US 4,888,949 A · Propulsion system for a small vehicle

Abstract

The invention is vehicle propulsion system having a pump driven by an engine, a hydraulic motor driven by the pump, and a ground engaging wheel driven by the hydraulic motor. On the drive shaft connected between the engine and the pump is a flywheel whose moment of inertia is varied by radially translating weights on the flywheel. Under normal vehicle operating conditions, the weights are translated outward, whereby rotational energy is stored in the flywheel. When more power is needed then the engine can provide, the weights on the flywheel translate inwardly so that the flywheel imparts rotational energy to the pump through the drive shaft. The propulsion system has means to maintain the engine in a narrow r.p.m. range where the engine is most efficient. Vehicle speed and direction is varied by controlling the flow speed and direction from the pump, which determines the speed and direction of the hydraulic motor. The system also has an override mode wherein the engine speed is set at a new, higher level when a foot pedal operated by the vehicle operator exceeds a given range of movement.

Claims10

Dependent claims

A propulsion system for supplying power to a driven wheel of a vehicle comprising:

an engine;
a drive shaft extending from the engine;
a hydraulic circuit including a pump connected to the drive shaft, whereby the engine drives the pump;
means for varying the volume of fluid displaced by the pump per revolution of the drive shaft;
a hydraulic motor in the circuit driven by the pump;
an output shaft extending from the hydraulic motor for engagement with a driven wheel of a vehicle;
a flywheel mounted on the drive shaft having weights radially slideable toward or away from the center of the flywheel;
a flywheel regulator means for controlling the radial position of the weights with respect to the flywheel wherein the flywheel regulator means translates the weights radially inwardly when the drive shaft speed is below a selected value and translates the weights outwardly when the drive shaft speed exceeds the selected value;
an engine regulator means for normally maintaining the drive shaft speed between upper and lower limits, said lower limit exceeding the selected value to which the flywheel regulator responds.

6 more elements

A propulsion system for supplying power to the driven wheel of an engine comprising an engine;

a drive shaft extending from the engine;
a hydraulic circuit including a pump connected to the drive shaft whereby the engine drives the pump;
means for varying the volume of fluid displaced by the pump per revolution of the drive shaft;
a hydraulic motor in the circuit driven by the pump;
an output shaft extending from the hydraulic motor for engagement with a driven wheel of a vehicle;
and an energy absorbing flywheel assembly mounted to the drive shaft for maintaining the drive shaft at a substantially constant speed during variations in torsional load on the drive shaft, the flywheel assembly including:
a collar fixed on the drive shaft;
a plurality of elongate guide members extending radially from the collar;
a weight retained in each of the guide members slideable between the radially inner and outer ends of the guide members;
means to bias the weights radially outwardly in the guide members;
a cable guide means at the radially inner end of each of the guide members;
a ring axially slideable on the shaft and rotatable therewith;
a cable connected between the ring and each of the weights, the cables extending radially inwardly from the weights, thence around the cable guide means, and thence along the drive shaft to the ring;
a means for translating the ring along the drive shaft to translate the weights radially;
a tachometer means for controlling the translating means in response to drive shaft speed.

12 more elements

Dependencies are inferred from the claim text.

Propulsion system for a small vehicle

Life of this patent

Propulsion system for a small vehicle

Life of this patent

Abstract

Claims10