Hybrid vehicles
First Claim
1. In a method of controlling an internal combustion engine of a hybrid vehicle, said engine being operatively connected to drive wheels of said vehicle through a clutch, said vehicle further comprising a traction motor operatively connected to drive wheels of said vehicle, a starter/generator motor operatively connected to said engine for starting said engine and for providing electrical power in response to torque from said engine, a battery bank adapted to store electrical energy to power said traction motor and to start said engine, at least one inverter/charger adapted to cooperate with said traction motor and said starter/generator such that said traction motor can be operated to provide torque to said road wheels responsive to electrical power from said battery bank, or to provide electrical power to said battery bank responsive to torque from said road wheels, and such that said starter/generator can be operated to provide torque to start said engine, or to provide electrical power to said battery bank responsive to torque provided by said engine, and a microprocessor adapted to control operation of said engine, said traction motor, said starter/generator, and said at least one inverter/charger, so as to control flow of torque and electrical power therebetween in response to sensed parameters, the improvement comprising:
- establishing at least four vehicle operating modes, including;
a mode I, wherein said engine is not operated and said vehicle is propelled by torque from said traction motor in response to electrical power drawn from said battery bank;
a mode II, wherein said vehicle is propelled by torque from said traction motor in response to electrical power drawn from said battery bank, and said starter/generator is driven by torque provided by said engine to provide electrical power to recharge said battery bank;
a mode III, wherein said vehicle is propelled by torque from said engine;
a mode IV, wherein said vehicle is propelled by torque from said engine and from said traction motor in response to electrical power drawn from said battery bank;
wherein said microprocessor controls operation of said engine, said traction motor, said starter/generator, and said at least one inverter/charger in response to the instantaneous torque demands (RL) of said vehicle, and such that said engine is operated only in response to a load equal at least to a predetermined minimum value of its maximum torque output.
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Accused Products
Abstract
A hybrid vehicle comprises an internal combustion engine, a traction motor, a starter motor, and a battery bank, all controlled by a microprocessor in accordance with the vehicle'"'"'s instantaneous torque demands so that the engine is run only under conditions of high efficiency, typically only when the load is at least equal to 30% of the engine'"'"'s maximum torque output. In some embodiments, a turbocharger may be provided, activated only when the load exceeds the engine'"'"'s maximum torque output for an extended period; a two-speed transmission may further be provided, to further broaden the vehicle'"'"'s load range. A hybrid brake system provides regenerative braking, with mechanical braking available in the event the battery bank is fully charged, in emergencies, or at rest; a control mechanism is provided to control the brake system to provide linear brake feel under varying circumstances.
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Citations
16 Claims
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1. In a method of controlling an internal combustion engine of a hybrid vehicle, said engine being operatively connected to drive wheels of said vehicle through a clutch, said vehicle further comprising a traction motor operatively connected to drive wheels of said vehicle, a starter/generator motor operatively connected to said engine for starting said engine and for providing electrical power in response to torque from said engine, a battery bank adapted to store electrical energy to power said traction motor and to start said engine, at least one inverter/charger adapted to cooperate with said traction motor and said starter/generator such that said traction motor can be operated to provide torque to said road wheels responsive to electrical power from said battery bank, or to provide electrical power to said battery bank responsive to torque from said road wheels, and such that said starter/generator can be operated to provide torque to start said engine, or to provide electrical power to said battery bank responsive to torque provided by said engine, and a microprocessor adapted to control operation of said engine, said traction motor, said starter/generator, and said at least one inverter/charger, so as to control flow of torque and electrical power therebetween in response to sensed parameters, the improvement comprising:
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establishing at least four vehicle operating modes, including; a mode I, wherein said engine is not operated and said vehicle is propelled by torque from said traction motor in response to electrical power drawn from said battery bank; a mode II, wherein said vehicle is propelled by torque from said traction motor in response to electrical power drawn from said battery bank, and said starter/generator is driven by torque provided by said engine to provide electrical power to recharge said battery bank; a mode III, wherein said vehicle is propelled by torque from said engine; a mode IV, wherein said vehicle is propelled by torque from said engine and from said traction motor in response to electrical power drawn from said battery bank; wherein said microprocessor controls operation of said engine, said traction motor, said starter/generator, and said at least one inverter/charger in response to the instantaneous torque demands (RL) of said vehicle, and such that said engine is operated only in response to a load equal at least to a predetermined minimum value of its maximum torque output. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A brake system for a hybrid vehicle, said vehicle comprising a drive train including an internal combustion engine operated to provide vehicle propulsive torque only during predetermined modes of operation of said vehicle and at least one traction motor and corresponding inverter/charger adapted to provide vehicle propulsive torque during predetermined modes of operation of said vehicle and to provide electrical energy responsive to torque from wheels of said vehicle during a regenerative braking mode of operation of said vehicle, a battery bank adapted to provide electrical energy to said motor as required and to accept charging energy from said motor when operated as a generator during said regenerative braking mode of operation of said vehicle, and a microprocessor for controlling the mode of operation of said vehicle, said brake system comprising:
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a brake pedal adapted to be operated by a driver of said vehicle, a hydraulic brake system coupled to said brake pedal and comprising at least one master cylinder and a number of wheel brakes operatively connected to said master cylinder for retarding said vehicle upon actuation of said pedal, a sensor for providing a signal to said microprocessor responsive to motion of said brake pedal, a sensor for providing a signal to said microprocessor responsive to the state of charge of said battery bank, a device controllable by said microprocessor to vary the resistance to motion of said pedal during braking responsive to the amount of regenerative braking being provided, wherein said microprocessor controls the amount of regenerative braking provided upon motion of said pedal responsive to the state of charge of said battery bank, and controls the resistance to motion of said pedal during braking responsive to the amount of regenerative braking being provided. - View Dependent Claims (11, 12, 13)
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14. A heating, ventilation, and air conditioning (HVAC) system for a hybrid vehicle, said vehicle comprising a drive train including an internal combustion engine run only during predetermined modes of operation of said vehicle and at least one traction motor adapted to provide vehicle propulsive torque during predetermined modes of operation of said vehicle, a battery bank adapted to provide electrical energy to said motor as required, said HVAC system comprising:
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a duct having a fan disposed therein for forcing air along said duct; an evaporator in said duct; an air conditioning compressor connected to said evaporator, and driven by an electric motor powered by said battery bank; a heater core in said duct and connected to a cooling system of said engine; and an electrical-heating element in said duct and connected to said battery bank. - View Dependent Claims (15)
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16. A method for determining the relative sizes of the internal combustion engine, starting/charging and traction motors, and battery bank of a hybrid vehicle comprising said components, said method comprising the steps of:
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a. selecting an internal combustion engine having sufficient torque to drive the vehicle without trailer at medium to high speed along a moderate grade; b. sizing the starting/charging motor to provide an engine load during battery charging equal to at least approximately 30% of the engine'"'"'s maximum torque output; c. sizing the traction motor to provide adequate torque at zero speed to overcome the maximum grade specified from rest, with the starter motor assisting as needed; d. determining the maximum power drawn by the selected motor under full power conditions; e. calculating the battery voltage under load that will be required to provide the power to be drawn by the motor(s) under full power conditions, and so that the ratio of the battery voltage under load to the peak current drawn by the motor(s) is at least 2.5;
1, andf. selecting the battery bank to provide the calculated voltage under peak load conditions.
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Specification