Exhaust CO Emissions Research Articles

Boiler Retrofit for the Utilization of Biodiesel

Fuel oil used in the boiler is able to substitute with biodiesel. In lower blends, there are no engine modification needed, but some researchers recommended some technical adjustments in order to maintain the boiler's performance and equipment durability. This study consists of the comparison between the performance of boiler before and after retrofitting on the use of biodiesel. The diesel oil was introduced in biodiesel blends of 10% (B10), 20% (B20) and 25% (B25). A fire tube boiler was used for the test with pressure of 3 bar and heat input capacity of 60,000 kcal. The boiler retrofit is conducted by fine tuning the fan damper scale (FDS) and adding a heating feature on fuel system. It was specifically intended to maintain the quality of combustion and boiler efficiency as well as to avoid an increase in fuel consumption. The combustion behaviour was monitored by exhaust emissions of CO, NOx, and SO 2 . The fan damper scale (FDS) and fuel temperature is adjusted by the increasing portion of biodiesel used. The fuel heating apparatus was set at temperature of 40 o C for the use of B10, and 60 o C for B20 and B25. The FDS adjustment was successfully resulted a reduction in rate of combustion air by average of 9.2%. The boiler retrofitting for the utilization of B10, B20 and B25 showed an increase in boiler efficiency by 0.64%, 0.42% and 2.6% respectively. The boiler retrofitting is surprisingly reduced the fuel consumption by average of 11.2%.

A Comparative Study of an Lpg- Spark Ignition Engine using Liquid Sequential Injection Technique

The development of liquid phase Liquefied Petroleum Gas (LPG) as an alternative fuel for the gasoline fuel is becoming popular in spark ignition engines. In this research, an experimental work was conducted on a1.6L 4-cylinder multi-port injection engine. The engine was retrofitted with a Liquid Sequential Injection (LSI) LPG system. Its performance in terms of brake power, brake torque, brake specific fuel consumption (BSFC) and exhaust gas emissions (CO, CO 2 , HC, O 2 , and NOx) were evaluated from 1500rpm to 4000rpm with half-open and wide open throttle positions. In comparison with gasoline, the brake torque and brake power for LPG were higher, but the BSFC and exhaust emission of CO and CO 2 for LPG are lower.

Effect of Variant End of Injection Period on Combustion Process of Biodiesel Combustion

Biodiesel is an alternative fuel as a replacement to the standard diesel fuel in combustion diesel engine. The biodiesel fuel has a significantly influences throughout the combustion process and exhaust emission. The purpose of this research is to investigate the combustion process behavior during the End of Injection (EOI) period and operates under variant conditions using Rapid Compression Machine (RCM). Experimental of RCM is used to simulate a combustion process and combustion characteristics of diesel engine combustion. Three types of biodiesel blend which are B5, B10 and B15 were tested at several injection pressures of 80 MPa, 90 MPa and 130 MPa under different ambient temperatures, 750 K to 1100 K. The results of this study showed that the ignition delay slightly reduced with increasing the content of biodiesel blends from B5, B10 and B15 and became more shorten as the injection pressure been enhanced. As the injection pressure increased, the behavior of combustion pressure at end of injection is reduced, radically increased the NOX emission. It is noted that the process of combustion at the end of injection increased as the ambient temperature is rising. In fact, higher initial ambient temperature improved the fuel atomization and mixing process. Under the biodiesel combustion with higher ambient temperature condition, the exhaust emission of CO, O2, and HC became less but increased in NOX emission. Besides, increased in blends of biodiesel ratio are found to enhance the combustion process, resulted a decreased in HC emissions.

STUDY AND COMPARISON OF EMISSION CHARACTERISTICS OF N-BUTANOL / DIESEL BLEND IN CI ENGINE

A lot of emphasis is being laid on the use of biodegradable fuel directly or in blends with diesel to control harmful exhaust emissions and to help environment by reducing global warming in addition to reducing dependence on import of fossil fuels. An experimental study was conducted to study and compare the emission characteristics of n-butanol/diesel blend and diesel. The experiment was conducted on single cylinder, four stroke kirloskar diesel engine with different blends of n-butanol/diesel blends. The exhaust emissions of HC, CO, CO2 and O2 were measured with Neptune make analyzer.

Melon oil methyl ester: an environmentally friendly fuel

Demand for energy is growing across the globe due to the direct relationship between the well-being and prosperity of people and energy usage. However, meeting this growing energy demand in a safe and environmentally friendly manner is a key challenge. To this end, methyl esters (biodiesels) have been and are being widely investigated as alternatives to fossil fuels in compression ignition engines. In this study, melon (Colocynthis Citrullus Lanatus) oil was used to synthesize biodiesel (methyl ester) using the transesterification method in the presence of a sodium hydroxide promoter. The emissions profile of the biodiesel was investigated by setting up a single-cylinder four-stroke air-cooled CI engine connected to a TD115-hydraulic dynamometer and an Eclipse Flue Gas Analyzer (FGA) with model number EGA4 flue gas analyzer. The engine was run at engine speeds of 675, 1200 and 1900rpm for biodiesel/diesel blends at 21°C on a volume basis of 0/100(B0), 10/90(B10), 20/80(B20), 30/70(B30), 40/60(B40) and 50/50(B50). The test showed a downward trend in the emissions profile of the biodiesel, with remarkable reductions of about 55% in the dangerous-carbon monoxide exhaust gas pollutant and 33.3% in the unfriendly SOX from 100% diesel to B30-biodiesel concentration. Increasing the speed from 675 to 1200 and then to 1900 rpm also afforded further reductions in CO and SOX exhaust emissions. NOX however increased marginally by 2.1% from the same 100% diesel to the B30-biodiesel composition. Based on the remarkable reduction in CO and SOX and the marginal increase in NOX as the concentration of the biodiesel increased in the blends, the study concludes that melon oil methyl ester is an environmentally friendly fuel.

Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture

Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE). This paper investigates the effects of using argon (Ar) gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include the compression ratio, stroke length, and engine speed and argon concentration. Output parameters like TE, volumetric efficiency, heat release rates, brake power, exhaust gas temperature and emissions of NOx, CO2 and CO were studied in a thermal barrier coated SI engine, under variable argon concentrations. Results of this study showed that the inclusion of Argon to the input air of the thermal barrier coated SI engine has significantly improved the emission characteristics and engine’s performance within the range studied.

The CO/NOx Emissions of Swirled, Strongly Pulsed Jet Diffusion Flames

The CO and NOx exhaust emissions of swirled, strongly pulsed, turbulent jet diffusion flames were studied experimentally in a coflow swirl combustor. Measurements of emissions were performed on the combustor centerline using standard emission analyzers combined with an aspirated sampling probe located downstream of the visible flame tip. The highest levels of CO emissions are generally found for compact, isolated flame puffs, which is consistent with the quenching due to rapid dilution with excess air. The imposition of swirl generally results in a decrease in CO levels by up to a factor of 2.5, suggesting more rapid and compete fuel/air mixing by imposing swirl in the coflow stream. The levels of NO emissions for most cases are generally below the steady-flame value. The NO levels become comparable to the steady-flame value for sufficiently short jet-off times. The swirled coflow air can, in some cases, increase the NO emissions due to a longer combustion residence time due to the flow recirculation within the swirl-induced recirculation zone. Scaling relations, when taking into account the impact of air dilution over an injection cycle on the flame length, reveal a strong correlation between the CO emissions and the global residence time. However, the NO emissions do not successfully correlate with the global residence time. For some specific cases, a compact flame with a simultaneous decrease in both CO and NO emissions compared to the steady flames was observed.

Specific engine performance and gaseous emissions characteristics of European test cycle and worldwide harmonized driving cycle for a heavy-duty diesel engine

This study compares the engine operating behavior and regulated gaseous emissions characteristics between the reference European cycles (ESC/ETC) and the worldwide harmonized driving cycles (WHSC/WHTC), which will be applied in the Euro VI heavy-duty diesel engine emissions regulations, for the diesel particulate filter (DPF) equipped Mercedes 12 L diesel engine. The speed and load distribution for two additional representative harmonized cycles which cover a more realistic operating range for a heavy duty engine were established to verify the engine performance over wide range of the cycle work, fuel consumption, and exhaust system temperature as well as engine coolant temperature for repeated validation tests. The WHTC, including an additional test with cold start and transient operation before the hot start, had a substantial influence on the THC, CO, NOx, and PM exhaust emissions levels because of the engine heat-up time and temperature rising characteristics of aftertreatment device. Moreover, the different engine operating conditions of the WHSC influenced on the specific engine performance and gaseous emissions behavior unlike those of the ESC. Finally, the statistical analysis results through repeated tests validated the stationary and transient cycles running at the fully warm-up condition, however, those of WHTC were closely dependent on the inclusion of cold start condition or aggressive acceleration gradient of engine speed and load trace.

Evaluation of the Effectiveness of Heating Systems Applied in City Buses

The paper presents energy saving opportunities in by analyzing two types of auxiliary heating systems. Objects of study were two heaters differing in power requirements and fuel consumption (used for water heating system). The heaters were installed in city buses of the same layout and identical convector heaters fitted for optimum temperature of the vehicle interior and the engine. Through the use of a portable device SEMTECH DS (PEMS) the exhaust emissions of CO, HC, NOx, CO2were measured. The testing of the heaters for emissions and the testing of the temperature distribution inside the vehicle were performed in stationary conditions, determining the impact of the heating on the energy consumption of the heaters and temperature comfort inside the vehicle. The measurements were performed for each vehicle at the same ambient temperature, which was about 10°C [2, 3, 5]. So that the temperature increase inside the vehicle could be compared the tested vehicles were conditioned before the measurement. The obtained temperature distributions were determined along with a relative increase in the temperature in the vehicle interiors heated by the tested objects. The temperature measurement was performed with the use of six thermocouples utilizing a signal converter - IOTECH PERSONAL DAQ 3000.

Numerical Investigation on Combustion Behaviors of Direct-Injection Spark Ignition Engine Fueled with CNG-Hydrogen Blends

This paper deals with the subject of natural gas-Hydrogen blends as alternative fuel for spark ignition engine. First, a brief overview on previous works in this field was presented. Then, a numerical investigation focusedon the effect of hydrogen addition on the performances and emissions was also presented. A CFD approach using CONVERGE CFD Code was applied on a direct injection spark ignition engine at low regime and lean mixtures. A detailed chemistry associated with AMR (Adaptive Mesh Refinement) technique was adopted. To illustrate the effect of hydrogen addition to natural gas, three hydrogen fractions are considered 0%, 10% and 18%. The obtained results showthatthe promotion of the chemical reaction with hydrogen addition is mainly due to the increase of free radicals H, O, OH in the flame as a result of hydrogen addition. Hence, the heat release rate starting is advanced with the increase of hydrogen fraction while the combustion duration decreases. It is observed that the heat release rate and the maximum in cylinder temperature increase when hydrogen is added. Exhaust CO emissions decreases with the increase of hydrogen fraction, while NOx emissions increase. Hydrogen addition could give a great potential to reduce soot formation.

A novel diesel oxidation catalyst with low SO2 oxidation activity and capable of meeting Euro V emission standards

A diesel oxidation catalyst was prepared from several high performance materials: the new rare earth oxygen storage compound Ce 0.75 Zr 0.25 O 2 -Al 2 O 3 , the composite oxide Ti 0.9 Zr 0.1 O 2 and chromium-modified ß molecular sieve. These component materials were characterized and used to prepare a Pt-based catalyst designed to reduce diesel engine exhaust emissions. The results of low temperature N2 adsorption-desorption and oxygen storage capacity tests demonstrated that Ce 0.75 Zr 0.25 O 2 -Al 2 O 3 exhibits a large specific surface area and excellent oxygen storage capacity, and that Ti 0.9 Zr 0.1 O 2 exhibits superior textural properties. Evaluations of catalytic activity showed that the catalyst prepared from these materials has reduced capacity for the oxidation of SO 2 but high catalytic activity towards the oxidation of hydrocarbons (HC) and CO, and is also able to convert the exhaust soluble organic fraction at temperatures as low as 140 °C. Tests using a domestic YC4F-type diesel engine found that exhaust treated by the catalyst prepared in this research is capable of meeting the HC and CO emission requirements of the Euro V standard. 制备了具有高性能的稀土储氧材料Ce 0.75 Zr 0.25 O 2 -Al 2 O 3 , 14;Ti 0.9 Zr 0.1 O 2 复合材料和Cr改性的β分子筛(Cr-β分子筛), 14;并以此制备了单Pt型柴油车尾气净化氧化型催化剂. 低温N 2 吸附-脱附、储氧量测试结果表明, 14;Ce 0.75 Zr 0.25 O 2 -Al 2 O 3 样品具有较大的比表面积和优异的储氧性能, 14;Ti 0.9 Zr 0.1 O 2 复合材料也具有优越的织构性能. 催化剂对HC和CO具有较高的催化活性, 14;可使SOF在140 °C开始转化, 14;且具有较低的SO 2 氧化活性. 在YC4F国Ⅳ柴油机的测试结果表明, 14;经该催化剂处理后的尾气排放能够满足欧Ⅴ排放标准对HC和CO排放要求. A high performance diesel oxidation catalyst was prepared which demonstrated the ability to meet the Euro V standard for HC and CO exhaust emission content requirements.

A comprehensive inventory of the ship traffic exhaust emissions in the Baltic Sea from 2006 to 2009.

This study addresses the exhaust emissions of CO2, NOx, SOx, CO, and PM2.5 originated from Baltic Sea shipping in 2006–2009. Numerical results have been computed using the Ship Traffic Emissions Assessment Model. This model is based on the messages of the automatic identification system (AIS), which enable the positioning of ships with a high spatial resolution. The NOx emissions in 2009 were approximately 7 % higher than in 2006, despite the economic recession. However, the SOx emissions in 2009 were approximately 14 % lower, when compared to those in 2006, mainly caused by the fuel requirements of the SOx emission control area (SECA) which became effective in May 2006, but affected also by changes in ship activity. Results are presented on the differential geographic distribution of shipping emissions before (Jan–April 2006) and after (Jan–April 2009) the SECA regulations. The predicted NOx emissions in 2009 substantially exceeded the emissions in 2006 along major ship routes and at numerous harbors, mostly due to the continuous increase in the number of small vessels that use AIS transmitters. Although the SOx emissions have been reduced in 2009 in most major ship routes, these have increased in the vicinity of some harbors and on some densely trafficked routes. A seasonal variation of emissions is also presented, as well as the distribution of emissions in terms of vessel flag state, type, and weight.

Combustion and emission characteristics of alcohol fuels in a CAI engine

The combustion and emission characteristics of alcohol fuels in a controlled auto-ignition (CAI) combustion engine have been investigated. Combustion characteristics were studied by heat releases analysis through in-cylinder pressure measurement and auto-ignition reactions through high-speed chemiluminescence imaging. By means of the negative valve overlap, varied amount of residual gas was trapped in the cylinder to achieve the controlled auto-ignition with/without spark-assisted ignition. Total chemiluminescence images were captured with a high speed camera equipped with a high repetition image intensifier. Methanol, ethanol and their blends with gasoline were tested and their combustion and emission characteristics were compared with the results of gasoline.Alcohol fuels, in particular methanol, resulted in advanced auto-ignition and faster combustion than that of gasoline. In addition, their use could lead to substantially lower HC, NOX and CO exhaust emissions. Spark-assisted ignition was most effective on gasoline combustion by advancing ignition timing and initiating flame kernel at the centre of combustion chamber but it had marginal effect on alcohol fuels. Auto-ignition always took place at the perimeter of the chamber and occurred earlier with alcohol fuels because of their greater heat release and fuel reforming reactions during the negative valve overlap period. Chemiluminescence of the gasoline fuel was most visible and it decreased with increasing percentage of oxygenated fuels.

Experimental and analytical investigation of lean premixed methane/air combustion in a mesoscale counter-flow reactor

Combustion-based personal power systems have great potential for applications that demand high energy density, compact, and durable components. Through the use of heat recirculation, increased combustor firing rates and extension of flammability limits can be achieved. This study examines the combustion of lean methane/air reactant mixtures below the conventional flammability limit in a mesoscale heat-recirculating counter-flow reactor. An analytical model, previously developed for reforming in the counter-flow reactor, was adapted and applied to study lean operation. Results qualitatively describe the operating principle of the reactor and its behavior in response to changes in inlet conditions. Experiments determined the stable operating range of the reactor. Peak reactor wall temperature measurements indicate superadiabatic operation. Exhaust emissions of CO and NOx range from 35 to 143ppm and 5 to 25ppm, respectively, and emission indices as a function of firing rate are presented. Unburned hydrocarbons were detected at the lowest firing rates.

The effect of a homogeneous combustion catalyst on exhaust emissions from a single cylinder diesel engine

This paper reports a series of experimental investigations into the effect of an Fe-based homogeneous combustion catalyst on the emission characteristics from a four-stroke single cylinder diesel engine. The catalyst contained ferrous picrate as the active ingredient in a composite organic solvent mixture which could be homogeneously dissolved into a commercial diesel fuel at ultra low dosage ratios. The engine tests were conducted at four different engine loads and at two steady speeds of 2800rpm and 3200rpm, respectively. Engine exhaust emissions of CO, unburnt hydrocarbons (UHCs) and NOx were measured using an AVL gas analyser and the particulate emissions were evaluated in terms of smoke opacity using a Bosch smoke meter. The results showed that, in addition to the benefit of improved fuel efficiency, the homogeneous combustion catalyst significantly reduced the emissions of particulate matter, CO and UHC from diesel engines. Compared with the reference diesel, up to 3.7% reduction in the brake specific fuel consumption was achieved when the diesel fuel was treated with the catalyst. The use of the catalyst also led to significant reductions in the particulate matter, CO and UHC emissions, with the maximum reductions being 39.5%, 21.1% and 13.1%, respectively. The NOx emissions, however, increased slightly, by ca. 6%, which was consistent with the improved combustion performance as reasonably expected.

Combustion Performance in a Semiclosed Cycle Gas Turbine for IGCC Fired With CO-Rich Syngas and Oxy-Recirculated Exhaust Streams

Our study found that burning a CO-rich gasified coal fuel, derived from an oxygen–CO2 blown gasifier, with oxygen under stoichiometric conditions in a closed cycle gas turbine produced a highly-efficient, oxy-fuel integrated coal gasification combined cycle (IGCC) power generation system with CO2 capture. We diluted stoichiometric combustion with recycled gas turbine exhaust and adjusted for given temperatures. Some of the exhaust was used to feed coal into the gasifier. In doing so, we found it necessary to minimize not only CO and H2 of unburned fuel constituents but also residual O2, not consumed in the gas turbine combustion process. In this study, we examined the emission characteristics of gasified-fueled stoichiometric combustion with oxygen through numerical analysis based on reaction kinetics. Furthermore, we investigated the reaction characteristics of reactant gases of CO, H2, and O2 remaining in the recirculating gas turbine exhaust using present numerical procedures. As a result, we were able to clarify that since fuel oxidation reaction is inhibited due to reasons of exhaust recirculation and lower oxygen partial pressure, CO oxidization is very sluggish and combustion reaction does not reach equilibrium at the combustor exit. In the case of a combustor exhaust temperature of 1573 K (1300 °C), we estimated that high CO exhaust emissions of about a few percent, in tens of milliseconds, corresponded to the combustion gas residence time in the gas turbine combustor. Combustion efficiency was estimated to reach only about 76%, which was a lower value compared to H2/O2-fired combustion while residual O2 in exhaust was 2.5 vol%, or five times as much as the equilibrium concentration. On the other hand, unburned constituents in an expansion turbine exhaust were slowed to oxidize in a heat recovery steam generator (HRSG) flue processing, and exhaust gases reached equilibrium conditions. In this regard, however, reaction heat in HRSG could not devote enough energy for combined cycle thermal efficiency, making advanced combustion technology necessary for achieving highly efficient, oxy-fuel IGCC.

Combustion behaviour of a heavy duty common rail marine Diesel engine fumigated with propane

This paper presents results from the testing of a heavy duty common rail marine Diesel engine with electronically controlled two stage liquid fuel injection, operating under load on a test bench with propane mixed into the inlet air at various rates. Results are presented for a range of engine loads, with brake mean effective pressure up to 22bar at 1800rpm. The electronic engine control unit is not modified and allowed to respond to the addition of propane according to its inbuilt map. This results in retarded injection timing with increased propane addition at some test points. At each test point, constant engine speed and brake torque are maintained for various rates of propane addition. Cylinder pressure and the injector activation voltage are recorded with a high speed data acquisition system. Apparent heat release rate is calculated from the measured cylinder pressure. At high rates of propane addition very high pressure rise rates and severe knock are measured. At the high brake mean effective pressure conditions tested, knock limits propane supply rates to less than 20% by energy. Small increases in thermal efficiency are indicated with moderate rates of propane addition. Exhaust emissions of NOx, CO, HC and smoke are measured. CO, HC and smoke emissions increase significantly with increasing propane addition. For high propane supply rates, two distinct peaks in heat release rate are measured. Analysis is made of the flammability of the propane–air mixtures at the elevated temperatures at the end of the compression stroke, using the modified Burgess–Wheeler Law. At propane supply rates greater than 25%, the propane–air mixture is flammable in its own right at compression temperature. The apparent heat release rate, fuel injection timing and flammability data allow analysis of the mechanism of the combustion process with propane fumigation.

Performance and Emission Analysis of DI Diesel Engine Fuelled with Methyl Esters of Beef Tallow and Diesel Blends

This paper evaluates the possibility of using methyl esters from animal fats as an alternative fuel for diesel. Biodiesel is an alternative fuel produced from different kinds of vegetable oils and animal fats. It is an oxygenated, non-toxic, sulfur free, biodegradable and renewable fuel that can be used in diesel engines without any significant modifications. Performance and exhaust emissions of direct injection diesel engine have been experimentally investigated with methyl esters of beef tallow as neat biodiesel (B100) and its blend (B5, B25, B50 and B75) with diesel fuel. Engine performance parameters namely brake power, brake specific fuel consumption, brake thermal efficiency and exhaust emissions of CO, HC, NOx, and smoke density were determined for different loading conditions and at constant engine speed of 1500rpm. The test result indicates that there is a slight decrease in brake thermal efficiency and increase in specific fuel consumption for all the blended fuels when compared to that of diesel fuel. The drastic reduction in carbon monoxide, unburned hydrocarbon and smoke density were recorded for all the blended fuels as well as with neat biodiesel. However, in the case of oxides of nitrogen, there is a slight increase for all the blended fuels and with neat biodiesel when compared to diesel fuel. On the whole, methyl esters of beef tallow and its blends with diesel fuel can be used as an alternative fuel for diesel in direct injection diesel engines without any significant engine modification.

Pollutant Emission Reduction and Engine Performance Improvement by Using a Semi-Direct Injection Spark Ignition Engine Fuelled by LPG

ABSTRACTReducing motorcycle exhaust emissions to improve air quality is important in Asia, due to the large number of motorcycles. This study describes and proposes a lean-burn system for reducing pollutant emissions and improving motorcycle engine performance. The lean-burn system, called semi-direct injection (SDI), is comprised of high-swirl charge, injection during intake-valve opening, and liquefied petroleum gas (LPG) injection. A conventional motorcycle engine with port fuel injection (PFI) and spark ignition (SI) was retrofitted by designing a new intake port with a controllable plate to enhance the swirl of intake flow. The swirl ratio was increased to 3.4, enhancing the turbulence of air flow inside the combustion chamber, and the lean limit was extended to 1.7 of relative air/fuel ratio (lambda). The engine was tested at a low-load region which includes most operating points of the ECE-40 driving cycle. A complete engine performance map was produced and a comparison was undertaken between the new design and regular gasoline engines. The results show that brake-specific energy consumption (BSEC) decreased by 19.2%. Brake-specific exhaust emissions of CO2, NOx and CO were decreased by 27%, 47% and 94%, respectively. HC emissions were increased by 4.5%.

Experimental and Study of an Direct-Injection, Single Fuel CNG Engine

In this paper, a single fuel in-cylinder, direct injection compressed natural gas (CNG) engine was presented, which was modified form a 175F gasoline engine, with the 80C196KC single chip microprocessor as the controller. The structure and function of the CNG engine control system, the drive circuits of the injection system, matching its parameters and establishing the control algorithms are introduced. An oxygen sensor was used to adjust the mixture ratio to restore the engine power and reduced the exhaust emission; peak-holding drive circuit of injector was applied to improve its responsibility and spare more electrical energy; high energy ignition system was designed to produce and distribute high enough energy. The result of experimental shows that the power of CNG engine is no lower than 95% of the power of gasoline engien in the most conditions. The exhaust emissions of HC and CO are obviously reduced, compared with the gasoline engine.