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. CRANK DRIVE WITH TOOTHING FOR PISTON MACHINES
Inventor : Dr. Mustafa YOUSSEF
Applicant: Thermal PowerTec Ltd., Zurich/ Swizerland
A reciprocating piston machine with a new crank drive for use as an internal combustion engine or working machine essentially consists of at least one cylinder. The connecting rod (4) is mounted on the one hand on the piston via the piston pin (3) and on the other hand is firmly connected to a ring gearwheel (5).
The ring gear is toothed with a crank gear (8a) and a planetary gear (6). The crank gear (8a), which is firmly connected to the crank cheeks (13), has a radius that corresponds to the crank radius and half the radius of the ring gear (5). The pins of the planetary gear (6) and reversing gear (7) are mounted between the two planetary cheeks (9), which can rotate around the crank pin (8).
When the piston moves downwards, the connecting rod and ring gear (5) move axially downwards without deflection.
Advantages of this present piston engine:
- The axial connecting rod movement without deflection leads to the loss of lateral forces in the piston pin joints and between the pistons and the cylinder wall
- The friction losses between the pistons and the cylinder wall are greatly reduced, resulting in a reduction of approx. 2%, which results in an increase in engine efficiency by around 2 percentage points. This reduces consumption and CO2 emissions
- There is no cylinder ovality
- One advantage of the 180° V-engine is the small engine height due to the horizontal arrangement of two opposite cylinders with a common crank and a ring gear.
A disadvantage of bearing friction by the addition of reversing gear (7) will mitigate the desired reduction of losses.
"Animation OF THE New Piston Motor1"
"Animation OF THE New Piston Motor1"
2. New 180°-V-Engine
In the second example of the new piston engine, two opposing right and left cylinders of a 180°-V-engine are represented by the front view in Fig. (2). The 180°-V-engine is arranged with horizontal cylinders. The two cylinders share a common ring gear (5), a crank gear (8a), a reversing gear (7), and a planetary gear (6a) with two planetary cheeks (9). The piston pair uses a common ring gear (5) and crank gear (8a).
The new 180°-V-engine has a 180° bank angle. Each pair of opposing pistons moves along the same cylinder axis and is connected by two connecting rods (4), which are firmly attached to a common connecting rod ring (5) (Gig. 2). The Fig. shows the front view of two opposing piston pairs of the new 180°-V-engine.
During axial piston movement in the power stroke of the right cylinder, the right connecting rod (4), which is mounted in the piston pin (3) and firmly connected to the ring gear (5), moves. Since the left connecting rod (4) is also firmly connected to the ring gear (5), the piston in the left cylinder moves in an expansion or compression stroke.
A design of the new piston engine with two opposing right and left cylinders of a boxer engine is shown in the image (3b). The boxer engine is arranged with horizontal cylinders. Each cylinder has a piston, a connecting rod (4), a ring gear (5), a crank gear (8a), two planetary discs (9), as well as gears (6a) and (7). The two crankpins (8) are connected to the crankshaft and offset by 180°. The characteristic arrangement of its cylinders, which lie horizontally opposite each other and meet like two boxers, is notable.
The new 180°-V-engine or the boxer engine must consist of an even number of cylinders arranged on two cylinder banks and can be built with a cylinder count of 2, 4, 6, 8, 10, or 12.
br>In a new V-engine with multiple cylinders, the two cylinder banks are inclined against each other at a bank angle <180° (Fig. 3b). Each cylinder has a piston, a connecting rod (4), a ring gear (5), a crank gear (8a), two planetary discs (9), as well as gears (6a) and (7)."