[Taboleo] Even in Heavy Traffic, 20 km/l Fuel Efficiency: K5 LPG Hybrid Test Drive Review

Developed through Ministry of Environment Technology Development Project
Currently Pilot Tested at 4 Corporate Taxi Companies
Good Fuel Efficiency Improvement and Greenhouse Gas Reduction Effects

The K5 LPG full hybrid vehicle developed through the Environmental Technology Development Project, a national project by the Ministry of Environment. It was created by modifying the existing K5 gasoline hybrid vehicle. Photo by Kang Hee-jong

Recently, many consumers considering the purchase of electric vehicles have turned their attention to hybrid vehicles due to inconveniences with charging and safety concerns. The popularity of hybrid vehicles is soaring day by day. The advantages of hybrid cars, which are more eco-friendly and fuel-efficient compared to conventional internal combustion engine vehicles, are becoming more prominent.

Currently, most hybrid vehicles sold on the market are gasoline-based. In response, the Ministry of Environment has promoted a national project to develop hybrid vehicles using LPG, which is more environmentally friendly compared to gasoline. This project, titled "Development of 2-liter Class LPG Full Hybrid Passenger Vehicle Technology," was conducted over two years starting in 2021.

The project was led by Bluegent Technology Research Institute as the main research and development organization, with participation from the Korea Automotive Technology Institute, Hanyang University, and Ajou University.

With the cooperation of the Korea LPG Association, the reporter test-drove a K5 vehicle equipped with the 2-liter class LPG hybrid system developed under the Ministry of Environment's national project. From the 1st to the 7th, the vehicle was driven over 100 km mainly during commuting and around the home on weekends to check the fuel efficiency of the LPG hybrid car.

The primary route used was from the home in Gwangjang-dong, Seoul, to the Korea Chamber of Commerce and Industry in Seoul. On the morning of the 5th, around 6:40 AM, the route was chosen starting from home, passing through Gangbyeonbuk-ro, Kumho Tunnel, and Toegye-ro to the Chamber of Commerce. Driving steadily at 50-60 km/h on Gangbyeonbuk-ro, the fuel efficiency quickly rose to 15-17 km/l. Upon entering city streets, the fuel efficiency immediately increased to 19-20 km/l. On city roads with lower speeds, the driving sections using the battery and electric motor increased, showcasing the true value of the hybrid vehicle.

LPG hybrid vehicles showed fuel efficiency of up to 23 km per liter on the early morning commute without traffic, and 19 to 20 km per liter on the evening commute. Photo by Kang Hee-jong

The next day’s commute followed a route through Gangbyeonbuk-ro, Namsan 1st Tunnel, Euljiro, and then to the Chamber of Commerce. On this day, the average fuel efficiency exceeded 23 km/l. The return trip was driven only on city roads rather than main roads, and over several days, the average fuel efficiency consistently remained between 19-20 km/l.

The K5 LPG hybrid vehicle switched frequently between the electric motor and internal combustion engine depending on driving speed and vehicle conditions. When switching from electric vehicle mode, where vibrations were not felt, to the internal combustion engine, a slight tremor was momentarily noticeable. Aside from this, there was no discomfort during driving.

This vehicle was developed by modifying an existing K5 gasoline hybrid vehicle. In the space under the trunk where the spare tire is usually stored, a donut-shaped LPG gas tank is installed. As a result, the trunk space was slightly reduced, but a golf bag fit comfortably.

Donut-shaped LPG fuel tank installed in LPG hybrid vehicles. Photo by Kang Hee-jong

Trunk space of an LPG hybrid vehicle. The LPG fuel tank is placed in the spare tire space, making it slightly narrower than before, but it is still sufficient to store items such as golf bags. Photo by Kang Hee-jong

In terms of fuel efficiency, the results were very satisfactory. According to data released by Bluegent, the developer of the vehicle, the combined fuel efficiency was 15.8 km/l, but actual city driving showed much better fuel efficiency. Thanks to this, it is expected that fuel costs can be significantly reduced. As of the fourth week of July, the national average LPG fuel price was 982 KRW, which is about 57% of the gasoline price of 1,714 KRW.

Most importantly, the greenhouse gas emissions of the LPG hybrid vehicle are 79 g/km, which is more than 9% lower than the 87 g/km emissions of gasoline hybrid vehicles. Compared to existing LPG passenger cars, carbon emissions have been reduced by 45%.

The LPG hybrid vehicle’s engine delivers a maximum output of 155 horsepower, and the motor provides a maximum output of 38.6 kW. The engine’s maximum torque is 19.7 kg·m, and the motor’s maximum torque is 205 Nm.

LPG hybrid vehicles are expected to have high demand among taxi drivers who are sensitive to fuel efficiency, similar to LPG vehicles. However, a certain cost must be borne during modification. There is no official plan from manufacturers to release this vehicle commercially.

Currently, this vehicle is being pilot-operated by four corporate taxi companies: Yuchang Sangun (Seoul), Seokyung Transport (Incheon), Sinjang Taxi (Hanam), and Sinjin Transport (Cheonan). By December of this year, the plan is to measure the vehicle’s performance and real fuel efficiency through at least 100,000 km of actual driving and verify durability under the harsh driving conditions typical of taxis.

A representative from the Korea LPG Association stated, "Monitoring results of the corporate taxis under pilot operation show very high satisfaction in terms of economic efficiency," adding, "We are considering expanding the pilot project in the future."