Most commonly used type of internal combustion engine:

In-line engines are the designation of the design of a reciprocating piston engine, the cylinders are in a row. In-line engines are by far the most common type of internal combustion engine in cars, trucks, marine diesel engines (up to 14 cylinders) and motorcycles. Four-cylinder in-line engines are most commonly used.

V-engine is a design of a reciprocating piston engine with several cylinders. In the classic V-engine, the two cylinder banks stand against each other at the bank angle on the crankcase below. After the in-line engine, it is the most widespread engine design.

Frictional losses in piston engines:

Otto engines have an efficiency between 20% and a maximum of 35%.

Based on 100 percent fuel energy in an Internal combustion engine, only around 30 percent of the energy from the engine is output as useful power via the crankshaft.

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Frictional losses in the internal combustion engine reduce efficiency and have a negative effect on consumption. An important lever against consumption in the combustion engine is the minimization of friction.
The pure share of waste heat from engine friction is around 10 percent. The frictional energy is lost as waste heat.

Frictional losses in internal combustion engines are caused by the vibratory motion of pistons and valves and rotary motion in bearings. The friction losses between piston and cylinder are greatest. A significant proportion of the friction losses is caused by the plain bearings for connecting rods and crankshafts that are commonly used today.
As can be seen from the Stribeck curve, a hydrodynamic bearing passes through the three stations of static or boundary friction, mixed friction and fluid friction during operation.

Piston friction:
Piston friction occurs on the contact surfaces between the piston rings and the cylinder bore and between the piston skirt and the cylinder bore. A thin one forms on this contact surface Oil film in which a shear stress is generated.

The mechanical losses in the motor amount to between 9% and 10% of the full load power and are almost entirely dependent on the speed. The friction share of the piston group is approx. 5% and that of the crankshaft approx. 3% of the losses. An important lever in the combustion engine is the minimization of friction.
Since the internal combustion engine will continue to play a decisive role in the future and under the pressure of ever stricter CO2 limits, the engine developers optimize every component in terms of its friction in order to reduce fuel consumption. The reduction of fuel consumption and CO2 emissions are and will remain the main challenges for automobile manufacturers worldwide.

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A reduction in the friction losses caused by the Sliding bearing and piston by 1% (from 9% to 8% while the net power remains constant) increases the motor efficiency by approx. 1 percentage points (e.g. from 30% to 31%) i.e. the increase in motor efficiency is 3,3%. This leads to a reduction in fuel consumption and CO2 emissions.

The task is to develop a piston machine in which
1- The connecting rod should be moved if possible without deflection (close to its cylinder axis), thereby reducing the lateral forces on the piston and reducing the friction between the piston and the cylinder wall
2- the bearing friction of the connecting rod and the crankshaft should be reduced.


Inventor : Dr. Mustafa YOUSSEF
Applicant: Thermal PowerTec Ltd., Zurich/ Swizerland

A piston machine for use as a 4- or 2-stroke engine or as a working machine (compressor or pump) consisting of a housing in which an even number of cylinders, preferably four cylinders, which are arranged on two cylinder banks, have the same number of pistons (2) and piston rod (3), an equilateral rocker arm (4), a crank connecting rod (5) and a crankshaft (12) with a crank (11). A piston connecting rod (3) is connected to the piston on the one hand by a piston pin (8) and on the other hand to the rocker arm (4). When the piston moves between the top and bottom dead centre, the rocker arm performs a rotary oscillating movement. As a result, the crank connecting rod (5) connected to the rocker arm (4) moves in a downward and upward movement and causes the crank (11) and the crankshaft (12) to rotate.

Figures 1 to 3 show an example of the invention; a reciprocating piston engine with four cylinders divided into two rows, according to the four-stroke process:

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Options for connecting the piston rod (3) to the rocker arm (4):
- A piston connecting rod (3) has a fixed connection with a pin on the edge spindle of the rocker arm (4) and the edge spindle is stored in the edge of the rocker arm
- The other possibility is that a piston connecting rod (3) is mounted by a Bearing on the rocker arm edge (4).

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Other Execution:
Another design for the connection of the rocker arm (4) with the crank connecting rod (5) and the crank (11) is shown in Fig. 4. The rocker arm (4) has a third arm (15) which is arranged obliquely or vertically and can be arranged below or above the axis of rotation of the rocker arm (4). The crank connecting rod (5) connects the crank (11) with the arm (15) through two bearings. The arm (15) rotates swinging with the rocker arm and, with the crank connecting rod (5), brings the crank and the crankshaft in continuous rotary motion.


The new piston engine has the following advantages over the conventional 4-cylinder piston engine:

- A reduction in the number of cranks in the crankshaft from four to one crank leads to less construction costs for the crankshaft

- Reduction of the full rotation in several bearings to rotary oscillating with a small angle of rotation (from 360 to 50 )

- It is easier to change the type of contact from sliding to roller bearings

- The lateral piston forces on the cylinder walls are generated by a practically axial movement of the piston connecting rod (3) with a small deflection (gama = 3 )

- A reduction in the friction losses caused by the Sliding bearing and piston by 1% (from 9% to 8%) increases the motor efficiency by approx. 1 percentage points (e.g. from 30% to 31%) i.e. the increase in motor efficiency is 3.3%. This leads to a reduction in fuel consumption and CO2 emissions.

- The radius of eccentricity of the crankshaft can be selected larger or smaller for a certain piston stroke length