POWER OUTPUT APPARATUS, VEHICLE EQUIPPED WITH THE SAME, AND METHOD OF CONTROLLING POWER OUTPUT APPARATUS

• US 20090292449A1
• Filed: 05/26/2009
• Published: 11/26/2009
• Est. Priority Date: 05/23/2008
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: FUSHIKI, Shunsuke, YAMAZAKI, Makoto
• Granted Patent: US 8,306,720 B2
• Time in Patent Office: Days
• US Class Current: 701/103
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 30/188 Controlling power parameters of the driveline, e.g. determining the required power
• CPC Class Codes: F02D 41/0042 Controlling the combustible mixture as a function of the canister purging, e.g. control of injected fuel to compensate for deviation of air fuel ratio when purging
• CPC Class Codes: F02D 41/0045 Estimating, calculating or determining the purging rate, amount, flow or concentration
• CPC Class Codes: F02M 25/0827 by monitoring engine running conditions
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

In a power output apparatus, when the fuel vapor concentration is high and the target purge rate is high, an operating point on a purge priority operating line is selected as a target operating point of an engine. As a result, the intake manifold negative pressure greater than that when an operating point on an optimum fuel efficiency operating line is selected, so that the flow rate of purge gas released from a canister is increased. When the fuel vapor concentration does not fall within a high-concentration range, the necessity to immediately purge fuel vapor trapped in the canister into the intake pipe is low, and thus an operating point on the optimum fuel efficiency operating line is selected to keep the engine operating at high fuel efficiency.

Claims

1. A power output apparatus comprising:

an internal combustion engine;

a fuel tank in which fuel supplied to the internal combustion engine is stored;

a fuel vapor trap that traps fuel vapor in the fuel tank, and purges the trapped fuel vapor into an intake pipe of the internal combustion engine;

an electric motor that drives a drive shaft;

an input and output device that is connected to three shafts comprising an output shaft of the internal combustion engine, the drive shaft and a rotary shaft, and supplies or receives power to or from one of the three shafts, based on power supplied to or received from the remaining two of the three shafts;

a generator that generates electric power using the power received via the rotary shaft;

a fuel vapor parameter detector that detects a parameter associated with a fuel vapor amount as an amount of fuel vapor trapped in the fuel vapor trap; and

a controller that sets a required power to be transmitted to the drive shaft, wherein;

when a purge priority condition that comprises at least a condition that the parameter associated with the fuel vapor amount and detected by the detector falls within a specified high-fuel-amount range is satisfied, the controller sets a target operating point of the internal combustion engine to a purge priority operating point, at which the internal combustion engine generates the same power as when the engine operates at an optimum fuel efficiency operating point, at which the engine operates at optimum fuel efficiency, but operates at a higher rotational speed with smaller torque;

when a certain purge priority canceling condition is satisfied, after the target operating point of the internal combustion engine is set to the purge priority operating point, the controller sets the target operating point of the internal combustion engine to the optimum fuel efficiency operating point; and

the controller controls the internal combustion engine, the electric motor and the generator, based on the set required power and the target operating point of the internal combustion engine, and executes a purge control for releasing the fuel vapor trapped by the fuel vapor trap into the intake pipe, utilizing a negative pressure of the intake pipe.

2. The power output apparatus according to claim 1, wherein the purge priority condition comprises at least a condition that the parameter associated with the fuel vapor amount and detected by the detector falls within the specified high-fuel-amount range, and a ratio of a purge gas flow to an intake air flow falls within a specified high-ratio range.

3. The power output apparatus according to claim 1, wherein the purge priority canceling condition comprises at least a condition that a total purge gas amount calculated from the time when the target operating point of the internal combustion engine is set to the purge priority operating point falls within a specified large-amount range.

4. The power output apparatus according to claim 1, wherein the purge priority canceling condition comprises at least a condition that the parameter associated with the fuel vapor amount and detected by the detector does not fall within the specified high-fuel-amount range.

5. The power output apparatus according to claim 1, wherein the detector detects a fuel concentration in purge gas as the parameter associated with the fuel vapor amount.

6. The power output apparatus according to claim 1, further comprising an operating line storage device that stores an optimum fuel efficiency line, on which the internal combustion engine operates at optimum fuel efficiency, and a purge priority line, as operating lines used to set an operating point representing the rotational speed and torque of the internal combustion engine, wherein the internal combustion engine operates at a higher rotational speed with smaller torque at a given operating point on the purge priority operating line so as to generate a certain power, as compared with those of the engine operating at a given operating point on the optimum fuel efficiency operating line so as to generate the same power, and wherein

the controller sets the target operating point of the internal combustion engine to an operating point on the purge priority line when the purge priority condition is satisfied, and sets the target operating point of the internal combustion engine to an operating point on the optimum fuel efficiency line when the purge priority canceling condition is satisfied.

7. A vehicle on which the power output apparatus according to claim 1 is installed, and which has an axle coupled to the drive shaft.

8. A method of controlling of a power output apparatus that includes an internal combustion engine, a fuel tank in which fuel supplied to the internal combustion engine is stored, a fuel vapor trap that traps fuel vapor in the fuel tank, and purges the trapped fuel vapor into an intake pipe of the internal combustion engine, an electric motor that drives a drive shaft, an input and output device that is connected to three shafts comprising an output shaft of the internal combustion engine, the drive shaft and a rotary shaft, and supplies or receives power to or from one of the three shafts, based on power supplied to or received from the remaining two of the three shafts, a generator that generates electric power using the power received via the rotary shaft, and a fuel vapor parameter detector that detects a parameter associated with a fuel vapor amount as an amount of fuel vapor trapped in the fuel vapor trap, comprising:

setting a required power that is transmitted to the drive shaft;

setting a target operating point of the internal combustion engine to a purge priority operating point, at which the internal combustion engine generates the same power as when the engine operates at an optimum fuel efficiency operating point, at which the engine operates at optimum fuel efficiency, but operates at a higher rotational speed with smaller torque, when a purge priority condition that comprises at least a condition that the parameter associated with the fuel vapor amount that is detected by the detector falls within a specified high-fuel-amount range is satisfied;

setting the target operating point of the internal combustion engine to the optimum fuel efficiency operating point when a purge priority canceling condition is satisfied after the target operating point of the internal combustion engine is set to the purge priority operating point; and

controlling the internal combustion engine, the electric motor and the generator, based on the set required power and the target operating point of the internal combustion engine when executing purge control to purge the fuel vapor trapped by the fuel vapor trap into the intake pipe, utilizing a negative pressure of the intake pipe.

9. The method of controlling according to claim 8, wherein the purge priority condition comprises at least a condition that the parameter associated with the fuel vapor amount and detected by the detector falls within the specified high-fuel-amount range, and a ratio of a purge gas flow to an intake air flow falls within a specified high-ratio range.

10. The method of controlling according to claim 8, wherein the purge priority canceling condition comprises at least a condition that a total purge gas amount calculated from the time when the target operating point of the internal combustion engine is set to the purge priority operating point falls within a specified large-amount range.

11. The method of controlling according to claim 8, wherein the purge priority canceling condition comprises at least a condition that the parameter associated with the fuel vapor amount and detected by the detector does not fall within the specified high-fuel-amount range.

12. The method of controlling according to claim 8, wherein

when the purge priority condition is satisfied, the target operating point of the internal combustion engine is set to an operating point at which the internal combustion engine operates at a higher rotational speed with smaller torque than when the engine satisfies the purge priority canceling condition, while generating the same amount of power;

and

when the purge priority canceling condition is satisfied, the target operating point of the internal combustion engine is set to an operating point at which the internal combustion engine operates at a lower rotational speed with larger torque than when the engine that satisfies the purge priority condition, while generating the same amount of power.