Applied-ignition internal combustion engine with variable valve drive

Patent metadata

Field	Value
Publication number	US-9752470-B2
Application number	US-201514645858-A
Country	US
Kind code	B2
Filing date	Mar 12, 2015
Priority date	Mar 21, 2014
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

A system and method is provided for an at least partially variable valve drive in an internal combustion engine. In one example, the at least partially variable valve drive comprises a hydraulically adjustable actuating device which may be charged with pressurized oil via an oil pressure line which branches off from an oil circuit.

First claim

The invention claimed is:

1. An applied-ignition internal combustion engine comprising:
at least one cylinder head with at least one cylinder, each cylinder having at least two inlet openings for the supply of fresh air via an intake system and/or at least two outlet openings for the discharge of exhaust gases via an exhaust-gas discharge system;
a first pump for supplying engine oil to the internal combustion engine, thus forming a first oil circuit;
at least two at least partially variable valve drives having at least two valves which are movable between a valve closed position and a valve open position in order to open up and block the at least two inlet or outlet openings of a cylinder, having valve spring means for preloading the valves in a direction of the valve closed position, and having at least two hydraulically adjustable actuating devices arranged in a second oil circuit for opening the valves counter to a preload force of the valve spring means, each actuating device comprising a cam which is arranged on a camshaft and which, as the camshaft rotates, can be brought into engagement with at least one cam follower element, whereby the associated valve can be actuated;
a second oil pump arranged in the second oil circuit upstream of the actuating devices; and
a solenoid valve separating the first oil circuit from the second oil circuit, the solenoid valve arranged directly upstream from the second oil pump,
wherein each hydraulically adjustable actuating device can be charged with pressurized oil via an oil pressure line which branches off from the second oil circuit downstream of the second pump, there being arranged in the oil pressure line a controllable shut-off element which blocks or opens up the oil pressure line, and
wherein the cams of the at least two hydraulically adjustable actuating devices of the at least two at least partially variable valve drives are rotatable.

2. The applied-ignition internal combustion engine of claim 1 , wherein the cams are rotatable relative to one another.

3. The applied-ignition internal combustion engine of claim 2 , wherein the cams are arranged on an at least two-part camshaft which comprises at least two camshaft sections that are rotatable relative to one another, at least one cam being arranged on a first camshaft section and at least one cam being arranged on a second camshaft section.

4. The applied-ignition internal combustion engine of claim 3 , wherein the at least two-part camshaft comprises, as the first camshaft section, a hollow shaft and, as the second camshaft section, a shaft arranged rotatably in the hollow shaft.

5. The applied-ignition internal combustion engine of claim 1 , having a crankshaft which is at least connectable in terms of drive to the camshaft, wherein the cams are rotatable relative to one another, and wherein the cams are rotatable relative to the crankshaft even when the crankshaft is stationary.

6. The applied-ignition internal combustion engine of claim 1 , wherein each hydraulically adjustable actuating device has a separate oil pressure line which branches off from the second oil circuit downstream of the second pump and via which the actuating device can be charged with pressurized oil, there being arranged in the separate oil pressure line a controllable shut-off element which blocks or opens up the separate oil pressure line.

7. The applied-ignition internal combustion engine of claim 1 , wherein the hydraulically adjustable actuating devices of the at least two at least partially variable valve drives of a cylinder have a common oil pressure line which branches off from the second oil circuit downstream of the second pump and via which the actuating devices can be charged with pressurized oil, there being arranged in the common oil pressure line a controllable shut-off element which blocks or opens up the common oil pressure line.

8. The applied-ignition internal combustion engine of claim 7 , wherein the common oil pressure line branches downstream of the controllable shut-off element, with a branch leading to each actuating device.

9. The applied-ignition internal combustion engine of claim 1 , wherein the valves of the at least two inlet openings and/or of the at least two outlet openings of each cylinder each belong to an at least partially variable valve drive.

10. The applied-ignition internal combustion engine of claim 1 , having at least two cylinders, wherein at least two cylinders are configured in such a way as to form at least two groups with in each case at least one cylinder, the valves of the at least two inlet openings and/or of the at least two outlet openings of the at least one cylinder of a first group belonging in each case to an at least partially variable valve drive, and the valves of the at least two inlet openings and/or of the at least two outlet openings of the at least one cylinder of a second group belonging in each case to a non-variable valve drive.

11. The applied-ignition internal combustion engine of claim 1 , wherein at least one cylinder block, which can be connected to the at least one cylinder head and which serves as an upper crankcase half, is provided for holding a crankshaft in at least two bearings.

12. The applied-ignition internal combustion engine of claim 11 , wherein the first pump supplies engine oil via a supply line to a main oil gallery from which ducts lead to the at least two bearings, thus forming the first oil circuit.

13. The applied-ignition internal combustion engine of claim 1 , wherein each actuating device of the at least two at least partially variable valve drives comprises at least one switchable, unilaterally mounted rocker arm.

14. The applied-ignition internal combustion engine of claim 13 , wherein each rocker arm is switchable in a two-stage fashion, such that two valve lifts of different magnitude can be realized.

15. A method for operating an engine, comprising:
operating a first pump to supply engine oil to a first oil circuit;
determining a target intake and/or exhaust valve timing and lift based on engine operating conditions;
determining an oil pressure required in an oil infeed line for target valve timing, the oil infeed line arranged in a second oil circuit downstream of a solenoid valve and upstream of a second pump, the first and second oil circuits separated by the solenoid valve;
determining an oil pressure required in an oil pressure line based on the determined target lift, the oil pressure line arranged in the second oil circuit downstream of the second pump and having a controllable shut-off element arranged therein;
actuating the solenoid valve and the second pump to provide the determined oil pressure required in the oil infeed line; and
actuating the shut-off element to provide the determined oil pressure required in the oil pressure line.

16. The method of claim 15 , further comprising adjusting output of the first and second oil pumps based on the determined oil pressures required in the oil infeed line and the oil pressure line.

17. A method for operating an engine, comprising:
operating a first pump to supply engine oil to a first oil circuit;
determining a target intake and/or exhaust valve timing and lift based on engine operating conditions;
determining an oil pressure required in an oil infeed line for target valve timing, the oil infeed line arranged in a second oil circuit downstream of a solenoid valve and upstream of a second pump, the first and second oil circuits separated by the solenoid valve;
determining an oil pressure required in a separate oil pressure line branching f

Assignees

• Ford Global Tech Llc

Inventors

• Van Den Heuvel Bas Lambertus
• Hemink Wilbert
• Fritsche Richard
• Conee Claudia
• Willems Werner
• Sommerhoff Franz Arnd
• Hans Christian

Classifications

• F01L9/025

  Mechanical Engineering · mapped topic

• F01L2001/34423

  Details relating to the hydraulic feeding circuit · CPC title

• F01L2001/0473

  Composite camshafts, e.g. with cams or cam sleeve being able to move relative to the inner camshaft or a cam adjusting rod · CPC title

• F01L13/0021 Primary

  by modification of rocker arm ratio · CPC title

• F01L1/3442

  using hydraulic chambers with variable volume to transmit the rotating force · CPC title