EP2841290A1

EP2841290A1 - Hydraulic hybrid

Info

Publication number: EP2841290A1
Application number: EP13709764.8A
Authority: EP
Inventors: Ralf Kochhan; Taghi Akbarian
Original assignee: Deutz AG
Current assignee: Deutz AG
Priority date: 2012-04-26
Filing date: 2013-03-02
Publication date: 2015-03-04
Also published as: DE102012008192A1; US20150113969A1; JP6346168B2; WO2013159851A1; US10040343B2; JP2015533201A

Abstract

Hybrid system, consisting of an internal combustion engine (1) with attached and/or integrated hydraulic pumps (2) for supplying consumers (5) and/or a drive unit (12), at least one engine control device (3) for electronic engine and/or injection regulation, at least one hydraulics control device (4) for controlling at least one hydraulic consumer (5), at least one pressure retention valve (6), at least one changeover valve (7) and at least one hydraulic pressure accumulator (8).

Description

hydraulic hybrid

DESCRIPTION

Hydrostatic drive machines consist of an internal combustion engine, several hydraulic pumps, lines, valves, controls, motors and hydraulic cylinders. Such systems are for. B. known from DE 1020 09 824 B4. The excess energy is stored in an electric battery.

This is disadvantageous in that additional batteries and other electric motors are required to use the excess energy; furthermore, these systems only consider the hydraulic side.

The object of the present invention is to obviate the above drawbacks and to provide a hybrid system which efficiently bypasses existing inventories, particularly with regard to optimizing the operating points of the engine with particular regard to fuel consumption, dynamic engine behavior, noise level and wear.

The object is achieved by a hybrid system according to claim 1 or by a method according to claim 10.

To optimize these machines, the excess energy or engine power is stored in lean load phases of the internal combustion engine for dispensing or increasing the available system power, in phases with high or excessive power requirements in hydraulic accumulators. The optimization consists in the fact that for a short time more power is available in the system than the combustion engine can deliver at the current operating point. Therefore, the system is more powerful and the behavior is more dynamic under load changes. At the same time, by recovering braking energy, the braking power of the system or of the engine can be increased, and the engine's towing can be avoided or reduced. The occurring maximum speeds on the internal combustion engine can be significantly reduced. In low load phases, the free engine power is then available for the storage charging.

Provided according to the invention is a system for detecting the state or the state values of the engine, the hydraulics and the devices on the one hand, and a subsystem for engine power braking effect optimization by means of hydraulic energy storage, for. B. pressure accumulator in the form of bladder or diaphragm accumulators or piston accumulators, on the other.

The system consists of an internal combustion engine with built-in or integrated hydraulic pumps for working and / or driving circuit, an engine control unit for electronic engine and injection control, a hydraulic control unit for controlling the hydraulic consumers, hydraulic control modules, actuators and valves, a pressure-holding valve, at least one reversing valve and at least one hydraulic pressure accumulator.

The engine control unit records engine-specific measured values. These include the coolant temperature, the charge air pressure, the load torque, the injection quantity, the engine speed, the rail pressure, the fuel pressure and the speed setpoint. On the basis of these measured values, manipulated variables for motor control are determined in the control unit with the help of parameters, characteristic curves and maps. The respective operating point of the motor is determined and set in this way. In the system shown here in FIG. 1, the engine control unit has further measured values such as the hydraulic pressure in the hydraulic accumulator, the hydraulic pressure and temperature of the working circuit, the hydraulic pressure and temperature of the traction drive, and the swivel angle of the working and driving pumps. From the hydraulic control unit information about the state, such. As the operating point, the respective hydraulic components and the requested load supplied by the components to the engine control unit. In the engine control unit, the control of the charging and discharging processes of the pressure accumulator takes place as required in dependence on the above-mentioned data.

The charging (Loading, Fig. 2) of the memory is initiated by opening the valve A in the working group and / or the valve B in the driving circle. The control is effected in dependence on the ratio of the hydraulic pressures to Pspeise P _Sp Eicher of the torques M _ver fügbar _st to _M) and in function of the engine temperature T _K, and the hydraulic temperature T _Sp else. as shown in Figure 2.

If the given conditions are fulfilled, the engine control unit checks on the basis of further characteristic values whether a loading (FIG. 2) makes sense.

Brake Energy Regeneration

If the engine is towed, ie M | _St is negative, then the complete power of the engine plus the braking power for loading (Figure 2) is available. The valve A and / or the valve B are opened until the memory is loaded or one of the requirements is no longer met. If the engine speed is higher than the target speed, ie n _as _n <n, then the full available power is (M _ver fügbar - M | _St) for Loading (Fig. 2) are available. The valve A and / or the valve B are opened until the memory is charged, or one of the conditions is no longer met. Is the engine idling and the coolant temperature above a minimum temperature n | _St = n _blank and T '> T _min, then is the complete available power (M _ver fügbar - M | _St) (Fig. 2) for Loading available valve A and / or valve B are open until the store is loaded or one of the prerequisites is no longer met.

Is the engine in a light load phase and the available torque is significantly higher than M | _St , then the loading (Fig.2). In addition, the loading (FIG. 2) may be activated or deactivated by the engine control unit when the engine is in an unfavorable operating point, e.g. B. with regard to the fuel consumption, the emission behavior, the boost pressure, the noise level and the measured values and information of the hydraulic control unit is located and can be achieved by switching the function of a more suitable operating point.

Alternatively, the loading (FIG. 2) can also be steplessly regulated via a control valve in order to realize a gentler switching on / off of the engine load.

The discharge (Boost, Fig. 3) of the memory is initiated by opening the valve A in the working group and / or the valve B in the circle. The control is effected in dependence on the ratio of the hydraulic pressures to Pspeise P _Sp Eicher of the torques M F _O _ver gbar to M | _St and as a function of the engine temperature T _K, and the hydraulic temperature T _Sp eise-

If the specified conditions are fulfilled, the engine control unit checks on the basis of further characteristic values whether a boost (FIG. 3) makes sense.

Can the motor deliver no more power at the current operating point, ie Mavailable = f ^■ M | _st (f = safety factor, eg 0.9), then valve A and / or valve B is opened until the accumulator is discharged, or one of the conditions is no longer fulfilled. Is the engine in the smoke or other power limitation, ie M _V available = f ^■ M | _St (f = safety factor, eg 0.9), valve A and / or valve B is opened until the accumulator is discharged, or one of the requirements is no longer met.

If the engine (1) greatly accelerated, ie n _Gra is> N (adjustable speed gradient), valve A and / or valve B is opened until the memory is discharged, or one of the requirements is no longer met.

At high pressure drop of the feed pressure by fast load switching in the hydraulic circuit, d. H. PGradient> P (adjustable feed pressure gradient factor), valve A and / or valve B will be opened until the tank is discharged or one of the requirements is no longer met.

In addition, boosting (Figure 3) may be activated / deactivated by the engine control unit when the engine is operating at an unfavorable operating point (eg, with respect to such parameters as fuel economy, emissions, boost pressure, noise level, readings, and hydraulic controller information ) and by switching the function a more suitable operating point can be achieved.

The reduction of the working speed for optimum fuel consumption optimization is illustrated, for example, in FIG.

At high dynamic requirements, engine speeds in the range of about 1800-2,300 rpm near the engine power maximum are required to have sufficient torque reserves at the inevitable speed drops, an increase in torque curve at decreasing speeds in this range of speeds is Episode. In addition, expensive limit load controls must be provided to prevent stalling of the engine. If the working speed is reduced in the range of the nominal torque of the engine from about 1400 to 1600 rpm, the sudden dynamic load peaks can be optimally absorbed by boosting (FIG. 4).

The reduction of the working speed for noise reduction is shown in FIG.

At high dynamic requirements, engine speeds in the range of about 1800 - 2300 rpm near engine power maximum are necessary to have sufficient torque reserves at the inevitable speed drops available, an increase in torque curve with decreasing speeds in this speed range is the result. In addition, expensive limit load controls must be provided to prevent stalling of the engine.

If the working speed is reduced in the range of the nominal torque of the engine from about 1400 to 1600 rpm, the sudden dynamic load peaks can be absorbed by boosting (FIG. 4).

The increase of the boost pressure is shown in FIG. In order to improve the dynamic behavior of the engine, in phases with a very low torque level, the loading function (FIG. 6) can be activated in order to increase the output torque and thus the boost pressure. This is typically done just before a large torque request is required by the hydraulics. Due to the associated increase in boost pressure, the turbocharger reacts much better when the hydraulic load is applied. To relieve the engine also the boost function (Fig. 1, Fig. 5) can be activated and at the same time the reversing valve 7 are opened. Then, the hydraulic pump 2 acts as a motor and can significantly improve the dynamic behavior of the overall system by providing the crankshaft of the internal combustion engine 1 or its ring gear on the flywheel. stored energy from the hydraulic accumulator 8 in the internal combustion engine 1 initiates.

In an alternative embodiment, the boosting via a control valve can also be controlled continuously to realize a smoother turning on / off of the engine load.

A starter support (Starting) can also be done via the stored energy in the hydraulic accumulator 8 by means of the hydraulic pump 2.

The unloading of the memory is initiated by opening the valve A in the working group and / or the valve B in the car.

The control is Pspeise to P _Sp eicher depending on the ratio of the hydraulic pressures of the torques M _ver fügbar to M | _St and depending on the engine temperature T "and the hydraulic _Spe temperature T ISE

If the engine speed is zero, valve A and / or B and the reversing valve are actuated and the hydraulic pump is used as a starter motor for the internal combustion engine.

In high base load applications, the energy from the accumulator (8) can be supplied in the same form to assist the starter in cranking the engine as long as the engine speed is less than the idle speed (n _{) st} <n _Lee r) -

The Starting support can take over an automatic Star Stop function. If the motor is idling for a parameterizable time t, the motor is then automatically stopped. If the engine speed is equal to zero and the driver / operator of the device steps on the accelerator pedal, valve A and / or valve B and the reversing valve 7 are actuated automatically and the hydraulic pump is used as a starter motor for the internal combustion engine 1. uses. This leads to high savings in fuel consumption. In addition, the start of the engine 1 happens without burdening the electric starter of the engine. The number of charging / discharging cycles of the hydraulic accumulator in the lifetime is usually higher than the number of possible starting operations in the electric starter.

Bring the engine to operating temperature faster

At cold ambient temperatures and very low engine load, the internal combustion engine only heats up very slowly to the actual operating temperature. In this cold phase, the wear of the engine is high and the fuel consumption is not optimal. By repeatedly charging / discharging the hydraulic accumulator dynamic loads can be generated, which bring the engine up to operating temperature faster. By applying the above-mentioned functionalities, the performance of the working machine can advantageously be increased, the fuel consumption and the wear of the engine are reduced and the engine utilization is optimized. Due to the temporary extra power, downsizing can be carried out, which means as much as, an engine with less displacement can be used, which is energetically more favorable.

The application principle can be used in all systems with combustion or gas engine in conjunction with hydraulic consumers and hydrostatic drives.

Abbreviations

Feed = pressure in the hydraulic supply circuit

Accumulator = pressure in hydraulic accumulator

Tspeise = temperature in the hydraulic supply circuit

T _max = maximum permissible temperature in the hydraulic accumulator

T _min = minimum permissible temperature in the hydraulic accumulator

ni _st = current speed of the internal combustion engine

n _so n = current setpoint speed of the engine

n _Lee r = idling speed of the internal combustion engine Mavailable = currently available maximum torque of the

internal combustion engine

M | _St = currently delivered torque of the internal combustion engine T _K = coolant temperature of the internal combustion engine

T _max = maximum permissible coolant temperature for function T _min = minimum permissible coolant temperature for function riGradient = speed gradient

PGradient = gradient feed pressure

reference numeral

1 internal combustion engine

2 hydraulic pump

3 consumers

4 hydraulic control unit

5 consumers

6 pressure relief valve

7 reversing valve

8 accumulator

9 control module

10 actuator

11 valve

12 drive unit

13 temperature sensor

14 pressure sensor

15 pressure sensor

16 pressure sensor

Claims

1. Hybrid system, comprising an internal combustion engine (1) with attached and / or integrated hydraulic pumps (2) for supplying consumers (5) and / or drive unit (12), at least one engine control unit (3) for electronic engine and / or injection control at least one hydraulic control unit (4) for controlling at least one hydraulic consumer (5), at least one pressure-maintaining valve (6), at least one reversing valve (7) and at least one hydraulic pressure accumulator (8).

2. hybrid system according to claim 1,

characterized in that the hydraulic consumer 5 by means of control module (9) is controllable.

3. hybrid system according to claim 1 or 2,

characterized in that the drive unit (12) by means of actuator (10) is designed to be communicable.

4. hybrid system according to one or more of the preceding claims, characterized in that the actuator (10) by means of Hydrauliksteuer- device (4) is designed to be communicable.

5. Hybrid system according to one or more of the preceding claims,

characterized in that the hydraulic accumulator (8) has at least one pressure sensor (14).

6. hybrid system according to one or more of the preceding claims,

characterized in that between the control module (9) and reversing valve (7), a pressure sensor is arranged.

7. Hybrid system according to one or more of the preceding claims,

characterized in that between the actuator (10) and hydraulic pump (2) a pressure sensor (16) is arranged.

8. hybrid system according to one or more of the preceding claims,

characterized in that the temperature sensor (13), the pressure sensor (14), the pressure sensor (15) and the pressure sensor (16) are arranged communicably with the engine control unit (3).

9. Method for Operating a Hybrid System

characterized in that a hydraulic system according to one or more of the preceding claims is used.

10. The method according to claim 9,

characterized in that the engine and machine state constantly monitored by said sensors and the loading and unloading of the hydraulic accumulator for optimizing the engine / machine dynamics and / or the load behavior is controlled.

11. The method according to claim 9,

characterized in that the engine and machine status constantly monitored by said sensors and the loading and unloading of the hydraulic accumulator to optimize the engine / engine dynamics and / or the load behavior is controlled in compliance with the emission behavior of the engine.