Overview
ISO 4024:1992 - "Road vehicles - Ignition coils - Low-tension cable connections" specifies the dimensional requirements for low‑tension (low‑voltage) cable terminations used on ignition coils in ignition systems for spark‑ignited internal combustion engines of road vehicles. This second edition replaces ISO 4024:1977 and extends the original requirements to include M6 threaded connections.
Key topics and technical requirements
- Scope: Dimensions for low‑tension cable connections on road‑vehicle ignition coils.
- Terminal types: Defines two main terminal styles:
- Threaded terminals (recommended thread sizes: M5 for negative polarity; M6 preferred for positive polarity; for dry ignition coils M6 is required for the positive polarity).
- Blade (quick‑connect) terminals, including 6.3 mm × 0.8 mm tabs (with hole) as illustrated.
- Marking: Positive and negative polarities must be permanently marked with “+” and “−”; characters at least 2 mm high.
- Connection limits: A maximum of two permanent connections per polarity is permitted; multiple‑blade connectors are allowed.
- Manufacturer discretion: Exact terminal positioning is left to the manufacturer, while dimensions and test/acceptance criteria must comply with the standard.
- Referenced test/termination standards: Blade/tab terminations are required to comply with relevant ISO quick‑connect standards (ISO 8092 series) and related test/performance provisions.
Applications and who uses it
- Automotive OEMs and Tier‑1 suppliers use ISO 4024 to standardize ignition coil terminal designs for compatibility across vehicle platforms and harness assemblies.
- Ignition‑coil manufacturers adopt the dimensional and marking rules to ensure interchangeability and correct polarity identification.
- Electrical connector and cable harness suppliers reference the standard to produce mating terminals and quick‑connect fittings that meet automotive requirements.
- Test laboratories and conformity assessors use the dimensional and referenced test standards for quality control and component acceptance.
- Aftermarket parts manufacturers rely on the standard when designing replacement coils and connector kits to ensure fit and safe installation.
Related standards
- ISO 8092‑1 / ISO 8092‑2 - road vehicle quick‑connect terminations (tabs and test/performance requirements)
- ISO 10455 - dry ignition coils used with rotating high‑voltage distributors (referenced in ISO 4024)
ISO 4024:1992 is essential for ensuring mechanical and electrical compatibility of low‑tension connections on ignition coils, improving interchangeability and safety in automotive ignition systems.