nitrous oxide (N2O) did not show a clear trend with fuel hydrogen content or intake temperature, but definitively increased for the higher engine speed.

Experimental and numerical study of split injection strategy on balancing the ultra-lean burn and high compression ratio engine design

In this study, the aim of split injection is to strike a balance between the ultra-lean burn mode and high compression ratio method by experimented and numericized. Under ultra-lean condition, no matter single injection mode or split injection mode, both knock percentage and combustion stability does not monotonically decrease with the retarded injection timing. Considering the combustion stability and knocking, first injection timing of 300 oCA BTDC and second injection timing of 190 oCA BTDC is choose as optimized strategy, which achieves knock frequency of 16 % and COVIMEP of 3.69 %. Based on optimized injection strategy, the indicated specific fuel consumption achieves 184.53 g/KWh. With the split injection, a deeper ultra-lean burn can be achieved without the severe knock and combustion fluctuation and obtain ultra-low NOx emissions of 2.8 ppm. The numericized result also demonstrates that because of the ultra-lean conditions, the flame grows more slowly, and then the temperature of the un-burn zone rises significantly as a result of the primary flame stream. Meanwhile, the propagation speed to the exhaust valve side appears to be substantially slower than in other directions. As a result, auto-ignition can be seen near the exhaust valve. When using split injection, the flame kernels do not propagate as fast and deep as in the case of single injection because of the cooling effect. This drops temperature in the unburned end-gas region and thus reduces knocking tendency.

Split Injection Strategy Optimization to Achieve Ideal Stratified‐Charge Mixture and Reinforce Ultralean Burn in a High Compression Ratio Direct Injection Spark Ignition Engine

Ultralean burn is considered an effective way to enhance the thermal efficiency of direct injection spark ignition engines. Herein, under ultralean burn condition, the split injection strategy is induced to investigate the in‐cylinder mixture distribution, combustion characteristics, and emissions by simulation in a high compression ratio engine model. First, the homogeneity index shows that compared with the single injection method, the split injection strategy shows better stratification of the mixture gas at the early stage of the compression stroke, which results in higher in‐cylinder pressure and heat release. Meanwhile, the results of heat balance show that split injection shows a slight effect on ignition delay, but significantly shortens combustion duration and advances CA50, and thus the exhaust loss is decreased. Second, with the decrease of a second injection fuel mass, the rich mixture is formed near the spark plug, thus reducing the ignition delay and combustion duration. Third, the split injection strategy presents faster flame kernel growth and propagation. A larger flame area is observed with the second injection mass decreasing. Finally, as the second fuel injection mass is reduced, NOx emissions increases continuously, while the soot emission decreases.

Numerical comparative study on performance and emissions characteristics fueled with methanol, ethanol and methane in high compression spark ignition engine

Methane, methanol and ethanol are three common high-octane alternative fuels. As fuels for high compression ratio engines, they can improve thermal efficiency while preventing knocking. However, each of these three fuels has its own physicochemical properties and presents different engine performance. This study compares in detail the performance, combustion and emissions of a high-compression-ratio SI engine fueled by methanol, ethanol and methanol. A 4-cylinder high compression ratio SI engine simulation model was built based on 1-D simulation platform. The engine was converted from a CI diesel engine with a CR of 17.5, and the methanol, ethanol of methane injector was installed in the intake port. The results showed that for the methanol, ethanol and methane fuels, under the same engine speeds and equivalence ratios, the BP and BT of methanol were higher than ethanol and methane fuels, methane has the lowest BP and BT; methane has a lower BSFC and BTE than methanol and ethanol, with methanol having the highest BSFC and BTE; the CO and NOx emissions of methanol were lower than ethanol and methane fuels; the HC and CO2 emissions of methane were lower than methanol and ethanol fuels.

Thermal efficiency improvement of lean burn high compression ratio engine coupled with water direct injection

The turbocharged downsizing gasoline direct injection (GDI) engines aiming for lower fuel consumption, lower emissions, and higher performance have been regarded as the future hybrid electrical vehicle (HEV) pathway. To improve the thermal efficiency of the HEV engine under lean burn operation, a water direct injection (WDI) system and a high-energy ignition (500 mJ) system were proposed in an Atkinson cycle GDI engine with a high compression ratio of 17. The effect of homogeneous lean burn, water injection ratio (WIR), and spark timing (ST) on engine knock, combustion process, and indicated thermal efficiency (ITE) improvement was studied. The result shows WDI at an earlier stage of the compression stroke (100° CA BTDC) could mitigate knock without significantly increasing combustion instability. When WIR increased to 50%, the engine knock decreased 82.7%, the indicated specific fuel consumption (ISFC) dropped 9.9% as the ST advanced from 1.6° to 9° CA BTDC. The maximum brake torque spark timing (MBT) could be further advanced by extending the lean burn limit (LBL). The wider LBL was achieved with a larger WIR. At λ = 1.1, CO emission reduced by 5 ∼ 7 times and reached 570 ppm, and unburned hydrocarbons were reduced by 9%∼13%. Less than 500 ppm of NOx was noted when λ ≥ 1.5 under each WIR case. The IMEP was extended from test basic 8.3 bar to 13 bar with an increase of 47.73%. The remarkably high ITE of 47.09% can be achieved with a controllable knock level at lean burn condition (λ = 1.9), with an increase of 7.84% compared with the stoichiometric test basic IMEP of 8.3 bar.

Exploring the Possibility of Achieving Partially Premixed Charge Compression Ignition Combustion of Biodiesel in Comparison to Ultra Low Sulfur Diesel on a High Compression Ratio Engine

ABSTRACT The combustion characteristics of biodiesel operating in the Low Temperature Combustion (LTC) regime, via Partially Premixed Charge Compression Ignition Combustion (PPCI), is relatively unknown. Therefore, this study compares engine performance and emissions of ultra-low sulfur diesel (ULSD) and waste cooking oil biodiesel through an attempted PPCI methodology. The Fuel Injection Timing (FIT) was gradually altered from conventional combustion timing (12.0° for biodiesel and 12.5° for ULSD) to 35.0° before top dead center. Results indicated that the fuel consumed to maintain the required load condition increased gradually for both ULSD and biodiesel due to the start of combustion shifting further into the compression stroke for each injection advancement. Nitrogen oxides (NOx), particulate matter (PM), carbon monoxide, and total hydrocarbons were marginally lower for biodiesel compared to ULSD. There was limited success in reducing both NOx and PM emissions simultaneously by varying the FIT alone for both fuels. The high compression ratio of the engine utilized was a major limiting factor in achieving LTC. Importantly, the Negative Temperature Coefficient (NTC) behavior of biodiesel and its impact on ignition delay was successfully captured. The operating conditions used in this study are closer to a production engine as compared to shock tube and constant volume combustion systems typically used to validate chemical kinetic (CK) models. Moreover, data surrounding NTC and its influence on ignition delay with biodiesel in CI engines is limited in the literature. Thus, the results presented provide valuable data that could be utilized to help validate CK models investigating the behavior of biodiesel fuels.

Numerical and Experimental Study on Knock Sources in Spark Ignition Engine with Electromagnetic Valve Train

As one of the most common engine types in nowadays, the thermal efficiency of spark-Ignition (SI) engine is limited due to the lower compression ratio. Various technical solutions have been proposed to suppress knock and improve compression ratio of SI engines. In this paper, an new technical solution based on electromagnetic valve train (EMVT) was proposed to suppress knock of spark ignition engines, so that high compression ratio (HCR) engine (13:5) was obtained. Moreover, experimental and numerical analyses were carried out to optimize the proposed EMVT strategy. The result showed that the proposed EMVT strategies could well suppress the engine knock by reducing end-gas temperature and pressure and improving the spark-flame rate, resulting in significantly enhanced power, economic, and emission characteristics of SI engines. This study provides theoretical basis and technical approach for the development of internal combustion engines with high efficiency and high compression ratio.

Effects of hydrogen addition on combustion, thermodynamics and emission performance of high compression ratio liquid methane gas engine

It is a potential approach to improve the fuel efficiency that the liquid methane gas (LMG) purified from liquefied natural gas (LNG) is fueled with the high compression ratio (CR) engine, while the actual effect is restricted by the lowcombustion velocity of methane. To solve this problem and further improve the LMG engine performance, the approach of hydrogen addition to LMG engine was investigated by combining experiment with numerical simulation. Based on experimental data, the computational fluid dynamics (CFD) model coupled with reduced chemical kinetic mechanism was built and calibrated, which was then employed to study the effects of different hydrogen energy fraction (HEF) on combustion, thermodynamic and emission of LMG engine. The results show that, the peak of heat release rate (HRR) increases sharply with the HEF rising and leads the maximum in-cylinder pressure to increase. The indicated thermal efficiency of LMG engine first increases and then decreases, and the maximum falls in the HEF range between 8% and 12%. Although the combustion velocity of mixture gas is obviously increased by hydrogen addition, the detonation trend still becomes larger and it increases by 10 times as HEF changes from 12% to 20%. As the HEF increases from 0 to 20%, NOx emission increases continuously, while CO and CH4 emissions decrease due to the higher combustion temperature. All these provided direction for improving LMG engine performance, and offered theoretical basis for selecting technology routes to meet emission regulations.

Comparing methods for improving spark-ignited engine efficiency: Over-expansion with multi-link cranktrain and high compression ratio with late intake valve closing

A common approach of high efficiency engines is to utilize high compression with late intake valve closing (LIVC) to realize an over-expanded cycle. A multi-link cranktrain can also realize an over-expanded cycle with the same geometric intake displacement as a baseline engine while extending the expansion stroke. These two types of over-expanded cycle engines and a baseline engine are investigated and compared in this simulation study. The baseline engine model is calibrated based on the experimental results from a four-cylinder, boosted, spark-ignited engine with compression ratio (CR) of 10.5:1. The CR of high compression ratio engine and multi-link over-expanded engine is 13.0:1 and 10.5:1, respectively. The over-expansion ratio of multi-link engine is 1.5. These three engines were optimized and investigated at three conditions: 1300 rpm 330 kPa net IMEPnet, 1500 rpm 1300 kPa IMEPnet, and 2500 rpm 1000 kPa IMEPnet. At 1300 rpm 330 kPa IMEPnet, multi-link over-expanded engine and high compression engine both used LIVC. With LIVC, the net indicated efficiency of the high compression engine and multi-link engine were improved by 5.2% and 2.4% (relative), respectively, compared to the same engine without LIVC. Multi-link over-expanded engine benefited from its lower knock propensity and over-expansion at medium to high load conditions. At 1500 rpm 1300 kPa IMEPnet, the net indicated efficiency of the multi-link engine was 13.7% and 14.2% (relative) higher than the high compression engine and baseline engine, respectively. At the peak brake efficiency condition of the high compression engine, the net indicated efficiency of multi-link engine was 8.6% (relative) higher than the high compression engine.

Comparative study on combustion and emission characteristics of methanol/hydrogen, ethanol/hydrogen and methane/hydrogen blends in high compression ratio SI engine

Currently, alternative energy sources such as hydrogen and alcohol are increasingly used in IC engines. There is a gap in the literature of both experimental and numerical studies considering hydrogen addition in a high compression ratio engine (using methanol/hydrogen, ethanol/hydrogen and methane/hydrogen blends). Therefore, in this study, the combustion and emission performance analysis of methanol, ethanol and methane with different hydrogen volume ratios were carried out. The results showed that as the hydrogen addition, the ignition delay and the combustion duration were extended. Under the same ratio of hydrogenation, the ignition delay and combustion duration of methane/hydrogen are longer than methanol/hydrogen and ethanol/hydrogen blends. As the hydrogen ratio increases, the HC and NOx emissions of the methanol/hydrogen, ethanol/hydrogen and methane/hydrogen are increased, and the CO and CO2 emissions are decreased. Under the same ratio of hydrogenation, the engine power and BSFC of methanol/hydrogen blend is better than ethanol/hydrogen and methane/hydrogen blends, the HC and NOx emissions of the methanol/hydrogen are higher than the ethanol/hydrogen and methane/hydrogen blends, The CO emissions of methanol/hydrogen and methane/hydrogen blends are lower than the ethanol/hydrogen blends.

Methanol production using hydrogen from concentrated solar energy

Concentrated solar thermal technology is considered a very promising renewable energy technology due to its capability of producing heat and electricity and of its straightforward coupling to thermal storage devices. Conventionally, this approach is mostly used for power generation. When coupled with the right conversion process, it can be also used to produce methanol. Indeed methanol is a good alternative fuel for high compression ratio engines. Its high burning velocity and the large expansion occurring during combustion leads to higher efficiency compared to operation with conventional fuels. This study is focused on the system level modeling of methanol production using hydrogen and carbon monoxide produced with cerium oxide solar thermochemical cycle which is expected to be CO2 free. A techno-economic assessment of the overall process is done for the first time. The thermochemical redox cycle is operated in a solar receiver-reactor with concentrated solar heat to produce hydrogen and carbon monoxide as the main constituents of synthesis gas. Afterwards, the synthesis gas is turned into methanol whereas the methanol production process is CO2 free. The production pathway was modeled and simulations were carried out using process simulation software for MW-scale methanol production plant. The methanol production from synthesis gas utilizes plug-flow reactor. Optimum parameters of reactors are calculated. The solar methanol production plant is designed for the location Almeria, Spain. To assess the plant, economic analysis has been carried out. The results of the simulation show that it is possible to produce 27.81 million liter methanol with a 350 MWth solar tower plant. It is found out that to operate this plant at base case scenario, 880685 m2 of mirror's facets are needed with a solar tower height of 220 m. In this scenario a production cost of 1.14 €/l Methanol is predicted.

Application of biogas to supply the high compression ratio engine

The study concerns the use of biogas as a fuel for supplying a modified self-ignition engine. As a result of the modifications made, the compression ratio was reduced and the engine was equipped with an ignition system and an electronically activated engine throttle. The changes have made it possible to burn biogas in a high compression ratio engine. The paper presents the results of research conducted on a low power cogeneration system with engine that drives an electrical machine cooperating with a 380/400 V network. The analysis includes, among other things, the possibility of producing electricity using biogas. The paper presents the influence of regulatory parameters such as the volume and composition of the supplied gas mixture and the degree of throttle opening on the obtained engine operation indicators and the driven electric machine. The tests were carried out in relation to the obtained ecological indicators depending on the concentration in the exhaust of such substances as: HC, CO, NOx.

The knock study of high compression ratio SI engine fueled with methanol in combination with different EGR rates

Methanol, with a high octane index, is considered to be one of the most ideal fuels for high compression ratio engines. In this paper, the SAGE models combined with methanol chemical reaction kinetics (consisting of 46-species and 247-elementary reactions) are used to study knock combustion. Knock combustion is simulated in a high compression ratio SI methanol engine with different EGR rates. The results show that the introduction of EGR into the combustion chamber can reduce the knock intensity and delay the knock onset time. Without EGR, the intake side of the combustion chamber is prone to knocking mostly. As the EGR rate increases, the exhaust side of the combustion chamber is the most likely to knocking. OH radicals can be considered an indicator of the temperature, and H2O2 can be regarded as an indicator of the propagating flame front. OH marks the knock phase duration and HCO marks the onset of knocking. The reaction intensities of CH2O, H2O2, CO and OH species are higher than other species during knocking combustion. The greater the reaction rate is, the greater the knock intensity will be.

Experimental study on combustion, emissions and thermal balance of high compression ratio engine fueled with liquefied methane gas

To improve the fuel efficiency of liquefied natural gas engine, an approach was proposed in our previous study, in which the liquefied natural gas is first purified into liquefied methane gas and then fueled to high compression ratio engine. To further evaluate the fuel efficiency of liquefied methane gas engine, in this study the thermal balance test was carried out, and then the thermodynamic performance of liquefied methane gas engine was analyzed and various kinds of energy losses were disintegrated. On this basis, the influence factors of various forms of energy flow in liquefied methane gas engine were discussed by combining with combustion and thermodynamics processes. Results show that, the proportions of indicated work in high-pressure cycle, exhaust energy and heat transfer loss are mainly influenced by engine speed. The high-pressure cycle efficiency increases with engine speed and the maximum value reaches 49.6% due to the higher compression ratio. The variation trend of exhaust energy proportion is similar as that of high-pressure cycle efficiency, while the proportion of heat transfer loss decreases with the engine speed increasing. Although the maximum high-pressure cycle efficiency appears in high speed conditions, the maximum effective thermal efficiency still appears at low speed due to the effect of friction loss and pumping loss (especially the former). Therefore, for the low speed conditions, the effective thermal efficiency of LMG engine can be further improved by optimizing the thermodynamic process (or combustion parameters); while for the high speed conditions, it is better to reduce the friction loss and pumping loss.

Combustion and energy distribution of hydrogen-enriched compressed natural gas engines with low heat rejection based on Atkinson cycle

In order to reduce the heat loss and improve the indicated thermal efficiency of hydrogen-enriched compressed natural gas engines, this article presents a combination of Atkinson cycle with high compression ratio and low heat rejection on the hydrogen-enriched compressed natural gas prototype engine with 55% hydrogen blend. The combustion characteristics and energy distribution of the prototype and modified engines were investigated by simulation, and the conclusions are as follows: the pressure and temperature of modified engines are higher than those of the prototype during the combustion process. Compared with the prototype, the modified engines present lower peak heat release rate, but faster combustion after ignition, and their CA50 are closer to top dead center. Although the high compression ratio engine with Atkinson cycle generates more heat loss, its indicated thermal efficiency still increases by 0.6% with the decrease in the exhaust energy. Furthermore, the high compression ratio engine with low heat rejection and Atkinson cycle combines the advantages of low heat loss and relatively longer expansion stroke, so its heat loss reduces obviously, and 61.6% of the saved energy from low heat rejection and Atkinson cycle can be converted into indicated work that indicates a 4.5% improvement in indicated thermal efficiency over the prototype, which makes it perform better in terms of power and fuel economy simultaneously.

Desarrollo y validación de un modelo cero dimensional de dos zonas para el análisis de la combustión en motores de encendido provocado

The growth of the automotive fleet in cities and the imminent depletion of traditional hydrocarbon deposits mean that research in the field of internal combustion engines focuses on generating strategies and developing technologies that allow a reduction in fuel consumption and pollutants emissions. The use of numerical models for simulation is an important tool for both researchers and designers as they allow to approach the performance of the engines under certain operating conditions without incurring in the expense involved in experimental studies and allow analyzing multiple phenomena that occur during combustion that are not easily evaluable from experimental measurements. In this study, a zero-dimensional two zones model which separates the combustion chamber into burned and unburned gases was developed seeking to study the combustion process in ignition engines using gaseous renewable fuel (biogas), using the Law of Wiebe and the chemical equilibrium to simulate the combustion process and the Woschni's semi-empirical correlation for heat transfer. The model is calibrated with information obtained from a high compression ratio (15.5: 1) engine of the combustion and thermal machines laboratory of the University of Antioquia. The main variables of combustion and engine performance (heat release rate, maximum pressure, indicated work, among others) were compared with the results of the model, as well as the emissions generated from CO and NO. There are low errors between the experimental values predicted by the model, with errors less than 10% for the main variables, except for the indicated work, with errors of 27%, and errors between 18% and 49% for the generated emissions, obtaining the highest errors as the degree of load of the motor increases.

ガソリン高圧噴射を用いた高圧縮比エンジンの燃焼技術（第 4報） ―部分負荷運転時の燃費性能の検討―

ガソリン高圧噴射を用いた高圧縮比エンジンの燃焼技術（第 4報） ―部分負荷運転時の燃費性能の検討―