SEAT, a member of the Volkswagen Group, continues to spearhead the introduction of compressed natural gas (CNG) technology, giving customers the widest choice of vehicles that are cleaner, more sustainable and offer even greater efficiency.

Each vehicle has been designed and developed at SEAT’s headquarters in Martorell, and represents a further step in the firm’s vehicle development program, showcasing the benefits of using CNG as the primary fuel.

SEAT is committed to boosting CNG as a sustainable alternative to conventional fossil fuels. It provides the opportunity to reduce CO2 emissions without impacting on our vehicles’ distinctive characteristics. And thanks to the technology’s compatibility with renewable bio-methane, it makes it an important part of the fuel mix as we move towards low emission mobility.

—Luca de Meo, President of SEAT

A CNG vehicle reduces CO₂ emissions by about 25% compared to a gasoline-driven equivalent. As well as ecological and tax benefits, TGI technology offers exceptionally low costs per kilometer—up to 50% cheaper than a gasoline equivalent model and 30% cheaper than a diesel—and with the further improvements SEAT has made to the technology, now it can go even further before needing to be refueled.

The major development is the introduction of a third CNG tank; in the case of the Ibiza and the Arona, the CNG range-only now reaches up to 360 km (based on WLTP), while the Leon can reach up to 440km (based on WLTP). This new configuration meets the demands of TGI customers who wanted an increased mileage in CNG mode.

With CNG technology SEAT has the advantage of being able to offer customers a real alternative that is both effective and modern, in a vehicle that costs virtually the same as an equivalent diesel model. Plus, the maintenance costs of the TGI models are similar to those of traditional combustion engine vehicles. The move means that vehicles are cleaner and even better value for money, helped greatly by CNG’s efficiency over other fuels.

SEAT is also supporting the development and availability of renewable bio-methane, which neutralizes CO₂ emissions generated through vehicle use. Only a pure electric vehicle running on 100% renewable energy would offer a better overall outcome.

SEAT’s decision to increase mileage in CNG mode rather than gasoline has come as a result of the demand by SEAT customers who currently use a CNG vehicle—drivers are systematically ending up choosing to use CNG since they are aware of the vehicle’s increased sustainability, the considerable savings on fuel, and they already know where the nearest supply points are on their regular driving routes.

The Mii Ecofuel, the Ibiza TGI and the Arona TGI use tanks made of high-strength steel, while the SEAT Leon 1.5 TGI EVO is fitted with a combination of one high-strength steel tank, which is smaller and located ahead of the rear axle—and two new large tanks located behind the rear axle, that are manufactured in a carbon fibre composite construction, significantly reducing their weight and optimizing weight distribution.

While the Mii, Ibiza, Arona and Leon all use natural gas as the main fuel, should the outside temperature fall below -10°C, the engine will start in gasoline mode while the gas injectors are heated to working temperature before activating the CNG circuit. The switchover happens automatically, and the driver doesn’t perceive any difference to the vehicle’s performance or dynamics, but the approach means vehicles can cope in all conditions.

In normal driving scenarios, SEAT’s CNG vehicles only use gasoline as an alternative fuel when the CNG tanks are empty, although with significant gas ranges, the need to use gasoline should be infrequent. But even in the event of using the gasoline tank, the switch is so seamless that the driver is unlikely to notice.

The SEAT Leon is manufactured on the MQB-A platform (Modularer Querbaukasten), and both the Ibiza and the Arona use MQB-A0 technology. These platforms give greater manufacturing flexibility and a more robust implementation, as well as achieving a very light, functional, safe body with enormous structural rigidity. All the TGI versions comply with the highest crash safety standards.

The Ibiza, the Arona and the Leon are produced at the SEAT plant in Martorell, Spain, while the Mii Ecofuel is manufactured at the Bratislava plant in Slovakia. Each model is assembled on the same line as other vehicles in SEAT’s line-up, but each has been adapted to meet the demands of using CNG as the primary fuel.

The CNG-fueled vehicles incorporate two (Mii Ecofuel) or three (Ibiza, Arona and Leon TGI) CNG tanks, a filling nozzle located behind the gasoline filler cover, gas pressure sensors and an electronic two-stage pressure regulator that effectively controls gas distribution to the CNG engine—both Ecofuel and TGI versions—are substantially modified and have many specific parts essential for an optimum operation in both gas and gasoline modes, as well as parts specially adapted to the characteristics of the combustion of natural gas (reinforced pistons and optimized piston rings, reinforced bearing shells, adapted camshafts, valve guide material and reinforced valve seats, nitrided exhaust valves, lambda sensor and catalytic convertor optimized for methane conversion, etc.).

Although CNG is stored at high pressure, (approximately 200bar), the storage tanks are built and homologated to withstand more than twice their maximum working pressure. The high-pressure pipe sections are made of stainless steel and electronic safety valves isolate each section of the high pressure circuit. The tanks themselves are fitted with thermal fuses that open in the unlikely event of extreme heat to release the gas which is then safely dispelled.

New SEAT Arona TGI. This is the first SUV in the world to use CNG technology and it enters one of the fastest growing segments in Europe. With three CNG tanks totalling 13.8 kg in capacity, it can achieve a range of up to 360 km in CNG mode (based on WLTP). Its 9-liter gasoline tank offers an additional 150km*=, giving it a total range of 510 km.

The new SEAT Arona TGI is available in all versions—Reference, Style, Xcellence and FR—featuring a 1.0 TGI three-cylinder, 12-valve engine, able to deliver 90PS between 4,000rpm and 5,500rpm, and a maximum torque of 160 N·m between 1,800rpm and 3,800rpm. This engine is equipped with a six-speed manual transmission to increase its efficiency and offer the smoothest of drives. Reaching a top speed of 172 km/h, the Arona TGI goes from 0 to 100 km/h in 13.2 seconds.

SEAT Ibiza TGI. The Ibiza reintroduces CNG into the range, this time with an extra gas tank, taking the total to three. With a total capacity of 13.8 kg providing a range of up to 360km (based on WLTP) in gas mode and a 9-liter gasoline tank adding another 150km, has a total range of 510km.

The SEAT Ibiza TGI is available with all of the trims, and comes with the same 1.0 TGI engine fitted in the Arona, and a six-speed manual transmission. Delivering a maximum of 90PS between 4,000rpm and 5,500rpm, its maximum torque of 160N·m is available between 1,800-3,800rpm. In terms of performance, this translates to a maximum speed of 180km/h, taking 12.1 seconds to reach 100km/h from a standing start.

SEAT Leon 1.5 TGI EVO. SEAT’s most efficient compact car has been upgraded to deliver 130PS of power versus the 110PS previously available. Now it’s also available in Xcellence and FR—n addition to the Style trim—as a five-door and ST estate version, with a choice of a six-speed manual transmission, or an automatic seven-speed DSG.

The new SEAT Leon 1.5 TGI EVO benefits from a third high-strength steel CNG tank, to add to the two new composite carbon fiber tanks located under the trunk floor.

The three tanks’ total capacity is 17.3 kg, giving the Leon TGI a range of up to 440km (based on WLTP) with either a manual or DSG gearbox, in CNG mode. In addition to this, it has a 9-liter gasoline tank, adding an extra 140km. In total, the Leon reaches 580km before it needs refueling.

The new 1.5 TGI EVO engine is a four-cylinder unit with four valves per cylinder and a capacity of 1,498cc. It has a variable geometry turbo, and a Miller cycle combustion process to maximise efficiency and performance. All in all, the engine delivers 130PS between 5,000rpm and 6,000rpm and maximum torque of 200N·m between 1,400rpm and 4,000rpm.

The performance of the new 1.5 TGI EVO engine is a significant improvement over the previous 1.4 TGI 110PS version, boasting a new top speed of 206km/h and an improved acceleration by almost a second over previous versions and types of transmission: it can now reach 100km/h in 9.9 seconds.

SEAT Mii Ecofuel. SEAT’s most urban model, with its 1.0 Ecofuel 68PS engine, can run for 290km (based on WLTP) with its two high-strength steel tanks totalling 10.9kg capacity. It also has a 9-liter gasoline tank adding another 150km, providing a total range of 440km.

The SEAT Mii’s port-injected 1.0 Ecofuel engine is coupled to a five-speed manual transmission, and offers a maximum output of 68PS at 6,200rpm, and a maximum torque of 90N·m at 3,000rpm. This translates to a maximum speed of 164km/h, hitting 100km/h in 16.3 seconds.