Octane Number Research Articles

Transfer of near infrared calibration for gasoline octane number based on screening consistent wavelengths combined with direct standardization algorithm

In order to share multivariate calibration models of gasoline research octane number between different near infrared spectrometers, a novel calibration transfer method, namely combination of screening consistent wavelengths and direct standardization (SWCSS-DS) was proposed. Firstly, screening wavelengths with consistent and stable signals (SWCSS) between instruments was used to select the wavelengths with best stability, and then direct standardization (DS) further corrected the systematic errors that still exist after the SWCSS was implemented. The spectra of 120 standard gasoline samples collected on two near infrared spectrometers of the same type were investigated in detail to verify the validity of the new algorithm. Compared results of other transfer methods such as SWCSS, Slope/Bias (S/B), direct standardisation (DS), and piecewise direct standardization (PDS), the root mean squared error for prediction (RMSEP) of SWCSS-DS algorithm for target samples was decreased from 5.75 to 0.295, and the Akaike information criterion value decreased from 1516 to 640, which were better than those of the SWCSS, S/B, DS and PDS algorithms. Therefore, the joint algorithm of SWCSS-DS has not only improved the universality of the master model, but also reduced the dimension of the spectral matrix and calibration equation, that would provide a more efficient model transfer strategy for the practical applications.

Optimization and screening of process parameters for the robust co-pyrolytic study of waste motor oil and rice stubble toward sustainable waste-to-fuel generation

The current study explores the co-pyrolysis of waste motor oil (WMO) and rice stubble in a designed lab-scale pyrolyzer to produce alternative energy fuels. The parameter screening was followed by optimization utilizing the Box-Behnken design (BBD). Reactor temperature (TR), mixing ratio (M), and holding time (t) affected the co-pyro-oil yield substantially. A maximum co-pyro-oil yield of 90.3% was achieved at a TR = 485 °C, t = 12.5 min, and M = 5% rice stubble to waste motor oil, which was further characterized and compared with the commercial diesel fuel properties. The highest research octane number of 76.15 was obtained for the co-pyro-oil (Co-PO), followed by the pyro-oil generated from only waste motor oil (POWMO). Consequently, the paraffin content increased to 64.34 wt% from 27.66 wt % for PO RS. The carbon number varied from C7–C17 for PO WMO and Co–Po, aligning with the diesel fuel requirements. Furthermore, a substantial enrichment in the physio-chemical properties of the produced Co-PO with reduced moisture content and enhancement in higher heating value (HHV) was also noticed. Hence, the generated Co-PO could be utilized as transport-grade fuel.

Solketal Synthesis from Glycerol and Acetone Using Amberlyst-36 Catalyst

Recently, biodiesel production has increased condiserably due to the use of B30 in Indonesia. As a side product of biodiesel production, glycerol is also produced in large amount. Glycerol conversion to fuel additive is one of promising path for glycerol utilization. Solketal is one of fuel additives that can be derived from glycerol and it may enhance octane number on gasoline. Solketal can be synthesized from glycerol and aceton by using Amberlyst-36 as catalyst. The aim of this paper was to study the effect of catalyst loading to glycerol conversion as well as to develop a kinetic model to correlate catalyst loading to kinetic parameter. A series of experiments were conducted in a batch reactor heated in water bath, equipped with cooler, and stirrer speed at 650 rpm for 180 minutes, mole ratio glycerol to acetone is 1:4, at temperature 500 C, varying catalyst loading at 1, 3, 5, 7 wt. %. The result showed that the highest glycerol conversion was achieved as high as 88.19% at 500 C temperature using 7 wt. % of catalyst.

Solketal Reaction Optimization by Glycerol Acetalization Using Amberlyst-36 Catalyst

Glycerol is an important chemical and widely used in many applications. Glycerol can be produced from a biodiesel industry as a by-product. In order to improve the economic value of glycerol as a by-product, it can be reacted with acetone to form solketal. Solketal can be used as a fuel additive to increase octane number. Reaction between glycerol and acetone can be catalyzed by Amberlyst-36. The objective of present study was to investigate the effect of mole ratio of glycerol:acetone and reaction temperature to the glycerol conversion. The process of acetalization was conducted in a batch reactor equipped with heater, temperature control, cooler and stirrer. The weight of catalyst was set on 5% based mass of glycerol and the stirrer speed was set on 650 rpm with reaction time of 3 hours. The mole ratio of glycerol to acetone was varied at 1:3, 1:4, 1:5 and 1:6, and the temperatures were varied on 40, 50 and 55 °C. The results showed that the highest conversion was 86.61 %, which was obtained at 120 minutes reaction, 50 °C and 1:6 mole ratio.

Piston geometry and stroke optimization for high efficiency propane spark ignition engines

Propane has unique properties and offers interesting characteristics for high-efficiency spark ignition engines. Its high volatility reduces or completely eliminates fuel-wall wetting and facilitates fuel air mixing. Furthermore, propane has a research octane number of 112 and a high octane sensitivity of 15. Finally, its laminar flame speed is on the same order as that of conventional gasoline, and it exhibits high dilution tolerance. Modern spark ignition internal combustion engines rely on fast combustion rates and high dilution to achieve high brake thermal efficiencies. To accomplish this, high stroke-to-bore ratios and high geometric compression ratios have been used in new engine designs. Therefore, propane’s relatively high laminar flame speeds, high knock resistance, and dilution tolerance make it an excellent candidate fuel for modern spark ignition engines. The objective of this work is to co-optimize the piston geometry and the engine stroke to maximize the efficiency of a spark-ignition engine fueled with propane. 3D computational fluid dynamics (CFD) simulations employing the extended coherent flamelet model were used to study the parametric effects of piston shape and stroke length. A piston geometry based on high performing pistons was parameterized using four controlling parameters. The piston geometry and engine stroke design space was explored using deterministic and quasi-random sampling techniques. A Gaussian process regression model was built using the simulation data to explain the results observed.

Optimization of Pyrolysis Process Parameters for Fuel Oil Production from the Thermal Recycling of Waste Polypropylene Grocery Bags Using the Box–Behnken Design

The impact of dumping plastic waste is realized in different ecosystems of the planet. Several methods have been adopted to dispose of these wastes for energy recovery. This study, for the first time, proposed the Box–Behnken design technique to optimize the pyrolysis process parameters for fuel oil production from waste polypropylene (PP) grocery bags using a semibatch-type pyrolytic reactor. The semibatch-type pyrolytic reactor was developed and employed to produce fuel oil from waste PP grocery bags. The effect of different process parameters on fuel oil production was comprehensively analyzed using the response surface methodology (RSM) with the conjunction of the Box–Behnken design (BBD). The BBD facilitates the prediction of the response variables with respect to changes in the input variables by developing a response model. The BBD was used to optimize the process parameters, such as the reaction temperature (400–550 °C), nitrogen flow rate (5–20 mL min−1), and substrate feed rate (0.25–1.5 kg h−1), and their effect on the responses were observed. The optimum response yields of the fuel oil (89.34 %), solid residue (2.74%), and gas yield (7.92%) were obtained with an optimized temperature (481 °C), a nitrogen flow rate (13 mL min−1), and a feed rate (0.61 kg h−1). The quadratic model obtained for the fuel oil response denotes the greater R2 value (0.99). The specific gravity and calorific value of the fuel oil were found to be 0.787 and 45.42 MJ kg−1, respectively. The fuel oil had higher research octane number (RON) (100.0 min) and motor octane number (MON) (85.1 min) values. These characteristics of the fuel oil were matched with conventional petroleum fuels. Further, Fourier transform infrared spectroscopy (FT-IR) and gas chromatography–mass spectroscopy (GC-MS) were used to analyze the fuel oil, and the results revealed that the fuel oil was enriched with different hydrocarbons, namely, alkane (paraffins) and alkene (olefins), in the carbon range of C4–C20. These results, and also the fractional distillation of the fuel oil, show the presence of petroleum-range hydrocarbons in the waste PP fuel oil.

Investigation of injection parameters coupled with fuel reactivity on combustion and emissions in dual direct-injection GCI engine

Fuel injection parameters and fuel reactivity significantly affect engine performance, combustion, and emissions. The dual direct-injection strategy could compensate for the insufficient heat release rate to improve the gasoline compression ignition (GCI) mode with medium injection pressure for high loads. This research aims to couple injection parameters and fuel reactivity to optimize the combustion, emissions, and engine performance of the dual direct-injection GCI mode at high loads. The effect of research octane number (RON) of gasoline, injection timing, and injection pressure of dual injection system on combustion and emissions was investigated. Results show that the optimized dual direct-injection GCI mode can simultaneously achieve high thermal efficiency, low emissions, and low maximum pressure rise rate (MPRR) at high loads with the maximum indicated mean effective pressure (IMEP) of about 16 bar with indicated thermal efficiency (ITE) of 48.5%. Delaying the injection timing of injector-1 reduced the peak pressure (Ppeak), MPRR, and NOx emissions. Ppeak, CO, NOx, and indicated specific fuel consumption (ISFC) decreased compared to the dual-injector simultaneous injection case when the injection timing of injector-2 was retarded to between 5 and 10°CA ATDC. Increasing the injection pressure of injector-2 reduced CO, THC, ISFC, and particulate emissions. Lower RON gasoline obtains higher ITE while higher RON gasoline obtains lower particulate emissions.

An overview concerning the utilization of fusel oil as an alternative fuel in the engine applications

Diesel engines will continue to be discussed in the coming years because of their harm to the environment resulting from emitted pollutants. These engines are unrivaled in the transportation industry owing to the high power achieved at high compression ratios. In recent years, studies have been carried out on the use of alternative fuels instead of diesel in compression ignition engines. Fusel oil (FO) is a by-product acquired from several types of agricultural biomass by different techniques. To conclude, in the present paper, researches in the published literature for diesel engines using fuel blends containing FO as an alternative fuel have been reviewed in detail. FO's high octane number, high oxygen content, and low freezing point make it stand out as a fuel additive. In addition, the calorific value of FO is lower than diesel, and its density and viscosity are higher. When FO is infused at different concentrations to diesel fuel (DF) or DF-biodiesel mixtures, fuel consumption increases in compression-ignition engines while engine power decreases compared to reference DF. There is a noticeable decrease in CO and NOx pollutants in fuel blends using FO. The amount of water in the FO has an adverse effect on diesel engines. In the article, firstly, the production and properties of FO are reviewed and its fuel properties are summarized. Then, the effects of diesel/FO and diesel/biodiesel/FO mixtures on engine performance and emissions are discussed. Finally, the positive and negative aspects of FO for diesel engines are summarized.

The Influence of Fuel Pump Pressure Variations on the Performance of 2-Stroke Gasoline Direct Injection Engines

The direction of technological development in 2-stroke gasoline direct injection engines is to improve engine performance and reduce exhaust gas pollution, where the solution to achieve this is to use a high-pressure electric fuel pump that produces stable fuel pressure and is practical in its application. This research aims to determine the influence of variations in fuel pressure on the performance, especially torque and power, of a 2-stroke gasoline direct injection engine. Tests were carried out on a 110 cc 2-stroke gasoline direct injection motorcycle engine using Research Octane Number (RON) 90 fuel at varying fuel pressures of 7.5 Bar, 8 Bar, and 8.5 Bar on a chassis dynamometer to obtain engine performance data in the form of torque and power. The results of this research show that increasing fuel pressure will increase the atomization of fuel particles so that it will influence increasing the performance of this engine, where maximum torque and power of 6.20 Nm and 2.00 kW are achieved at 3250 rpm, at a pressure of 8.5 Bar.

Biodiesel-Derived Waste Glycerol as a Green Template for Creating Mesopores in the ZSM-5 Catalyst for Aromatics Production Applications.

The present study provides a novel sustainable approach for the synthesis of the ZSM-5 catalyst using biodiesel-derived waste glycerol as a green template as well as a mesopore creator, which is here reported for the first time, to the best of our knowledge. The use of bioglycerol in the preparation of ZSM-5 (Zn-Z-G and Zn-Z-T) materials exhibited a typical MFI zeolite structure, indicating glycerol played a similar role to that of a typical (TPA+) template in the formation of the ZSM-5 zeolite structure. The Zn-Z-G material also exhibited a large mesopore in the ZSM-5 pore structure, suggesting that glycerol played both template and mesopore creator roles. Interestingly, Zn-Z-GT prepared by the dual-template route using bioglycerol along with typical TPA+ showed a MFI zeolite structure with special catalytic features such as hierarchical micromesopores and well-balanced acid sites. These results reveal that the use of bioglycerol along with a typical TPA+ template had a promotional effect on creating such special properties in the Zn-Z-GT material. The Zn-Z-GT catalyst exhibited excellent catalytic performance in the naphtha aromatization reaction, resulting in achieving ∼58 wt % of the aromatic product and useful gas byproduct (14 wt %) with a minimum coke content (∼4 wt %) in a 12 h reaction period ascribed to its combined effect of hierarchical micromesopores and well-balanced acidity with optimum Lewis acid sites. The liquid product possessing high alkyl-aromatics with a high octane value (RON ∼ 109) produced in the present study can be used as an octane booster for liquid gasoline. The high alkyl-aromatics (>50 wt %) content of the liquid product also attracts various petrochemical applications. The effective utilization of waste bioglycerol as a green template and mesopore creator for the preparation of Zn-Z-GT can exhibit sustainability in the resultant material.

EFEK BLENDING BAHAN BAKAR TERBARUKAN BUTANOL 5% PADA PERTAMAX TERHADAP PERFORMA MESIN BENSIN EFI 150 CC

Butanol is an alternative energy that is being developed to overcome the energy crisis. This is because butanol has a high Octane number and oxygen content so it can optimize engine performance. This research was carried out to determine the impact of adding butanol to Pertamax on gasoline engine performance. The engine used is a 150 cc EFI petrol engine. The fuel uses Pertamax with butanol additive. Testing uses speed variations of 1000 – 3000 rpm. Test results: The performance of the 150 cc EFI petrol engine using the Pertamax-butanol mixture (P95B5) has increased compared to using pure Pertamax fuel (P100). This can be seen from the increase in torque and power with Pertamax-butanol fuel (P95B5) of 3.57 N.m and 1.12 kW, the highest increase at rpm 3000. Engine fuel consumption decreased when butanol was added compared to pure Pertamax (P100). The lowest fuel consumption occurred with Pertamax-butanol (P95B5) fuel at 0.21 ml/s when the engine speed was 100 rpm. Meanwhile, the highest fuel consumption occurred in Pertamax fuel (P100) at 0.62 ml/s when the engine speed was 3000 rpm

Analysis of Fire and Explosion Consequences in Accidents Involving Premium Gasoline Tanker Trucks

Analysis of Fire and Explosion Consequences in Accidents Involving Premium Gasoline Tanker Trucks

Combustion characteristics of diisopropoxymethane, a low-reactivity oxymethylene ether

Oxymethylene ethers (OMEs) have been studied for use as low-sooting diesel fuel additives or substitutes; very little literature discusses OMEs as spark-ignition (SI) fuels due to their typically high cetane numbers. In this work, a lower-reactivity, branched OME, diisopropoxymethane (DIPM), is evaluated to determine its effectiveness as a spark-ignition fuel, as it is the lowest-reactivity OME (as determined by Indicated Cetane Number) thus far evaluated in the literature. DIPM is synthesized in-house via acetalization from isopropanol (iPrOH) and trioxane using standard OME production practices. DIPM was then tested in a rapid compression machine (RCM) for autoignition and spark ignition characteristics, and in a modified CFR engine to determine effective octane numbers. In the RCM, an autoignition temperature sweep was performed at stoichiometric conditions from 1000/T = 1.7 - 1.0, at 5:1 inert ratio (comparable to approximately 25% EGR), where it was found that DIPM has ignition delay times 5–10x faster than isooctane and displays NTC ignition behavior. Blends with iPrOH indicate that reactivity can be matched with isooctane with low blend ratios of iPrOH in DIPM. Flame speeds were tested with a laser spark for ignition in the RCM, where the flame speed of DIPM and isooctane is determined to be comparable at engine relevant conditions. In the CFR engine, effective RON and MON based on pressure trace frequency domain measurements were determined for DIPM and a 15 vol% iPrOH in DIPM blend. Neat DIPM has (R+M)/2 = 59 and a negative sensitivity of S = -18, consistent with its NTC behavior and higher reactivity. The DIPM/iPrOH blend has positive sensitivity and a pump-gasoline range (R+M)/2 = 89.3. DIPM on its own is unlikely to be an effective SI fuel, however, when blended with iPrOH as an ON booster, it may be a promising SI candidate fuel.

The sensitivity of pressure-based knock threshold values to alternative fuels: A comparison of methanol vs. gasoline

The heavy-duty industry typically uses a high cetane fuel to power their vehicles, currently typically fossil diesel. Switching to renewable fuels such as methanol requires a major changeover in engine technology. Due to the high octane number of methanol, the diesel engines will have to be replaced by more suitable spark-ignited engines. An accurate knock control system will then be needed to accommodate the high power density requirements of this sector. However, current pressure-based knock detection methods were primarily developed for gasoline fuel operation. Blindly copying these methods for a fuel which has vastly different knock properties can lead to suboptimal engine operation with an efficiency and power loss as result. In this work, experiments were conducted on a single cylinder port fuel injected spark-ignited CFR engine. The applicability of five different pressure-based knock metrics was reassessed for methanol fuel and their performance was compared to each other. Knock threshold values were established for both gasoline and methanol for the MAPO (maximum amplitude of pressure oscillations), AE (average energy) and MVTD (minimum value of third derivative) methods. The results show that the performance of the single peak metrics MAPO and IMPO (integral of modulus of pressure oscillations), and the time-averaged metrics AE and HRR (heat release rate) remains identical between methanol and gasoline operation. For the MVTD method however, the suggested low sampling rate of 1 sample/°ca is insufficient for methanol combustion since the fuel by nature already shows a narrow pressure peak. Overall, the HRR method outperforms the others through the addition of a noise constraint. The calculated knock threshold values, however, are drastically different between both fuels. Compared to gasoline, the thresholds for methanol were 1.25, 2.40 and 5.45 times higher for the MAPO, AE and MVTD methods respectively. This highlights the need for dedicated, fuel-specific, knock threshold values.

TECHNO-ECONOMICAL STUDY ON THE PRODUCTION OF HIGH OCTANE GASOLINE IN LIGHT NAPHTHA PLANT

The Indonesian government is optimizing the production of high-octane gasoline by utilizing existing ingredients that are plentiful and rarely used in Indonesia to keep up with the rising demand for it. Although light naphtha, a by product of the oil refinery process, has the potential to be transformed into fuel with a high Research Octane Number, its application has not yet been fully realized. The objective of this study is to carry out a study of the economic and technical feasibility of high-octane gasoline plants. A 10,000 barrel/day production potential has been built into the plant. In order to reach the RON objective of 98 for high-octane fuel, light naphtha, which has a Research Octane Number of 73, will need to be increased. The production process includes isomerization, depentanizing, and adsorption. From a technical perspective, this plant can produce high-octane gasoline from light naphtha with RON98. From an economic perspective, the Net Present Value is $ 138,247,252; Internal Rate of Return of 29.38 % per year; Pay Out Time is 3 years 5 months; and Break Even Point is 49 %. Overall, based on technical and economic perspectives, this power plant is feasible.

Specifications for applying high octane additives to the motor gasoline in hot climate

The article analyzes the use of high-octane additives to motor gasoline used in hot climates. We have studied anti-knock additives as additives to improve the octane number of gasoline. An additive based on alcohols, octane-Booster, was used as such additives. Laboratory studies were carried out on the physicochemical parameters of AI-80 and AI-92 gasoline with the addition of an anti-knock additive. The results of the studies show that when gasoline is used in hot climates, the addition of high-octane components based on alcohols increases the octane number, but at the same time the boiling point of the light fraction of gasoline decreases. With an increase in the percentage of additive, the boiling point of the light fractions reached 58°C. Taking into account all the experimental data obtained, we suggest adding a percentage of this additive of no more than 3%, which shows the optimal octane number and distillation temperature of 10% gasoline for hot climates. With a further increase in concentration to 5%, the octane number increases, but at the same time the distillation temperature of 10% gasoline sharply decreases, which can lead to increased friction losses. When the concentration increased above 5%, the octane number did not change. To ensure optimal engine operating conditions in hot climatic conditions, we suggest ensuring that the boiling point of gasoline at the beginning of distillation is not lower than 40°C ÷ 43°C, and the distillation temperature of 10% gasoline is not lower than 70°C.

Improvement of octane number in FCC gasoline through the extraction with urea/thiourea complex based on property analysis

By adding thiourea, the solution of urea in alcohol is improved, which facilitates the formation of a urea complex and benefits the increase in the octane number of FCC gasoline.

An easy but quantitative assessment of soot production rate and its dependence on temperature and pressure

The challenge of soot emission persists in combustion research due to the complexities of tracking the crucial stages of growth from fuel to soot nuclei and ultimately mature particles. Studying soot formation in flames often requires a sophisticated approach, involving detailed measurements of gaseous soot precursors and soot particles using multiple complementary diagnostics. On the other end of the spectrum of studies are simpler methods that capture the sooting tendency using a single index, akin to the cetane number in compression ignition engines and the octane number in spark ignition engines. This article seeks a middle ground, aiming to quantify the soot production rate while maintaining the simplicity of single-index characterizations. The approach involves establishing counterflow diffusion flames, measuring soot volume fraction through pyrometry, and accurately computing velocity and temperature profiles using a commercial code. These data allow for the quantification of the production rate from the soot governing equation. The methodology is applied to counterflow ethylene diffusion flames to examine the temperature dependence of the soot production rate across peak temperatures varying by several hundred degrees and pressures in the 1–32 atm range. The soot production rate per unit flame area falls within the range of 10−7–10−3 g/(cm2s) range and, when normalized with respect to the carbon flux, it ranges between 10−6 and nearly 10−2. On a logarithmic scale, it linearly correlates with the peak temperature at a fixed pressure. Although this study deals only with flames of ethylene, the approach can be generalized to any fuel. The resulting database should be valuable not only for industry practitioners but also to the scientific community for the global validation of detailed soot models.

Influences of Compression Ratio on Performance of Single Cylinder Otto Engine Using E50 Fuel

Ethanol mixed with a primary fuel is a promising alternative fuel. To increase performance, an optimal compression ratio must be set. The compression ratio is the ratio of the maximum volume divided by the minimum volume. Ethanol-gasoline mixtures have high octane and can be used in high-compression engines. This research aims to identify how changes in compression ratio can affect various aspects of engine performance, including torque, power, fuel efficiency, and thermal efficiency. This study is expected to reveal new insights that can aid in optimizing engine performance and developing a more comprehensive understanding of the characteristics of the E50 fuel within the context of Otto engine usage. A single-cylinder Otto engine was used for testing. Compression ratios of 9.3:1, 10.3:1, and 11.3:1 were tested. The results showed that the compression ratio of 9.3:1 produces a peak torque of 7.17 N∙m, peak power of 3.36 kW, lowest BSFC of 0.275 kg/kWh, and highest BTE of 37.49%. A compression ratio of 10.3:1 produces a peak torque of 7.21 N∙m, peak power of 3.57 N∙m, lowest BSFC of 0.281 kg/kWh, and highest BTE of 39.46%. A compression ratio of 11.3:1 produces a peak torque of 7.73 N∙m, peak power of 3.81 kW, lowest BSFC of 0.275 kg/kWh, and highest BTE of 40.36%. Compared with pertalite, E50 reduces torque by 9.25%, power by 9.93%, BSFC by 3.66%, and BTE by 8.76% at all compression ratios.

Investigation on flame propagation and end-gas auto-ignition of ammonia/hydrogen in a full-field-visualized rapid compression machine

Ammonia-hydrogen engine has attracted much attention due to its carbon-free nature. Given that ammonia has high knock resistance (indicated by its high research octane number of nearly 130), researchers are trying to increase the compression ratio (CR) to improve engines’ thermal efficiency. However, knocking cycles can still be detected in ammonia-hydrogen engines under elevated thermodynamic conditions. To further explore the ammonia-hydrogen knocking process, this study conducted a series of spark-ignition combustion experiments focusing on flame propagation and end-gas auto-ignition in a full-field-visualized rapid compression machine. Four ammonia-hydrogen blended fuels with hydrogen energy fractions of 0 % (H0), 10 % (H10), 20 % (H20), and 100 % (H100) were comparatively tested under the thermodynamic conditions of 30 bar and 750–985 K. The experimental results showed that the flame speed of H0, H10, and H20 is around 3–6 m/s under test conditions, much lower than that of H100, which exceeds 37 m/s at 30 bar/750 K. Strong end-gas auto-ignitions with maximum pressure amplitudes of 77 bar and 101 bar were recorded for H0 at 30 bar/985 K and H10 at 30 bar/915 K, respectively. The two auto-ignition events both exhibited detonation characteristics by clear wavefronts with speeds reaching up to 1620 m/s (H0) and 1812 m/s (H10). Based on the experimental results, simulations were carried out to analyze the chemical process during the end-gas auto-ignition. The simulated results showed that for H0 at 30 bar/985 K, the NO-, NO2-, and H2NO-related reactions contributed most to heat production, which improved the end-gas reactivity and promoted the occurrence of auto-ignition. For H10 at 30 bar/915 K, the H + O2 (+M) = HO2 (+M) became the most exothermic reaction, indicating the hydrogen addition significantly promoted the ammonia's end-gas auto-ignition. Additionally, the detonation events observed in this study can be well classified in the ε -ξdiagram.