Operation energy efficiency control method for electric vehicle driven by single motor

Abstract

According to the operation energy efficiency control method for the electric automobile driven by the single motor, n forward gears are provided, n is larger than or equal to 1, the speed of the first gear is the lowest, the gears are sequentially increased, the speed is also increased, and the speed of the n gear is the highest; the electric vehicle runs at the speed Vni, the power consumption per hundred kilometers of the electric vehicle running at the gear i is Wni, and the battery output power is Pni; the power consumption per hundred kilometers during driving at the (i + 1) gear is Wn (i + 1), and the output power of the battery is Pn (i + 1); n-1 > = i > = 1, the condition that Vni is the speed switching point of the i gear and the (i + 1) gear is that Wni = Wn (i + 1), Wni = Wn (i + 1) is replaced by Pni = Pn (i + 1), and the same conclusion is that when the speed of the electric vehicle is smaller than Vni, the i gear is used for driving; when the speed of the electric vehicle is greater than Vni, the electric vehicle runs at the (i + 1) gear; and when the speed of the electric vehicle is equal to Vni, the gear is not changed.

Description

Technical Field

[0001] The invention relates to an electric vehicle operation energy efficiency control method, in particular to an electric vehicle operation energy efficiency control method driven by a single motor. Background Art

[0002] As the "dual carbon" goal becomes a global consensus, replacing fossil energy with green and clean energy has become a major trend. Thermal power will become less and less, while green power will become more and more. Many countries have formulated a timetable for the withdrawal of fuel vehicles from the market. New energy vehicles, represented by electric vehicles, have developed rapidly in recent years, both in terms of research and production.

[0003] Once the appearance of an electric car is fixed, its drag coefficient is also fixed. Once the mechanical transmission structure and materials are fixed, its friction coefficient is also fixed. The same car hardware, the same road conditions, the same external environment, different control methods will have different operating energy efficiency. In order to meet the normal driving of electric vehicles under various working conditions, it is necessary to consider climbing, full load and some complex road conditions. The power of the electric motor of a single-motor-driven electric vehicle is configured according to the maximum power performance required at the maximum load and the highest design speed. When the speed and load of electric vehicles vary widely, if the control method is inappropriate, it will inevitably lead to low operating efficiency and serious waste of electric energy. People have conducted a lot of research on the operating energy efficiency of electric vehicles to improve the efficient operating range of electric vehicles, save electricity, and increase the cruising range of electric vehicles with the same battery capacity. Since the current electric vehicle operating energy efficiency test standards in various countries around the world are not unified, the constant speed values, acceleration and deceleration values ​​and duration values ​​used in the test are different, and the measured 100-kilometer power consumption data are also different, sometimes even very different. If a test standard is changed, the ranking will also change, causing consumers to be at a loss. This chaotic situation also reflects, from one aspect, that there is currently a lack of a unified optimal method for controlling the operating energy efficiency of electric vehicles.

[0004] For electric vehicles driven by a single motor, the single motor, each gear transmission mechanism and the appearance of the car can be regarded as a set of units. Multiple gears correspond to multiple sets of units. However, when the electric vehicle is running, only one set of units can be put into use at a time, so we can also regard electric vehicles driven by a single motor as a multi-unit system.

[0005] The document "Efficient Energy-Saving Control and Optimization for Multi-Unit Systems - A Guide for Electrical Engineers" (published by Springer), with its Chinese translation as "Efficient Energy-Saving Control and Optimization for Multi-Unit Systems - A Guide for Electrical Engineers", provides the optimal solution for the operating energy efficiency of a multi-unit system, proves Yao Theorem 1 for achieving optimal load distribution, and proves Yao Theorem 2 for achieving optimal unit switching. However, the book does not provide an engineering implementation method for the optimal solution for the operating energy efficiency of a multi-unit system. Summary of the invention

[0006] In order to improve the operating energy efficiency of an electric vehicle driven by a single motor, the present invention provides an operating energy efficiency control method for an electric vehicle driven by a single motor.

[0007] The technical solution adopted by the present invention to solve the technical problem is: an electric vehicle driven by a single motor adopts a stepped transmission with n forward gears, n≥1, the first gear has the lowest speed, the speed increases with the increase of gears, and the nth gear has the highest speed; the electric vehicle is driven at a speed V ni Driving, the power consumption per 100 kilometers in gear i is W ni , the battery output power is P ni ; The power consumption per 100 kilometers in i+1 gear is W n(i+1) , the battery output power is P n(i+1) ; n-1≥i≥1, V ni The condition for the speed switching point between gear i and gear i+1 is W ni = W n(i+1) , W ni = W n(i+1) Use P ni =P n(i+1) Instead, with the same conclusion, the electric vehicle speed is less than V ni When the electric vehicle speed is greater than V ni When the electric car speed is equal to V ni This gear switching method can achieve high energy-efficiency operation of electric vehicles driven by a single motor.

[0008] An electric vehicle driven by a single motor uses a continuously variable transmission. The minimum speed ratio change value that the continuously variable transmission can control is Δβ. The electric vehicle is driven at a speed V i Driving, the power consumption per 100 kilometers with speed ratio i is W i , the battery output power is P i ; The power consumption per 100 kilometers driven with speed ratio i-Δβ is W i-Δβ , the battery output power is Pi-Δβ ; The power consumption for driving 100 kilometers with speed ratio i+Δβ is W i+Δβ , the battery output power is P i+Δβ ; V i The condition for the switching point between speed ratio i and speed ratio i+Δβ is W i = W i+Δβ , W i = W i+Δβ Use P i =P i+Δβ Instead, with the same conclusion; V i The condition for the switching point between speed ratio i and speed ratio i-Δβ is W i = W i-Δβ , W i =W i-Δβ Use P i =P i-Δβ Instead, the same conclusion is reached; the electric vehicle speed is less than V i When the electric vehicle speed is greater than V i When the speed ratio is i+Δβ, the electric car speed is equal to V i When the speed ratio remains unchanged, such a speed ratio control method can realize the high energy efficiency operation of electric vehicles driven by a single motor.

[0009] In an electric vehicle driven by a single motor, a step-type transmission is used, with m reverse gears, m ≥ 1, and the first gear has the lowest speed. As the gears increase, the speed also increases, and the m gear has the highest speed. The electric vehicle is driven at a speed of V mi Driving, the power consumption per 100 kilometers in gear i is W mi , the power consumption per 100 kilometers in i+1 gear is W m(i+1) , m-1≥i≥1, V i The condition for the speed switching point between gear i and gear i+1 is W mi = W m(i+1) , the electric vehicle speed is less than V mi When the speed of the electric vehicle is greater than V mi When the electric car speed is equal to V mi This gear switching method can achieve high energy-efficiency operation of electric vehicles driven by a single motor.

[0010] In an electric vehicle driven by a single motor, a step-type transmission is used, with m reverse gears, m ≥ 1, and the first gear has the lowest speed. As the gears increase, the speed also increases, and the m gear has the highest speed. The electric vehicle is driven at a speed of V mi Driving, battery output power P when driving in i gear mi , the battery output power P when driving in i+1 gear m(i+1) , m-1≥i≥1, Vmi The condition for the speed switching point between gear i and gear i+1 is P mi =P m(i+1) , the electric vehicle speed is less than V mi When the electric vehicle speed is greater than V mi When the electric car speed is equal to V mi , the gear position remains unchanged.

[0011] The beneficial effect of the present invention is that this method provides a precise high-energy-efficiency operation control method for electric vehicles driven by a single motor, and since the technical measures adopted by the invention are mature, it can be implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0013] Figure 1 It is a preferred embodiment of the present invention.

[0014] Description of reference numerals:

[0015] 1-wheel; 2-wheel; 3-wheel; 4-wheel; 5-half-axle; 6-half-axle; 7-differential; 8-gearbox; 9-motor and electrical system; 10-battery; 11-rear axle. DETAILED DESCRIPTION

[0016] exist Figure 1 In the embodiment, the four wheels of the electric vehicle are wheel (1), wheel (2), wheel (3) and wheel (4), wheel (1) is connected to a half shaft (5), wheel (2) is connected to a half shaft (6), the output of the differential (7) is connected to the half shaft (5) and the half shaft (6), the input of the differential (7) is connected to the gearbox (8), the gearbox (8) has five forward gears, and the operating speeds are from low to high, namely, 1st gear, 2nd gear, 3rd gear, 4th gear and 5th gear, the motor (9) provides power to the gearbox (8), the electrical system (10) drives the motor (9), the battery (11) provides electrical energy to the electrical system (10), and the wheel (3) and the wheel (4) are connected together through the rear axle (12). The motor (9) and the gearbox (8) have five forward gear combinations, namely, the motor (9) and 1st gear, the motor (9) and 2nd gear, the motor (9) and 3rd gear, the motor (9) and 4th gear, and the motor (9) and 5th gear. When the electric vehicle is moving forward, the speed switching point between the first gear and the second gear has the following characteristics: the electric power output by the battery (11) is equal before and after the switching, P 51 is the electric power output by the battery (11) when the electric vehicle is running in the first gear, P 52 is the electric power output of the battery (11) when the electric vehicle is running in gear 2, and P 51 =P 52; It can also be expressed as, the electric vehicle's power consumption per 100 kilometers is equal before and after the switch, W 51 is the power consumption per 100 kilometers when the electric vehicle is running in the first gear, W 52 is the power consumption per 100 kilometers when the electric vehicle is running in the second gear, and W 51 = W 52 The switching point between the 2nd and 3rd gears has the following characteristics: the electric power output by the battery (11) is equal before and after the switching, P 52 is the electric power output by the battery (11) when the electric vehicle is running in the second gear, P 53 is the electric power output of the battery (11) when the electric vehicle is running in the third gear, and P 52 =P 53 ; It can also be expressed as, the electric vehicle's power consumption per 100 kilometers is equal before and after the switch, W 52 is the power consumption per 100 kilometers when the electric vehicle is running in the second gear, W 53 is the power consumption per 100 kilometers when the electric vehicle is running in the third gear, and W 52 =W 53 The switching point between the 3rd and 4th gears has the following characteristics: the electric power output by the battery (11) is equal before and after the switching, P 53 is the electric power output by the battery (11) when the electric vehicle is running in the third gear, P 54 is the electric power output of the battery (11) when the electric vehicle is running at gear 4, and P 53 =P 54 ; It can also be expressed as, the electric vehicle's power consumption per 100 kilometers is equal before and after the switch, W 53 is the power consumption per 100 kilometers when the electric vehicle is running in the third gear, W 54 is the power consumption per 100 kilometers when the electric vehicle is running in the 4th gear, and W 53 = W 54 The speed switching points of the 4th and 5th gears have the following characteristics: the electric power output by the battery (11) is equal before and after the switching, P 54 is the electric power output by the battery (11) when the electric vehicle is running in the 4th gear, P 55 is the electric power output of the battery (11) when the electric vehicle is running at gear 5, and P 54 =P 55 ; It can also be expressed as, the electric vehicle's power consumption per 100 kilometers is equal before and after the switch, W 54 is the power consumption per 100 kilometers when the electric vehicle is running in the 4th gear, W 55 is the power consumption per 100 kilometers when the electric vehicle is running in the 5th gear, W 53 = W 54 .

[0017] Those skilled in the art should recognize that although only one embodiment is described above, they are not all forms of the present invention. It should be understood that many modifications can be made without departing from the spirit and scope of the present invention. In the description of the present invention, the terms "forward gear" and "reverse gear" define forward and backward, which only represent two opposite directions of movement, can be redefined and interchanged, and cannot be understood as limiting the present invention; the terms "front", "rear", "left", "right", "up", "down", "inside", "outside" and the like indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. Those skilled in the art can implement the present invention in other forms without departing from the concept of the present invention, and therefore, other embodiments are also within the scope of the claims of the present invention.

Claims

1. A method for controlling the operating energy efficiency of an electric vehicle driven by a single motor. The electric vehicle driven by a single motor adopts a stepped transmission with n forward gears, n ≥ 1, and the first gear has the lowest speed. The speed increases with the increase of gears, and the nth gear has the highest speed. The characteristics are: The electric car is moving at a speed V ni Driving, the power consumption per 100 kilometers in gear i is W ni , the battery output power is P ni ; The power consumption per 100 kilometers in i+1 gear is W n(i+1) , the battery output power is P n(i+1) ; n-1≥i≥1, V ni The condition for the speed switching point between gear i and gear i+1 is W ni = W n(i+1) , W ni = W n(i+1) Use P ni =P n(i+1) Instead, with the same conclusion, the electric vehicle speed is less than V ni When the electric vehicle speed is greater than V ni When the electric car speed is equal to V ni , the gear position remains unchanged.

2. A method for controlling the operating energy efficiency of an electric vehicle driven by a single motor. The electric vehicle driven by a single motor adopts a continuously variable transmission. The minimum speed ratio change value Δβ that can be controlled by the continuously variable transmission is characterized by: The electric car is moving at a speed V i Driving, the power consumption per 100 kilometers with speed ratio i is W i , the battery output power is P i ; The power consumption per 100 kilometers driven with speed ratio i-Δβ is W i-Δβ , the battery output power is P i-Δβ ; The power consumption for driving 100 kilometers with speed ratio i+Δβ is W i+Δβ , the battery output power is P i+Δβ ; V i The condition for the switching point between speed ratio i and speed ratio i+Δβ is W i = W i+Δβ , W i = W i+Δβ Use P i =P i+Δβ Instead, with the same conclusion; V i The condition for the switching point between speed ratio i and speed ratio i-Δβ is W i = W i-Δβ , W i = W i-Δβ Use P i =P i-Δβ Instead, the same conclusion is reached; the electric vehicle speed is less than V i When the electric vehicle speed is greater than V i When the speed ratio is i+Δβ, the electric car speed is equal to V i The speed ratio remains unchanged.

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