Powertrain and Method for a Kinetic Hybrid Vehicle

Abstract

A kinetic hybrid device and method for a vehicle may include a planetary gear system configured as a continuously variable transmission comprised of three or four ports. The kinetic hybrid device and method may include a flywheel connected to a first port of the system, a final drive connected to a second port of the system, and the variator for the flywheel connected to a third or fourth port of the system. The prime mover and / or other power sources may share a port with the flywheel, but do not share a port with the final drive.

Description

CROSS REFERENCE TO RELATED APPLICATION(S)[0001]This application claims priority from a U.S. Non-provisional patent application Ser. No. 13 / 193,728, filed Jul. 29, 2011, and from U.S. Provisional Patent Application Ser. Nos. 61 / 438,267 filed Feb. 1, 2011; 61 / 471,213, filed Apr. 4, 2011; and 61 / 495,993, filed Jun. 11, 2011, and which all are incorporated by reference herein.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention pertains to a powertrain and method of a kinetic hybrid vehicle, such as a gas and / or electric powered vehicle that includes a flywheel. The powertrain and method may be used to store and use energy of the flywheel device for vehicle propulsion and optimizing fuel efficiency.[0004]2. Description of the Related Art[0005]Improving fuel economy is an important objective in vehicle design, since it enables reduced fuel consumption and reduced emissions. Especially with the current situation of dwindling fossil fuel resources and worsening en...

AI Technical Summary

Benefits of technology

[0016]In preferred embodiments of the present invention, one port manipulated by a variator can change the speed ratio between the other two or three ports. This allows the flywheel of the present invention to exchange energy with the vehicle, and it can also change the speed ratio between the engine and the final drive, allowing the engine to effectively transfer power to the vehicle's wheels across a full range of vehicle speeds. In other words, the flywheel and the engine can share a single CVT.

[0025]Whenever the engine is on, it is run in its highest efficiency state within a certain speed range and preferably a certain load, which can be adjusted or shared by the optional but beneficial torque motor / generator on the same port. Whenever the flywheel is driving the vehicle, the engine is off, and the vehicle consumes no fuel. The speeder motor / generator, or the variator, ensures that a constant power is delivered to the wheels so that the vehicle remains in cruise, regardless of whether it is driven by the engine or the flywheel. Hence, this method optimizes efficiency during cruise. Cruise includes situations where the vehicle operator does not intentionally accelerate or decelerate; in one non-limiting example, the vehicle speed might change slightly with road conditions such as a slope or incline that does not lead the vehicle operator to appreciably change the position of the throttle. Variations for a vehicle powered by a traction motor as the prime mover are also provided.

Problems solved by technology

Although automotive technology has been advancing and there have been improvements in fuel economy, there still exists an inherent conflict between fuel economy and accelerative power in conventional vehicles.

Thus an IC engine achieves its best efficiency at relatively high power; automotive vehicles, however, require only low power most of the time.

On the other hand, this means that when the vehicle is not accelerating, its engine is operating at a lower load level and lower efficiency state, wasting the maximum efficiency potential of the engine.

If a smaller engine is used, then the engine will be working at a higher efficiency to improve fuel consumption, but there will be less reserve power, which means poorer performance in acceleration.

In addition, much of the vehicle's kinetic energy is dissipated as heat in the brakes when decelerating, reducing the vehicle's potential fuel efficiency.

Although more efficient and environment friendly than some conventional vehicles, these electric hybrids may be difficult to produce without the added costs of a large traction motor, controller, and electrochemical and / or electric storage devices.

These costs, which may outweigh the amount of money saved from consuming less fuel, may result in an increased price to consumers that limits market penetration.

Aside from cost, a main disadvantage of electric hybrids is that they are greatly limited in the fuel economy improvements they can provide.

Part of conventional electric hybrids' efficiency limitations comes from the fact that energy is not stored in the same form it is used in.

There are typically four energy transformations by the time the energy is used, each resulting in a conversion loss.

These conversion losses typically comprise above one-third the original amount of energy initially recovered, such as from braking.

Another part of conventional electric hybrids' efficiency limitations comes from the inherent characteristics of motor / generators and batteries—namely, their power transfer limitations and reduced efficiency at high rates of charge and discharge.

Even when the electric storage consists of ultracapacitors, which are highly efficient at high rates of charge and discharge, the energy regenerated from deceleration is limited by the power of the traction motor.

Mechanical CVTs typically achieve only about a 6:1 transmission ratio, and cost quite a bit.

In the early days of flywheel vehicle development and even now in some industrial applications and Uninterruptible Power Supply (UPS) systems, energy is stored into and released from the flywheel via one or more motor / generator(s), traveling a 100 percent electromagnetic path from source to destination; these flywheel systems also suffer multiple energy conversions and limited efficiency due to conversion losses.

Another disadvantage is that both systems may have critical points where the variator motor / generator approaches zero speed (stall state, maximum current) and the system has poor efficiency unless the effect is mitigated through other means such as by mechanically braking the variator port when the motor / generator approaches zero speed.

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