
Single-stroke E-REX: 35 kg and 0,5 l volume produce 120 hp of power
Since the internal combustion engine became the main source of energy for cars, three of its main variants are mass-produced: with four, two strokes or with a Wankel rotor. The engines differ in power and fuel consumption per unit. However, the operating principle is similar: the air entering the cylinders mixes with fuel, all this ignites and pushes the piston.
The process is not complicated and over 100 years, internal combustion engines have become more economical and powerful. But this does not mean that gasoline engines have exhausted all their capabilities and cannot be improved further. Allegedly, their destiny is to “raise their hands up” in front of the advancing electric motors and batteries.
Encouraging (in terms of ICE modernization) messages come from the Spanish company INNengine, which has proposed a single-stroke (1T) opposed engine. It has a pair of pistons moving towards each other.
The cylinder block is round and made of aircraft aluminum. Photo: youtube.com
Fuel mixed with air is injected into the space formed between them. It ignites and causes the pistons to perform a reciprocating motion. It is communicated to the camshafts located at the opposite ends of the structure.
The pistons press on the wavy surface of the disk and it starts to rotate. Photo: youtube.com
The exhaust and intake ports (they are right in the cylinder) are located next to each other. As soon as the piston passes the second, a vacuum is created and a fresh portion of air is supplied. The fuel is ignited by a spark in the same way as in "classic" ICEs. The compression ratio is variable: this means that any type of fuel can be supplied to the cylinders - "anything that burns."
Eight-piston engine 1T in section. Photo: youtube.com
The adjustment is made by changing the position of the axial shaft. As a result, it is possible to adjust the ignition distribution and the compression force of the mixture. The ECU "deals" with the process.
Experiments were conducted to install such a 125-cube engine on a UAV. The power generated was 21 hp. For example, motorcycle, equipped with such a unit, can produce from seven to fifteen "horses" (four-stroke - less, 2T - more, with the same weight). The 1T engine almost does not emit harmful substances into the atmosphere and works smoother, especially when compared with the 4T.
The experiments continued further: the experimenters installed a single-stroke engine on a production Mazda MX-5 Miata. Initially, under the hood of this model was a 1,8-liter internal combustion engine, developing 142 hp. The specialists from INNengine installed their "single-stroke" of 500 "cubes", which produced 126 hp.
The 1T engine takes up less space with the same power. Photo: youtube.com
At the same time, it took up half the space and was much lighter. The engine was forced to supply air. Obviously, this is due to the low torque, since there is no lever from the pistons.
The first thought that comes to mind is installing similar units on motorcycles and drones (since they have already been tested). However, Spanish engineers believe that the ideal application of their development is hybrid cars. That is why the additional letter "e" is used in the designation of their "brainchild": E-REX.
Experimental 1T under the hood of the car. Photo: youtube.com
And indeed: if you take a single-stroke engine with a volume of 0,7 l, it will have a length of less than 40, a diameter of up to 25 cm. At the same time, its weight will be about 38 kg, and the developed power will be around 170 "horses". "Single-stroke" will take up little space, will not reduce the dynamic qualities of the electric car, and will increase the power reserve. Another possible area of application is small aviation.
Lightweight 1T is a good solution for drones and small aircraft. Photo: youtube.com
Today, the company is working to reduce harmful emissions from its internal combustion engine. It is expected that it will soon be upgraded to the Euro 7 standard, which will come into force in the EU in 2025. At the same time, the developers expect that hydrogen will be used as fuel.
The process is not complicated and over 100 years, internal combustion engines have become more economical and powerful. But this does not mean that gasoline engines have exhausted all their capabilities and cannot be improved further. Allegedly, their destiny is to “raise their hands up” in front of the advancing electric motors and batteries.
E-REX
Encouraging (in terms of ICE modernization) messages come from the Spanish company INNengine, which has proposed a single-stroke (1T) opposed engine. It has a pair of pistons moving towards each other.

Fuel mixed with air is injected into the space formed between them. It ignites and causes the pistons to perform a reciprocating motion. It is communicated to the camshafts located at the opposite ends of the structure.

The exhaust and intake ports (they are right in the cylinder) are located next to each other. As soon as the piston passes the second, a vacuum is created and a fresh portion of air is supplied. The fuel is ignited by a spark in the same way as in "classic" ICEs. The compression ratio is variable: this means that any type of fuel can be supplied to the cylinders - "anything that burns."

The adjustment is made by changing the position of the axial shaft. As a result, it is possible to adjust the ignition distribution and the compression force of the mixture. The ECU "deals" with the process.
About the power of a "single-stroke"
Experiments were conducted to install such a 125-cube engine on a UAV. The power generated was 21 hp. For example, motorcycle, equipped with such a unit, can produce from seven to fifteen "horses" (four-stroke - less, 2T - more, with the same weight). The 1T engine almost does not emit harmful substances into the atmosphere and works smoother, especially when compared with the 4T.
About the structure and application of a single-stroke engine
The experiments continued further: the experimenters installed a single-stroke engine on a production Mazda MX-5 Miata. Initially, under the hood of this model was a 1,8-liter internal combustion engine, developing 142 hp. The specialists from INNengine installed their "single-stroke" of 500 "cubes", which produced 126 hp.

At the same time, it took up half the space and was much lighter. The engine was forced to supply air. Obviously, this is due to the low torque, since there is no lever from the pistons.
Where can REX engines be used?
The first thought that comes to mind is installing similar units on motorcycles and drones (since they have already been tested). However, Spanish engineers believe that the ideal application of their development is hybrid cars. That is why the additional letter "e" is used in the designation of their "brainchild": E-REX.

And indeed: if you take a single-stroke engine with a volume of 0,7 l, it will have a length of less than 40, a diameter of up to 25 cm. At the same time, its weight will be about 38 kg, and the developed power will be around 170 "horses". "Single-stroke" will take up little space, will not reduce the dynamic qualities of the electric car, and will increase the power reserve. Another possible area of application is small aviation.

Today, the company is working to reduce harmful emissions from its internal combustion engine. It is expected that it will soon be upgraded to the Euro 7 standard, which will come into force in the EU in 2025. At the same time, the developers expect that hydrogen will be used as fuel.
- Sergey Mileshkin
- youtube.com, VK Video
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