JP2006232167A - Resistance estimation device of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To estimate a running resistance even in transition of a vehicle. <P>SOLUTION: An engine ECU calculates output torque of a wheel shaft at a driving wheel on the basis of the detected engine revolution and an inertia moment at an output shaft of an engine, calculates wheel shaft torque at the driving wheel on the basis of the detected wheel revolution and a wheel inertia moment at the driving wheel, and calculates a running resistance based on the difference between the output torque of the wheel shaft and the wheel shaft torque by means of a running resistance computing unit 120. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle resistance estimation device, and more particularly to a resistance estimation device that estimates a running resistance of a vehicle during a transition.

  When the vehicle travels, various traveling resistances such as air resistance and gradient resistance act on the vehicle. As a technique for estimating the running resistance acting on a running vehicle, for example, Japanese Patent Laid-Open No. 6-270714 (Patent Document 1) reliably executes an initialization output and reaches a target throttle valve opening in a short time. Disclosed is a constant-speed traveling control device that enables and avoids undershoot of vehicle speed. This constant speed travel control device estimates a travel resistance value from the current engine torque and the current vehicle acceleration, and based on the speed error between the current vehicle speed and the target vehicle speed and the travel resistance value, the target throttle valve opening degree Is determined, and the throttle valve opening degree of the negative pressure type throttle actuator is feedback-controlled to the target throttle valve opening degree to perform constant speed running control. The constant speed traveling control device initializes output corresponding to the actuator response dead time until the negative pressure in the diaphragm of the negative pressure type throttle actuator reaches a predetermined negative pressure corresponding to the target throttle valve opening at the start of constant speed traveling control. Initialization output time calculation means for calculating time, and feedback inhibition means for prohibiting feedback control of the throttle valve opening until the initialization output time elapses.

According to the constant speed traveling control device disclosed in Patent Document 1, it is possible to reach the target throttle valve opening in a short time and to avoid undershoot of the vehicle speed.
JP-A-6-270714

  Incidentally, the traveling resistance can be estimated by calculating the driving force of the vehicle for maintaining the vehicle speed when the vehicle is traveling at a constant speed. However, there is a problem that the running resistance cannot be estimated at the time of the vehicle transition such as when the vehicle is accelerated or decelerated. Although it is conceivable that the running resistance is used for cruise control, vehicle attitude control, and the like, there is a problem that proper control cannot be performed unless the running resistance during transition can be estimated.

  In the constant speed traveling control device disclosed in Patent Document 1, the traveling resistance is estimated from the engine torque, the vehicle weight, and the acceleration, but the torque consumed in the inertia system of the engine is not taken into consideration. It is impossible to accurately estimate the running resistance at the time of vehicle transition.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a resistance estimation device that can estimate a running resistance even when a vehicle is in transition.

  A resistance estimation device according to a first invention is a resistance estimation device that estimates a running resistance of a vehicle. The resistance estimation device calculates a first driving force in the driving wheel based on a means for detecting the rotational speed of the engine mounted on the vehicle, and the detected rotational speed and the moment of inertia in the output shaft of the engine. For calculating the second driving force in the drive wheel based on the detected rotation speed and the inertia moment of the vehicle in the drive wheel And means for estimating the running resistance based on the difference between the first driving force and the second driving force.

  According to the first invention, the estimating means includes the first driving force in the driving wheel calculated based on the engine speed and the moment of inertia in the output shaft, the wheel speed and the inertia moment of the vehicle in the driving wheel. Based on the difference from the second driving force calculated based on the driving resistance, the running resistance is estimated. The second driving force calculated based on the rotational speed of the wheel and the inertia moment of the vehicle in the driving wheel indicates a substantial driving force during the traveling of the vehicle. On the other hand, the first driving force calculated from the rotational speed of the engine and the moment of inertia in the output shaft is the driving force that is assumed to be expressed in the drive wheels by the torque output from the engine being transmitted through the power transmission path. Show. Therefore, the difference between the first driving force and the second driving force corresponds to the running resistance of the vehicle. Since the first driving force and the second driving force are calculated based on the moment of inertia of the engine or the vehicle, not only at the time of constant speed traveling, but also at the time of transition including acceleration or deceleration of the vehicle, The running resistance can be calculated. Therefore, it is possible to provide a resistance estimation device that can estimate the running resistance even when the vehicle is in transition.

  In the resistance estimation device according to the second invention, in addition to the configuration of the first invention, the calculating means calculates the output shaft torque of the engine based on the detected rotational speed and the moment of inertia of the engine. And means for calculating the first driving force of the driving wheel based on the output shaft torque and the reduction ratio in the power transmission path from the output shaft to the driving wheel.

  According to the second invention, the calculation means calculates the output shaft torque of the engine based on the detected engine speed and moment of inertia. That is, the torque consumed to rotate the output shaft can be calculated based on the amount of change in the engine speed based on the detected engine speed, that is, the angular acceleration of the output shaft and the inertia moment of the engine. . Therefore, based on the engine output shaft torque corresponding to the engine speed, the loss associated with the operation of the engine (for example, friction loss and pumping loss), and the torque consumed by the moment of inertia of the engine, The substantial torque output from the output shaft can be calculated. Based on the calculated output shaft torque and the reduction ratio in the power transmission path from the output shaft to the drive wheels, it is possible to calculate the first drive force that is assumed to be generated in the drive wheels.

  In the resistance estimation device according to the third invention, in addition to the configuration of the first invention, an automatic transmission including a torque converter and a transmission mechanism is mounted on the vehicle. The calculating means includes means for calculating the output shaft torque of the engine based on the detected rotational speed and the moment of inertia of the engine when the torque converter is not in the lock-up state, and the output shaft torque of the engine and the torque converter. Based on the torque ratio of the automatic transmission, based on the means for calculating the output shaft torque of the automatic transmission, the output shaft torque of the automatic transmission and the reduction ratio in the power transmission path from the automatic transmission to the drive wheels, Means for calculating a first driving force of the driving wheel.

  According to the third invention, the calculating means calculates the output shaft torque of the engine based on the detected engine speed and moment of inertia. Based on the amount of change in the engine speed based on the detected engine speed, that is, the angular acceleration and the moment of inertia of the engine, it is possible to calculate the consumption torque consumed when the output shaft is rotated. Therefore, based on the engine shaft torque corresponding to the engine speed, the loss associated with the operation of the engine (for example, friction loss and pumping loss), and the torque consumed by the moment of inertia of the engine, The substantial output shaft torque output from the output shaft can be calculated. Further, in a vehicle equipped with an automatic transmission, when the torque converter included in the automatic transmission is not in the lock-up state, the torque input to the input shaft of the torque converter and the torque output from the output shaft of the torque converter The torque ratio corresponds to the speed ratio between the input shaft and the output shaft. Therefore, if the torque converter is not in the lock-up state, the torque output from the output shaft of the torque converter can be calculated based on the output shaft of the engine and the torque ratio of the torque converter. Therefore, it is possible to calculate the first driving force that is assumed to be generated in the drive wheels based on the torque output from the output shaft of the torque converter and the reduction ratio in the power transmission path from the speed change mechanism to the drive wheels. it can.

  In the resistance estimation device according to the fourth invention, in addition to the configuration of any one of the first to third inventions, a braking device is mounted on the vehicle. The estimating means includes means for estimating the running resistance when the braking device is not operating.

  According to the fourth aspect of the invention, when the braking device mounted on the vehicle is activated, the calculated running resistance includes the braking force that is generated in the braking device when the running resistance is calculated. Therefore, when the braking device is not operating, the running resistance can be estimated with high accuracy by estimating the running resistance excluding the braking force.

  The resistance estimation device according to the fifth aspect of the invention further includes means for detecting the speed of the vehicle in addition to the configuration of any one of the first to fourth aspects of the invention. The estimating means includes means for estimating the running resistance when the change amount of the vehicle speed is equal to or less than a predetermined change amount.

  According to the fifth aspect of the present invention, when the amount of change in the speed of the vehicle is equal to or less than a predetermined amount of change, that is, when the vehicle travels at a constant speed, the running resistance is estimated accurately. can do.

  In the resistance estimation device according to the sixth invention, in addition to the configuration of any one of the first to fifth inventions, the estimation means estimates the running resistance when the supply of fuel to the engine is stopped. Means for.

  According to the sixth aspect of the invention, when the fuel supply to the engine is stopped, the vehicle is in a state where no driving force is expressed, that is, a state where the vehicle is decelerated due to running resistance. In such a case, the running resistance can be accurately estimated by estimating the running resistance.

  Hereinafter, a vehicle resistance estimation apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

A vehicle power train including the control device according to the present embodiment will be described. The vehicle control apparatus according to the present embodiment is realized by a program executed by an ECU (Electronic Control Unit) 1000 shown in FIG. In the present embodiment, the automatic transmission is described as an automatic transmission having a gear-type transmission mechanism that includes a torque converter as a fluid coupling.

  With reference to FIG. 1, a power train of a vehicle including a control device according to the present embodiment will be described. Specifically, the control device according to the present embodiment is realized by ECT (Electronic Controlled Automatic Transmission) _ECU 1020 shown in FIG.

  As shown in FIG. 1, the power train of this vehicle includes an engine 100, a torque converter 200, an automatic transmission 300, and an ECU 1000.

  The output shaft of engine 100 is connected to the input shaft of torque converter 200. Engine 100 and torque converter 200 are connected by a rotating shaft. Therefore, output shaft rotational speed NE (engine rotational speed NE) of engine 100 detected by the engine rotational speed sensor and input shaft rotational speed (pump rotational speed) of torque converter 200 are the same.

  The torque converter 200 has a lock-up clutch that directly connects the input shaft and the output shaft, a pump impeller on the input shaft side, a turbine impeller on the output shaft side, and a one-way clutch, and exhibits a torque amplification function. It consists of a stator. Torque converter 200 and automatic transmission 300 are connected by a rotating shaft. The output shaft rotational speed NT (turbine rotational speed NT) of the torque converter 200 is detected by a turbine rotational speed sensor. The output shaft rotational speed NOUT of the automatic transmission 300 is detected by an output shaft rotational speed sensor.

Such an automatic transmission 300 includes a plurality of friction elements such as clutches and brakes. Based on a predetermined operation table, clutch elements (for example, clutches C1 to C4) that are friction elements, brake elements (for example, brakes B1 to B4), and one-way clutch elements (for example, one-way clutches F0 to F3) are required. The hydraulic circuit is controlled so as to be engaged and released corresponding to each gear stage. Shift positions (shift positions) of the automatic transmission 300 include a parking (P) position, a reverse travel (R) position, a neutral (N), and a forward travel (D) position.

  The ECU 1000 that controls these power trains includes an engine ECU 1010 that controls the engine 100 and an ECT_ECU 1020 that controls the automatic transmission 300.

  ECT_ECU 1020 receives a signal representing output shaft rotational speed NOUT detected by the output shaft rotational speed sensor. ECT_ECU 1020 receives an engine speed signal representing engine speed NE detected by the engine speed sensor from engine ECU 1010. Further, ECT_ECU 1020 receives a signal representing turbine rotational speed NT detected by a turbine rotational speed sensor of the torque converter.

  These rotation speed sensors are provided to face the teeth of the rotation detection gear attached to the input shaft of torque converter 200, the output shaft of torque converter 200, and the output shaft of automatic transmission 300. These rotational speed sensors are sensors that can detect slight rotations of the input shaft of the torque converter 200, the output shaft of the torque converter 200, and the output shaft of the automatic transmission 300. This is a sensor using a magnetoresistive element.

  Further, ECT_ECU 1020 outputs an engine control signal (for example, a throttle opening signal) to engine ECU 1010, and engine ECU 1010 controls engine 100 based on the engine control signal and other control signals. ECT_ECU 1020 outputs a lockup clutch control signal for torque converter 200. Based on this lockup clutch control signal, the engagement pressure of the lockup clutch is controlled. The ECT_ECU 1020 outputs a solenoid control signal to the automatic transmission 300. Based on this solenoid control signal, the linear solenoid valve, the on-off solenoid valve, etc. of the hydraulic circuit of the automatic transmission 300 are controlled, and friction is established so as to constitute a predetermined speed gear stage (for example, first speed to fifth speed). The engagement element is controlled to be engaged and released.

  The ECT_ECU 1020 receives a signal representing the opening of the accelerator pedal operated by the driver from the accelerator opening sensor 2100 via the engine ECU 1010. ECU 1000 has a memory in which various data (threshold values, shift maps, etc.) and programs are stored.

  The vehicle resistance estimation apparatus according to the present invention is realized by an engine ECU 1010. In the present invention, engine ECU 1010 detects a driving force (1) in a driving wheel (not shown) calculated based on the number of revolutions of engine 100 and the moment of inertia of the engine output shaft, and wheel speed sensor 2200. It is characterized in that the running resistance is estimated by calculating the difference between the driving force (2) in the driving wheel calculated based on the rotation speed and the inertia moment of the vehicle in the driving wheel.

  The inertia moment of the vehicle and the inertia moment of the engine may be obtained experimentally. For example, the moment of inertia at the output shaft of engine 100 is based on the relationship between the rotational speed and the friction loss as shown in FIG. 2 (A) and the time variation of the rotational speed of engine 100 as shown in FIG. 2 (B). Can be calculated based on this. That is, the relationship between the rotational speed of the engine 100 and the friction loss is determined by calculating R (1) corresponding to NE (1) and R (2) corresponding to NE (2) through experiments, as shown in FIG. A relationship as shown in A) can be derived. Further, an experiment for stopping the fuel supply from the predetermined rotational speed NE (3) of the engine 100 can lead to a temporal change in the rotational speed of the engine 100 as shown in FIG. The moment of inertia of the engine can be calculated by the following equation: R (friction loss) = I (moment of inertia of engine 100) × ΔNE (amount of change in rotational speed). Therefore, as shown in FIG. 2 (B), the amount of change ΔNE in the rotational speed during the time interval Δt is calculated, and the friction loss R at the rotational speed during Δt is derived from FIG. The moment of inertia can be calculated.

  Further, the inertia moment of the vehicle and the inertia moment of the engine may be approximately calculated based on element information (for example, dimensions and weight) of each component constituting the vehicle and the engine, The calculation may be performed by CAE (Computer Aided Engineering) analysis, and the calculation method of the moment of inertia of the vehicle and the engine may be a known technique and is not particularly limited. Preferably, when the automatic transmission 300 has a stepped transmission mechanism, it is desirable to calculate in advance the moment of inertia of the vehicle corresponding to the shift stage. For example, when the vehicle starts when the shift position is the first speed and when the vehicle starts when the shift position is the second speed, the gear ratio and the power transmission path are different, so the inertia moment of the vehicle in the drive wheels is also different. is there. When the automatic transmission 300 has a continuously variable transmission mechanism, a map indicating the relationship between the transmission gear ratio (gear ratio) and the inertia moment of the vehicle may be stored in advance.

  In the following description, a resistance estimation device realized by hardware (arithmetic circuit) of engine ECU 1010 will be described, but may be realized by a program (software) executed by engine ECU 1010 instead of hardware.

  Hereinafter, with reference to FIG. 3, a description will be given of a case where engine ECU 1010, which is a vehicle estimation device according to the present embodiment, calculates travel resistance.

  Engine ECU 1010 includes a shaft torque calculator 102. The shaft torque calculator 102 outputs an engine shaft torque corresponding to a value obtained by subtracting the pumping loss and the friction loss of the engine 100 from the indicated torque to the engine output calculator 110 described later. The indicated torque indicates torque calculated from a map showing the relationship among shaft torque, engine speed, and intake air amount.

  Engine ECU 1010 further includes a multiplier 104, a differentiator 106, a consumption torque calculator 108, and an engine output calculator 110. Multiplier 104 is a coefficient K for converting the unit of revolution (rpm) into the unit of angular velocity (rad / s or deg / s) to the number of revolutions of engine 100 corresponding to the revolution number detection signal transmitted from engine 100. The value multiplied by is output to the differentiator 106. The differentiator 106 outputs an angular acceleration corresponding to a value obtained by time differentiation of the value input from the multiplier 104 to the consumed torque calculator 108. Consumed torque calculator 108 outputs to engine output calculator 110 the consumed torque of the engine inertia system corresponding to the value obtained by multiplying the angular acceleration input from differentiator 106 by the moment of inertia of engine 100.

  The engine output calculator 110 outputs the difference between the engine shaft torque input from the shaft torque calculator 102 and the consumed torque due to the inertia system of the engine 100 input from the consumed torque calculator 108 as the output torque of the engine 100. .

  Engine ECU 1010 further includes a speed ratio calculator 112 and a torque ratio calculator 114. The speed ratio calculator 112 receives the engine speed corresponding to the engine speed detection signal transmitted from the engine 100 and the turbine speed of the torque converter 200. Speed ratio calculator 112 calculates a speed ratio based on the rotational speed of engine 100 and the turbine rotational speed, and outputs the speed ratio to torque ratio calculator 114. The torque ratio calculator 114 calculates a torque ratio based on the speed ratio input from the speed ratio calculator 112 and a map stored in advance showing the relationship between the speed ratio and the torque ratio, which will be described later. Output to the converter output calculator 116.

  Engine ECU 1010 further includes a converter output calculator 116 and a multiplier 118. The converter output calculator 116 outputs a value obtained by multiplying the engine output torque input from the engine output calculator 110 by the torque ratio input from the torque ratio calculator 114 to the multiplier 118 as an output torque of the torque converter. Multiplier 118 is a running resistance calculator which will be described later with the output torque of the wheel shaft corresponding to a value obtained by multiplying the output torque of the torque converter input from converter output calculator 116 by a coefficient A converted into the output torque of the wheel shaft. 120 is output. The coefficient A is set based on the reduction ratio in the power transmission path from the output shaft of the torque converter 200 to the drive wheels. Therefore, when the automatic transmission 300 has a stepped transmission mechanism, the coefficient A is set to a different value depending on the shift stage. When the automatic transmission 300 has a continuously variable transmission mechanism, the relationship between the reduction ratio based on the ratio (speed ratio) between the turbine rotation speed and the output shaft rotation speed of the automatic transmission 300 and the coefficient A is shown. The map may be stored in advance.

  Engine ECU 1010 further includes a multiplier 202, a differentiator 204, and a wheel shaft torque calculator 206. The multiplier 202 multiplies the wheel speed detected by the wheel speed sensor 2200 by a coefficient K for converting the wheel speed unit (rpm) into the angular speed unit (rad / s or deg / s). Output to. The differentiator 204 outputs a value obtained by differentiating the angular velocity input from the multiplier 200 with respect to time, that is, angular acceleration, to the wheel shaft torque calculator 206. The wheel axis torque calculator 206 outputs a wheel axis torque corresponding to a value obtained by multiplying the angular acceleration input from the differentiator 204 by the moment of inertia of the vehicle in the drive wheels to the travel resistance calculator 120 described later.

  Engine ECU 1010 further includes a running resistance calculator 120. The travel resistance calculator 120 calculates the difference between the wheel shaft output torque input from the multiplier 118 and the wheel shaft torque input from the wheel shaft torque calculator 206. The running resistance calculator 120 outputs a running resistance corresponding to the calculated torque.

  An operation of engine ECU 1010 that is the vehicle resistance estimation device according to the present embodiment based on the above configuration will be described.

  During acceleration of the vehicle, the angular acceleration of the output shaft of engine 100 is calculated based on the detected engine speed. The consumption torque of the inertia system of the engine is calculated by multiplying the calculated angular acceleration and the inertia moment of the engine 100. Therefore, by subtracting the consumption torque of the engine inertia system from the engine shaft torque calculated by subtracting the friction loss and the pumping loss accompanying the operation of the engine 100 from the indicated torque, a substantial output torque of the engine 100 is obtained. Is calculated.

  Further, the output shaft of engine 100 is connected to the input shaft of torque converter 200. Therefore, the output torque output from torque converter 200 is calculated by multiplying the output torque of engine 100 by the torque ratio calculated according to the speed ratio between the engine speed and the turbine speed. The output torque output from the torque converter 200 is multiplied by a coefficient A based on the speed reduction ratio in the power transmission path from the automatic transmission 300 to the drive wheel to calculate the output torque of the wheel shaft in the drive wheel. At this time, the output torque of the wheel shaft is calculated using a coefficient A corresponding to the ratio (speed ratio) between the gear position of the automatic transmission 300 or the turbine rotational speed and the output shaft rotational speed of the automatic transmission 300.

  On the other hand, the angular acceleration of the wheel shaft is calculated based on the detected wheel speed. The wheel shaft torque is calculated by multiplying the calculated cuck acceleration and the inertia moment of the vehicle at the drive wheel. At this time, the wheel shaft torque is calculated by using the inertia moment of the vehicle corresponding to the ratio between the gear position of the automatic transmission 300 or the turbine rotational speed and the output shaft rotational speed of the automatic transmission 300.

  Then, the wheel shaft torque expressed in the drive wheel based on the output torque of the wheel shaft assumed to be expressed in the wheel shaft based on the rotation speed of the engine 100 and the wheel speed detected by the wheel speed sensor 2200. The difference between and corresponds to the running resistance.

  In the above description, the vehicle running resistance when the torque converter 200 is not in the lock-up state has been described. However, when the torque converter 200 is in the lock-up state, the rotational speed of the input shaft and the output shaft of the torque converter 200 are described. The number of revolutions is the same. Therefore, the torque ratio in the torque converter 200 may be calculated as “1”, or the engine ECU 1010 receives the signal indicating that the torque converter 200 is in the lockup state from the ECT_ECU 1020. The ECU 1010 may calculate the running resistance using a configuration as shown in FIG.

  That is, the engine ECU 1010 includes a speed ratio calculator 112 as shown in FIG. 4 in comparison with the configuration in which the engine ECU 1010 calculates the running resistance when the torque converter 200 described with reference to FIG. The torque ratio calculator 114 and the converter output calculator 116 are not necessary.

  Therefore, the engine output calculator 110 corresponds to a value obtained by subtracting the consumption torque of the inertia system of the engine 100 input from the consumption torque calculator 108 from the engine shaft torque input from the shaft torque calculator 102. The output torque is output to the multiplier 118. Multiplier 118 outputs a wheel shaft output corresponding to a value obtained by multiplying the input output torque of engine 100 by a coefficient A converted to an output torque of the wheel shaft to running resistance calculator 120. Even when the configuration as shown in FIG. 4 is used, it is possible to calculate the running resistance of the vehicle when the torque converter 200 is in the lock-up state.

  As described above, according to the vehicle resistance estimation device according to the present embodiment, the wheel shaft torque calculated based on the wheel speed and the inertia moment of the vehicle in the drive wheel is substantially equal to the vehicle traveling. Indicates driving force. On the other hand, the wheel shaft output torque calculated from the engine speed and the moment of inertia of the output shaft is the torque that is output from the engine through the power transmission path and is assumed to be generated in the drive wheels. Show. Therefore, the difference between the output torque of the wheel shaft and the wheel shaft torque corresponds to the running resistance of the vehicle. Since the wheel shaft output torque and wheel shaft torque are calculated based on the moment of inertia of the engine or vehicle, not only during constant speed travel, but also during transitions such as when the vehicle is accelerating or decelerating, the running resistance Can be calculated. Therefore, it is possible to provide a resistance estimation device that can estimate the running resistance even when the vehicle is in transition.

  Also, the consumption torque consumed when the output shaft is rotated is calculated based on the change amount of the engine rotation speed based on the detected engine rotation speed, that is, the angular acceleration of the output shaft and the inertia moment of the engine. it can. Therefore, based on the engine shaft torque corresponding to the engine speed, the loss associated with the operation of the engine (for example, friction loss and pumping loss), and the consumption torque consumed by the engine inertial system, The substantial output torque output from can be calculated. Based on the calculated output shaft torque and the reduction ratio in the power transmission path from the output shaft to the drive wheel, the output torque of the wheel shaft that is assumed to be developed in the drive wheel can be calculated.

  Preferably, the engine ECU estimates the running resistance when a braking device (not shown) mounted on the vehicle is not operating. When the braking device mounted on the vehicle is operated, when the traveling resistance is estimated, the estimated traveling resistance includes a braking force expressed in the braking device. Therefore, when the braking device is not operating, the running resistance can be accurately estimated by estimating the running resistance excluding the braking force.

  More preferably, the engine ECU estimates the running resistance when the change amount of the vehicle speed is equal to or less than a predetermined change amount. When the amount of change in the speed of the vehicle is equal to or less than a predetermined amount of change, that is, when the vehicle is traveling at a constant speed, the traveling resistance can be estimated accurately by estimating the traveling resistance. .

  More preferably, the engine ECU estimates the running resistance when the fuel supply to the engine is stopped. When the supply of fuel to the engine is stopped, the vehicle is in a state where no driving force is expressed, that is, a state where the vehicle is decelerated due to running resistance. In such a case, the running resistance can be accurately estimated by estimating the running resistance.

  Therefore, the conditions for estimating the running resistance (the conditions for improving the accuracy as described above, the time interval for performing the estimation, etc.) are narrowed down according to the accuracy of the running resistance required when controlling the behavior of the vehicle. Thus, it is possible to estimate the running resistance with the accuracy required for the applied vehicle control.

  Preferably, it is desirable to calculate the running resistance by applying the configuration shown in FIG. 4 to a vehicle equipped with a manual transmission. The manual transmission is directly connected from the output shaft of the engine to the input shaft of the transmission mechanism via a clutch. Therefore, when the engine ECU has the configuration as shown in FIG. 4, it is possible to estimate the running resistance of the vehicle on which the manual transmission is mounted.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a figure which shows the structure of the vehicle by which engine ECU which is a control apparatus of the engine which concerns on this Embodiment is mounted. It is a figure which shows the relationship between an engine speed and friction loss, and the time change of an engine speed. It is a block diagram (the 1) of engine ECU which is an engine control apparatus which concerns on this Embodiment. It is a block diagram (the 2) of engine ECU which is an engine control apparatus which concerns on this Embodiment.

Explanation of symbols

  100 engine, 102 shaft torque calculator, 104, 118, 202 multiplier, 106, 204 differentiator, 108 consumption torque calculator, 110 engine output calculator, 112 speed ratio calculator, 114 torque ratio calculator, 116 converter output Calculator, 120 Travel resistance calculator, 200 Torque converter, 206 Wheel shaft torque calculator, 300 Automatic transmission, 1000 ECU, 1010 Engine ECU, 1020 ECT_ECU, 2100 Accelerator opening sensor, 2200 Wheel speed sensor.

Claims (6)

A resistance estimation device for estimating a running resistance of a vehicle,
Means for detecting the rotational speed of an engine mounted on the vehicle;
Calculation means for calculating a first driving force in the drive wheel based on the detected rotational speed and the moment of inertia in the output shaft of the engine;
Means for detecting the rotational speed of the wheel;
Means for calculating a second driving force in the driving wheel based on the detected number of revolutions and a moment of inertia of the vehicle in the driving wheel;
A resistance estimation device comprising: an estimation means for estimating the running resistance based on a difference between the first driving force and the second driving force. The calculating means includes
Means for calculating an output shaft torque of the engine based on the detected rotational speed and the moment of inertia of the engine;
The means for calculating the first driving force of the driving wheel based on the output shaft torque and a reduction ratio in a power transmission path from the output shaft to the driving wheel. Resistance estimation device. The vehicle is equipped with an automatic transmission including a torque converter and a transmission mechanism,
In the case where the torque converter is not in a lock-up state, the calculating means
Means for calculating an output shaft torque of the engine based on the detected rotational speed and the moment of inertia of the engine;
Means for calculating an output shaft torque of the automatic transmission based on an output shaft torque of the engine and a torque ratio of the torque converter;
Means for calculating a first driving force of the drive wheel based on an output shaft torque of the automatic transmission and a reduction ratio in a power transmission path from the automatic transmission to the drive wheel. Item 2. The resistance estimation apparatus according to Item 1. The vehicle is equipped with a braking device,
The resistance estimating apparatus according to claim 1, wherein the estimating means includes means for estimating the running resistance when the braking device is not operating. The resistance estimation device further includes means for detecting the speed of the vehicle,
5. The resistance estimation according to claim 1, wherein the estimating means includes means for estimating the running resistance when a change amount of the speed of the vehicle is equal to or less than a predetermined change amount. apparatus.   The resistance estimating apparatus according to claim 1, wherein the estimating means includes means for estimating the running resistance when fuel supply to the engine is stopped.

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