Dual crankshaft engine with counter rotating inertial masses

Abstract

A dual crankshaft internal combustion engine is symmetrically constructed to form a perfectly balanced engine assembly. A first crankshaft, having a first end, a second end, and being formed of a shape and with a torsional flexibility, is housed within a cylinder block and connected to a first series of cooperating pistons and cylinders. A second crankshaft, having a first end and a second end, is formed of substantially the same shape as the first crankshaft and has substantially the same torsional flexibility as the first crankshaft. The second crankshaft is also housed within the cylinder block and connected to a second series of cooperating pistons and cylinders, while being positioned parallel to the first crankshaft, with the first end of the first crankshaft being positioned adjacent to the second end of the second crankshaft.

Description

FIELD OF INVENTION[0001]The present invention pertains to the art of internal combustion engines used in vehicles and, more specifically, to a balance and noise reduction system for a dual crankshaft engine.BACKGROUND OF THE INVENTION[0002]Conventional internal combustion engines employ piston and cylinder arrangements that tend to vibrate during operation. The vibration often creates a disturbance in a vehicle passenger compartment and is considered undesirable.[0003]Most internal combustion engines develop power in impulses generated by the explosion of a combination of air and fuel in the engine's cylinders. The power is transferred to pistons that are located in the cylinders and are coupled to a rotating crankshaft with connecting rods. The power then flows to a flywheel that is connected to other downstream components of a powertrain. All conventional, single crankshaft, piston engines have a firing frequency vibration caused by uneven torque delivery to the flywheel. On a com...

AI Technical Summary

Benefits of technology

[0011]In operation, the cylinders preferably have a firing order where the piston motion is diametrically symmetrical. That is to say that the rear piston of the left cylinder bank has a motion that is substantially identical to and in phase with the motion of the front piston of the right cylinder bank. Likewise, the second piston from the rear of the left bank is in phase with the second piston from the front of the right bank, etc. Also, the to

Problems solved by technology

The vibration often creates a disturbance in a vehicle passenger compartment and is considered undesirable.

All conventional, single crankshaft, piston engines have a firing frequency vibration caused by uneven torque delivery to the flywheel.

The torque that causes vibrational speed variations of the flywheel reacts against the cylinder block and causes torsional vibration of the cylinder block.

This fluctuating torque causes one source of vibration.

Other disturbing engine vibrations are caused by unbalanced accelerations of internal engine components, especially linear accelerations of the piston masses within the cylinder bores.

Inline and opposed 6-cylinder engines, as well as inline and 90 degree V8 engines, usually have theoretically perfect balance of piston acceleration forces, but most other engines have residual unbalanced forces or moments.

For example, all single crankshaft V6 engines with less than 180 degrees of bank angle have inherent unbalanced couples due to piston acceleration forces.

Furthermore, all conventional single crankshaft engines have unbalanced torsional accelerations imposed upon the block structure due to flywheel rotational accelerations.

However, there are numerous undesirable qualities with such a design.

First, the arrangement is very noisy in operation because the single gearset has backlash and rattles each time the direction of torque transfer reverses.

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