LPG-fueled Vehicles Research Articles

Development and Implementation of LPG/Gasoline Bi-Fuel Engine Teaching Media for Vocational High Schools

In 2022, the World Liquified Petroleum Gas Association (WLPGA) reported that there are more than 28.3 million LPG-fueled vehicles used throughout the world with an increasing trend in the last 20 years. The growth of LPG-fueled vehicles will require more mechanics from vocational school graduates who master environmentally friendly technology. Considering the availability of resources, Muhammadiyah Vocational High School 1 Bandongan Magelang (SMK MUTU Bandongan) has the potential to complement the competencies of graduates with mastery and skills in servicing modern and environmentally friendly vehicles, as one of their uniqueness from others. Therefore, we develop and implement environmentally friendly automotive technology learning media, especially LPG-fueled vehicles at SMK MUTU Bandongan. This is an implementation of research on LPG-fueled vehicles over the last 10 years. Activities are carried out through (1) rebuilding and reconditioning the engine which will be modified into a bi-fuel engine; (2) procurement and installation of converter kits; and (3) increasing teacher competency.

STUDI EKSPERIMEN KINERJA SISTEM REFRIGERASI SETENGAH SIKLUS PADA KENDARAAN BERBAHAN BAKAR LPG

The Air Conditioning (AC) system is an important requirement for vehicle passengers to get thermal comfort. However, the AC system draws power from the engine to drive the compressor. Meanwhile, vehicles driven by Liquefied Petroleum Gas (LPG) provide decent cooling potential to assist the main air conditioning system. Therefore, this study aims to examine the effect of cooling on LPG-fueled vehicles by utilizing LPG flow to be used as a secondary refrigerant. The research was carried out on a 1495 cc engine with a special evaporator which was tested at variations of blower speed 1, 2, and 3. The tests were carried out at engine speeds of 1000, 2000, and 3000 rpm. The results showed the lowest cooling effect at blower speed level 1 with engine speed of 1000 rpm and the highest at blower speed level 3 with engine speed of 3000 rpm. The greatest cooling effect is obtained at 373 Watts at 3000 rpm engine speed and level 3 blower speed.

Cooling effect characteristic of the novel half-cycle refrigeration system on a liquefied petroleum gas (LPG) fueled vehicle

• An experimental investigation of the harvested cooling effect in LPG-fueled vehicles was studied. • The cooling effect is calculated by considering the mixing ratio of water vapor in air. • Half-cycle refrigeration system contributes to the total engine efficiency of the vehicle. • EER of up to 21.06 was obtained by comparing the cooling effect ( q ̇ a ) and blower power ( w ̇ b ). This paper reports on the experimental investigation of the cooling effect harvested in liquefied petroleum gas (LPG)-fueled vehicles. The heat required to vaporize the LPG in a vaporizer, which was originally transferred by the engine coolant, was replaced by air flow. The fuel line was modified by adding an evaporator equipped with an expansion valve between the LPG tank and regulator. The no-load tests were carried out on a Daihatsu 1945 cc engine at 1000, 2000, and 3000 rpm with three different levels of air mass flow rate obtained through the setting of the electric blower switch. The LPG consumption was determined by the engine load instead of being regulated by an external valve. By considering the air temperature and humidity mixing ratio ( X ), a cooling effect of 0.89 kJ‧s −1 was achieved at an LPG mass flow rate of 0.407 g‧s −1 . This represents the fuel consumption of a 1495 cc engine at 3000 rpm and reduces the temperature to approximately 14 °C. The energy efficiency ratio of the half-cycle refrigeration system in LPG-fueled vehicles was also reported, which ranged from 6.77 to 21.06 for LPG mass flow rates of 0.139–0.407 g‧s −1 and air mass flow rates of 0.049–0.062 kg‧s −1 . Although the cooling effect produced is lower than that of the primary air conditioning (AC) system (vapor compression system) in passenger and pick-up vehicles, it has potential as a secondary AC system when combined with the primary AC system through a hybrid system.

Cooling power characteristics of half-cycle refrigeration system in LPG fuelled vehicles by auxiliary chiller as heat exchanger

This study reports an experimental investigation of cooling power harvesting in LPG-fueled vehicles. The heat of vaporization for LPG in the vaporizer which is initially transferred from the engine coolant is modified by circulating low-temperature water by adding a chiller which placed on a three-passenger pick-up car. Low-temperature water is circulated from the chiller to the vaporizer and back to the chiller by a pump to transfer the cooling power. Meanwhile, the air from the cabin is flowed by an electric blower across the chiller and back to the cabin to transfer heat to the water loop in the chiller. The test was carried out on Daihatsu 1945 cm3 at 1000, 2000, and 3000 rpm, where LPG consumption followed the engine load and obtained LPG mass flow rates of 0.022, 0.236, and 0.350 g⋅s−1. With this vaporizer-chiller combination, the average cooling power of 41.51, 52.05, 110.29 W is obtained at 1000, 2000, and 3000 rpm, respectively. With an average cooling power of 124.5 W at 3000 rpm, it was proven to compensate for the thermal load in the cabin by 15.312, 11.67, and 80.31 kJ at 100, 2000, and 3000 rpm for 60 min of testing. This method can be applied as a secondary AC system to improve the performance of the main AC system in a vehicle. The actual cooling power from the LPG to the water loop can be increased by modifying the heat transfer contact area in the vaporizer cavity or by applying a high-efficiency vaporizer.

Fuel Control Systems for Planetary Transmission Vehicles: A Contribution to the LPG-fueled Vehicles Community

The bi-fuel system vehicle (gasoline/LPG) has been developed for a long time because it has the ability to switch fuels, both built as an original equipment manufacturer (OEM) or as a modified vehicle. However, on vehicles with planetary automatic transmissions, additional control systems are needed to produce optimal performance, both on gasoline and LPG operations, especially on uphill roads. Old vehicles with planetary automatic transmissions are not equipped with road slope angle sensors, so on uphill roads and the driver has not mastered road conditions, the engine tends to stop suddenly. Therefore, this study aims to develop a fuel control system (LPG operation) on a planetary automatic transmission to control gear shifts based on the level of the road slope. A simulation with MATLAB Simulink we used to create a control system, with objective function and constraint defined. As a result, the control system can recognize the level of the road slope to control the speed gear shift. This control system is promising and reliable to be implemented in real conditions.

Emissions of nitrogen oxides and volatile organic compounds from liquefied petroleum gas-fueled taxis under idle and cruising modes

Liquefied petroleum gas (LPG) as an alternative fuel is increasingly used in mainland China, few reports are however available about emissions from LPG-fueled vehicles. In this study, 26 LPG-fueled taxis in Guangzhou, south China were tested using a chassis dynamometer to obtain their emission factors of nitrogen oxides (NOx) and volatile organic compounds (VOCs) under idle and cruising (10–60 km h−1) modes. The emission factors of NOx on average increased with speed from 4.13 g kg-fuel−1 at idling to 71.1 g kg-fuel−1 at 60 km h−1 at a slope of 10.6 g kg-fuel−1 per 10 km h−1 increase in speed. Alkanes were the most abundant (71.9%) among the VOCs in the exhaust, followed by alkenes (25.2%), ethyne (2.7%), and aromatic species (0.2%). Emission factors of VOCs at idling averaged 8.24 g kg-fuel−1, higher than that of 6.23–7.36 g kg-fuel−1 when cruising at 10–60 km h−1, but their ozone formation potentials (OFPs) were lower at idling (15.8 g kg-fuel−1) than under cruising (19.1–23.8 g kg-fuel−1) largely due to higher emission of more reactive alkenes under cruising mode. Emissions of both NOx and VOCs increased significantly with mileages. Measured emission factors of NOx and reactive VOCs in this study suggested that replacing the gasoline-powered taxis with the LPG-fueled taxis with LPG-gasoline bi-fuel engines and no efficient after-treatment devices would not benefit in reducing the emissions of ozone precursors, and strengthening the emission control for LPG vehicles with dedicated LPG engines and after-treatment converters, as did in Hong Kong, could further benefit in reducing the emission of photochemically active species when using LPG as alternative fuels.

ANALYSIS OF EVAPORATOR EFFECTIVENESS ON 1/2 CYCLE REFRIGERATION SYSTEMS: A CASE STUDY ON LPG FUELED VEHICLES

The ½ cycle refrigeration system on LPG fueled vehicles has a significant cooling effect. However, the cooling is very dependent on the heat exchange process in the evaporator. Therefore, this paper analyses the deviation of the actual cooling curve from the ideal scenario carried out on a laboratory scale. The analytical method used is the calculation of the effectiveness of the evaporator, which compares the actual to the potential heat transfer capacity. The LPG flow rate was varied from 1-6 g/s, while the evaporation pressure ranged between 0.05, 0.10, and 0.15 MPa, which applied to compact type evaporators with dimensions of 262 ´ 200 mm, with a thickness of 65 mm. The research results confirm that the higher the LPG mass flow rate, the lower the heat transfer effectiveness. At the higher LPG mass flow rate, heat transfer occurs less optimally, due to incomplete evaporation of LPG in the evaporator.

LPG-Fueled Vehicles: An Overview of Technology and Market Trend

This article presents an overview of the technology status and market trends of LPG-fueled vehicles through the literature approach to re-evaluate their future. In the review, it is discovered that LPG vehicles are globally increasing, though with a concentration in some countries. Of the 25 countries included in the World LPG Association (WLPGA) annual report 2018, Turkey, Poland, India, Ukraine, and Mexico are the countries with the best LPG vehicle trends in average of 23%. Meanwhile, Australia, Japan, South Korea, United Kingdom, the Netherlands, France, and Germany with a long history of implementing LPG as an alternative fuel has experienced a decline in the 2013-2017 period by 17%. This was allegedly due to the penetration of diesel-fueled vehicles over the last ten years. Moreover, developed countries experiencing decline have succeeded in developing electric-based vehicles such as Hybrid Electric Vehicle (HEV), Plug-in hybrid electric vehicle (PHEV), Battery Electric Vehicles (BEV), and Fuel Cell Electric Vehicles (FCEV) due to stringent demands for emission standards.

Fuel control system modeling for LPG fueled engine using Adaptive Neuro-Fuzzy Inference Systems (ANFIS)

LPG is an alternative fuel for gasoline engines that have almost all basic properties, such as energy content, octane number, automatic ignition temperature, flame speed, and flammability limits. The CO, CO2, HC, and NOx emissions produced by LPG engines are lower than current gasoline engines. However, LPG vehicles with first generation LPG kits (vaporizer and mixer) generally waste fuel during deceleration. Therefore, this study develops fuel control during deceleration with Adaptive Neuro-Fuzzy Inference Systems (ANFIS). Simulation results show that the controller is able to provide a more realistic picture of the dynamics of AFR during deceleration. In conclusion, ANFIS is very promising to be implemented as an AFR controller in LPG-fueled vehicles.

Energy Efficiency Ratio (EER) of Novel Air Conditioning System on LPG Fuelled Vehicle: A Lab-Scale Investigation

Alternative fuels have become an effective solution to reduce the impact of road transport on the environment. On the other hand, the growing uses of air-conditioning (AC) have contributed to worsening the fuel economy of passenger vehicles. Liquid petroleum gas (LPG), if injected in the gaseous phase to power SI engines, may allow reducing the fuel consumption due to AC devices through the recovery of cooling energy from the fuel systems. This paper presents lab-scale tests of an air conditioning system prototype for LPG-fuelled vehicles. The prototype has been assembled using standard vehicle components to quantify the cooling energy recoverable from the LPG evaporation before the fuel is injected into the engine intake manifold. Temperature and humidity of the air exiting the LPG evaporator are measured for fuel mass flow rates typical of light-duty vehicles. The energy efficiency ratio (EER) of the prototype achieves 2.72 when cooling power equals 1.2 kW. Although the system tested needs improvements, the experimental data show that the cooling energy recovered by LPG evaporation can significantly reduce the power consumption of standard AC systems in passenger cars.

Fuel as secondary refrigerant on LPG fuelled vehicle: A thermodynamics analysis

In LPG-fueled vehicles, there is a potential cooling from LPG evaporation in the fuel line. Cooling power is obtained without reducing the caloric value of the fuel supplied to the engine. Thus, LPG functions like a refrigerant before it is burned in the combustion chamber. Consequently, there is a change in fuel efficiency. Therefore, this paper presents a new thermodynamic analysis on LPG-fueled vehicles by harvesting cooling power in the fuel line. The total fuel efficiency is calculated by summing the indicated thermal power added by cooling power to the fuel energy supplied. The results show that the A/C system from the fuel line can increase the total fuel efficiency of 3.16%.

Harvesting Cooling Effect on LPG-Fueled Vehicles for Mini Cooler: A Lab-Scale Investigation

This article presents an investigation of the actual cooling effect on a lab-scale prototype of LPG-fueled vehicles. The cooling effect is obtained from heat absorption by LPG on the vaporizer. Water with a mass flow rate of 1, 2 and 3 lpm is flowed from the cooling box to the LPG evaporator and flow back to the cooling box. The car used in this study has a capacity of 1500 cc that rotates 1000, 1500, and 2000 rpm. The results showed that there was a relationship between cooling power with the increase in engine speed and mass flow rate of water that crosses the evaporator. The biggest cooling power is 378 Watts at 1000 rpm with a water mass flow rate of 3 lpm.

Potential of ½ cycle refrigeration system for food transport application

Maintaining the quality of food products from an agricultural land and farms to the final consumer is usually conducted through the car-cooling box. However, as long as the refrigeration equipment takes energy from the car engine, it will significantly increase fuel consumption. Therefore, this paper presents the concept of 1/2 cycle refrigeration system on LPG-fueled vehicles to reduce fuel consumption due to the load of the refrigeration system. From the numerical study, the ½ cycle refrigeration system on LPG-fueled vehicles is potential to be applied on the car-cooling box as the secondary refrigeration system. This system provides a considerable potential cooling effect of 0.8 kW at LPG flow rate of 2.4 g/s.

Refrigeration effect and energy efficiency ratio (EER) calculation of 1/2 cycle refrigeration system on LPG-fueled vehicles

This paper presents a lab-scale experiment on the prototype of the ½ cycle refrigeration system of an LPG-fueled vehicle. LPG before being sent to the engine is used as a heat absorbing medium. The experiment was carried out at 0.15 MPa evaporation pressure and 1-6 g/s of LPG flow rate which representing of Light Duty Vehicle (LDV) fuel consumption. The results of this study indicate that ½ cycle refrigeration system capable of producing refrigeration effect of more than 1.2 kW with EER of 2.72.

Continuous effectiveness of replacing catalytic converters on liquified petroleum gas-fueled vehicles in Hong Kong

To mitigate the concentrations of air pollutants in the atmosphere, an intervention program of replacing the converters of liquefied petroleum gas (LPG) fueled vehicles was implemented by the Hong Kong government between October 2013 and April 2014. Data of ambient volatile organic compounds (VOCs) and other trace gases continuously monitored from September 2012 to April 2017 at a roadside site were used to evaluate the continuous effectiveness of the replaced catalytic converters on the reduction of air pollutants. The measurement data showed that LPG-related VOCs (propane and n/i-butanes) and several trace gases (CO, NO and NO2) decreased significantly from before to after the program (p < 0.01). To further assess the efficiency of the program, five periods covering before the program, during the program, 1st year after the program, 2nd year after the program and 3rd year after the program were categorized. The values of propane and n/i-butanes decreased from Period-1 (before the program) to Period-2 (during the program), and from Period-2 to Periods 3–5 (after the program) (p < 0.01). In addition, the reduction rates of propane and n/i-butanes remained high and constant in Periods 3–5, suggesting that either had the vehicle owners themselves routinely replaced the converters at suitable interval afterwards, or were their vehicles caught by a remote sensing program checking excessive emissions. Source apportionment analysis indicated that LPG-fueled vehicular emissions were the top contributor to ambient VOCs in the roadside environment while the VOCs emitted from LPG-fueled vehicles indeed decreased at a rate of 4.21 ± 2.38 ppbv/year (average ± 95% confidence interval) from Period-1 to Period-5 (p < 0.01). Furthermore, the photochemical box model simulations revealed that the net negative contribution of VOCs and NOx emitted from LPG-fueled vehicles to O3 production strengthened at a rate of 1.9 × 10−2 pptv/day from Period-1 to Period-5 (p < 0.01). The findings proved the continuous effectiveness of the intervention program, and are of help to future control strategies in Hong Kong.

Modeling of Deceleration Fuel Cut-off for LPG Fuelled Engine using Fuzzy Logic Controller

At the time of deceleration, continuous LPG flow in LPG fuelled engine causing over fuel consumption and increasing exhaust emissions, while the engine does not need fuel. Therefore, this paper presents a simulation of deceleration fuel cut-off (DFCO) system. Given that the fuel system control is complex and non-linear, modeling with fuzzy logic controller (FLC) has been selected because of simple, easy to understand and tolerant to improper data. The engine modeling is divided into several sections, including intake manifold dynamics and engine dynamics. The input values were processed by the membership function. A series of simulation results indicate that DFCO can be applied. The combination of throttle valve position, engine speed and manifold pressure is able to cut LPG flow at deceleration. As a conclusion, DFCO system is promising to be applied on LPG-fuelled vehicles for saving fuel and reducing emissions.

Reactive Calcination Route for Synthesis of Highly Active NiCo2O4 Catalyst for Abatement of Cold-Start CO–HC Emissions from LPG Vehicles

An idea of an exotic route of reactive calcination (RC) of a precursor (co-precipitated basic carbonates of nickel and cobalt) for the synthesis of highly active NiCo2O4−δ spinel catalyst (Cat-R) for oxidation of CO and HCs emissions from LPG fueled vehicles is reported in the present paper. The route involved feed of a low concentration of chemically reactive 4.5% CO–air mixture over the precursor at low temperature of 433 K in the beginning and finally increased to 573 K. The precursor was also calcined around 573 K following two other methods: (1) conventionally in stagnant air (Cat-S) and (2) in flowing air (Cat-F) for comparative studies. The catalysts were characterized by XRD, N2 sorption techniques, TPR, SEMEDX and XPS. The formation of spinel structure is confirmed in all the catalysts. The activity measurement showed that total oxidation of lean mixture of CO–LPG occurred at the lowest temperature of 433 K over Cat-R in comparison to Cat-F (451 K) and Cat-S (458 K). The total combustion of the CO–LPG mixture at such low temperature of 433 K was never reported earlier. The remarkable activity of Cat-R over Cat-F and Cat-S in oxidation of CO–LPG mixture is due to the formation of partially reduced NiCo2O4−δ (Cat-R) oxygen deficient structure having the highest surface area smallest crystallites and highly dispersed homogeneous morphology when produced following the RC-route. The activity order of the catalysts produced by various calcination strategies for CO and LPG oxidation was as follows: RC > flowing-air > stagnant-air. Cat-R was also compared with noble metal and the catalytic activity order in the decreasing sequence was as follows: Cat-R > Cat-F > Cat-S > Cat-Pt. Stability test of the catalyst showed that the Cat-R has satisfactory catalytic stability. Thus the Cat-R is the most suitable for abatement of cold-start emissions of CO and HCs from LPG fuelled vehicles.

Cooling effect characteristics of a ½ cycle refrigeration system on an LPG fuel system

This paper presents a new concept for air-conditioning systems in Liquefied Petroleum Gas (LPG) fuelled vehicles, a ½ cycle refrigeration system. Prior to being used in an engine as a fuel, LPG serves as a refrigerant. Harvesting of cooling from LPG was carried out by an auxiliary evaporator. Initially, to evaporate LPG in an Original Equipment Manufactured (OEM) vaporizer, water coolant is used. In these systems, the thermal energy to evaporate LPG is obtained from air driven by an electric blower. Cold air exiting from the evaporator may then be supplied to the cabin. The test results show that the actual cooling effect produced is as high as 1.2 kW for an LPG flow rate of more than 3 g/s and an air mass flow rate of 16 g/s. In conclusion, the ½ cycle air conditioning system is a promising application for LPG-fuelled vehicles to reduce the load on air-conditioning systems.

Effectiveness of replacing catalytic converters in LPG-fueled vehicles in Hong Kong

Abstract. Many taxis and public buses are powered by liquefied petroleum gas (LPG) in Hong Kong. With more vehicles using LPG, they have become the major contributor to ambient volatile organic compounds (VOCs) in Hong Kong. An intervention program which aimed to reduce the emissions of VOCs and nitrogen oxides (NOx) from LPG-fueled vehicles was implemented by the Hong Kong government in September 2013. Long-term real-time measurements indicated that the program was remarkably effective in reducing LPG-related VOCs, NOx and nitric oxide (NO) in the atmosphere. Receptor modeling results further revealed that propane, propene, i-butane, n-butane and NO in LPG-fueled vehicle exhaust emissions decreased by 40.8 ± 0.1, 45.7 ± 0.2, 35.7 ± 0.1, 47.8 ± 0.1 and 88.6 ± 0.7 %, respectively, during the implementation of the program. In contrast, despite the reduction of VOCs and NOx, O3 following the program increased by 0.40 ± 0.03 ppbv (∼ 5.6 %). The LPG-fueled vehicle exhaust was generally destructive to OH and HO2. However, the destruction effect weakened for OH and it even turned to positive contribution to HO2 during the program. These changes led to the increases of OH, HO2 and HO2 ∕ OH ratio, which might explain the positive O3 increment. Analysis of O3–VOCs–NOx sensitivity in ambient air indicated VOC-limited regimes in the O3 formation before and during the program. Moreover, a maximum reduction percentage of NOx (i.e., 69 %) and the lowest reduction ratio of VOCs ∕ NOx (i.e., 1.1) in LPG-fueled vehicle exhaust were determined to give a zero O3 increment. The findings are of great help to future formulation and implementation of control strategies on vehicle emissions in Hong Kong, and could be extended to other regions in China and around the world.

On-road chasing measurement of exhaust particle emissions from diesel, CNG, LPG, and DME-fueled vehicles using a mobile emission laboratory

We designed and applied a mobile emission laboratory for on-road measurements of exhaust particles emitted from conventional diesel, compressed natural gas (CNG), liquefied petroleum gas (LPG), and dimethyl ether (DME)-fueled vehicles. Fuel type and vehicle driving conditions significantly affected the particle size distribution and the number concentrations of the nucleation mode. For all buses, the size distributions of particles in the exhaust under idling conditions had larger mode diameters than at constant speed conditions of 50 km/h or 80 km/h. The nucleation mode (< 50 nm) fraction of diesel, CNG, LPG, and DME at a constant speed of 50 km/h was 53%, 63%, 79%, and 99%, respectively, indicating that the DME-fueled bus emitted the most nanoparticles. As the vehicle speed increased from 50 km/h to 80 km/h, the nucleation mode fraction of diesel, CNG, LPG, and DME changed to 43%, 99%, 99%, and 99%, representing a significant increase in the number concentrations of nanoparticles in the CNG and LPG-fueled vehicles. The particle size distributions in the exhaust of diesel, CNG, LPG, and DME-fueled vehicles were not affected by increase in the chasing distance.