INTERNAL COMBUSTION ENGINES
STATE OF THE ART OF THE ENGINE 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.
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.
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.
1. NEW PISTON ENGINE WITH ROCKER ARMS AND CRANK DRIVE
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:
the processes in the cylinders through an animation:
"Animation OF THE New Piston Motor1"
The new Motor1 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
2. NEW PISTON ENGINE WITH SERRATED CONNECTING RODS AND CRANK DRIVE
Inventor : Dr. Mustafa YOUSSEF
Applicant: Thermal PowerTec Ltd., Zurich/ Swizerland
A piston engine consists of a housing with an even number of cylinders, preferably four cylinders, arranged on two banks of cylinders (Figures 1,2,3). The toothed connecting rod (3) is connected to the piston via the piston pin (10) on the one hand and to a gear wheel (4) on the other. The drive crank (7) is connected to the gear wheel (4) through the central spindle (6) and the connecting rod (5) connects the crank mechanism (7) to the crank (11).
When the piston moves between the top and bottom dead center, the connecting rod (3) moves axially without deflection and the gear wheel performs a torsional vibration movement. As a result, the drive crank (7) and connecting rod (5) move up and down, and the crank (11) and crankshaft (12) rotate continuously. The four-cylinder engine requires only one crank (11) that transmits the piston work in the four cylinders to the crankshaft (12).
To support the connecting rods (3), rollers (16) can be used to reduce friction.
the processes in the cylinders through an animation:
"Animation OF THE New Piston Motor2"
Advantages:
- Reducing the number of cranks from four to one reduces the bearingnumber of the crankshaft from 9 to 3 and leads to less friction and less construction work on the crankshaft
- Due to the axial piston connecting rod movement without deflection, the piston side forces on the cylinder walls are avoided and the piston friction is reduced and the sliding friction of the piston pins (10) is eliminated. The reduction in friction losses leads to an increase in engine efficiency and a reduction in fuel consumption and CO2 emissions
- Changing the bearing type from slidein to roller bearings of the middle spindle (6) and the crankshaft (12) is easy.