DE3521403A1 - Internal combustion engine with a supercharger - Google Patents

Abstract

The internal combustion engine (10) has a supercharger (23), which is driven by way of a hydrostatic transmission (12, 18). The pump (12) of the hydrostatic transmission is adjustable. It is actuated by an electronic control unit (28) to which at least the position of the accelerator pedal (25) and advantageously also the speed of the internal combustion engine (10) are fed. By appropriate programming of the control unit (28) it is possible to operate the supercharger so that the internal combustion engine is supercharged even at low speeds without the risk of overcharging in the upper speed range. <IMAGE>

Description

352U03

200 73

31.5. 1985 Wd / Kc

ROBERT BOSCH GMBH, 7OOO Stuttgart 1

Internal combustion engine with a charger prior art

The invention is based on an internal combustion engine according to the preamble of claim 1. Usually, the superchargers of internal combustion engines are directly from this or with the interposition of a mechanical transmission gear driven and regulated according to the speed of the internal combustion engine or the boost pressure. This has the disadvantage that the internal combustion engine is poorly charged at low speeds and that overloading can occur in the upper speed range.

Advantages of the invention

The machine according to the invention with the characteristic Features of the main claim has the advantage that it is charged even at low speeds can be and that the risk of overloading in the upper speed range by appropriate control or regulation of the loader is excluded. The boost pressure can be controlled depending on the pedal.

352U03

20073

Further advantageous refinements of the invention emerge from the subclaims.

drawing

An embodiment of the invention is shown in the drawing and explained in more detail in the following description. FIG. 1 shows a schematic representation of an internal combustion engine with a supercharger drive, FIGS. 2 and 3 slide grams.

Description of the embodiment

In FIG. 1, an internal combustion engine is designated by .10, which drives an adjustable pump 12 via a clutch 11. The actuator 13, which adjusts the delivery rate, is adjusted with the aid of an electric or hydraulic actuator Ii +. The pump sucks in pressure medium via a suction line 15 from a container λβ and conveys this via a pressure line 37 to a hydraulic motor 18. In the suction line 15, a so-called suction throttle 19 is arranged. A line 20 leads from the hydraulic motor 1-8 to the container or to the suction line behind the throttle 19.

The hydraulic motor drives a charger 23 via a mechanical transmission gear 22, which feeds compressed air to the internal combustion engine 10 via a pipe 2h.

The control of the boost pressure is essential. For this purpose, the position of the accelerator pedal 25 is controlled by an electrical Line 26 and the speed of the internal combustion engine also input to an electronic control unit 28 via an electrical line 27. Of this goes via an electrical line 29 to a signal

■ ■■ - £ -

-S-

Servomotor ik. From the position of the accelerator pedal 25 and the speed of the internal combustion engine, the boost pressure for the charger 23 is calculated and regulated in the electronic control unit 28. There are three types of control:

■ 1, With a sensor, the actual boost pressure is behind determined by the charger, compared in the electronics with the setpoint generated there and, in the event of deviations, the Pump adjusted to a larger or smaller flow rate. For this purpose, the pump adjustment can be controlled electrically Formed flow adjustment. If the actual boost pressure is less than the calculated target value, the pump is set to a higher flow rate adjusted. As a result, the speed of the hydraulic motor increases and thus the supercharger, and the boost pressure rises.

2. The open timing chain system works with less effort. The boost pressure sensor is dispensed with. The characteristic curve "boost pressure versus boost speed" is called viewed with sufficient accuracy. In the electronic control unit instead of the boost pressure setpoint, a setpoint for the boost speed is calculated using this characteristic curve, from this a setpoint for the flow rate of the pump. From the also known speed of the internal combustion engine The electronics now calculate the currently correct degree of adjustment of the pump and give the flow rate adjustment device this setpoint before,

3, It is also possible to use the boost pressure-drive pressure characteristic to use. The pressure in the hydrostatic drive circuit increases proportionally with the boost pressure (see Characteristic curve Figure 2), In the electronics, the setpoint for the boost pressure, the accelerator pedal position and engine speed is derived was derived, a setpoint for the pump pressure was determined and specified for the pump adjustment.

ORIGINAL INSPECTED

20073

This must be a pressure control with a variable, electrically controlled target value, as it was the state of Technology is. So that the drive reacts quickly enough to changes, a dynamic torque component must be used for acceleration or delaying the masses of the gearbox and loader. Appropriately happens this by adding in the control electronics for the drive pressure setpoint generation a strong D behavior is provided. This makes the setpoint for the pump pressure dynamic Excessive or undershot, the amount and duration of the excess depending on the rate of change of the setpoint depend. With this increase in pressure, the torque reserve is then made available for rapid acceleration of the masses .

The internal combustion engine is supercharged in the above manner even at low speeds without the risk of overloading in the upper speed range. The boost pressure is freely selectable; it can be controlled depending on the accelerator pedal. The risk of overloading in the upper speed range is also avoided in that the pump 12 is suction-throttled by the throttle 19, its flow rate at higher Speed remains constant. The inclusion of the charger in the engine map control is possible.

Claims (1)

20073 May 31, 1985 Wd / Κσ ROBERT BOSCH GMBH, 7OOO Stuttgart 1 Expectations \\ J internal combustion engine with a charger, characterized in that the drive of the charger (23) by a
hydrostatic transmission (12, 18) is carried out, the pump is designed as a variable displacement pump, which is driven by the internal combustion engine (10), that an electronic control unit (28) is provided, to which at least the position of the accelerator pedal (25) is entered and the the charge pressure is calculated from this value, and that the pump is also adjusted according to this determined value so that the necessary charge pressure is reached
will. 2. Machine according to claim 1, characterized in that
that the speed of the internal combustion engine is also input to the electronic control unit (28). 3. Machine according to claim 1 and / or 2, characterized in that a boost pressure sensor is provided and daS this will stop the pump. U-. Machine according to claim 1 and / or 2, characterized in that that the boost pressure-boost speed characteristic is used to determine the flow rate of the current-regulated pump and thus the boost pressure via the speed of the supercharger to adjust. 20073 5. Machine according to claim 1 and / or 2, characterized in that the boost pressure-drive pressure characteristic curve is used is to control the pressure in the hydrostatic transmission by setting the pressure-regulated pump accordingly adjust the boost pressure. 6. Machine according to one of claims 1 to 5 »thereby characterized j that the pump has a suction throttle control for the purpose of limiting the maximum speed of the loader (19). 7. Machine according to one of claims 1 to 6, characterized in that between the hydraulic motor (18) and a mechanical transmission gear (22) is arranged on the loader (23).