VISTA Knock Window Set

This MotoHawk™ block controls the location within the engine cycle and the duration of the Noise Detection Window (NDW) and Knock Detection Window (KDW) that is used by the VISTA IC to measure knock.

Block ID

Library

MotoHawk_lib/Knock Blocks

Description

Overview

The Noise Detection Window (NDW) signal is synonymous with the ProSAK reference window signal. The Knock Detect Window (KDW) synonymous with the ProSAK knock window signal. These windows should be used in the same fashion. In essence these windows define when the knock signal is actively integrated by the VISTA IC. Integration begins when the start event occurs and continues until the stop event is observed.

VISTA will generate as many pulses as there are TDC Angles and will distribute the pulses about the cycle based upon these values. The start and stop timings should be sized such that they will complete in time. For example, if there are TDCs every 180degCA then the start and stop event must define an angular duration that will be smaller than 180degCA.

Timings have a fixed point scaling where a value of 1 represents 0.0625 degrees crank angle before firing TDC (x16degBfTDC). Negative timings represent an after TDC timing.

Timing Update Considerations

The timing values controlled by this block utilize the existing Encoder TDC Offset (see the Encoder Definition block) to correctly locate the pulse in the crank angle domain. The compensation for any Encoder TDC Offset is only applied by this knock timing block when it executes. Therefore, to use the Encoder TDC Offset block, for example, to change the offset value at runtime, the model would need to place any knock timing blocks in the model so that they would execute subsequently to any TDC offset change.

Thus, if the Encoder TDC Offset block executes at start-up then this timing block must, at a minimum, execute at start-up after the Encoder TDC Offset block has executed. If the Encoder TDC Offset block is executed periodically (for example, at every RTI), then this timing block must likewise execute periodically afterwards, because otherwise the offset could change after the knock timing block executes.

In summary, because the signal controlled by this block takes the Encoder TDC Offset value into account, this block should execute periodically or after the Encoder TDC Offset has been applied.

Block Parameters

Parameter Field	Values	Comments/Description
Name	Alpha-numeric text, single-quote enclosed	Name of the VISTA knock device to be affected.