Start Quantity Control, Basic Function - GF07.08-P-1052A
Engine 139, 176, 177, 254, 256, 260, 264, 274, 279, 282
Engine 177, 256
Overview
This document contains information on:
- General
- Function requirements
- Function
- Cold start enrichment
- Post-start enrichment
- Warm-up enrichment
General
To achieve stable and smooth engine running, the fuel/air mixture is enriched via the combustion engine control unit.
The following enrichment phases are determined:
- Cold start
- Post-start phase
- Warming-up phase
Function requirements
- Engine management switched on (terminal 87M)
- Engine in operation
Function
Cold start enrichment
In order to facilitate engine starting procedure, an additional fuel quantity is injected during starting procedure. To do this, combustion engine control unit calculates required injection duration of injection valves for starting mixture enrichment. The higher the coolant temperature, the shorter the injection duration calculated by combustion engine control unit. In order to compensate for reduced start quantity when battery voltage is low, combustion engine control unit increases the injection duration.
Post-start enrichment
To ensure that engine continues to run flawlessly, post-start enrichment compensates for fuel condensing on cold cylinder barrels. To do this, combustion engine control unit calculates injection duration of injection valves and extends it.
Warm-up enrichment
The quantity of fuel condensed in the still cold cylinder barrels is compensated for by warm-up enrichment. Injection duration of injection valves is extended by combustion engine control unit.
In order to additionally heat combustion chambers, during warm-up phase exhaust gas recirculation is activated.
The lambda control monitors the injection duration as soon as this is enabled.
| Function schematic | |||
| Function schematic for start quantity control | Engine 256 in model 465.2 | PE07.70-P-2500-97L | |
| Engine 177 in model 465.2 | PE07.70-P-2500-97K | ||
| Engine 260 in model 118, 177, 247 Engine 264 in model 167 | PE07.70-P-2500-97A | ||
| Engine 282 in model 118, 177, 247 | PE07.70-P-2500-97B | ||
| Engine 176, 177 in model 167 Engine 177 in model 290 as of model year 2021 |
PE07.70-P-2500-97C | ||
| Engine 139 in model 118, 177, 247 | PE07.70-P-2500-97D | ||
| Engine 254 in model 167 as of model year 2023 Engine 254 in model 206, 214, 236, 254 Engine 256 in model 214, 223, 236 |
PE07.70-P-2500-97E | ||
| Engine 176 in model 223 | PE07.70-P-2500-97F | ||
| Engine 177 in model 192, 223, 232 | PE07.70-P-2500-97G | ||
| Engine 139 in model 192, 206, 232, 236, 254 | PE07.70-P-2500-97H | ||
| Engine 279 in model 223 | PE07.70-P-2500-97I | ||
| Engine 274 in model 213 as of model year 2021 | PE07.70-P-2500-97J | ||
| Additional basic functions | |||
| Combustion engine control unit, basic function | GF07.08-P-9890A | ||
| Fuel injectors, basic function | Engine all with direct injection | GF07.03-P-2000A | |
| Basic function of injection valve | Engine all with intake manifold injection | GF07.03-P-2001A |