Valve Actuating Variable Adaptation for Engine Tolerance Errors

Solution Overview

Problem

Conventional camshaft adjusters in internal combustion engines suffer from production-related and installation-related tolerances, leading to systematic errors in valve operation, particularly in operating states with high residual exhaust gas, which increases emissions by affecting the air charge and engine torque.

Innovation Solution

A method for adapting the valve actuating variable based on charge specifications, using intake manifold pressure measurements and correction variables to minimize errors, allowing for precise control of camshaft adjusters without additional sensors or lower tolerance camshaft adjusters, by setting specific operating states and comparing charge specifications to adapt valve operating parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional camshaft adjusters are used with standard tolerances, then manufacturing cost is reduced, but valve operation accuracy deteriorates leading to increased emissions

Engineering Contradiction:

Improvevalve operation accuracyVSAvoidemissions

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The system performs preliminary determination of charge specifications and calculates correction variables before actual valve actuation. By pre-calculating the adaptation of valve actuating variables based on measured charge specifications, the system compensates for tolerances in advance, ensuring accurate valve operation without requiring higher manufacturing precision components

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes the valve actuating variable by adding a correction variable to compensate for systematic errors. Instead of improving mechanical tolerances, the patent modifies the control parameter (valve actuating variable) dynamically based on measured charge specifications, thereby maintaining valve operation accuracy while using standard tolerance components

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If additional sensors are added to improve charge measurement accuracy, then valve operation accuracy improves, but device complexity increases

Engineering Contradiction:

Improvecharge measurement accuracyVSAvoidsensor quantity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses existing sensors (intake manifold pressure sensor, crankshaft position sensor) to determine charge specifications without requiring additional dedicated charge measurement sensors. The charge specification is derived from readily available measurements combined with engine operating parameters, allowing the system to self-determine air charge using existing infrastructure

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Existing sensors serve multiple functions: the intake manifold pressure sensor is used both for charge determination and for detecting operating states. The crankshaft position sensor provides both timing information and rotational speed data. This multi-functional use of existing sensors avoids additional hardware while maintaining measurement precision

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Manufacturing precision

If camshaft adjuster tolerances are reduced, then valve operation accuracy improves, but manufacturing cost increases

Engineering Contradiction:

Improvecamshaft adjuster toleranceVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The system performs preliminary determination of charge specifications and calculates correction variables before actual valve actuation. By pre-calculating the adaptation of valve actuating variables based on measured charge specifications, the system compensates for tolerances in advance, ensuring accurate valve operation without requiring higher manufacturing precision components

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes the valve actuating variable by adding a correction variable to compensate for systematic errors. Instead of improving mechanical tolerances, the patent modifies the control parameter (valve actuating variable) dynamically based on measured charge specifications, thereby maintaining valve operation accuracy while using standard tolerance components

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10151253B2Method and device for adapting a valve actuating variable for an intake and/or exhaust valve of an internal combustion engine

Publication Date: 2018.12.11 ROBERT BOSCH GMBH

AI summary

A method for adapting a valve actuating variable for controlling an intake and/or an exhaust valve of an internal combustion engine, including setting a predetermined operating state of the internal combustion engine; determining a charge specification, which specifies an instantaneous air charge in one of the cylinders of the internal combustion engine, in the predetermined operating state; and adapting the valve actuating variable as a function of the charge specification.