Charge Compression Ignition Engine Combustion Research Articles

Multiple fuel injection strategy for premixed charge compression ignition combustion engine using biodiesel blends

In the last decade, advanced combustion techniques of the low-temperature combustion (LTC) family have attracted researchers because of their excellent emission characteristics; however, combustion control remains the main issue for the LTC modes. The objective of this study was to explore premixed charge compression ignition (PCCI) combustion mode using a double pilot injection (DPI; pilot-pilot-main) strategy to achieve superior combustion control and to tackle the soot-oxides of nitrogen (NOx) trade-off. Experiments were carried out in a single-cylinder research engine fueled with 20% v/v biodiesel blended with mineral diesel (B20) and 40% v/v biodiesel blended with mineral diesel (B40) vis-à-vis baseline mineral diesel. Engine speed and rate of fuel-mass injected were maintained constant at 1500 rpm and 0.6 kg/h mineral diesel equivalent, respectively. Pilot injection timings (at 45° and 35° before top dead center (bTDC)) and fuel quantities were fixed, while three fuel injection pressures (FIPs) and four different start of the main injection (SoMI) timings were investigated in this study. Results showed that multiple pilot injections resulted in a stable PCCI combustion mode, making it suitable for higher engine loads. For all test fuels, advancing SoMI timings led to relatively lesser knocking; however, engine performance characteristics degraded at advanced SoMI timings. B40 exhibited relatively superior engine performance among different test fuels at lower FIP; however, the difference in engine performance was insignificant at higher FIPs. Fuel injection parameters showed a significant effect on emissions, especially on the NOx and particulates. Advancing SoMI timing resulted in 20%–50% lower particulates emissions with a slight NOx increase; however, the differences in emissions at different SoMI timings reduced at higher FIPs. Somewhat higher particulates from biodiesel blends were a critical observation of this study, which was more dominant at advanced SoMI timings. Qualitative correlation between NOx-total particulate mass (TPM) was another critical analysis, which exhibited the relative importance of different fuel injection parameters for other alternative fuels. Overall, B20 at 700 bar FIP and 20° SoMI timing emerged as the most promising proposition with some penalty in CO emission.

Enabling robust simulation of polyoxymethylene dimethyl ether 3 (PODE3) combustion in engines

PODE3 reaction mechanism developments are still in the early stages with very limited research. In particular, reaction mechanisms to characterize PODE3 combustion are neither sufficiently compact nor robust for 3D numerical simulations. Hence, the current work seeks to develop a compact yet reliable PODE3 reaction mechanism, embedded with appropriate chemistry to describe polycyclic aromatic hydrocarbon reactions. A decoupling methodology has been employed to achieve the desired outcome. The final mechanism comprises only 120 species and 560 reactions even after including components of diesel and gasoline surrogates. It has been validated with ignition delay times, laminar flame speeds, jet-stirred reactor species concentration profiles, flame species concentration profiles, extinction strain rates, heat release rates in constant volume combustion chamber, homogeneous charge compression ignition engine combustion, and direct injection compression ignition engine combustion. In a numerical investigation conducted using gasoline/diesel/PODE3 blends, soot emissions are observed to decrease with PODE3 increment, which establishes PODE3 as a promising additive. Intriguingly, the current study has also discovered that with 15% PODE3 addition, soot and its precursors will increase in concentration during combustion, though this effect will be outweighed by oxidative effects towards the end. Overall, the new mechanism has been proven suitable and feasible for engine simulations.

Performance Evaluation of Homogeneous Charge Compression Ignition Combustion Engine – A Review

The development of HCCI combustion technology has been drawing a great deal of attention from researchers. This survey explains ongoing research methodologies and results. HCCI combustion, other than conventional combustion, is purely based on chemical kinetics. At present the automobile sector faces the problem of emissions and needs to develop clean technologies. However, HCCI operation still has issues such as ignition control, combustion phasing control, operating range control, cold start, and UHC (unburned hydrocarbon) and CO (carbon monoxide) emissions. The challenge is to overcome these problems without compromising other engine parameters and performance. For HCCI, the mixture preparation is especially important, while the compression ratio, IVC (inlet valve closure) timing, inlet pressure, inlet temperature and EGR play a very prominent role in controlling it. This paper will go through a detailed discussion of all the above conditions.

Split Injection Strategies for Biodiesel-Fueled Premixed Charge Compression Ignition Combustion Engine—Part I: Combustion, Performance, and Emission Studies

Abstract In this study, a single-cylinder research engine was used to investigate the comparative combustion, performance, and emissions characteristics of the engine in a premixed charge compression ignition (PCCI) mode combustion vis-a-vis baseline compression ignition (CI) mode combustion using three test fuels, namely, B20 (20% v/v biodiesel blended with mineral diesel), B40 (40% v/v biodiesel blended with mineral diesel), and mineral diesel. For both combustion modes, experiments were performed at constant fuel injection pressure (FIP, 700 bar), engine speed (1500 rpm), and fuel energy input (0.7 kg/h diesel equivalent). PCCI mode combustion experiments were performed at four different start of main injection (SoMI) timings using two different pilot fuel injection strategies, namely, single pilot injection (SPI, 35 deg before top dead center (bTDC)) and double pilot injection (DPI, 35 deg, and 45 deg bTDC). Results showed that advancing SoMI timing for both CI and PCCI combustion modes resulted in knocking; however, the DPI strategy resulted in relatively lesser knocking compared with the SPI strategy. The performance of PCCI mode combustion was relatively inferior compared with baseline CI mode combustion; however, biodiesel blends slightly improved the performance of PCCI mode combustion. Overall, this study shows that the PCCI mode combustion operating load range can be improved by using the DPI strategy.

Experimental investigation of the relationship between thermal barrier coating structured porosity and homogeneous charge compression ignition engine combustion

Heat transfer has a profound influence on homogeneous charge compression ignition combustion. When a thermal barrier coating is applied to the combustion chamber, the insulating effect magnifies the wall temperature swing, decreasing heat transfer during combustion. This enables improvements in both thermal and combustion efficiency without the detrimental impacts of intake charge heating. Increasing the temperature swing requires coatings with lower thermal conductivity and heat capacity. A promising avenue for simultaneously decreasing both thermal conductivity and capacity is to increase the porosity fraction. A proprietary solution precursor plasma spray process enables discrete organization of the porosity structure, called inter-pass boundaries, which in turn produces a step-reduction in thermal conductivity for a given porosity level. In this investigation, yttria-stabilized zirconia is used to create four different thermal barrier coatings to study the potential of structured porosity as means of improving the “temperature swing” behavior in a homogeneous charge compression ignition engine. The baseline coating is “dense YSZ,” applied using a standard air-plasma spray process. Next, significant reductions of the thermal conductivity are achieved by utilizing the solution precursor plasma spray process to create inter-pass boundaries with a moderate overall porosity. Performance, efficiency, and emissions are compared against both a baseline configuration with a metal piston and an air-plasma spray “dense YSZ” coating. Experiments are carried out in a single-cylinder gasoline homogeneous charge compression ignition engine with exhaust re-induction. Experiments indicate that incorporating structured porosity into thermal barrier coatings produces tangible gains in combustion and thermal efficiencies. However, there is an upper limit to porosity levels acceptable for homogeneous charge compression ignition engine application because an elevated porosity fraction leads to excessive surface roughness and undesirable fuel interactions. Comparison of the coatings showed the best results with coating thickness of up to 150 µm. Thicker coatings led to slower surface temperature response and attenuated swing temperature magnitude.

Effects of refinery stream gasoline property variation on the auto-ignition quality of a fuel and homogeneous charge compression ignition combustion

The combination of in-cylinder thermal environment and fuel ignition properties plays a critical role in the homogeneous charge compression ignition engine combustion process. The properties of fuels available in the automotive market vary considerably and display different auto-ignition behaviors for the same intake charge conditions. Thus, in order for homogeneous charge compression ignition (HCCI) technology to become practically viable, it is necessary to characterize the impact of differences in fuel properties as a source of ignition/combustion variability. To quantify the differences, 15 gasolines composed of blends made from refinery streams were investigated in a single-cylinder homogeneous charge compression ignition engine. The properties of the refinery stream blends were varied according to research octane number, sensitivity (S = research octane number − motor octane number) and volumetric contents of aromatics and olefins. Nine fuels contained 10% ethanol by volume, and six more were blended with 20% ethanol. Pure ethanol (E100) and an un-oxygenated baseline fuel (RD3-87) were included too. For each fuel, a sweep of intake temperature at a consistent load and engine speed was conducted, and the combustion phasing given by the crank angle of 50% mass fraction burned was tracked to assess the sensitivity of auto-ignition to fuel chemical kinetics. The experimental results provided a wealth of information for predicting the HCCI combustion phasing from the given properties of a fuel. In this study, the original octane index correlation proposed by Kalghatgi based solely on fuel research octane number and motor octane number was found to be insufficient for characterizing homogeneous charge compression ignition combustion of refinery stream fuels. A new correlation was developed for estimation of auto-ignition properties of practical fuels in the typical HCCI engine. Fuel composition, captured by terms indicating the fraction of aromatics, olefins, saturates and ethanol, was added to generate the following formula: [Formula: see text]. The results indicate a significantly improved estimation of combustion phasing for gasoline fuels of varying chemical composition under low-temperature combustion conditions. Quantitative findings of this investigation and the new octane index correlation can be used for designing robust HCCI control strategies, capable of handling the wide spectrum of fuel chemical compositions found in pump gasoline.

Particulate Size Distribution from Diesel–Dimethyl Ether Dual Fuel Premixed Compression Ignition Combustion Engine

AbstractParticulate matter (PM) emission has been a concern in recent years because of its impact on the atmospheric environment and human health. Recently the dual-fuel premixed charge compression ignition (PCCI) combustion strategy has become a popular option of reducing PM emissions from compression-ignition engines. In the current paper, the variations of PM emissions from the diesel–dimethyl ether (DME) dual-fuel premixed charge compression ignition combustion engine are investigated under the various input DME energy ratios, diesel injection timings, speeds, and loads. An electrical low pressure impactor (ELPI) is used for characterizing the particle number/mass and size distribution. The particulate number and mass concentrations for DME-diesel dual-fuel premixed charge compression ignition operation are lower than those of conventional direct-injection compression ignition (DICI) operation and reduce with a rise of port DME ratio under all operating conditions because of oxygen content and no C-C ...

Study on combustion and emission of a dimethyl ether-diesel dual-fuel premixed charge compression ignition combustion engine with LPG (liquefied petroleum gas) as ignition inhibitor

A scheme of the DME-diesel dual-fuel PCCI (premixed charge compression ignition) combustion is an attractive option of relatively high thermal efficiency, low emission and operating costs as well as availability of wide DME (dimethyl ether) resource. However, one of the main problems in the DME-diesel dual-fuel PCCI operation is that an early start of combustion easily leads to detonation due to high cetane number and better auto-ignition property of DME, and above-mentioned phenomenon is especially pronounced with a large DME energy ratio or at higher loads. Thus, LPG (liquefied petroleum gas), as a kind of ignition inhibitor, is added into DME for changing the property of port premixed fuel, and the effects of LPG quantity on the combustion and exhaust performance of a DME-diesel dual-fuel PCCI engine is investigated in this paper. Experimental results show that the appearing positions of the maximum cylinder pressure and mass-averaged temperature shift towards later crank angles and their peak values decline slightly when LPG mass fraction in DME/LPG mixture (fL) increases. The start of combustion postpones, and the combustion duration shortens with a rise of fL. Simultaneously, brake thermal efficiency and NOx emission reduce slightly; whereas the number concentration of particles firstly increases but then decreases with a rise of fL.

Numerical modeling on homogeneous charge compression ignition combustion engine fueled by diesel-ethanol blends

This paper investigates the performance and emission characteristics of HCCI engines fueled with oxygenated fuels (ethanol blend). A modeling study was conducted to investigate the impact of ethanol addition on the performance, combustion and emission characteristics of a Homogeneous Charge Compression Ignition (HCCI) engine fueled by diesel. One dimensional simulation was conducted using the renowned commercial software for diesel and its blend fuels with 5% (E5) and 10% ethanol (E10) (in vol.) under full load condition at variable engine speed ranging from 1000 to 2750 rpm with 250 rpm increment. The model was then validated with other researcher’s experimental result. Model consists of intake and exhaust systems, cylinder, head, valves and port geometries. Performance tests were conducted for volumetric efficiency, brake engine torque, brake power, brake mean effective pressure, brake specific fuel consumption, and brake thermal efficiency, while exhaust emissions were analyzed for carbon monoxide (CO) and unburned hydrocarbons (HC. The results showed that blending diesel with ethanol increases the volumetric efficiency, brake specific fuel consumption and brake thermal efficiency, while it decreases brake engine torque, brake power and brake mean effective pressure. In term of emission characteristics, the CO emissions concentrations in the engine exhaust decrease significantly with ethanol as additive. But for HC emission, its concentration increase when apply in high engine speed. In conclusion, using Ethanol as fuel additive blend with Diesel operating in HCCI shows a good result in term of performance and emission in low speed but not recommended to use in high speed engine. Ethanol-diesel blends need to researched more to make it commercially useable.

Study on the effect of hydrogen addition to dimethyl ether homogeneous charge compression ignition combustion engine

The auto-ignition characteristics of dimethyl ether (DME)/H2/Air blends (hydrogen blending ratio ranging from 0% to 70%) in homogeneous charge compression ignition (HCCI) combustion engine are investigated by calculation method using zero-dimension single-zone model. All the simulated mixtures demonstrated a two-stage heat release phenomenon at different crank angles. The results show that the hydrogen addition can retard the auto-ignition timing of DME in HCCI combustion engine. The ignition timing at low temperature is retarded slightly with the hydrogen addition, and the ignition timing at high temperature is delayed significantly due to the increased negative temperature coefficient duration. Chemical kinetic analysis reveals that the competition of OH radicals between hydrogen and DME could be the reason why the low temperature reactions of DME are mitigated. H2O2 molecules decompose at about 1000 K and initiate the high temperature reactions of the mixtures.

Effect of heat transfer on the reduction of the detailed chemical kinetics mechanism in a homogeneous charge compression ignition combustion engine

In homogeneous charge compression ignition engines, the ignition takes place in the absence of any external source, initiated by the autoignition of the well-mixed in-cylinder charge. The heat loss from the hot combustion gases to the surroundings causes the thermal conditions in the cylinder to deteriorate. These conditions are governed by the interaction of the chemical processes with the temperature and pressure changes in the cylinder. As a result, the heat release rate and the heat transfer inside the combustion chamber play significant roles in the homogeneous charge compression ignition combustion mode. The use of detailed chemical kinetics mechanisms in predictive combustion models increases the simulation time, which makes the utilization of these mechanisms questionable. As a result, reduced mechanisms of smaller sizes are required. However, in developing a reduced chemical kinetics mechanism from the detailed chemical kinetics mechanism, it is not common to consider the role of heat transfer, and this is needed to focus on only the kinetics aspects of homogeneous charge compression ignition. The objective of this work is to investigate the effect of heat transfer (through the boundaries of the combustion chamber) on the development of the reduced mechanisms from the detailed mechanisms. A single-zone combustion model is used to simulate the homogeneous charge compression ignition engine. Insignificant species and reactions of the detailed GRI-Mech 3.0 mechanism are eliminated by employing a two-stage reduction process based on a directed relation graph with error propagation and principal-component analysis methods respectively. Several different operating conditions are considered. The results demonstrate that the reduction process based on the directed relation graph with error propagation is hardly affected by considering the heat transfer. However, taking into account the heat transfer slightly influences the reduction process based on the principal-component analysis. Simulation outcomes from the generated mechanisms under adiabatic conditions and non-adiabatic conditions agree closely with the results obtained from the detailed mechanism. The differences in the crank angle when 50% of heat is released, the peak pressure and the maximum heat release between the original mechanisms and the reduced mechanisms are less than 1° crank angle, 1% and 1% respectively. Therefore, for a chemical mechanism reduction strategy, considering the heat transfer component will lead to only a minor effect on the generated reduced mechanism.

Investigation of the combustion and emission characteristics of partially premixed compression ignition in a heavy-duty diesel engine

Partially premixed compression ignition in a diesel engine is a combustion mode between diffusion combustion and homogeneous charge compression ignition combustion, the combustion controllability and the emission performances of which are close to those of a homogeneous charge compression ignition combustion engine; the mixing period plays a key role in realizing partially premixed compression ignition, and a long premixed process before combustion is necessary to make the fuel and air mix well. Partially premixed compression ignition combustion in a boosted six-cylinder heavy-duty diesel engine is realized by adjusting the injection timing and the rate of exhaust gas recirculation based on a single injection. The effects of the injection timing, the exhaust gas recirculation rate and the load rate on the combustion and the heat release pattern are studied. The factors which influence the mixing period and the ignition delay and its regularity are researched. Endoscope technology and the two-colour method are also used to gain an insight into partially premixed compression ignition combustion. The results show that both early injection and late injection have a long mixing period, which helps to form a more homogeneous mixture, and no diffusion combustion is found in the heat release rate curves. Premixed combustion and low-temperature combustion are the key factors in reducing the particulate matter emissions and nitrogen oxide emissions simultaneously. However, the low-temperature combustion and the dilute mixture may lead to incomplete combustion; consequently, for relatively late-injection conditions, the hydrocarbon and carbon monoxide emissions increase dramatically and the fuel consumption becomes worse. In these partially premixed combustion patterns, the effect of the injection pressure on the particulate matter and nitrogen oxide emissions is not clearly observable. At lower load rates, partially premixed compression ignition combustion displays a low-temperature and a high-temperature two-stage heat release. When the engine load rate is increased to 50%, diffusion combustion appears in the early-injection modes, which leads to higher nitrogen oxide and particulate matter emissions.

Characterization of exhaust particulates from diesel fueled homogenous charge compression ignition combustion engine

Engine exhaust particulates undergo different processes in the ambient environment such as agglomeration, coagulation, surface condensation, adsorption, and oxidation before evolving as mature particles. Conventional CI engines emit a significant mass/number of particulates due to heterogeneous combustion. However this problem can be resolved by using an advanced combustion technology named as Homogeneous Charge Compression Ignition (HCCI), which has potential to substantially reduce particulates and NOx simultaneously and deliver efficiencies comparable to conventional CI combustion. In the present study involving homogeneous mixture of diesel and air, an electrically heated diesel vaporizer was developed. Experiments were performed at different relative air-fuel ratios and EGR levels. Enrichment of the mixture increases the peak in-cylinder temperature, which was effectively controlled by EGR under leaner HCCI conditions. A partial flow dilution tunnel was used to collect particulate samples for trace metal content and Benzene Soluble Organic Fraction (BSOF), which is considered to be a marker of toxicity. This analysis showed that the trace metals detected were comparatively lower in HCCI particles. Trace metal concentration increased with application of EGR in the HCCI engine. BSOF content of the HCCI particulates increased when the mixture becomes leaner as well as with increasing EGR. Physical characterization of particulates was also carried out using engine exhaust particle sizer (EEPS), which measures the particle size-number distribution for the nano-particles in the exhaust. The particles collected on the filter paper were also analyzed for morphology using scanning electron microscopy (SEM).

Numerical study of EGR effects on reducing the pressure rise rate of HCCI engine combustion

The effects of the inert components of exhaust gas recirculation (EGR) gas on reducing the pressure rise rate of homogeneous charge compression ignition engine combustion were investigated numerically by utilizing the CHEMKIN II package and its SENKIN code, as well as Curran’s dimethyl ether reaction scheme. Calculations were conducted under constant volume combustion and engine combustion (one compression and one expansion only, respectively) conditions. Results show that with constant fuel amount and initial temperature and pressure, as EGR ratio increases, combustion timings are retarded and the duration of thermal ignition preparation extends non-linearly; peak values of pressure, pressure rising rate (PRR), and temperature decrease; and peak values of heat release rate in both low temperature heat release (LTHR) and high temperature heat release decrease. Moreover, maximum PRR decreases as CA50 is retarded. With constant fuel amount, mixtures with different EGR ratios can obtain the same CA50 by adjusting the initial temperature. Under the same CA50, as EGR ratio increases, the LTHR timing is advanced and the duration of thermal ignition preparation is extended. Maximum PRR is almost constant with the fixed CA50 despite the change in EGR ratio, indicating that the influence of EGR dilution on chemical reaction rate is offset by other factors. Further investigation on the mechanism of this phenomenon is needed.

Effects of the fuel injection ratio on the emission and combustion performances of the partially premixed charge compression ignition combustion engine applied with the split injection method

Currently, due to the severity of world-wide air pollution by substances emitted from vehicles, emission control is being enforced more strictly, and it is expected that the regulation requirements for emission will become even more severe. A new concept combustion technology that can reduce the Nitrogen oxides (NOx) and PM in relation to combustion is urgently required. As a core combustion technology among new combustion technologies for the next generation engine, the homogenous charge compression ignition (HCCI) is expanding its application range by adopting a multiple combustion mode, a catalyst, direct fuel injection and partially premixed charge compression ignition combustion using the split injection method. This paper used a split injection method in order to apply the partially premixed charge compression ignition combustion method without significantly altering engine specifications of the multiple combustion mode and practicality by referring to the results of studies on the HCCI engine. Furthermore, the effects of the ratio of the fuel injection amount on split injection are investigated. From the test results, the adequate combination of the ratio of the fuel injection amount for the split injection method has some benefit on exhaust and fuel economy performance in a naturally aspirated single cylinder diesel engine.

Effects of Heat Release Mode on Emissions and Efficiencies of a Compound Diesel Homogeneous Charge Compression Ignition Combustion Engine

A compound diesel homogeneous charge compression ignition (HCCI) combustion system has been developed based on the combined combustion strategies of multiple injection strategy and a mixing enhanced combustion chamber design. In this work, a STAR-CD based, multidimensional modeling is conducted to understand and optimize the multiple injection processes. The parameters explored included injection timing, dwell time, and pulse width. Insight generated from this study provides guidelines on designing the multipulse injection rate pattern for optimization of fuel-air mixing. Various heat release modes created by different injection strategies are investigated by experimental comparison of combustion efficiency, heat loss, and thermal efficiency. It is demonstrated that the process of fuel evaporation and mixing are strongly influenced by pulse injection parameters. Through control of the parameters, the stratification and autoignition of the premixed mixture, and the heat release mode can be controlled. The dispersed mode of heat release created only by the compound diesel HCCI combustion is a flexible mode in combustion control. The thermal efficiency with this mode can reach approximately to as high as that of conventional diesel combustion, while the NOx and smoke emissions can be reduced simultaneously and remarkably.

Performance of multi-dimensional models for simulating diesel premixed charge compression ignition engine combustion using low- and high-pressure injectors

An engine CFD model has been developed to simulate premixed charge compression ignition (PCCI) combustion using detailed chemistry. The numerical model is based on the KIVA code that is modified to use CHEMKIN as the chemistry solver. The model was applied to simulate ignition, combustion, and emissions processes in diesel engines operated to achieve PCCI conditions. Diesel PCCI experiments using both low- and high-pressure injectors were simulated. For the low-pressure injector with early injection (close to intake valve closure), the model shows that wall wetting can be minimized by using a pressure-swirl atomizer with a variable spray angle. In the case of using a high-pressure injector, it is found that late injection (SOI = 5 ° ATDC) benefits soot emissions as a result of low-temperature combustion at highly premixed conditions. The model was also used to validate the emission reduction potential of an HSDI diesel engine using a double injection strategy that favours PCCI conditions. It is concluded that the present model is useful to assess future engine combustion concepts, such as PCCI and low-temperature combustion (LTC).

Selecting the optimum quasi-steady-state species for reduced chemical kinetic mechanisms using a genetic algorithm

A genetic optimization algorithm has been applied to the selection of quasi-steady-state (QSS) species in reduced chemical kinetic mechanisms. The algorithm seeks to minimize the error between reduced and detailed chemistry for simple reactor calculations approximating conditions of interest for a computational fluid dynamics simulation. The genetic algorithm does not guarantee that the global optimum will be found, but much greater accuracy can be obtained than by choosing QSS species through a simple kinetic criterion or by human trial and error. The algorithm is demonstrated for methane–air combustion over a range of temperatures and stoichiometries and for homogeneous charge compression ignition engine combustion. The results are in excellent agreement with those predicted by the baseline mechanism. A factor of two reduction in the number of species was obtained for a skeletal mechanism that had already been greatly reduced from the parent detailed mechanism.

99/02719 Use of high efficiency gas turbine power generation to address environmental issues

The effect of dimethyl-ether (DME) second injection was investigated in a single-cylinder direct injection compression ignition engine for homogeneous charge compression ignition combustion. Two different fuels, hydrogen and DME were used as main fuels. DME second injection timing and quantity were varied to control the combustion phasing of homogeneous charge compression ignition engine combustion. DME second injection timing was varied from 100 crank angle degrees before top dead centre to 5 after top dead centre. The DME injection quantity was varied from 5 mg to 9 mg. When DME injection was 9 mg, DME was injected by two strategies, which are single injection and split injection. Both single fuel and dual fuel combustion were influenced by DME second injection timing. When DME was used as a main fuel, combustion was stable regardless of the all injection timing while indicated mean effective pressures were lower than the dual-fuelled combustion. The Ignition delay of DME was much shorter than that of hydrogen due to its low auto-ignition temperature and higher cetane number. DME injection timing and quantity controlled the hydrogen ignition delay when hydrogen was used as a main fuel. With 5 mg of DME second injection, some injection timing showed misfire, therefore, increased DME injection quantity was required for stable combustion. 7 mg of DME second injection lead the highest indicated mean effective pressure.