Power Products Technology

BLAST (Boosted Low Speed Torque)

Intelligent Technology Aiming for a “Pleasant and Invigorating Acceleration”

1. The Birth of BLAST

Honda introduced its first outboard engine in 1960 to a market dominated by 2-stroke engines.

Although 2-stroke engines are simply-structured, lightweight, and have the advantage of high-output from a small displacement, 4-stroke engines have higher fuel efficiency and environmental performance.

In line with the desire of Honda’s founder to “not contaminate the water we ride on,” Honda has consistently developed environmentally-friendly 4-stroke outboard engines.

To realize Honda’s characteristic “joy of sailing,” the goal was to design a 4-stroke engine with acceleration rivaling that of a 2-stroke, while maintaining fuel efficiency and environmental performance. The answer was BLAST, Honda’s unique air/fuel ratio and ignition timing technology, first equipped on the BF90 in 2006, now a standard feature for the BF40 - BF250 models*.

*As of November, 2014

BLAST (Boosted Low Speed Torque) Named to give the impression of explosive, nimble acceleration
BLAST
BF250: One of many BLAST-equipped models

2. BLAST Mechanism and Advantages

Without sufficient power (torque) when accelerating from a standstill, the boat’s bow will be raised (“bow up”) causing an unsatisfactory ride, and prevent the boat from “planing” - its most fuel-efficient state.

2-stroke engines are lighter, with more power (torque) than 4-stroke engines, realizing a better acceleration from a standstill. The goal of BLAST was to reproduce the same acceleration with a 4-stroke engine.

BLAST maximizes torque for full-throttle acceleration by controlling the air-fuel ratio, while determining ignition timing near knocking limits through spark-advance control.

By incorporating BLAST, acceleration from a standstill is improved, and the boat reaches the fuel-efficient planing state faster.

BLAST realizes both the “joy of sailing” and superior fuel efficiency and environmental performance in a 4-stroke outboard engine.

Video Title

Controlling Air / Fuel Ratio