Methods of operating a series hybrid vehicle
First Claim
1. A method of powering a secondary power source in a series hybrid vehicle, the method comprising:
- monitoring an amount of available stored secondary energy within an energy storage device;
monitoring vehicle speed;
based on the amount of available stored energy at a given vehicle speed, selectively powering the secondary power source with either a portion of the amount of available stored energy or a portion of an amount of direct input energy, or with a combination of the portion of the amount of available stored energy and the portion of the amount of direct input energy, wherein selectively powering the secondary power source comprises disproportionately varying one or more of a plurality of selected thresholds of the available stored energy as a function of a change in vehicle speed;
operating an engine at a first selected power level when the amount of available stored secondary energy is within an upper range;
operating the engine at a second selected power level when the amount of available stored energy is within a lower range;
operating the engine at one of a range of selected power levels when the amount of available stored energy is within a middle range; and
varying one or more of the plurality of thresholds further comprises defining the upper, the middle, and the lower ranges of available stored energy at least in part based on vehicle speed.
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Abstract
A method for operating a series hybrid vehicle is provided, in which an engine generates secondary power that is either stored or used as direct input energy by a secondary power source to provide motive power to the vehicle. Regenerative braking is used to convert kinetic energy of the vehicle into secondary energy, which is also stored. When the vehicle driver makes a power demand, the secondary power source is powered by secondary energy from an energy storage device, direct input energy generated by the engine, or both, depending on the amount of stored secondary energy in combination with vehicle speed. When in use, the power level at which the engine is operated is also determined on the basis of available stored energy and vehicle speed. At higher vehicle speeds, the amount of stored energy is allowed to be depleted in order to increase the available storage capacity for regenerative braking.
167 Citations
12 Claims
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1. A method of powering a secondary power source in a series hybrid vehicle, the method comprising:
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monitoring an amount of available stored secondary energy within an energy storage device; monitoring vehicle speed; based on the amount of available stored energy at a given vehicle speed, selectively powering the secondary power source with either a portion of the amount of available stored energy or a portion of an amount of direct input energy, or with a combination of the portion of the amount of available stored energy and the portion of the amount of direct input energy, wherein selectively powering the secondary power source comprises disproportionately varying one or more of a plurality of selected thresholds of the available stored energy as a function of a change in vehicle speed; operating an engine at a first selected power level when the amount of available stored secondary energy is within an upper range; operating the engine at a second selected power level when the amount of available stored energy is within a lower range; operating the engine at one of a range of selected power levels when the amount of available stored energy is within a middle range; and varying one or more of the plurality of thresholds further comprises defining the upper, the middle, and the lower ranges of available stored energy at least in part based on vehicle speed. - View Dependent Claims (2, 3, 4)
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5. A method of operating a series hybrid vehicle, comprising:
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using only secondary energy to provide motive power to the vehicle; operating an engine to generate secondary energy when an amount of available stored secondary energy is below a first selected threshold; monitoring vehicle speed; selecting a value of the first selected threshold based on vehicle speed, and disproportionately and inversely varying the value of the first selected threshold in relation to changes in vehicle speed; and controlling an amount of the secondary energy drawn from the available stored secondary energy to provide motive power to the vehicle, as compared to an amount of the secondary energy provided as direct input energy generated by the engine, on the basis of the amount of available stored secondary energy at a given vehicle speed. - View Dependent Claims (6)
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7. A method of operating a series hybrid vehicle, comprising:
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using only secondary energy to provide motive power to the vehicle; operating an engine to generate secondary energy when an amount of available stored secondary energy is below a first selected threshold; monitoring vehicle speed; selecting a value of the first selected threshold based on vehicle speed, and disproportionately and inversely varying the value of the first selected threshold in relation to changes in vehicle speed; and controlling a power level at which the engine is operated based on the amount of available stored secondary energy, by selecting the power level based on the amount of available stored secondary energy at a given vehicle speed, operating the engine at one of a plurality of preselected power levels and selecting the one of the plurality of preselected power levels according to an inverse relationship with the amount of available stored secondary energy, wherein; each of the plurality of preselected power levels lies within a predefined range for efficient operation of the engine; the plurality of preselected power levels includes a predefined minimum power level for efficient operation of the engine; the plurality of preselected power levels includes a predefined maximum power level for efficient operation of the engine; and the plurality of preselected power levels includes a range of predefined power levels for efficient operation of the engine that lie between the predefined minimum power level and the predefined maximum power level. - View Dependent Claims (8, 9)
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10. A method of powering a secondary power source in a series hybrid vehicle, the method comprising:
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monitoring an amount of available stored secondary energy within an energy storage device; monitoring vehicle speed; based on the amount of available stored energy at a given vehicle speed, selectively powering the secondary power source with either a portion of the amount of available stored energy or a portion of an amount of direct input energy, or with a combination of the portion of the amount of available stored energy and the portion of the amount of direct input energy; operating an engine at a first selected power level when the amount of available stored secondary energy is within an upper range; operating the engine at a second selected power level when the amount of available stored energy is within a lower range; operating the engine at one of a range of selected power levels when the amount of available stored energy is within a middle range; and varying one or more of a plurality of thresholds that define the upper, the middle, and the lower ranges of available stored energy at least in part based on vehicle speed, wherein each of the first selected power level, the second selected power level, and the power levels of the range of selected power levels is a respective preselected power level comprising a preselected engine speed and a preselected torque value.
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11. A method of operating a series hybrid vehicle, comprising:
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using only secondary energy to provide motive power to the vehicle; operating an engine to generate secondary energy when an amount of available stored secondary energy is below a first selected threshold; monitoring vehicle speed; selecting a value of the first selected threshold based on vehicle speed; and controlling an amount of the secondary energy drawn from the available stored secondary energy to provide motive power to the vehicle, as compared to an amount of the secondary energy provided as direct input energy generated by the engine, on the basis of the amount of available stored secondary energy at a given vehicle speed. - View Dependent Claims (12)
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Specification