Engine Simulator-2.0

Engine Simulator 2.0

Engine simulator for ECU testing based on the Speeduino V0.4 and the ESP32-32U DevKitC.

The system connects to the ECU through the standard Speeduino 40-pin IDC connector and generates signals to simulate real engine operation.

Architecture

Signals generated by the ESP32

Manually controlled signals (potentiometers)

ECU input signals

ECU outputs monitoring

Speeduino outputs such as injectors, ignition/coils, fan, idle, VVT, boost, and fuel pump are read by the ESP32 through CD4050BE buffers for timing calculation (Phase 2).

Firmware features

• 64 trigger wheel / crank patterns (ArduStim compatible): 60-2, 36-1, 24-1, LS1, 58X, Chrysler NGC, BMW N20, GM 40-tooth OSS, and many others
• RPM inertia model: cranking from 0 to 350 RPM, then idle at 850 RPM + (TPS × 6150), with low-pass filtering
• Start/Stop button: starts and stops the engine with a cranking ramp, idle stabilization, and gradual shutdown
• Dynamic MAP simulation: 100 kPa with engine off, 85 kPa during cranking, and 30–100 kPa depending on RPM and TPS
• Dynamic CLT simulation: gradual warm-up, fan cooling, and Newton cooling when engine is off
• USB serial interface: ArduStim protocol for configuring trigger wheel and crank pattern, as well as RPM mode from TunerStudio
• Speeduino timing monitoring (Phase 2): input capture via ISR on 9 CD4050BE inputs (4 injectors + 4 coils + fan), measuring injector on-time, pulse frequency, duty cycle, ignition dwell and advance
• WiFi AP + web dashboard (Phase 3): SSID EngineSimulator2.0, password 1234567890, IP 192.168.254.1, responsive dashboard at /, allows selecting one of 64 trigger patterns and persists the setting to NVS memory
• Startup synchronization mode (Sync Mode): Passive (autonomous start) or Active (real ECU-driven start), selectable from the /setup page and persisted to NVS

Startup synchronization (Sync Mode)

When the engine is started (physical Start/Stop button or /api/start), the simulator behaves according to the selected Sync Mode, configured on the /setup web page and stored in NVS (key syncMode):

The firing detection reuses the Phase 2 input-capture ISRs: the injector/ignition ISRs update the event markers lastInjEventUs / lastIgnEventUs, exposed through the hasRecentInjection/Ignition/Firing(windowMs) helpers in timing.cpp. The active mode value is also reported in the /api/data JSON payload as "syncMode":0|1.

Verification status

Details and references: doc/WORKING_VERSION_EN.md.

Directory structure

Engine Simulator 2.0/
├── Engine_Simulator_2_0/         # ESP32 firmware (single source tree; folder name = sketch name)
│   ├── Engine_Simulator_2_0.ino  # Main sketch (timer, simulation, state machine)
│   ├── comms.cpp / comms.h       # Serial command parser (ArduStim protocol)
│   ├── globals.h                 # Shared data structures (incl. SyncMode enum)
│   ├── timing.cpp / timing.h     # Injector/ignition input capture (Phase 2)
│   ├── web.cpp / web.h           # WiFi AP + dashboard + /setup + /api/data (Phase 3)
│   └── wheel_defs.h              # 64 trigger wheel definitions
├── Hardware/                     # PCB design (KiCad 10.0)
│   └── Engine Simulator 2.0/
│       ├── *.kicad_sch           # Schematic
│       ├── *.kicad_pcb           # PCB layout
│       ├── *.kicad_pro           # KiCad project
│       ├── BOM.md                # Bill of materials (updated from netlist)
│       └── Gerbers/              # Manufacturing files (Gerber + drill)
├── doc/                          # Documentation (English + Italian)
│   ├── ESP32U_PIN_ASSIGNMENT_EN.md / _IT.md
│   ├── SPEEDUINO_V04_IDC40_PINOUT_EN.md / _IT.md
│   ├── dupont_pinout_EN.md / _IT.md
│   └── WORKING_VERSION_EN.md / _IT.md
├── images/                       # README assets
├── README.md                     # This file (English)
├── README_IT.md                  # Italian README
└── LICENSE                       # MIT

Hardware requirements

Main components

Voltage levels

Build and upload

Prerequisites

• Arduino IDE or Arduino CLI
• ESP32 board package installed: esp32:esp32 via Board Manager
• Selected board: ESP32 Dev Module or ESP32-WROOM-32U
• Libraries for the dashboard (Phase 3): use ESP32Async (compatible with ESP32 core v3.3.x and mbedTLS 3; the classic me-no-dev version does not compile)
  • ESP Async WebServer (arduino-cli lib install "ESP Async WebServer")
  • Async TCP (arduino-cli lib install "Async TCP")

Compile and upload

# Via Arduino CLI (first time: install the dashboard libraries as well)
arduino-cli lib install "ESP Async WebServer" "Async TCP"
arduino-cli compile --fqbn esp32:esp32:esp32 "Engine_Simulator_2_0"
arduino-cli upload --fqbn esp32:esp32:esp32 --port COMx "Engine_Simulator_2_0"

Configuration

The trigger wheel/crank pattern can be selected in the following ways:

1. Dashboard web interface (recommended): connect to WiFi EngineSimulator2.0 (password 1234567890) and open http://192.168.254.1 -> page /setup to select the pattern and the Sync Mode (both persisted to NVS memory)
2. USB serial (115200 baud): use command X to select the next pattern, or S<n> to select by index
3. ArduStim GUI: desktop software connecting via serial to configure patterns and modes

Project notes

• The integrated MAP sensor on the Speeduino V0.4 (IDC Pin 11) cannot be used as an alternative to the DAC-generated signal from the ESP32 for simulation. In this case, the MAP pin of the IDC must be disconnected and re-routed to the proper simulation output.
• The fan is managed with feedback: Speeduino controls it, and the ESP32 reads it to model CLT temperature.
• The IAT and O2 potentiometers are purely manual and do not affect the ESP32 simulation. They are used to test ECU corrections.
• The KiCad PCB (Hardware/Engine Simulator 2.0/) is complete: 2-layer routing with a solid GND plane on the bottom copper layer and thermal reliefs. DRC: no clearance errors and no unconnected pads; only cosmetic warnings remain.
• The design is intended to be a compact, low-cost and fully functional engine simulation interface for ECU testing and development.

Manufacturing outputs (Gerber + drill)

Manufacturing files are generated with kicad-cli and are ready for any fabrication house (JLCPCB, PCBWay, PCBcart):

• Hardware/Engine Simulator 2.0/Gerbers/ — Gerber RS-274X, 9 layers (F_Cu, B_Cu, F_Paste, B_Paste, F_Mask, B_Mask, F_SilkS, B_SilkS, Edge_Cuts) + .gbrjob file
• Hardware/Engine Simulator 2.0/Gerbers/ — Separate Excellon drill files: -PTH.drl (plated holes, 0.3–2.2 mm) and -NPTH.drl (non-plated holes)
• Hardware/Engine Simulator 2.0/Engine_Simulator_2.0_FAB_gerbers.zip — ZIP archive containing all Gerber and drill files, ready for direct upload to the manufacturer

Board: 2 layers, 100 × 100 mm, thickness 1.6 mm, HASL finish, minimum trace width 0.2 mm, minimum clearance 0.21 mm, minimum drill 0.3 mm (via) / 2.2 mm (M2 mounting holes, PTH connected to GND).