Honda Patent on TJI (CBR-1000)

[zelot]

I think the point is to decrease fuel consumption at part throttle rather than increase power.

How do motorcycles deal with cylinder deactivation? Are they completely undrivable or is it a viable option?

Cylinder de-activation is already common in Superbike racing. For example, the BMW SR1000RR Superbike cuts down to 2 cylinders when the bike is heavily leant over and on the smallest part of the tyre. Then uses the traction control electronics to determine when to bring the other cylinders in as the rider accelerates off the turn and gives the bike more gas. This is on the standard electronics that come with the road bike!

[J.A.W.]

I think the point is to decrease fuel consumption at part throttle rather than increase power.

How do motorcycles deal with cylinder deactivation? Are they completely undrivable or is it a viable option?

Cylinder de-activation is already common in Superbike racing. For example, the BMW SR1000RR Superbike cuts down to 2 cylinders when the bike is heavily leant over and on the smallest part of the tyre. Then uses the traction control electronics to determine when to bring the other cylinders in as the rider accelerates off the turn and gives the bike more gas. This is on the standard electronics that come with the road bike!

It was also used 45 years ago by Yamaha tuner Kel Carruthers on the factory 750/4 2T engine
when raced on the dirt by Kenny Roberts - an ignition kill switch button was added for the rider
to manually press, & selectively cut a cylinder - when the tyres of the day were found to be
severely traction-limited under the impulses of the ~130hp mill, really powering out of corners.

[jjns1234]

does the new MY21 Fireblade come with this system?

[adineo55]

might be adopted on MY23 series Fireblade models

[Hoffman900]

https://www.hondarandd.jp/point.php?pid=1422&lang=en

A study of combustion methods was conducted using 3D combustion simulation with the aim of enhancing power at full load and thermal efficiency at partial load for a big-bore spark ignition gasoline engine for large motorcycles. The effect of passive pre-chamber jet combustion on power was confirmed at full load. It was further confirmed that a jet sprayed from the pre-chamber into the main chamber caused an increase in turbulent kinetic energy that sped up combustion, and that increasing the compression ratio from 10.1 to 12.1 resulted in an enhancement of 3.6% in indicated work at full load compared to conventional SI combustion. At partial load, the effect of pre-chamber jet 2plug combustion, achieved by ignition in the pre-chamber after the ignition of the main-chamber side-plug with the aim of enhancing combustion stability, was confirmed. The jet sprayed from the pre-chamber facilitates ignition by coming into contact with the flame surface generated by the earlier ignition of the main-chamber side-plug. It was confirmed that this resulted in an increase in indicated thermal efficiency of 1.7 points at partial load compared to conventional SI combustion.

TLDR: TJI improves TKE and flame area, reducing propensity for knock for a given cylinder pressure / fuel, allowing for higher geometric compression, however, it struggles / doesn’t work well at part throttle and requires a chamber side spark plug.