Motor Vehicle with Simulator of Performance of a Mechanical Gearbox

Abstract

A vehicle having a motor with a transmission, provided with a fixed gear ratio, to a propelling unit includes a virtual gearbox including a microprocessor, operatively interfaced with the motor and programmed to manage and check the generation of motor driving torque, limiting, at the motor output, a maximum angular velocity and a maximum torque which are variable with a predetermined law.

Claims

1. A method comprising: receiving a speed of a vehicle from a speed gauge of the vehicle; receiving an acceleration level from an acceleration pedal of the vehicle; setting limits of a maximum angular velocity and a maximum torque of an electrical motor according to a predetermined rule, wherein the predetermined rule is set according to the speed of the vehicle; and providing, by the electric motor, an angular velocity and a torque to a transmission with a fixed gear ratio according to the acceleration level, the maximum angular velocity, the maximum torque, and the speed of the vehicle.

2. The method of claim 1, wherein the limits of the maximum angular velocity and the maximum torque simulate a plurality of gear ratios of a gearbox.

3. The method of claim 1, wherein the angular velocity and the torque generate a counter-driving power according to the acceleration level being a negative acceleration.

4. The method of claim 3, wherein the counter-driving power has a variable intensity that varies according to the speed and acceleration level.

5. The method of claim 3, wherein the counter-driving power: is used for vehicle braking; simulates downshifting; or simulates engine braking caused by intrinsic friction of an internal combustion engine.

6. The method of claim 1, comprising: receiving a clutch slip level; and simulating, using the angular velocity and the torque, an engagement and a disengagement of a mechanical clutch according to the clutch slip level.

7. The method of claim 1, comprising reproducing a sound according to the angular velocity and the torque, wherein the sound corresponds to a real internal combustion engine in a same condition.

8. The method of claim 1, wherein the torque and the angular velocity are variable according to a continuously variable transmission.

9. The method of claim 1, comprising receiving a gear selection, wherein the torque and the angular velocity are determined according to the gear selection.

10. The method of claim 9, wherein the selecting is activated automatically.

11. A vehicle comprising: a speed gauge; an acceleration pedal; an electrical motor; a transmission comprising a fixed gear ratio; and and a microprocessor configured to: receive a speed of the vehicle from the speed gauge; receive an acceleration level from the acceleration pedal; receive a predetermined rule; set limits of a maximum angular velocity and a maximum torque of the electrical motor according to the predetermined rule, wherein the predetermined rule is set according to the speed of the vehicle; and provide, by the electric motor, an angular velocity and a torque to the transmission according to the acceleration level, the maximum angular velocity, the maximum torque, and the speed.

12. The vehicle of claim 11, wherein the limits of the maximum angular velocity and the maximum torque simulate a plurality of gear ratios of a gearbox.

13. The vehicle of claim 11, wherein the angular velocity and the torque generate a counter-driving power according to the acceleration level being a negative acceleration.

14. The vehicle of claim 13, wherein the counter-driving power has a variable intensity that varies according to the speed and acceleration level.

15. The vehicle of claim 13, wherein the counter-driving power: is used for vehicle braking; simulates downshifting; or simulates engine braking caused by intrinsic friction of an internal combustion engine.

16. The vehicle of claim 11, wherein the microprocessor is configured to: receive a clutch slip level; and simulate, using the angular velocity and the torque, an engagement and a disengagement of a mechanical clutch according to the clutch slip level.

17. The vehicle of claim 11, wherein the microprocessor is configured to: reproduce a sound according to the angular velocity and the torque, wherein the sound corresponds to a real internal combustion engine in a same condition.

18. The vehicle of claim 11, wherein the torque and the angular velocity are variable according to a continuously variable transmission.

19. The vehicle of claim 11, wherein the microprocessor is configured to: receive a gear selection, wherein the torque and the angular velocity are determined according to the gear selection.

20. The vehicle of claim 19, wherein the selecting is activated automatically.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The advantages of the invention are more apparent in the detailed description which follows, with reference to the accompanying drawings which illustrate an example, non-limiting embodiment of the invention, in which:

[0013] FIG. 1 is a schematic functional block diagram of a vehicle according to this invention.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0014] With reference to FIG. 1 of the accompanying drawings, the numeral (1) denotes in its entirety a vehicle having a motor (10) with a transmission (11), with fixed gear ratio (ip), to a propelling unit (12) shown as the driving wheels of the vehicle (1).

[0015] The vehicle (1) is preferably—by way of example and without limiting the invention—a go-kart equipped with an electric motor (10).

[0016] The motor (10) and the transmission (11) can be dynamically connected by a coupling (17) that makes the motor (10) independent of the wheels (12) and that, once the motor (10) has been started with no load, allows gradual application of the external load.

[0017] The vehicle (1) comprises a virtual gearbox (13), that is to say, a simulator of the performance of a mechanical gearbox which electronically simulates the latter by means of suitable real-time check of the parameters for generating and supplying driving torque for the motor (10).

[0018] More particularly, said virtual gearbox (13) comprises microprocessor means (14), located on a suitable printed circuit board, which are operatively interfaced with the motor (10) and programmed to manage and check the generation of the maximum driving torque (Co) parameters, with constant power, preferably maximum, and with angular velocity (n at the motor (10) output, that is to say, at the transmission (11) input, which are variable, with a suitably predetermined law.

[0019] The variable velocity (n) is correlated with a corresponding driving torque of the motor (10) according to variable gear ratios (i1;i2;i3; . . . in), preferably with separate values relating to the different gears that a hypothetical discontinuous speed variation mechanical gearbox would have, if the latter were actually and physically present in the vehicle (1).

[0020] Selecting means (15) for selecting the velocity (n) at the transmission (11) input are provided associated with a steering wheel (20) of the vehicle (1). Said selecting means can be activated with a manual command, deliberately, issued by the vehicle driver, from the steering wheel (20), and transmitted as input to the microprocessor means (14) for starting [0021] for each characteristic gear of the virtual gearbox (13)—and in real time all of the processing operations that allow a corresponding suitable electric motor (10) management in terms of torque (C) and corresponding angular velocity (n) with vehicle (1) constant power, preferably maximum.

[0022] Obviously, the microprocessor means (14) can manage the supply of driving power even according to different functions, which are in any case correlated with the simulation of an automatic gearbox that is real and physically present on the vehicle (1).

[0023] In fact, they can allow simulation, via software, even of a variation of the velocity (n) according to multiple gear ratios (i1;i2;i3 . . . in), whose values are programmable as desired by the user, for example, according to a mathematical progression, different on each occasion, for example selected relative to distinctive features of the various tracks on which the go-kart may race.

[0024] Moreover, the microprocessor means (14) may manage the operating parameters of the electric motor (10) in such a way as to also generate, if necessary, a counter-driving torque useful for vehicle (1) braking.

[0025] That function can be exploited, for example, to advantageously simulate downshifting, that is to say, “engine braking” due, for example, to intrinsic friction of an internal combustion engine. Therefore, all conditions able to give the vehicle driver sensations of inertia, of mass, like those that would be felt when driving a vehicle powered by an internal combustion engine.

[0026] Moreover, said counter-driving force may be modulated, even with variable intensity using a different law of variation, depending on the virtual gear, in the progression of gears of the gearbox, or in the idle state in which the vehicle (1) is stationary with the motor (10) running.

[0027] The microprocessor means (14) can also allow generation of the driving torque (Co) of the motor (10) simulating the law of progression during acceleration (picking up again, or from a standing start) of a real vehicle operating with inertias and frictions whose numerical values are processed by the microprocessor means (14).

[0028] The microprocessor means (14) can manage operating parameters of the electric motor (10) even simulating engagement and disengagement of a mechanical clutch.

[0029] Sound reproducing means (16) can also be provided, for reproducing sounds, corresponding to the sound spectrum of a real internal combustion engine (10), sounds that are harmonised, depending on the motor (10) speed, where the expression virtual speed means the speed that an engine system would have with a gearbox having the same gear ratio selected as in the virtual gearbox.

[0030] In the above description reference was made to a vehicle able to move with a torque (C) and velocity (n) which are variable according to a gear ratio (i) that is stepped, that is to say, having a series of separate predetermined ratios. However, it is clear that the driving torque supply parameters of the motor (10) may also be implemented in such a way as to simulate a continuously variable transmission if that law of simulation is of interest.

[0031] To better explain several distinctive features of the invention, the following non-limiting comparison may be used by way of example. Consider a vehicle with a hypothetical mechanical gearbox having separate ratios and reduction ratios of i1=2, i2=1.5 and i3=1, with a constant torque curve equal to 50 Nm and n=5,000 rpm, maximum values, which respectively allow the achievement of maximum speeds for each gear of 25 km/h, 37.5 km/h and 50 km/h, with respective torques at the wheels of 100 Nm, 75 Nm and 50 Nm. Then take a vehicle with the invention installed and install a motor (10) able to supply a constant torque of 100 Nm from 0 to 5,000 rpm, with a fixed reduction ratio if=1. When virtual gear No. 1 is engaged in the vehicle, the electric motor is set in real time to supply a maximum of 100 Nm of torque from 0 to 2,500 rpm, allowing the vehicle to reach the maximum speed of 25 km/h with a torque at the wheels of 100 Nm, precisely as in vehicle 1 in gear No. 1. Then, when virtual gear No. 2 is engaged, the electric motor (10) is choked so that it supplies a maximum of 75 Nm of torque at the wheels with a maximum speed of 37.5 km/h, just like in gear No. 2 of the vehicle equipped with the mechanical gearbox, and so on.

[0032] It is possible to calculate the virtual revolutions per minute (rpm) of the electric motor (10) in order to make them equivalent to the motor (10) that has a mechanical gearbox. In that way, with virtual gear No. 1 engaged, when the vehicle reaches the speed of 25 km/h, the virtual revolutions per minute (rpm) are 5,000. This makes it possible to reproduce a simulated sound that emulates the tone of a motor (10) with a gearbox, and to reproduce on a display the virtual rpm of the motor, in a condition such that, for example, first gear is engaged and the rev counter is at the full-scale position, when the rpm are 2,500 (but the virtual rpm are 5,000).

[0033] The invention achieves the proposed aims, also providing the additional advantages of high levels of operating effectiveness and stability, as well as being inexpensive to make, maintain and use.

[0034] In conclusion, the invention operates by performing fully electronic adjustment and management of the drive unit driving power generating and supplying curves, operations that are carried out in real time as a virtual simulation of the dynamics of a vehicle equipped with a mechanical gearbox having multiple gears. All of that is done despite the fact that the vehicle in question is actually fitted with a physical transmission having a single, fixed ratio.

[0035] The invention described above is susceptible of evident industrial application. It may also be modified and adapted in several ways without thereby departing from the scope of the following claims.

[0036] Moreover, all details of the invention may be substituted by technically equivalent elements.